Critical Minerals Refining HVAC Duct Guide — Lithium Hydroxide, Rare Earth, Battery-Grade Nickel + Cobalt Sulphate, Vanadium Electrolyte and Spherical Graphite Anode Refining

1. The Australian critical-minerals refining build — what changed since 2022

For most of the past three decades Australia mined critical minerals and shipped them as concentrate to overseas refineries — spodumene to East Asia, monazite to Malaysia, nickel sulphide concentrate to smelters in northern Asia and the Nordic region, and bauxite mostly to our own alumina refineries but with material going to Asia as well. The economics were straightforward: the country had the ore, the rest of the world had the refining capacity, and the trade flowed accordingly. The refining margin — typically 60–80 percent of the metal-in-concentrate value — was captured offshore.

That model has been overturned in the four years to 2026 by a combination of federal industrial policy, downstream automotive demand and trade-flow risk. The Future Made in Australia programme announced in the 2024 federal Budget put approximately 22.7 billion AUD over ten years behind value-added domestic processing, with the Critical Minerals Production Tax Credit at 40 percent of eligible processing capex from 2026 the single biggest line item. The Department of Industry, Science and Resources (DISER) and the Department of Climate Change, Energy, the Environment and Water (DCCEEW) jointly run the Critical Minerals Strategy 2030, which lists 31 critical minerals (lithium, cobalt, nickel, rare earth elements, graphite, vanadium and 25 others) for which domestic processing capacity is a strategic priority. The Critical Minerals Industry Council Australia coordinates the operating companies and the Future Battery Industries Cooperative Research Centre (FBI CRC, based in Perth) runs the technical R&D pipeline. The Australian Strategic Materials Critical Minerals List frames the diplomatic conversation with allied trading partners — every one of the minerals listed above is on a parallel "critical" list in the United States, European Union, Japan, Korea and Canada.

The downstream demand has moved in parallel. Battery-grade lithium hydroxide, nickel sulphate and cobalt sulphate are direct precursors to high-nickel cathode active material (NMC811, NCA, LMFP) used in the European and North American battery gigafactories we discussed in our companion Battery Gigafactory HVAC Duct Guide. Rare earth elements (neodymium, praseodymium, dysprosium, terbium) are essential for the permanent magnets used in EV traction motors and offshore wind turbine generators — the same offshore wind turbine programmes we cover in our solar PV cell, module, perovskite, tracker and recycling manufacturing HVAC duct guide. Vanadium electrolyte (vanadyl sulphate VOSO4) is the active material in vanadium redox flow batteries used in long-duration grid storage. Spherical graphite is the only commercial anode material at scale for lithium-ion cells, and the 99.95+ percent purity grade demanded by battery-grade is a refining operation as much as a mineral processing one.

The capital programme that this combination has triggered is the largest single industrial build in Australian history outside the original Pilbara iron ore expansion of the 1970s. IGO Limited and Tianqi Lithium Energy Australia have commissioned Train 1 at Kwinana for 24,000 t/yr battery-grade LiOH·H2O and have Train 2 under construction. Albemarle Australia at Kemerton WA is running Train 1, Train 2 and is building Train 3 and Train 4 — at full build the Kemerton complex will be the largest single-site lithium hydroxide refinery globally outside East Asia at approximately 100,000 t/yr LiOH·H2O. Wesfarmers WesCEF and SQM have built the Mt Holland mine and Kwinana refinery as the Covalent Lithium joint venture. Lynas Rare Earths is commissioning the Kalgoorlie Light Rare Earths plant alongside the existing Mt Weld concentrate operation; the Lynas Advanced Materials Plant (LAMP) in Malaysia historically did the refining downstream of Mt Weld, but the Kalgoorlie facility moves the cracking-and-leaching step onshore. Iluka Resources at Eneabba is building the first end-to-end domestic rare earth refinery. BHP Nickel West at Kwinana operates the largest single battery-grade nickel sulphate facility in Australia, taking nickel matte from Mt Keith and Leinster and producing 100,000 t/yr nickel sulphate hexahydrate. Renascor Resources at the Battery Anode Materials (BAM) plant in South Australia is commissioning the country's first spherical graphite anode purification line, taking concentrate from the Siviour graphite mine.

The HVAC implication of this build is significant. Every one of these projects runs through a refinery flowsheet that is dominated by aggressive reagents (sulphuric acid, hydrochloric acid, hydrofluoric acid, sodium hydroxide, chlorine, ammonia, kerosene solvent extraction), severe corrosion environments (acid mist, chloride, fluoride), regulated occupational exposures (chlorine 0.5 ppm, ammonia 25 ppm, sulphuric acid mist 1 mg/m³, HF 1.8 mg/m³, nickel sulphate 0.1 mg/m³, vanadium 0.05 mg/m³, cobalt 0.05 mg/m³), combustible-dust hazards (lithium metal, graphite, Al/Mg/Ti/Zr contamination) and — in the case of rare earth — radiological controls under ARPANSA for the naturally occurring thorium-232 and uranium-238 in the concentrate. The HVAC ductwork specification across all of these is dominated by a single material: 316L (UNS S31603) stainless steel, the molybdenum-stabilised austenitic grade that survives the chloride, fluoride, sulphate and chlorine environments where 304L pits within months and galvanised steel surrenders the zinc coating in weeks. This guide is the engineer's reference our team uses when scoping the SBKJ machinery — SBAL-V in 316L mode, SBSF-1525 round-duct flanging, SB-ZF1500 stitchwelder, SBPC1500 plasma cutter, SBLR-600 welder — for projects across this build.

2. The Australian regulatory stack — AS, NFPA, ARPANSA and Safe Work Australia

Critical-minerals refining HVAC sits at the intersection of more regulatory documents than almost any other industrial sector covered on this site. The compliance question on every project is not whether one standard applies — they all apply — but how the layered requirements interact across the leach circuit, the solvent extraction train, the crystalliser exhaust, the radiological battery limit and the operator amenity block.

2.1 AS 1668.2 — mechanical ventilation in buildings

AS 1668.2:2012 sets the building-services baseline for occupied spaces. In a critical-minerals refinery this drives the outdoor-air rate at every pulpit, crane cabin, control room, electrical room, laboratory, amenity block and administration building. The standard requires 10 L/s per occupant minimum outdoor air for typical office and control-room occupancy. Where AS 1668.2 matters most in refining is the pulpit pressurisation requirement: it sets the engineering basis for the 25–50 Pa positive pressure that prevents acid mist, chlorine, ammonia, kerosene vapour, nickel sulphate aerosol and radiological dust ingress into the operator cabin. The make-up air requirement layered on top of LEV — every cubic metre extracted from a process area must be balanced by tempered outdoor make-up air — drives total refinery HVAC ductwork volume up by a factor of two to three compared with a building of equivalent floor area but no process exhaust.

2.2 AS 4254 — ductwork construction

AS 4254.1 (flexible ductwork) and AS 4254.2 (rigid ductwork) are the Australian duct construction standards that govern gauge, joint type, pressure class and reinforcement spacing. For critical-minerals refining the typical pressure class is medium-pressure on supply and return runs (up to 750 Pa static), high-pressure on scrubber bypass and main collection ducts (up to 2,500 Pa static), and ultra-high-pressure on the negative side of the ID fan upstream of the stack. The standard sets out the leakage class requirements (Class A, B, C) that drive fabrication tolerance — SMACNA Class B equivalent for general HVAC, Class C for scrubber-side ducting where leakage of corrosive gas to the surrounding building is unacceptable. AS 4254.2 also drives the duct joint specification: TDF or AS angle flange for galvanised and 304L medium-pressure; continuous seam-welded flange or full-perimeter gasket compression for 316L scrubber-side high-pressure.

2.3 AS 1530.4 — fire-resistant ductwork

AS 1530.4 classifies fire-resistant duct construction for smoke-spill and stair-pressurisation duty. Critical-minerals refineries have significant fire-load zones — solvent extraction kerosene drum stores, reagent stores with acid and caustic in IBC, electrical substations near rectifier transformers, fuel oil supply rooms — and the duct passing through these zones must be rated for the specified fire-resistance level (typically 60/60/60 to 120/120/120 of structural integrity, insulation and integrity). AS 1851 overlays the maintenance requirements for fire dampers, smoke-spill dampers and motorised dampers along the route.

2.4 AS/NZS 60079 — explosive atmospheres

AS/NZS 60079 (Explosive atmospheres) and the underlying IEC 60079 series classify hazardous areas. Critical-minerals refineries have multiple Zone classifications: Zone 1 (gas, present in normal operation) around the solvent extraction kerosene area, the LiCl electrolysis cell room (chlorine), and any reagent IBC store; Zone 2 (gas, present only abnormally) around ammonia precipitation tanks and fuel supply trenches; Zone 21 (dust, present in normal operation) around the lithium hydroxide crystalliser and graphite spheronisation; Zone 22 (dust, present only abnormally) around the spodumene calciner discharge and rare earth precipitation filter. The classification drives Ex-rated electrical equipment requirements for fans, motors, instrumentation, lighting and switchgear, and it drives bonding and grounding of every duct segment to prevent static-discharge ignition of combustible dust.

2.5 AS 1940 — flammable and combustible liquids

AS 1940 (Storage and handling of flammable and combustible liquids) drives the kerosene, fuel oil, diesel and reagent IBC requirements. Critical-minerals refineries use significant volumes of kerosene as the carrier solvent in solvent extraction (typically 50–200 m³ of working kerosene inventory across the SX train) and large quantities of acid and caustic reagent in IBC. Each storage area is a hazardous-area zone under AS/NZS 60079 and requires AS 1940-compliant ventilation, bunding and spill containment.

2.6 AS 3957 — dust hazard

AS 3957 underpins the dust-hazard classification at the spodumene receiving, calciner discharge, rare earth concentrate handling, graphite spheronisation and calcined nickel sulphate handling. Spodumene is a hard, abrasive ore (Mohs 6.5–7); rare earth concentrate is moderately abrasive; graphite is soft but generates fines that flow freely. Capture velocity at every hood is 1.0–1.5 m/s, transport velocity 18–22 m/s, abrasion-resistant lining (chromium-carbide overlay or ceramic-bead) at elbows where particle impact angle exceeds 30 degrees.

2.7 NFPA 660 — combustible dust (formerly NFPA 484, NFPA 652, NFPA 654, NFPA 655, NFPA 664, NFPA 61)

NFPA 660, which consolidated the previous family of combustible-dust standards into a single combined standard from 2025, applies to multiple dust streams in a critical-minerals refinery. Lithium metal dust at the crystalliser and dryer is a Class D combustible metal that reacts violently with water — wet sprinkler systems are prohibited in the lithium handling rooms, and the dust extract system must use dry collection with inert-gas blanketing. Graphite anode purification dust is also combustible (Kst around 70–90 bar·m/s, MIE 30–100 mJ depending on particle size distribution). The fluoride-leach residue dust in rare earth refining and the calcined product across multiple processes can carry combustible metal contamination (Al, Mg, Ti, Zr). NFPA 660 requires a written Dust Hazard Analysis (DHA) at every dust-handling step, deflagration venting per NFPA 68 or chemical suppression on bag filters and cyclones, isolation valves per NFPA 69 between the baghouse and the upstream duct trunk to prevent flame propagation, bonded and grounded duct construction with electrical continuity verified by bonding test, spark-resistant fan construction per AMCA 99-0401, and Ex-rated electrical equipment in the dust zone.

