Crystallization
Cobalt is a structurally constrained critical material: it has no dedicated mine and is recovered almost entirely as a by-product of copper and nickel operations, so the annual volume entering the market is set by copper mine plans…
Technology brief
Cobalt is a structurally constrained critical material: it has no dedicated mine and is recovered almost entirely as a by-product of copper and nickel operations, so the annual volume entering the market is set by copper mine plans…
The challenge
Primary use cases:
Outputs / uses: cathode cobalt for high-energy lithium-ion batteries (no near-term substitute at equivalent energy density and cycle life), nickel-based superalloys for turbine hot sections, hydroprocessing catalysts. Copper and nickel recovered as co-products from the same stream; clean water returned; arsenic and uranium immobilised; acid drainage neutralised.
Industries and users: copper-cobalt mine operators, battery recyclers (EU, USA), aerospace and defense (turbine superalloys), strategic-supply programs.
Scale: container-class modules, single units or multi-unit cascades on one water circuit. Reference module 200 m³/day ≈ 70,000 m³/year.
ARBOK solution
Cobalt is a structurally constrained critical material: it has no dedicated mine and is recovered almost entirely as a by-product of copper and nickel operations, so the annual volume entering the market is set by copper mine plans rather than by battery demand. The supply chain narrows to two chokepoints — the Democratic Republic of the Congo at approximately 73% of world mine output, and China at approximately 70–78% of global refining. In 2025 the DRC introduced export quotas, capping 2026 exports at 96,600 t against world production of roughly 220,000 t in 2024; the market inverted from surplus into structural deficit, and cobalt metal moved from about $56/kg at the start of 2026 to approximately $60/kg by April 2026.
ARBOK addresses a supply source that is neither quota-bound nor refinery-bound: cobalt already dissolved in aqueous streams. Two streams are targeted — acid mine drainage together with leach solutions, raffinates and tailings waters of the Central African Copperbelt, and the effluent of spent-battery processing. These waters are pumped, monitored and treated at operator expense regardless of whether metal is recovered from them; ambient-temperature deep-vacuum phase separation converts that obligatory treatment into recovery.
> Core technology and architecture: see ARBOK-VC (Vacuum Cracking). This entry covers the cobalt-specific feedstock, mechanism, market and economics.
Feed enters a vacuum chamber held under deep vacuum. Under this pressure water evaporates at ambient temperature and condenses as clean water, while the dissolved load concentrates in the residual liquor. No heat is supplied to the process: the process temperature equals the temperature of the incoming stream and of the surroundings. Efficient heat recuperation reduces net energy demand. The core process employs no membranes, no electrodes and no added chemical reagents, and discharges no liquid effluent.
Why cobalt escapes into water in the first place. In the oxide and mixed ores of the Copperbelt, copper and cobalt are leached simultaneously in sulphuric acid, with a reducing agent — typically sulphur dioxide added as sodium metabisulphite — required to reduce Co(III) minerals to the soluble divalent state. Cobalt therefore enters solution as Co²⁺ and, in most DRC flowsheets, is recovered from the raffinate of the low-grade copper solvent-extraction circuit rather than from a dedicated cobalt leach. Recovery from raffinate is incomplete and grade-sensitive; heap and dump leach solutions are never fully collected; sulphide minerals in tailings and waste rock generate sulphuric acid on exposure to air and water and mobilise metals into acid mine drainage. Cobalt is unusually mobile under these conditions — more so than copper — because Co²⁺ remains soluble across a wide pH range and does not readily precipitate until neutralisation is deliberately imposed. The operator therefore pays twice: the metal is lost from the product stream, and the same stream must then be neutralised with lime or equivalent reagents at typically $1–3 per m³ treated.
Three platform characteristics specific to cobalt-bearing mine waters:
Cobalt-specific step. As water is removed, Co²⁺ concentrates in the residual liquor; product grade is reached by a secondary pass through the same separation stage rather than by a distinct chemical circuit. Copper and nickel accompanying cobalt are recovered from the same stream, so a single installation produces several saleable fractions plus water.
Limitations stated in the source. Design depends almost entirely on feed concentration, and reported cobalt concentrations in the Katanga region span four orders of magnitude — from approximately 0.003 g/L in near-neutral environmental discharge waters, through mixed mine and process waters, to raffinate grade of 1–3 g/L, with extreme mine-water values reaching tens of g/L. A recovery project therefore does not face a single "average" feed but a choice of tie-in point. Module sizing, cobalt output and revenue scale approximately linearly with feed concentration. The figures below constitute a module-level model built on platform parameters; project-level output is set by site conditions and is established from site assay.