2.8 NFPA 68 and NFPA 69 — explosion venting and prevention

NFPA 68 (Standard on Explosion Protection by Deflagration Venting) sets the design basis for explosion vent panels on bag filters, cyclones and enclosed dust-handling equipment. The vent area is sized against the dust's Kst value and the enclosure's reduced explosion pressure (Pred) — for lithium metal dust at Kst 200+ bar·m/s the required vent area is significant and often drives the bag filter geometry. NFPA 69 (Standard on Explosion Prevention Systems) covers the alternative or supplementary measures: oxygen reduction via inert blanket, fast-acting isolation valves on the duct trunk, suppression systems with rapid powder discharge.

2.9 ASHRAE Applications Chapter 35 — industrial drying

ASHRAE Handbook Applications Chapter 35 (Industrial Drying) provides the international engineering reference for the calciner exhaust design at spodumene decrepitation, rare earth oxide calcination, nickel sulphate crystallisation drying and graphite thermal purification. The chapter covers heat and mass balance, dryer exhaust handling, recovery economics and acid dew point considerations on the cold side of the dryer.

2.10 AS 4036 + AS 4037 — boiler and pressure equipment

AS 4036 (Boilers — Steam plant) and AS 4037 (Pressure equipment — Examination and testing) apply to the steam-generating equipment that feeds the refinery — typically natural gas-fired or in some cases coal-fired industrial boilers producing 50–200 t/h saturated steam for digestion, crystalliser duty and reagent heating. The boiler house HVAC scope (combustion air supply, flue gas duct, building ventilation, control room) is conventional industrial work — galvanised steel duct, except for the cold-side flue duct on coal-fired boilers where residual SO2 condensation drives 316L stainless from the economiser outlet to the stack.

2.11 AS 1851 + AS 2865 — fire dampers and confined spaces

AS 1851 (Routine service of fire-protection systems and equipment) governs the fire damper, smoke-spill damper and motorised damper maintenance. AS 2865 (Confined spaces) governs the entry-permit system for any operator entering a duct, a scrubber housing, a baghouse internal or a precipitator hopper — every flange location designed for SBKJ duct must allow safe confined-space entry without disturbing adjacent process equipment.

2.12 ARPANSA RPS 9 — radiation protection in mining and mineral processing

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) publishes the Radiation Protection Series (RPS) — RPS 9 (Code for Radiation Protection in Mining and Mineral Processing) is the operative document for rare earth refining and zircon-bearing mineral sands. It sets the worker dose limit at 20 mSv/yr (5-year averaged with no more than 50 mSv in any single year) and the public dose limit at 1 mSv/yr above background. The licence to operate is granted by the state radiation safety regulator — the WA Radiation Safety Council for Mt Weld and Kalgoorlie, the NT Department of Health for Nolans Bore, the SA Environment Protection Authority for the BAM plant — under a comprehensive radiation management plan that includes the HVAC engineering response described in section 6.

2.13 Australian Strategic Materials Critical Minerals List + DISER + DCCEEW Critical Minerals Strategy 2030

The Australian Strategic Materials Critical Minerals List frames the diplomatic conversation with allied trading partners. The DISER and DCCEEW Critical Minerals Strategy 2030 sets the federal policy framework and channels funding (Critical Minerals Facility, Critical Minerals Production Tax Credit, Future Made in Australia Innovation Fund). The Critical Minerals Production Tax Credit at 40 percent of eligible processing capex from 2026 is the largest single financial incentive in the package and is directly applicable to the SBKJ machinery purchase where the buyer is the operating company or the project EPC contractor — SBKJ engineers can issue the documentation needed for the buyer's tax credit claim against the duct fabrication line capex.

2.14 Safe Work Australia Workplace Exposure Standards

The Safe Work Australia register of Workplace Exposure Standards (WES) for airborne contaminants is the engineering driver for every duct sized in the refinery. The standards relevant to critical-minerals refining are:

• Chlorine (Cl2): 0.5 ppm time-weighted average (TWA), 1.0 ppm short-term exposure limit (STEL) — at the LiCl electrolysis cell room and any chlorine reagent area.
• Ammonia (NH3): 25 ppm TWA, 35 ppm STEL — at the ammonium hydroxide precipitation circuit used in nickel-cobalt separation and pH adjustment.
• Sulphuric acid mist (as H2SO4): 1 mg/m³ TWA — at the sulphation roast, acid leach, pressure filter and crystalliser circuits.
• Hydrofluoric acid (HF): 1.8 mg/m³ TWA (about 2 ppm) — at the graphite anode purification circuit and any fluoride-leach residue handling.
• Respirable dust: 10 mg/m³ inhalable, 3 mg/m³ respirable; respirable crystalline silica (RCS): 0.05 mg/m³ — at every dry handling step.
• Oxygen: 19.5–23.5 percent breathable atmosphere — relevant to inert-blanketed lithium handling and confined-space entry.
• Thorium-232 + Uranium-238 (NORM): ARPANSA dose limits 20 mSv/yr worker, 1 mSv/yr public above background — at every rare earth refining step and at zircon-bearing operations.
• Graphite dust: 4 mg/m³ inhalable, 1 mg/m³ respirable, plus combustible-dust controls under NFPA 660 — at every graphite handling step.
• Nickel (Ni) as metal and inorganic compounds: 1 mg/m³ TWA, nickel sulphate (NiSO4) specifically: 0.1 mg/m³ STEL — at the nickel sulphate crystalliser and dryer. Nickel sulphate is the killer chemical for refinery worker exposure and the 0.1 mg/m³ STEL drives the LEV design at the BHP Nickel West Kwinana plant.
• Cobalt (Co) and inorganic compounds: 0.05 mg/m³ TWA — at the cobalt sulphate refining circuit. Cobalt is a known sensitiser and the WES is set lower than the underlying chemical hazard alone would suggest.
• Vanadium pentoxide (V2O5): 0.05 mg/m³ TWA — at every step of the vanadium electrolyte plant. V2O5 is one of the most toxic transition metal oxides in mainstream industrial production.
• Lithium dust: no specific Australian WES, but engineering target 1 mg/m³ inhalable, with skin contact controls because lithium dust on damp skin generates alkali burn through LiOH formation.

3. Lithium hydroxide refining — the workhorse battery-grade route

Battery-grade lithium hydroxide monohydrate (LiOH·H2O, typically >56.5 percent Li2O equivalent and <100 ppm total impurities) is the dominant lithium chemical for the high-nickel cathode chemistries (NMC811, NCA, LMFP) that dominate the European, North American and Korean battery gigafactory pipeline. Australian production is centred at three primary sites: Kwinana WA (the Tianqi Lithium Energy Australia / IGO Limited joint venture, Train 1 at 24,000 t/yr commissioned and Train 2 under construction), Kemerton WA (Albemarle Australia, the largest single-site lithium hydroxide refinery outside East Asia at full build with four trains targeting approximately 100,000 t/yr LiOH·H2O), and the Mt Holland and Kwinana operation (Wesfarmers WesCEF and SQM as the Covalent Lithium joint venture). Pilbara Minerals at Pilgangoora, Mineral Resources at Mt Marion and Wodgina, Greenbushes (the Talison joint venture between IGO and Albemarle, the world's largest hard-rock lithium operation), Liontown Resources at Kathleen Valley NSW and Core Lithium at Finniss NT (paused) make up the upstream spodumene concentrate supply.

3.1 Spodumene receiving and crushing

Spodumene concentrate (LiAlSi2O6, typically 6.0 percent Li2O grade with 1.0–2.5 percent moisture, particle size D80 around 200 µm) arrives at the refinery in covered road trains or rail wagons from the upstream concentrator plant. The unloading station, sample station, storage shed and conveyor transfer points generate fugitive dust at every transfer. Spodumene itself is non-toxic and non-combustible but generates respirable fines (RCS at 0.05 mg/m³ is the binding limit) and the concentrate carries flotation reagent residue (xanthate odour, in trace concentration). The HVAC scope here is conventional dust extract: galvanised carbon steel for the cold-side dust mains, abrasion-resistant lining at elbows, capture velocity 1.0–1.5 m/s at every hood and transport velocity 18–22 m/s in the duct main. Bag filter discharge with deflagration venting per NFPA 660 (the spodumene itself is inert but tramp metal contamination drives the spark-resistant fan specification). SBKJ SBAL-V and SBTF cover this scope in galvanised mode.

3.2 Spodumene calciner — decrepitation at 1050°C

Alpha spodumene (the natural mineral phase) is essentially insoluble in dilute sulphuric acid at any reasonable temperature, and the lithium cannot be extracted economically. The trick is the decrepitation step: spodumene is heated to 1,050–1,100°C in a rotary kiln or a fluidised-bed calciner for 30–60 minutes, during which the alpha phase converts to the metastable beta phase (LiAlSi2O6 in a different crystal structure) with around 20–30 percent volume increase that cracks every particle and exposes lithium to subsequent leach. The decrepitation kiln is the heart of the lithium refinery and the single most energy-intensive process step — typically 1.5–2.5 GJ per tonne of concentrate, delivered as natural gas combustion or in some designs as coal.

The calciner kiln HVAC scope is dominated by the flue gas system. Combustion air is supplied by primary and secondary air fans to the burner; flue gas leaves the kiln at 1,000–1,100°C, passes through a cyclone heat-recovery train (where preheated raw concentrate is fed countercurrent to the flue), exits the cyclone at 200–400°C, and then runs through an alumina-injection dry scrubber (for residual fluoride and SO2 carry-over from any trace organic in the concentrate, plus the flotation reagent residue) before a fabric filter and stack discharge. Volumetric flow on a 60,000 t/yr concentrate calciner is 60,000–120,000 Nm³/h flue gas. Duct material on the hot side from kiln exit to cyclone exit is refractory-lined carbon steel (650–800°C service); from cyclone to dry scrubber 309S/310S austenitic stainless (250–350°C); from dry scrubber to stack 316L stainless (140–180°C condensing-acid service). NOx emissions at the stack outlet are managed against state EPA EPL limits — selective non-catalytic reduction (SNCR) urea injection at the kiln freeboard is the standard mitigation. SBKJ scope is the cold-side 316L duct from the dry scrubber outlet through the ID fan to the stack base; the hot-side refractory-lined kiln duct is heavy welded fabrication procured separately.

3.3 Sulphation roast — turning beta-spodumene into Li2SO4

The beta-spodumene from the calciner is cooled and milled to roughly 100 µm, mixed with 93–98 percent sulphuric acid, and roasted at 250–300°C in a rotary or paddle-mixer reactor for 30–60 minutes. The reaction converts the lithium in the beta-spodumene to water-soluble lithium sulphate (Li2SO4) while leaving the aluminium and silicon as insoluble residue:

2 LiAlSi2O6 + H2SO4 → Li2SO4 + Al2O3·4SiO2 + H2O

The HVAC challenge in the sulphation roast is the acid mist evolved from the reactor exhaust. Sulphuric acid mist at the reactor vent typically runs at 5–20 mg/m³ before mist eliminators, plus residual SO3 and steam vapour. The Safe Work Australia WES for sulphuric acid mist is 1 mg/m³ TWA, so the extract system must deliver three orders of magnitude reduction at the breathing zone. The duct material from the reactor hood through to the mist eliminator is 316L stainless throughout — 304L pits at the acid concentration and temperature, and galvanised steel dissolves the zinc coating within weeks. The duct slope is 1:200 minimum to the engineered condensate drain at every low point; the drain sump itself is 316L with PP-lined inspection access for the highest acid concentration. After the mist eliminator the gas is washed in a packed caustic scrubber and discharged to the stack. SBKJ SBAL-V in 316L mode covers the rectangular cold-side duct after the scrubber; SBSF-1525 round-duct flanging covers the round runs; the SB-ZF1500 stitchwelder is used for the continuous-seam scrubber housing and the acid-mist sump tank.

3.4 Water leach and pressure filtration

The roasted residue is water-leached at 60–90°C to extract the lithium sulphate into aqueous solution. The leach tanks are agitated; the residue is filtered on pressure filters or rotary vacuum filters; the filter cake is washed with hot water and the wash liquor returned to the leach. The HVAC scope here is similar to the roast — local exhaust at every tank vent and filter discharge, 316L stainless duct, sloped to drainage, mist eliminator upstream of fan. The volumetric flow is lower than the roast (the leach is mostly water vapour at modest acid loading) but the duct cross-section is similar because the gas needs the same residence time in the mist eliminator.

3.5 Impurity removal — iron, aluminium, magnesium, calcium

The pregnant leach solution from the water leach is impure — it contains residual aluminium, iron, magnesium and calcium from the concentrate, plus traces of zinc, copper, manganese and other transition metals. A series of pH adjustment steps with lime, soda ash or sodium hydroxide precipitate each impurity in turn and a series of filtration steps remove the precipitated solids. The HVAC scope is local exhaust at each precipitation tank and filter — 316L stainless duct, modest acid mist loading (the solution is nearly neutral at this point), mist eliminator at each branch, ammonia capture (from any ammonium hydroxide additions) at the ammonia precipitation step. The Safe Work Australia WES for ammonia at 25 ppm TWA is the binding limit at the ammonia-route precipitation step.

3.6 Solvent extraction — the kerosene area

The lithium-sulphate pregnant liquor downstream of impurity removal can be further purified by solvent extraction — kerosene-borne organic phosphate extractants (Cyanex 936P, LIX series or similar) selectively load lithium from the aqueous solution into the organic phase, and the organic phase is stripped in a second stage to produce a high-purity lithium solution. The kerosene solvent extraction circuit is AS/NZS 60079 Zone 1 throughout — kerosene flash point at around 38–60°C and the organic loading involves significant aerosolisation. The HVAC scope is hooded extract at every mixer and settler, capture velocity 1.0 m/s, 316L stainless duct with bonded continuity for static-discharge control, Ex-d ATEX fan motors, no internal sources of ignition. The vent stack discharges to atmosphere via a flame arrestor and the gas concentration at the stack is kept below 25 percent of the lower explosive limit (LEL) under worst-case conditions.

Kerosene losses from the SX circuit are an operating cost — typical losses are 1–5 percent of the inventory per year, mostly as entrainment into the aqueous phase and as evaporation from the open mixer-settler surfaces. The HVAC extract carries kerosene vapour at concentrations of 10–500 ppm before discharge, well below LEL but a regulated emission under state EPA EPL boundary air quality limits. Capture velocity at the mixer-settler hood is the engineering trade-off — too high and the kerosene loss to atmosphere increases, too low and the operator exposure to vapour exceeds workplace standards.

3.7 Lithium carbonate precipitation (intermediate)

Many lithium refineries produce lithium carbonate (Li2CO3) as an intermediate or as a final product for some battery chemistries (LFP), by adding sodium carbonate to the high-purity lithium sulphate solution and precipitating Li2CO3 at 80–95°C. The reaction releases CO2 vapour at the precipitation tank surface. The HVAC scope is hooded local exhaust at each precipitation tank, 316L stainless duct, CO2 capture for boundary air quality compliance (not strictly required by Safe Work Australia for short-term operator exposure since CO2 is at modest concentration, but increasingly required by net-zero reporting frameworks).

3.8 Lithium hydroxide production — the conversion route

Battery-grade lithium hydroxide can be produced via two main routes from the high-purity lithium sulphate or lithium carbonate solution. The conversion route precipitates lithium hydroxide directly by reacting lithium sulphate with calcium hydroxide:

Li2SO4 + Ca(OH)2 → 2 LiOH + CaSO4·2H2O

The gypsum (CaSO4·2H2O) precipitates and is filtered out; the lithium hydroxide solution is concentrated and crystallised. Alternatively the electrolysis route operates a chlor-alkali style cell on lithium chloride brine (made by converting Li2SO4 to LiCl by ion exchange or barium chloride precipitation):

2 LiCl + 2 H2O → 2 LiOH + Cl2 + H2

The electrolysis route produces chlorine gas at the anode and hydrogen at the cathode, both of which require dedicated handling. The HVAC scope at the electrolysis cell room is severe — chlorine concentration in the cell gas is up to 99 percent dry Cl2 by volume, against a Safe Work Australia WES of 0.5 ppm TWA at the operator breathing zone. The engineering response (see section 3.10) is direct-coupled scrubbing with FRP construction in the wet section.

3.9 Lithium hydroxide crystalliser and dryer

The lithium hydroxide solution at this point is high-purity and battery-grade in composition but needs concentration and crystallisation to monohydrate LiOH·H2O. Forced-circulation or draft-tube evaporative crystallisers operate at 50–80°C under vacuum, concentrating the solution to saturation and growing crystals to product size (typically D50 100–300 µm). The crystallised LiOH·H2O is centrifuged, washed and dried at 60–90°C in a fluid-bed dryer.

The HVAC scope here is the most engineering-intensive step in the lithium refinery. Lithium hydroxide is a strong alkali — direct skin contact with dry LiOH dust causes alkali burn through reaction with skin moisture, and inhalation of LiOH dust is a respiratory irritant. The engineering target at the breathing zone is 1 mg/m³ inhalable lithium dust (no specific Australian WES but adopted from the chemical hazard alone). Lithium metal in trace concentrations from any reduction at the crystalliser (very small but present) is a Class D combustible metal under NFPA 660 — water-reactive, prohibited from wet sprinkler systems, dry collection only with inert-gas blanketing. The crystalliser and dryer rooms are AS/NZS 60079 Zone 21 (dust, present in normal operation) and the extract system must be:

• Hooded at every aerosolisation point — crystalliser vapour body, centrifuge discharge, dryer feed hopper, dryer exhaust, packaging chute.
• 316L stainless duct throughout — the alkali environment attacks galvanised steel zinc within days and pits 304L within months on the dust concentration encountered.
• Bonded conductive duct with electrical continuity verified by bonding test under NFPA 660.
• Spark-resistant fan per AMCA 99-0401 — typically aluminium impeller in a bronze rubbing-ring housing, or non-sparking polyethylene composite.
• Bag filter with deflagration vent per NFPA 68, isolation valve per NFPA 69 between the bag filter and the upstream duct trunk to prevent flame propagation back through the trunk if the bag filter deflagrates.
• Ex-d ATEX motor per AS/NZS 60079.
• Dry collection only — no wet scrubber, no water washdown, no wet sprinkler. Inert-gas blanket (N2 or CO2) over the bag filter discharge hopper.

The SBKJ recommendation here is SBAL-V in 316L mode for the rectangular hood plenum and the lower duct branches, SBSF-1525 round-duct flanging for the round runs to the bag filter, SB-ZF1500 stitchwelder for continuous-seam scrubber-style housings (though there is no wet scrubber in this service the bag-filter inlet plenum benefits from welded construction to control inboard leakage), SBPC1500 plasma cutter for 316L cut-to-length parts and the SBLR-600 welder for site repairs. The spark-resistant fan and the Ex-d motor are SBKJ-supplied as part of the package.

3.10 LiCl electrolysis chlorine handling (alternative route)

Where the refinery uses the electrolysis route (LiCl → LiOH + Cl2 + H2) the chlorine handling is the single most demanding HVAC engineering item in the entire critical-minerals build. The electrolysis cell room contains 100–1,000 cells operating in series, each producing 1–10 kg/h of dry chlorine at the anode. The cell hood gas is collected directly into a chlorine main and ducted to a two-stage caustic scrubber (typically 5–15 percent NaOH circulating concentration in packed towers) where the chlorine is absorbed as sodium hypochlorite and discharged as a regulated waste liquid.

Duct material from the cell hood to the scrubber inlet is FRP (vinyl ester or epoxy vinyl ester resin) or PP-lined carbon steel — chlorine at high concentration attacks every grade of stainless steel including 316L, and only fluoropolymer-lined or all-FRP construction is acceptable. This battery limit is outside SBKJ duct fabrication scope and is referred to specialist FRP duct fabricators (typical Australian suppliers include Plascon, Specialised Composite Australia and Fibrelogic). After the caustic scrubber the chlorine concentration drops below 1 ppm and the scrubber-outlet duct from the demister to the stack returns to 316L stainless inside SBKJ scope.

The cell room building HVAC (supply air, operator pulpit positive-pressure outdoor air, control room) is 316L stainless from SBKJ, fabricated on the SBAL-V in 316L mode with bonded continuity for static-discharge control in case of any chlorine leak from the cell hood. Continuous chlorine monitoring per AS 1668.2 is mandatory at the cell room ceiling, operator breathing zone and outdoor air intake — typically electrochemical sensors with a detection limit of 0.1 ppm and an alarm setpoint of 0.5 ppm (the Safe Work Australia TWA limit). Above 1 ppm (the STEL limit) the supply fan shuts down automatically, the cell room evacuation alarm sounds and the cell hood extract steps up to maximum flow.

3.11 Lithium hydroxide packaging — battery-grade

The final crystallised LiOH·H2O is packaged in flexible intermediate bulk containers (FIBC, around 1 tonne capacity) or sealed drums with moisture barrier liners. The packaging room is a controlled environment — the product picks up moisture and CO2 from the atmosphere within minutes of exposure, degrading the battery-grade specification. Modern Australian LiOH refineries operate the packaging room as a dry room at -20 to -40°C dewpoint with HEPA-filtered supply air, similar in principle (though less extreme) to the battery gigafactory dry rooms covered in our Battery Gigafactory HVAC Duct Guide. The supply air is dehumidified by a desiccant rotor system; the packaging room is positively pressurised at 12.5–25 Pa relative to corridors; the duct is 304L stainless on supply (the room itself is alkali-clean) and 316L return because operator-generated lithium dust returns to the AHU on the return path. The SBKJ scope is SBAL-V in 304L mode for the supply duct and 316L mode for the return duct, with HEPA terminal filter housings procured separately.

4. Battery-grade nickel sulphate refining

Battery-grade nickel sulphate hexahydrate (NiSO4·6H2O, typically >22 percent Ni content and <10 ppm of each major impurity except cobalt) is the dominant nickel chemical for high-nickel cathode chemistries. Australian production is centred at BHP Nickel West Kwinana (around 100,000 t/yr nickel sulphate hexahydrate from Mt Keith and Leinster sulphide ore matte, the largest single Australian operation), with Wyloo Metals (Andrew Forrest's group, having acquired Western Areas) and IGO at Nova-Bollinger operating upstream nickel-copper sulphide mines, and Mincor Resources at Kambalda providing additional concentrate.

4.1 Nickel refining flowsheet — sulphate route

Nickel sulphate is produced from nickel matte (typically 70–75 percent Ni grade nickel-sulphur matte from the smelter) by sulphuric acid leach at elevated temperature and pressure. The matte is crushed, milled and pumped to an autoclave or atmospheric leach reactor operating at 80–95°C with sulphuric acid; the nickel dissolves as nickel sulphate; residual iron, copper, cobalt and other impurities are precipitated or solvent-extracted in subsequent steps. The pregnant liquor is purified, concentrated and crystallised to produce battery-grade NiSO4·6H2O.

4.2 The nickel sulphate WES — the killer for refinery design

The Safe Work Australia WES for nickel as the metal and inorganic compounds is 1 mg/m³ TWA. Nickel sulphate specifically, however, is set at 0.1 mg/m³ STEL — an order of magnitude tighter than the general metal limit. This reflects the substantially greater respiratory toxicity of the soluble nickel salts including the sulphate, and it is the binding constraint on the LEV design at every Australian nickel sulphate refinery. The implication is that capture velocity at every aerosolisation point — the crystalliser vapour body, the centrifuge discharge, the dryer feed, the dryer exhaust, the packaging chute — must be 1.5–2.0 m/s (higher than the standard 1.0 m/s capture velocity used in less demanding services) and the duct cross-section must be sized for transport velocity of 18–22 m/s with no horizontal runs that could allow settling of nickel sulphate fines.

4.3 Acid leach extract

The autoclave or atmospheric leach reactor generates sulphuric acid mist at the vent — typical loading 10–50 mg/m³ before mist eliminators against the 1 mg/m³ WES. The duct from the reactor hood through the mist eliminator is 316L stainless throughout — the molybdenum in 316L stabilises the alloy against the chloride contamination present in Western Australian groundwater used as process water at Kwinana. Slope to drainage at 1:200, condensate drain sumps at every low point, mist eliminator (chevron or mesh pad) upstream of the fan, caustic scrubber discharge to stack. SBKJ SBAL-V in 316L mode handles the cold-side rectangular duct; SBSF-1525 handles round runs; SB-ZF1500 stitchwelder handles the scrubber housing and acid-mist sump tank.

4.4 Cobalt separation by solvent extraction

The pregnant leach solution contains nickel along with cobalt, copper, iron and other transition metals. Cobalt separation is typically by solvent extraction using a phosphorus-based extractant (Cyanex 272 or similar) in a kerosene carrier — the kerosene SX circuit operates at AS/NZS 60079 Zone 1, 316L stainless duct with bonded continuity, Ex-d ATEX fan motors and discharge via flame arrestor stack. Cobalt loaded into the organic phase is stripped at a separate stage and the cobalt sulphate solution is forwarded to the cobalt sulphate crystalliser (covered in section 5). The HVAC scope here mirrors the lithium SX circuit described in section 3.6.

4.5 Nickel sulphate crystalliser and dryer

The purified nickel sulphate solution is concentrated and crystallised to NiSO4·6H2O. Forced-circulation evaporative crystallisers operate at 60–80°C under vacuum. The crystallised hexahydrate is centrifuged, washed and dried at modest temperature (60–80°C) — going higher converts the hexahydrate to lower hydrates which is not the battery-grade specification. The dried product is packaged in FIBC for shipment to cathode active material producers.

The HVAC design at the crystalliser and dryer is dominated by the 0.1 mg/m³ STEL on nickel sulphate. Every aerosolisation point is hooded at 1.5–2.0 m/s capture velocity; the duct is 316L stainless with continuous-seam welded construction (TDF or SBSF-1525 flanging only at scheduled maintenance access); the bag filter is sized for high capture efficiency (99.95 percent on 0.3 µm equivalent — H13 HEPA-grade) with the bag housing designed for bagged-glove change-out to keep operator exposure below the WES. The discharge stack is monitored continuously for total nickel emission against AS 3580 state EPA boundary air quality limits.

SBKJ scope at the Kwinana refinery — and at any new nickel sulphate facility coming online — is SBAL-V in 316L mode for the rectangular hood plenum and bag-filter inlet plenum, SBSF-1525 flanging on round runs, SB-ZF1500 stitchwelder for the continuous-seam bag-filter inlet plenum and the crystalliser exhaust hood weldments, SBPC1500 plasma cutter for 316L cut-to-length parts and HEPA-frame plenum panels, and SBLR-600 welder for site repairs.

5. Cobalt sulphate refining

Cobalt sulphate heptahydrate (CoSO4·7H2O) is the dominant cobalt chemical for battery-grade cathode use. Australian production is currently smaller in scale than lithium or nickel but growing — Cobalt Blue at Broken Hill NSW operates a dedicated cobalt refinery, Jervois Mining at Idaho USA and historically Australian Mines at Sconi QLD have operated or proposed cobalt operations, and significant cobalt is produced as a co-product at the BHP Nickel West Kwinana refinery. Glencore-controlled operations historically also produced cobalt as a co-product at Murrin Murrin (currently under different ownership).

The cobalt sulphate refining flowsheet parallels the nickel sulphate route — sulphuric acid leach of the cobalt-bearing feed, solvent extraction separation from impurities, precipitation and crystallisation. The Safe Work Australia WES for cobalt is 0.05 mg/m³ TWA — half the nickel sulphate STEL — and cobalt is additionally a known respiratory and skin sensitiser, so the WES is set lower than the chemical toxicity alone would dictate. The LEV design parallels nickel sulphate but with even tighter engineering controls: capture velocity at every aerosolisation point at 1.5–2.0 m/s, hood enclosure rather than hood face wherever possible, 316L stainless duct, bag filter with H13 HEPA-grade housing, continuous monitoring at the discharge stack.

SBKJ scope at any Australian cobalt sulphate refinery is identical in machinery selection to the nickel sulphate scope — SBAL-V in 316L mode, SBSF-1525 flanging, SB-ZF1500 stitchwelder, SBPC1500 plasma cutter, SBLR-600 welder. The difference is in the LEV design margin — every duct on a cobalt sulphate circuit is sized for one extra step of capture-velocity margin because of the sensitiser status, and the bag filter housing is built to the higher containment standard.

6. Rare earth refining — Mt Weld, Eneabba, Nolans Bore, Yangibana, Browns Range

Rare earth refining is the most regulatorily complex HVAC environment in the Australian critical-minerals build. The combination of solvent extraction with kerosene at Zone 1 hazardous area, fluoride and chloride chemistry, calcination at 1,000–1,200°C, combustible-dust controls under NFPA 660 for the calcined product, and — critically — ARPANSA radiological controls for the naturally occurring thorium-232 and uranium-238 in the bastnasite, monazite and xenotime concentrates places rare earth refining at the intersection of more regulatory documents than any other refinery in the country.

6.1 Australian rare earth landscape

Lynas Rare Earths (ASX:LYC) operates the Mt Weld mine in Western Australia — the largest single rare earth source in the Australian and allied-nations supply chain — and historically shipped concentrate to the Lynas Advanced Materials Plant (LAMP) in Kuantan Malaysia for refining. The Kalgoorlie Light Rare Earths plant under construction (commissioning targeted 2024–2025) moves the cracking-and-leaching step onshore, transforming the Mt Weld concentrate into a mixed rare earth carbonate (MREC) that is then refined offshore to individual oxide products. Iluka Resources (ASX:ILU) at Eneabba in the WA Mid-West is building the first Australian end-to-end rare earth refinery — covering separation, oxide production and downstream metal — under a federal critical-minerals offtake. Arafura Rare Earths (ASX:ARU) at Nolans Bore in the NT is building a fully-integrated refinery including separation. Hastings Technology Metals (ASX:HAS) at Yangibana WA is focused on heavy rare earth (dysprosium, terbium). Northern Minerals (ASX:NTU) at Browns Range NT was an early heavy-RE producer; the project is currently between phases.

6.2 ARPANSA NORM — the radiological battery limit

Rare earth concentrate contains naturally occurring radioactive material (NORM). The bastnasite and monazite minerals carry 0.1–10 percent ThO2 (thorium dioxide) and 0.01–1 percent U3O8 (yellowcake uranium oxide) depending on the ore body. The daughter products of the natural thorium-232 decay chain include radium-228 (half-life 5.75 years), actinium-228, thorium-228, radium-224 (half-life 3.6 days), radon-220 thoron (half-life 56 seconds), polonium-216, lead-212, bismuth-212 and lead-208. The uranium-238 decay chain includes thorium-234, protactinium-234, uranium-234, thorium-230, radium-226 (half-life 1,600 years), radon-222 (half-life 3.8 days), polonium-218, lead-214, bismuth-214, lead-210, bismuth-210, polonium-210 and lead-206. The longer-lived daughters accumulate at the refining step where the parent isotopes are concentrated by the chemical process, and refinery hot spots can develop dose rates significantly above ambient even on equipment that handles trace concentrate.

ARPANSA's Radiation Protection Series RPS 9 (Code for Radiation Protection in Mining and Mineral Processing) is the operative document. Worker dose limit is 20 mSv/yr (5-year averaged, no more than 50 mSv in any single year). Public dose limit at the site boundary is 1 mSv/yr above background. Lynas operates Kalgoorlie under a comprehensive radiation management plan agreed with ARPANSA, the WA Radiation Safety Council and the WA Department of Mines, Industry Regulation and Safety (DMIRS).

6.3 Concentrate receiving, cracking and leaching

The mixed rare earth concentrate arrives at the refinery in sealed FIBC containers or sealed drums (mandatory containment under ARPANSA RPS 9 for any concentrate above 1 percent ThO2 or 0.1 percent U3O8). The concentrate is sampled in a sealed glove-box sample station, then cracked by either acid bake (sulphuric acid at 200–300°C, the classic monazite cracking route) or alkaline leach (sodium hydroxide at 140–160°C, the bastnasite-favoured route) to break down the mineral matrix and release the rare earth content into solution. The cracking reactor is the first major HVAC battery limit.

The HVAC design here is layered. Local exhaust at every aerosolisation point — sample station, cracking reactor hood, leach tank vent, filter press discharge — is dedicated radiological exhaust separate from general HVAC return. HEPA H13 filtration (99.95 percent retention on 0.3 µm) is mounted upstream of the fan with bagged-glove change-out provision for safe filter replacement under containment. Continuous gross alpha, gross beta and gamma monitoring at the stack discharge records to the ARPANSA-required logbook. Duct material is 316L stainless throughout (the chloride and sulphate chemistry from cracking attacks 304L within months); the SB-ZF1500 stitchwelder is used for the continuous-seam HEPA-bag housing structures to eliminate flange leakage paths; SBSF-1525 flanges are used only at scheduled bagged-glove change-out points and the bagged-glove access provision is designed into every flange location.

The cracking reactor itself runs at acid mist loadings that drive the duct selection — 5–20 mg/m³ H2SO4 mist at the vent before mist eliminators against the 1 mg/m³ WES. Duct slope is 1:200 to engineered drains, condensate drain sumps at every low point, mist eliminator upstream of fan, caustic scrubber discharge to stack. The radiological battery limit and the acid-mist battery limit overlap at this duct — every section is both radiologically contaminated and acid-corrosive, and the 316L specification covers both demands.

6.4 Solvent extraction cascade — multi-stage SX

The rare earth pregnant leach solution contains 14 light, middle and heavy rare earth elements (lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium) plus yttrium. Separation into individual oxide products is by multi-stage solvent extraction — typically 100–500 mixer-settler stages in cascade, using organic phosphate extractants (Versatic acid, di-(2-ethylhexyl) phosphoric acid D2EHPA, or similar) in kerosene carrier. The SX building is the largest building in the refinery — at Kalgoorlie or Eneabba scale it can be 200–400 m long with multiple parallel cascades feeding the separation product trains.

The SX HVAC is the intersection of three regulatory regimes. AS/NZS 60079 Zone 1 throughout (kerosene flash point 38–60°C). Radiological contamination from the rare earth content (every stage is part of the ARPANSA battery limit). Acid and base aerosolisation at the aqueous phase. The HVAC scope is hooded extract at every mixer and settler (capture velocity 1.0–1.5 m/s), 316L stainless duct with bonded continuity for static-discharge control, Ex-d ATEX fan motors, vent direct to atmosphere via flame arrestor stack after HEPA H13 filtration. The HEPA bag housing is designed for bagged-glove change-out to allow filter replacement without dose to the maintenance crew.

6.5 Precipitation and calcination

Each individual rare earth product stream is precipitated as the carbonate, hydroxide, oxalate or fluoride and then calcined to the oxide at 1,000–1,200°C. Precipitation at 60–95°C in agitated tanks generates aerosol at the tank surface — modest loading but radiologically contaminated. Calcination at 1,000–1,200°C in rotary kilns, fluid-bed calciners or muffle furnaces generates flue gas at 200–400°C after the heat-recovery train, containing residual fluoride or chloride (from the precipitation chemistry), water vapour and rare earth oxide carry-over (combustible dust under NFPA 660 because of the Al/Mg/Ti/Zr contamination).

Duct material on the precipitation side is 316L stainless throughout, sloped to drainage, mist eliminator upstream of fan, scrubber discharge. On the calciner side: refractory-lined carbon steel from the kiln to the heat-recovery cyclone (800–1,000°C service), 309S/310S austenitic stainless from the cyclone to the scrubber (250–350°C), 316L from the scrubber to the stack (140–180°C condensing service). The cold-side 316L scope is SBKJ-supplied — SBAL-V in 316L mode for rectangular ducts, SBSF-1525 round-duct flanging for round runs, SB-ZF1500 stitchwelder for the scrubber housing and any radiological HEPA-bag housing structure, SBPC1500 plasma cutter for cut-to-length parts. The hot-side refractory-lined kiln duct is heavy welded fabrication procured separately.

6.6 NORM waste management

The refinery generates two principal NORM waste streams: the cracking residue (thorium-rich sand from monazite cracking, or sodium aluminate residue from bastnasite alkaline leach) and the spent HEPA filters from the radiological exhaust train. Both are managed as radioactive waste under the relevant state regulator's framework — the WA Radiation Safety Council classifies waste at Categories 1–4 by activity, with handling, storage and ultimate disposal requirements set out by the regulator. The HVAC engineering implication is that every HEPA bag housing must be designed for bagged-glove change-out — the spent filter is enclosed in a sealed bag inside the housing, the bag is sealed and removed without ever being exposed to the operator, and the sealed waste is transferred to the on-site radioactive waste store for ultimate disposal. The SBKJ machinery selection — SB-ZF1500 stitchwelder for continuous-seam bag housing structures (no leakage paths) and SBSF-1525 flanging only at the bagged-glove access provision — is the duct-side response to this requirement.

6.7 Worker amenity and change room

The radiological battery limit demands a controlled change-room and amenity sequence: workers enter through a clean change room, dress in radiologically-monitored work clothing, perform work in the process areas, exit through a dirty change room with personal monitoring (whole-body counters at exit, surface contamination monitors on hands and feet), shower, and re-enter the clean change room. The amenity HVAC must maintain the pressure cascade: clean change room positive to corridor, corridor positive to dirty change room, dirty change room positive to process area, process area negative to atmosphere via the dedicated radiological exhaust. The supply air to all rooms is 100 percent outdoor through HEPA filtration. Air change rates are 15–20 ACH in change rooms (to dilute any residual contamination) and 10–15 ACH in corridors. The duct material is 304L stainless (the air is clean on the supply side and the room is alkali-clean) with 316L return where the air leaving the dirty change room could carry radiological dust.

7. Vanadium electrolyte refining — redox flow battery service

Vanadium electrolyte (vanadyl sulphate, VOSO4) is the active material in vanadium redox flow batteries (VRFB) used for long-duration grid storage. The VRFB market is a smaller but growing segment of the energy storage landscape, with Australian developers including Australian Vanadium Limited (ASX:AVL) at the Tenement Esperance site WA and Tivan Limited (ASX:TVN) at the Nolans Bore NT site (where vanadium occurs as a co-product with rare earth). Internationally, VRFB megaprojects in California, Texas and the European Union are driving the demand profile.

7.1 Vanadium chemistry and refining route

Vanadium ore is typically a magnetite-rich titanomagnetite, processed by salt roast at 1,000–1,200°C with sodium carbonate or sodium chloride to convert vanadium to water-soluble sodium vanadate (NaVO3). The roasted residue is water-leached, the leach solution is purified by ion-exchange or solvent extraction, and the vanadium is converted via V2O5 (vanadium pentoxide) or directly to VOSO4 by sulphuric acid reduction. The final electrolyte product is a sulphuric acid solution of VOSO4 at 1.5–2.0 M concentration with controlled redox state for the VRFB charge–discharge cycle.

7.2 V2O5 — the toxicity driver

V2O5 (vanadium pentoxide) is one of the most toxic transition metal oxides in mainstream industrial production. The Safe Work Australia WES is 0.05 mg/m³ TWA — equivalent to cobalt and substantially tighter than the nickel and chromium limits. V2O5 dust is a respiratory irritant with sensitiser characteristics and acute toxicity at higher exposures (the LD50 in animal models is comparable to arsenic compounds). Every step in the vanadium refinery — the salt roast kiln exit, the cooled product handling, the leach reactor, the precipitation tanks, the V2O5 crystalliser and dryer, the VOSO4 conversion reactor — generates V2O5 or V-bearing aerosol that the HVAC must capture below the 0.05 mg/m³ WES.

7.3 Salt roast kiln HVAC

The salt roast kiln operates at 1,000–1,200°C in oxidising atmosphere. Flue gas at the kiln exit is 1,000–1,100°C carrying V2O5 carry-over, residual NaCl (from chlorine route), water vapour and combustion products. The flue runs through a cyclone heat-recovery train (exit at 200–400°C), then through a fabric filter or electrostatic precipitator for V2O5 capture, and finally through a wet scrubber for residual acid and chloride before stack discharge. Duct material is refractory-lined carbon steel on the hot side (800–1,200°C), 309S/310S austenitic stainless on the cooled side (250–350°C), and 316L stainless on the cold side after the scrubber (140–180°C condensing service). FRP is required if the chloride route is used because chloride condensation at the wet scrubber attacks even 316L over service life. The SBKJ scope is the 316L cold-side duct after the scrubber; the hot-side refractory-lined duct is heavy welded fabrication procured separately.

7.4 Vanadium leach, purification and crystallisation

The water-leached vanadate solution is purified by ion exchange or solvent extraction (the latter at Zone 1 for the kerosene SX circuit), then converted to V2O5 by acid precipitation and roast, or directly to VOSO4 by sulphuric acid reduction. The HVAC scope here is local exhaust at every reactor, mist eliminator upstream of fan, 316L stainless duct, scrubber discharge with continuous monitoring at the stack for V2O5 below the boundary air quality limit. The V2O5 crystalliser and dryer demand the tightest LEV in the refinery — capture velocity at 1.5–2.0 m/s at every aerosolisation point, 316L stainless throughout, bag filter with H13 HEPA-grade housing.

7.5 VOSO4 electrolyte packaging

The final VOSO4 electrolyte (typically supplied as a 1.5–2.0 M sulphuric acid solution) is packaged in plastic IBC with secondary containment for shipment to VRFB project sites. The packaging area HVAC is modest — local exhaust at the IBC fill nozzle to control acid mist (the 1 mg/m³ H2SO4 mist WES is the binding limit, vanadium aerosolisation from a sealed liquid product is minimal), 316L stainless duct, scrubber discharge.

8. Spherical graphite anode refining — the BAM plant in South Australia

Spherical graphite (battery-grade, 99.95+ percent carbon, particle D50 12–25 µm, spheronised shape for high tap density in cell anode coating) is the dominant anode material in lithium-ion cells globally. Australia's first spherical graphite refining capacity is at the Renascor Resources Battery Anode Materials (BAM) plant in South Australia, drawing on the Siviour graphite mine. Ecograf and Talga Group are commissioning or have proposed competing graphite anode operations.

8.1 Spherical graphite flowsheet

Graphite concentrate from the upstream flotation plant (typically 90–96 percent C content) is fed to a spheronisation mill — a high-shear ball mill or air-jet mill that mechanically reshapes flake graphite into pseudo-spherical particles by attrition. The spheronisation step yields the desired shape but also generates fine graphite dust as a co-product. The spheronised product is then purified to 99.95+ percent C by either thermal purification (acheson-style induction furnace or fluidised-bed reactor at 2,500–3,000°C — drives off all volatile impurities including silica, alumina and metallic contamination) or chemical purification by HF leach at 10–40 percent HF concentration and 50–90°C.

8.2 Spheronisation and combustible-dust controls

The spheronisation mill and the downstream classification (where the spheronised fines are separated from the desired product) are AS/NZS 60079 Zone 21 (combustible dust, present in normal operation). Graphite dust Kst is 70–90 bar·m/s and the minimum ignition energy (MIE) is 30–100 mJ depending on particle size distribution. The HVAC engineering is the standard NFPA 660 package: capture velocity 1.0–1.5 m/s at every aerosolisation point, transport velocity 18–22 m/s, bonded conductive 316L stainless duct (galvanised is unsuitable because spark generation at zinc–steel interfaces is a recognised ignition risk), spark-resistant fan per AMCA 99-0401, bag filter with deflagration vent per NFPA 68, isolation valve per NFPA 69 between the bag filter and upstream duct, Ex-d ATEX motor per AS/NZS 60079. The bag filter discharge is a dry collection — the spheronised fines are an economic by-product fed back into the upstream graphite concentrate.

8.3 HF leach purification

Where the chemical purification route is chosen (lower capex than thermal, lower energy but higher reagent cost and severe HF handling), the spheronised graphite is leached in 10–40 percent HF at 50–90°C in agitated reactors. The HF dissolves silicate impurities (SiO2 reacts to SiF4 + H2O) and metallic ash, leaving the purified graphite as filter cake which is washed with water to neutralise residual HF, dried and packaged. The HF leach circuit is the most aggressive HVAC environment in the entire critical-minerals build.

The Safe Work Australia WES for HF is 1.8 mg/m³ TWA (about 2 ppm) — significantly tighter than the chemistry alone would suggest because HF is a percutaneous toxicant. Even brief skin contact with concentrated HF is potentially fatal through systemic calcium chelation (HF penetrates the skin, depletes calcium and magnesium ions in the underlying tissue, and causes cardiac arrest from electrolyte imbalance). The HVAC scope at the HF leach is severe: hooded extract at every reactor (capture velocity 1.5 m/s), enclosed reactor with sealed agitator gland, dedicated extract main with HF capture in a sodium hydroxide wet scrubber (HF + NaOH → NaF + H2O, with the sodium fluoride solution being a regulated waste).

Duct material from the HF leach hood to the scrubber inlet is FRP (vinyl ester or epoxy vinyl ester resin) or PVDF-lined carbon steel — HF aggressively attacks every grade of stainless steel including 316L within weeks, and the only metallic alloys with acceptable HF resistance (Monel 400, Hastelloy C-276) are not economic at duct scale. This battery limit is outside SBKJ duct fabrication scope and is referred to specialist FRP duct fabricators. After the wet scrubber the cold-side duct from scrubber outlet to stack returns to 316L stainless inside SBKJ scope.

Continuous HF monitoring at the operator breathing zone is mandatory — typical detection limit 0.1 ppm with alarm setpoint at 1.8 ppm (the WES) and emergency shutdown at 2.5 ppm (above STEL). Skin contact controls (impermeable gauntlets, full-face shield, splash apron) are PPE rather than HVAC scope, but the HVAC engineering must remove HF aerosol from the breathing zone to allow the operator PPE to function as the last line rather than the first.

8.4 Thermal purification

Where the thermal purification route is chosen, the spheronised graphite is heated to 2,500–3,000°C in a graphite-electrode acheson-style induction furnace or a fluidised-bed reactor under inert (argon) blanket. At these temperatures every volatile impurity — silica, alumina, magnesium, iron, calcium, sodium, sulphur — evaporates and is carried out in the off-gas. The off-gas contains SiO and SiC vapour, residual metallic vapours, and inert carrier gas. The duct from the furnace exit to the heat-recovery cooler is refractory-lined carbon steel (1,200–2,000°C service, with internal refractory lining specified for the temperature gradient and the silica/SiC abrasion). Heat recovery is critical to the energy balance — typical thermal purification consumes 8–15 MWh per tonne of product. After the cooler the gas is at 200–400°C and 309S/310S austenitic stainless is acceptable; after the bag filter and scrubber the cold-side duct returns to 316L stainless. SBKJ scope is the cold-side 316L duct; the hot-side refractory-lined duct is heavy welded fabrication procured separately.

8.5 Spheronisation and packaging

The purified spherical graphite is finally classified, blended and packaged in FIBC for shipment to cathode active material producers. The packaging room HVAC is modest — local exhaust at the FIBC fill chute (capture velocity 1.0 m/s, graphite dust 4 mg/m³ inhalable + 1 mg/m³ respirable WES the binding limit), 316L stainless duct, bag filter discharge with deflagration vent under NFPA 660 (graphite dust is combustible throughout the process), spark-resistant fan.

9. Solvent storage, reagent room, laboratory and worker amenity

Across all six refining battery limits there are common building-services HVAC scopes that recur with similar engineering and similar SBKJ machinery selection.

9.1 Solvent extraction kerosene drum and IBC store

Working kerosene inventory at a typical lithium or rare earth refinery is 100–500 m³ — a significant volume of flammable liquid under AS 1940 and a Zone 1 hazardous area under AS/NZS 60079. The drum and IBC store HVAC is dedicated extract under AS 1940 sized for 1 air change per minute under worst-case spill scenario, 316L stainless duct (kerosene vapour is moderately corrosive on prolonged exposure), Ex-d ATEX fan motor, vent direct to atmosphere via flame arrestor stack. SBKJ SBAL-V in 316L mode and SBSF-1525 cover this scope.

9.2 Acid and caustic reagent room

The reagent storage room holds the sulphuric acid (typically 93–98 percent concentration in 25–100 m³ tanks), hydrochloric acid (10–35 percent concentration), sodium hydroxide (50 percent concentration), sodium carbonate (dry or as solution), ammonium hydroxide (28 percent NH3 by mass) and flotation reagent residue inventory. The room is AS 1940 + AS/NZS 60079 (Zone 2 for ammonia, Zone 1 for any volatile organic reagents) with dedicated extract sized for 12–20 ACH (well above the AS 1668.2 minimum for occupied space). Duct material is 316L stainless for the acid side and galvanised carbon steel for the caustic side; the room is segregated by chemistry (acid stores and caustic stores in separate rooms with separate extract) to prevent reagent cross-contamination in case of a spill.

9.3 Assay laboratory

Every refinery operates an on-site assay laboratory using XRF (X-ray fluorescence), XRD (X-ray diffraction), ICP-MS (inductively coupled plasma mass spectrometry), AAS (atomic absorption spectroscopy) and wet chemistry benches with fume hoods. The lab HVAC is conventional laboratory practice: fume hoods at 0.5 m/s sash-face velocity, 316L stainless duct (the laboratory wet chemistry uses HCl, HNO3, HF, H2SO4 in various combinations including perchloric acid digestion which requires a dedicated perchloric hood with washdown), dedicated extract separate from process building HVAC, scrubber discharge. The XRF and XRD instruments are not aerosolisation sources but require their own controlled-temperature room HVAC for instrument stability. The ICP-MS torch generates a small amount of argon plasma exhaust that is captured locally and routed to the lab extract main.

9.4 Worker amenity, change room and crib room

The worker amenity sequence depends on the contamination risk at the refinery. For radiological refineries (rare earth) the sequence is clean change room → dressing area → process building → dirty change room → personal monitoring (whole-body counters, hand/foot/clothing surface contamination monitors) → shower → re-entry to clean change room. For non-radiological refineries (lithium, nickel, cobalt, vanadium, graphite) the sequence is simpler but still includes a dressing area, controlled-access process area, exit through a clean-out station and shower. The amenity HVAC delivers 100 percent outdoor air through HEPA filtration (mandatory for radiological), 15–20 ACH in change rooms, 10–15 ACH in corridors, and maintains the pressure cascade described in section 6.7. Duct material is galvanised carbon steel for the comfort HVAC side and 304L stainless where the air may carry residual process aerosol from the dirty change room.

10. Pulpit, control room and electrical room HVAC

The operator pulpit (typically a glass-walled cabin overlooking the process floor), the central control room, the rectifier substation and the electrical and instrumentation rooms each have specific HVAC scope.

10.1 Pulpit pressurisation

Operator pulpit positive-pressure HVAC at 25–50 Pa with 100 percent outdoor air through G4 + F7 + H13 HEPA + activated carbon filtration is the engineering control that keeps process aerosol (chlorine, ammonia, sulphuric acid mist, HF, nickel sulphate, cobalt sulphate, V2O5, kerosene vapour, radiological dust) outside the operator breathing zone. Make-up air fan on UPS power for emergency operation; continuous monitoring at the outdoor air intake; automatic shutdown of the supply fan and operator evacuation alarm if the intake concentration exceeds the upper WES STEL. The pulpit HVAC duct is 316L stainless (the outdoor air intake near the discharge stack can carry residual process aerosol and 304L pits over time); SBKJ SBAL-V in 316L mode covers this scope, with HEPA terminal filter housings and activated carbon banks procured separately.

10.2 Central control room

The central control room (typically housing the DCS — distributed control system — operator stations, plant historian, supervisory dashboards) demands N+1 redundant chilled-water or DX cooling rated for 35–40°C Australian ambient design, low-leakage construction, smoke detection on supply, gas-tight dampers for emergency isolation in case of a major process leak. AS 4254 high-pressure construction; 304L or 316L duct for any room downstream of a radiological process area; galvanised for low-risk refineries. AS 1851 fire damper maintenance schedule.

10.3 Electrical and instrumentation rooms

The electrical and instrumentation rooms (housing motor control centres, variable speed drives, instrument panels and the DCS hardware) are positive-pressure clean-air environments with the same chilled-water or DX cooling and the same low-leakage construction. AS 1668.2 ventilation rate (10 L/s per occupant minimum); air-conditioning to 22–25°C dry-bulb for instrument reliability; 25–50 Pa positive pressure to keep dust and aerosol outside; redundant cooling for high-availability operation.

10.4 Rectifier substation cooling

Where the refinery uses DC electrolysis (LiCl route at the lithium refinery, any direct-electrowinning circuit) the rectifier substation is a significant thermal load. A 100 t/h chlor-alkali style cell delivers around 100–200 kA DC at 3–4 V per cell across 100–500 cells, totalling 30–80 MW DC of power delivery; transformer and rectifier losses are 2–5 percent of that, dissipated as heat in the substation. The HVAC scope is chilled-water or chilled-glycol cooling sized for the rectifier transformer and the air-cooled rectifier stack, mineral-oil-mist capture at oil-filled transformers (galvanised carbon steel duct, capture velocity 1.0 m/s), and SF6 leak detection per IEC 62271-4 on any gas-insulated switchgear. The substation building HVAC is conventional industrial — galvanised carbon steel duct, 8–12 ACH building ventilation.

11. SBKJ machinery — what we recommend and why

Across the six refining battery limits described above, the SBKJ machinery selection converges on a single core specification with minor variants. The recommendation matrix:

• SBAL-V auto duct line in 316L mode — the workhorse for all rectangular 316L duct across the refinery. Calciner cold-side scrubber outlet, sulphation roast acid-mist extract, acid leach LEV, SX kerosene area, LiCl scrubber outlet duct, LiOH crystalliser hood, nickel sulphate crystalliser hood, cobalt sulphate crystalliser hood, vanadium electrolyte crystalliser hood, graphite spheronisation extract, graphite thermal purification cold-side, RE cracking reactor hood, RE precipitation, RE calciner cold-side, pulpit pressurisation, control room, electrical room, amenity. The SBAL-V handles 0.6 mm to 2.0 mm 316L stainless coil in continuous-line operation, with TDF flange roll-forming integrated for AS 4254 medium-pressure and high-pressure construction. Output 25–35 metres of finished rectangular duct per shift on stainless.
• SBSF-1525 round-duct flanging line — for round 316L duct on the same battery limits where round runs are preferred over rectangular (typically long runs to bag filters, scrubber inlet/outlet, and connections to specialist process equipment). Diameter up to 1,525 mm; 316L specification with PTFE gasket compatibility.
• SB-ZF1500 stitchwelder — for continuous-seam welded construction on:
• Stainless reactor plenum — the housing around a leach or precipitation reactor where flange leakage is unacceptable;
• Acid scrubber housing — the wet scrubber shell where continuous welding eliminates flange seepage of corrosive aerosol;
• Radiological HEPA-bag duct — the HEPA bag housing structure where flange leakage paths must be eliminated to prevent radiological contamination of the surrounding building.
• SBTF spiral tubeformer — for round galvanised carbon steel duct on the building-services side (amenity, electrical room, control room return air) and round 304L stainless duct on lithium hydroxide packaging room supply. Diameters 100 to 1,500 mm standard, larger by special order.
• SBPC1500 plasma cutter — for 316L cut-to-length parts, branch fittings, HEPA-frame plenum panels and custom fabrications. Plasma is the only practical cutting process for 316L at duct gauge (0.8–2.0 mm) that delivers clean edges without contaminating the cut surface with mild-steel transfer (as oxy-fuel does).
• SBLR-600 welder — for site repairs on 316L stainless seams, particularly at flange joints where field re-work is required after installation. TIG welding on stainless is the standard process; the SBLR-600 is a portable TIG welder rated for the duty cycle.
• Spark-resistant fans per NFPA 660 — mandatory for every duct connection on the LiOH crystalliser, the graphite spheronisation, the graphite thermal purification cold side, and any duct downstream of a combustible-dust source. Typically aluminium impeller in bronze rubbing-ring housing, AMCA 99-0401 Type A or B construction depending on duty.
• IECEx / ATEX Ex-d motors — mandatory for every fan motor in AS/NZS 60079 Zone 1 (solvent extraction kerosene, LiCl electrolysis chlorine, ammonia precipitation circuit) and Zone 2. Specified per the buyer's zone classification drawing.

Outside SBKJ scope (referred to specialist FRP fabricators in Australia) is the FRP and PP-lined duct for direct chlorine contact at the LiCl electrolysis cell room and the direct HF contact at the graphite anode HF leach circuit. These are non-metallic duct fabrications that fall outside the SBKJ machinery range; the Australian specialist suppliers (Plascon, Specialised Composite Australia, Fibrelogic, and others) are well-established with the rare earth, graphite and chlor-alkali industries. SBKJ engineers can recommend specialist suppliers as part of the project quote.

12. Procurement and lead time on Australian critical-minerals projects

Australian critical-minerals refining projects run on 24–48 month schedules from final investment decision to ramp-up start, with the HVAC fitout in the middle quarter of the schedule. The procurement and scheduling implications for the SBKJ duct fabrication machinery:

• SBKJ machinery lead time: 8–14 weeks from order to delivery for the SBAL-V auto duct line in stainless configuration plus the supporting machinery (SBSF-1525, SB-ZF1500, SBPC1500, SBLR-600). Ocean freight to Fremantle (WA), Port Kembla or Port Botany (NSW), Port of Brisbane (QLD), Port of Darwin (NT) or Port Adelaide (SA) adds 4–6 weeks. Australian Border Force and Department of Agriculture customs clearance plus inland trucking adds 2–3 weeks. Installation and commissioning on the buyer's site adds 2–3 weeks. Total 16–28 weeks from purchase order to first article duct.
• 316L stainless coil lead time: at refinery scale (hundreds to thousands of tonnes) lead time is 8–16 weeks in 2026 markets, with Australian stockists (BlueScope, Sandvik, Salzgitter Mannesmann Australia, OneSteel via the Industrial Galvanising group) and international mill direct (Outokumpu Avesta Sweden, Acerinox Spain, Aperam Belgium) both viable. The mill order needs to be placed at the same time as the project structural steel order to align with the fabrication shop ramp-up.
• Specialist FRP duct lead time (HF and chlorine service): 16–24 weeks for fabricated FRP duct sections, with Australian specialist suppliers covering this scope.
• HEPA filter housings, mist eliminators and scrubbers: 12–20 weeks for the larger custom items.
• Spark-resistant fans and Ex-d motors: 8–12 weeks for AMCA 99-0401 and IECEx-certified product.
• Project EPC contractor pool: Worley (the biggest mining EPC and refinery EPC in Australia, including the Kemerton, Kwinana and Eneabba projects), Bechtel Australia, Hatch Australia and KBR each have active critical-minerals refining work in 2026. The fabrication scope is typically subcontracted to local sheet-metal fabricators who buy or lease the SBKJ duct-forming machinery to set up an on-site or near-site fabrication shop for the project duration.

SBKJ stocks 316L flange dies, plasma consumables, welder electrodes and TDF rollers on Box Hill North VIC after-sales stock for same-week despatch to any Australian critical-minerals refinery. The Critical Minerals Production Tax Credit at 40 percent of eligible processing capex from 2026 is applicable to the SBKJ machinery purchase where the buyer is the operating company or the project EPC contractor — SBKJ engineers can issue the documentation needed for the buyer's tax credit claim against the duct fabrication line capex.

13. Cost benchmarks and budget guidance

HVAC ductwork on an Australian critical-minerals refinery represents 4–8 percent of total facility capital cost. For a 24,000 t/yr battery-grade LiOH refinery at AUD 600–900 million capital cost (the Train 1 Kwinana benchmark), HVAC ductwork is AUD 25–70 million. For a 50,000 t/yr LiOH refinery at AUD 1.2–1.8 billion capital cost (the Kemerton or Mt Holland benchmark) HVAC is AUD 50–140 million. For the largest projects — Kemerton at full four-train build, Eneabba end-to-end RE — total HVAC ductwork can exceed AUD 200 million. Within this:

• 316L stainless duct (the workhorse): 55–75 percent of total ductwork spend.
• Specialist FRP duct (chlorine, HF): 5–15 percent.
• Refractory-lined carbon steel duct (calciner hot side): 10–20 percent.
• Galvanised carbon steel (amenity, electrical, control rooms): 5–10 percent.
• Insulation and fire-rated wrapping: 8–12 percent of installed ductwork cost.
• Spark-resistant fans, Ex-d motors, HEPA housings: 10–15 percent of total ductwork spend (the high-value equipment side).

The material cost component of 316L stainless ductwork is around 45 percent of installed price. Fabrication labour is around 25 percent, installation labour around 18 percent, insulation and accessories around 12 percent. The fabrication labour share is what local on-site fabrication with rented or owned duct-forming machinery directly attacks — moving from imported fabricated 316L duct to on-site fabrication can reduce installed cost by 20–30 percent on stainless work, accounting for machinery rental and operator training.

SBKJ machine economics on a critical-minerals refinery project: an SBAL-V auto duct line in 316L mode produces 25–35 metres of finished rectangular duct per shift. At a project rectangular duct quantity of 15,000 to 50,000 metres typical for a 24,000–50,000 t/yr LiOH refinery, one SBAL-V running double shift covers the project schedule with margin for rework and special fabrications. Spiral round duct quantity at 8,000 to 20,000 metres is covered by one SBSF-1525 running single or double shift. Total machinery cost is a small percentage of total fabrication labour saved, and with the Critical Minerals Production Tax Credit at 40 percent applicable to the capex the net cost is reduced further.

14. Australian regulatory and stakeholder map

The HVAC engineering on a critical-minerals refining project has to be signed off against multiple regulatory documents and reviewed by multiple stakeholders. The map:

• Federal: Department of Industry, Science and Resources (DISER) for the Critical Minerals Strategy 2030 and the production tax credit administration. Department of Climate Change, Energy, the Environment and Water (DCCEEW) for emissions reporting and the broader strategy. Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) for rare earth radiological compliance. Safe Work Australia for the workplace exposure standards. Australian Border Force and Department of Agriculture for import clearance.
• State (WA — where most lithium and rare earth refining sits): Department of Mines, Industry Regulation and Safety (DMIRS) for mine and refinery safety. WA Radiation Safety Council for rare earth radiological licensing. Department of Water and Environmental Regulation (DWER) for environmental licensing including air quality. WorkSafe WA for occupational health.
• State (NSW — Cobalt Blue, Liontown): NSW Resources Regulator. EPA NSW for environmental licensing. SafeWork NSW for occupational health.
• State (NT — rare earth and vanadium at Nolans Bore, Browns Range): Department of Industry, Tourism and Trade. NT EPA for environmental licensing. NT Worksafe for occupational health. NT Department of Health for radiation safety.
• State (SA — graphite at the BAM plant): Department for Energy and Mining. EPA SA for environmental licensing including radiation safety. SafeWork SA for occupational health.
• Industry bodies: Critical Minerals Industry Council Australia (coordinating the operating companies). Minerals Council of Australia (MCA, the broader industry body). Future Battery Industries Cooperative Research Centre (FBI CRC) based in Perth for the technical R&D pipeline. Australian Battery Industry Association.
• Operating companies: see section 1 — IGO Limited (TLEA JV Kwinana), Albemarle Australia (Kemerton), Wesfarmers WesCEF / SQM (Covalent Lithium Mt Holland), Pilbara Minerals, Mineral Resources, Greenbushes Talison (IGO + Albemarle JV), Liontown Resources, Core Lithium, Allkem (now Arcadium Lithium 2024 merger), Lynas Rare Earths, Iluka Resources, Arafura Rare Earths, Hastings Technology Metals, Northern Minerals, BHP Nickel West, Wyloo Metals, Mincor Resources, Cobalt Blue, Jervois Mining, Australian Vanadium, Tivan Limited, Renascor Resources, Ecograf, Talga Group.
• EPC contractors: Worley (the largest mining EPC and refinery EPC in Australia, including the Kemerton, Kwinana, Eneabba and many other current critical-minerals projects), Bechtel Australia, Hatch Australia, KBR. Each maintains active design and construction teams on Australian critical-minerals work in 2026.

15. Where SBKJ adds value beyond machinery supply

Australian critical-minerals refining projects are technically demanding and the duct fabrication line is one of the longer-lead capital items on the schedule. SBKJ's specific Australian-side contribution beyond machinery supply:

• Local engineering at Box Hill North VIC: our senior engineers are based in Australia and reachable in Australian business hours, with the same time zone as the buyer and the EPC contractor. No middle-of-the-night call escalation, no language barrier on the technical specification review.
• 316L coil specification review: we maintain working relationships with the Australian stainless coil stockists and the international mill suppliers, and we can review the buyer's coil specification against the SBAL-V tooling envelope before any coil is ordered. Where a coil specification is marginally compatible we flag the issue before the buyer commits to the mill order.
• Critical Minerals Production Tax Credit documentation: the 40 percent tax credit applies to eligible processing capex and the SBKJ duct fabrication line falls within scope. We issue the documentation pack the buyer's tax accountant needs to file the claim — invoice, asset description, capacity rating, eligible-asset classification — at no additional charge as part of the standard project package.
• Operator training in Australian English: first-article training on the buyer's site, full operator manual in Australian English (no language translation), and remote engineering support during the first 90 days of production at no additional charge.
• Same-week consumable despatch: 316L flange dies, plasma consumables, welder electrodes and TDF rollers on Box Hill North VIC after-sales stock for same-week despatch to any Australian critical-minerals refinery — Kwinana, Kemerton, Mt Holland, Kalgoorlie, Eneabba, Mt Weld, Nolans Bore, Yangibana, Browns Range, Kambalda, Broken Hill, Murrin Murrin, Sconi, BAM Whyalla and any other operating site.
• ARBS 2026 presence: our Australian entity Australia Ducting Pty Ltd is exhibiting at ARBS 2026 in May at the Melbourne Convention and Exhibition Centre (stand 236). Critical-minerals refinery EPC engineers and fabrication shop owners are welcome to meet our team in person during the show.
• Network of Australian specialist FRP and refractory suppliers: for the duct scope outside SBKJ's metallic-fabrication range (FRP for chlorine and HF service, refractory-lined carbon steel for the calciner hot side) we maintain working contacts with the established Australian specialist suppliers and can recommend or coordinate the procurement.

16. SBKJ commitment to the Australian critical-minerals industry

SBKJ Group is headquartered at Box Hill North VIC with engineering, sales and after-sales support staffed locally and reachable by Australian business hours (sales@sbkjduct.com, +61 435 074 994). Our engineering team has experience commissioning duct fabrication lines on critical-minerals refining projects across multiple jurisdictions, and we hold critical spares (316L flange dies, plasma consumables, welder electrodes, TDF rollers) in Victorian stock for same-week despatch to every Australian critical-minerals site listed above.

Our Australia presence is closely aligned with the Critical Minerals Industry Council Australia operating members, the Future Battery Industries Cooperative Research Centre in Perth, and the major EPC contractors building the Future Made in Australia critical-minerals capacity. We exhibit at ARBS 2026 in May at the Melbourne Convention and Exhibition Centre (stand 236 — operated by our Australian entity Australia Ducting Pty Ltd), and our engineers attend the FBI CRC annual technical conference and the Critical Minerals Conference series.

Every critical-minerals project we quote is reviewed by our senior engineering team before pricing is released — the difference between a 304L and a 316L specification is the difference between an acid-leach extract duct that fails in 18 months and one that lasts 20 years, the difference between a kerosene SX extract that ignites on a static-discharge event and one that operates safely for a 25-year refinery life, and the difference between a radiological HEPA-bag housing that releases NORM contamination to the surrounding building and one that holds the radiological boundary for the operating life of the refinery. We have seen the consequences of getting these decisions wrong on competitor-supplied work that we have later been called in to replace. We get the specification right the first time.

Frequently asked questions

Why is 316L stainless steel mandatory throughout a critical-minerals refinery?

Every Australian critical-minerals refining process — battery-grade lithium hydroxide, rare earth solvent extraction, nickel and cobalt sulphate, vanadium electrolyte and spherical graphite anode purification — runs on the same family of aggressive reagents: sulphuric acid at 60–95 percent concentration for sulphation roast and leach, hydrochloric acid for chloride leach and resin elution, hydrofluoric acid at low concentration for graphite purification, sodium hydroxide for precipitation and pH adjustment, chlorine gas at the lithium chloride electrolysis cell, nickel sulphate and cobalt sulphate mist at the crystalliser exhaust, and fluoride condensate at the rare earth precipitation circuit. Carbon steel pits within months across all of these services and galvanised steel surrenders the zinc coating to acid attack in weeks. 304L stainless develops pitting around chloride contamination in WA groundwater and Pilbara dust. 316L (UNS S31603) with 2.0–3.0 percent molybdenum is the only material that survives every service at acceptable life — typically 15–25 years against the 3–5 year life of 304L. The SBKJ recommendation is 316L throughout, fabricated on the SBAL-V in 316L mode.

What is the HVAC scope on a typical Australian lithium hydroxide refinery?

A 24,000–50,000 t/yr battery-grade LiOH refinery — Train 1 at Kwinana or any one train at Kemerton — runs through 12 major HVAC battery limits: spodumene receiving and crushing, calciner kiln, sulphation roast, acid leach and filter, solvent extraction kerosene area, LiCl electrolysis chlorine extract (where the electrolysis route is used), LiOH crystalliser and dryer, packaging room dry-room HVAC, reagent storage, assay laboratory, operator amenity, and electrical and substation HVAC. Total ductwork scope 25–45 km, the majority 316L stainless, all inside the SBAL-V 1,500 mm and SBSF-1525 1,525 mm rolling envelopes.

What does NFPA 660 require for lithium and graphite refining combustible dust?

NFPA 660 (which consolidated NFPA 484, 652, 654, 655 and 664 from 2025) applies to lithium metal dust (Class D, water-reactive — dry collection only with inert blanket), graphite dust (Kst 70–90 bar·m/s, MIE 30–100 mJ), and Al/Mg/Ti/Zr contamination in rare earth and vanadium calcined product. The mandatory controls are written Dust Hazard Analysis, deflagration venting on bag filters per NFPA 68, isolation valves per NFPA 69, bonded conductive duct, spark-resistant fans per AMCA 99-0401, and Ex-rated electrical equipment per AS/NZS 60079. SBKJ supplies bonded conductive 316L construction and spark-resistant fans as part of the package.

How is the chlorine exhaust from lithium chloride electrolysis handled?

The LiCl electrolysis cell generates chlorine at up to 99 percent dry concentration against a Safe Work Australia WES of 0.5 ppm TWA. The cell room is AS/NZS 60079 Zone 1. The cell hood gas is direct-coupled to a two-stage caustic scrubber (5–15 percent NaOH circulating) via FRP duct (outside SBKJ scope — referred to specialist FRP fabricators because chlorine attacks 316L at high concentration). After the scrubber the chlorine concentration drops below 1 ppm and the cold-side duct returns to 316L stainless inside SBKJ scope. Continuous chlorine monitoring at the cell room ceiling, operator breathing zone and outdoor air intake is mandatory under AS 1668.2.

How is rare earth NORM radiological exhaust managed?

Mt Weld, Nolans Bore and Yangibana rare earth concentrates contain Th-232 and U-238 with daughter products including Ra-226, Ra-228 and radon isotopes. ARPANSA RPS 9 sets the worker dose at 20 mSv/yr and the public dose at 1 mSv/yr above background. The HVAC engineering response is dedicated radiological exhaust separate from general HVAC, HEPA H13 filtration on every discharge upstream of fan, bagged-glove change-out at every filter housing, continuous gross alpha / gross beta / gamma monitoring at the stack, and sealed radioactive waste handling for spent filters. SBKJ supplies 316L duct fabricated on the SBAL-V in 316L mode with the SB-ZF1500 stitchwelder for continuous-seam HEPA-bag housing structures (no flange leakage paths) and SBSF-1525 flanges only at scheduled change-out access provisions.

How is the spherical graphite HF leach circuit ventilated?

The HF leach circuit operates at 10–40 percent HF concentration at 50–90°C with a Safe Work Australia WES of 1.8 mg/m³ TWA. HF attacks every grade of stainless steel including 316L, so the duct from the leach hood to the scrubber inlet is FRP or PVDF-lined carbon steel (outside SBKJ scope, specialist FRP fabricators only). After the scrubber the duct returns to 316L stainless inside SBKJ scope. The graphite combustible-dust battery limit upstream of the HF leach is NFPA 660 with spark-resistant fans and bonded conductive 316L duct.

What is the lead time for SBKJ machinery on a critical-minerals project?

16–28 weeks from purchase order to commissioning at the buyer's Australian site. 8–14 weeks SBKJ machine manufacture, 4–6 weeks ocean freight to Fremantle (WA), Port Kembla / Port Botany (NSW), Port of Brisbane (QLD), Port of Darwin (NT) or Port Adelaide (SA), 2–3 weeks customs clearance and inland trucking, 2–3 weeks installation, commissioning and operator training. Critical Minerals Production Tax Credit at 40 percent of eligible processing capex from 2026 is applicable — SBKJ issues the documentation pack for the buyer's tax claim.

What worker exposure standards drive the design?

The binding Safe Work Australia WES limits across the refinery battery limit: chlorine 0.5 ppm TWA / 1.0 ppm STEL (LiCl electrolysis); ammonia 25 ppm TWA / 35 ppm STEL (precipitation); sulphuric acid mist 1 mg/m³ TWA (leach and roast); HF 1.8 mg/m³ TWA (graphite purification); respirable dust 10 mg/m³ inhalable + RCS 0.05 mg/m³ (every dry handling step); thorium-232 and uranium-238 dose limits under ARPANSA at 20 mSv/yr worker (rare earth); graphite dust 4 mg/m³ inhalable + 1 mg/m³ respirable (graphite); nickel sulphate 0.1 mg/m³ STEL (the killer at the BHP Nickel West Kwinana crystalliser); cobalt 0.05 mg/m³ TWA (sensitiser); V2O5 0.05 mg/m³ TWA (extremely toxic, the vanadium electrolyte plant); lithium dust managed against 1 mg/m³ inhalable with alkali burn skin hazard. These limits drive capture velocity 1.0–2.0 m/s, transport velocity 12–18 m/s, mist eliminators upstream of fans, scrubbers at discharge, and operator pulpit pressurisation at 25–50 Pa positive with HEPA + activated carbon filtration.

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