Market and application
Illustrative module-level model: one container-class module treating 200 m³/day ≈ 70,000 m³/year at the conservative design basis of 0.2 g/L Co. Prices: approximately $60/kg for cobalt (April 2026) and approximately $13,300/t for copper (LME, July 2026). Copper assumed present at 0.5 g/L, a conservative figure for copper-belt waters.
| Line | Basis | Contribution |
|---|---|---|
| Cobalt | 70,000 m³/year at 0.2 g/L → approximately 14 t/year at $60/kg | approximately $0.84M/year |
| Copper and nickel co-products | same stream, no additional feed cost (0.5 g/L Cu, $13,300/t) | approximately $0.45M/year |
| Recycled water | 70,000 m³/year at $1/m³ in a water-constrained mining region | approximately $0.07M/year |
| Avoided acid-drainage neutralisation | elimination of separate lime treatment at $1–3/m³ | approximately $0.10M/year |
| Total per module | | approximately $1.45M/year |
The cobalt line is approximately 58% of the total; the remaining 42% derives from streams the operator currently treats as cost, before accounting for the removal of arsenic and uranium liabilities.
Sensitivity. Feed concentration dominates all other variables. On a raffinate-grade feed of 1 g/L Co, the cobalt line alone rises to approximately 70 t/year and approximately $4.2M/year, and the co-product and water credits are unchanged — the economics improve by roughly a factor of five relative to the 0.2 g/L basis.
Use cases
Primary use cases:
Outputs / uses: cathode cobalt for high-energy lithium-ion batteries (no near-term substitute at equivalent energy density and cycle life), nickel-based superalloys for turbine hot sections, hydroprocessing catalysts. Copper and nickel recovered as co-products from the same stream; clean water returned; arsenic and uranium immobilised; acid drainage neutralised.
Industries and users: copper-cobalt mine operators, battery recyclers (EU, USA), aerospace and defense (turbine superalloys), strategic-supply programs.
Scale: container-class modules, single units or multi-unit cascades on one water circuit. Reference module 200 m³/day ≈ 70,000 m³/year.
Implementation sequence: assay of the target water stream → selection of the recovery and secondary-pass configuration → module sizing → installation on the existing water circuit → commissioning.
Modules are container-class and automated, requiring minimal dedicated staffing, and operate at ambient temperature and pressure conditions compatible with renewable power. Because the tie-in is to a stream the operator already pumps and already treats, installation does not interfere with the primary mining or recycling flowsheet.
Two commercial structures are offered: outright purchase, or a build-own-operate-maintain arrangement under which the operator commits no capital and pays against recovered product and avoided treatment cost.
Platform basis: ARBOK-VC (Vacuum Cracking). Complementary solid spent-cell route: ARBOK-AVD (Arbok-AVD addresses the solid cell fraction, the vacuum phase-separation platform addresses the water). Co-recovery of copper from the same mine-water streams links directly to ARBOK-Copper-Waters. Multi-metal cascades on one water circuit relate this case to the other critical-materials cases on the same platform: ARBOK-Indium, ARBOK-Rhenium, ARBOK-Germanium-Gallium, ARBOK-Scandium-REE. Salt and ballast fractions separated by density connect to ARBOK-CRYSTALLIZER.
Tie-in points at site: existing acid-mine-drainage treatment circuit, copper solvent-extraction raffinate line, heap/dump leach collection, tailings water circuit, hydrometallurgical battery-recycler effluent.
Cobalt is a structurally constrained critical material: it has no dedicated mine and is recovered almost entirely as a by-product of copper and nickel operations, so the annual volume entering the market is set by copper mine plans rather than by battery demand. The supply chain narrows to two chokepoints — the Democratic Republic of the Congo at approximately 73% of world mine output, and China at approximately 70–78% of global refining. In 2025 the DRC introduced export quotas, capping 2026 exports at 96,600 t against world production of roughly 220,000 t in 2024; the market inverted from surplus into structural deficit, and cobalt metal moved from about $56/kg at the start of 2026 to approximately $60/kg by April 2026.
ARBOK addresses a supply source that is neither quota-bound nor refinery-bound: cobalt already dissolved in aqueous streams. Two streams are targeted — acid mine drainage together with leach solutions, raffinates and tailings waters of the Central African Copperbelt, and the effluent of spent-battery processing. These waters are pumped, monitored and treated at operator expense regardless of whether metal is recovered from them; ambient-temperature deep-vacuum phase separation converts that obligatory treatment into recovery.
> Core technology and architecture: see ARBOK-VC (Vacuum Cracking). This entry covers the cobalt-specific feedstock, mechanism, market and economics.
Primary use cases:
Outputs / uses: cathode cobalt for high-energy lithium-ion batteries (no near-term substitute at equivalent energy density and cycle life), nickel-based superalloys for turbine hot sections, hydroprocessing catalysts. Copper and nickel recovered as co-products from the same stream; clean water returned; arsenic and uranium immobilised; acid drainage neutralised.
Industries and users: copper-cobalt mine operators, battery recyclers (EU, USA), aerospace and defense (turbine superalloys), strategic-supply programs.
Scale: container-class modules, single units or multi-unit cascades on one water circuit. Reference module 200 m³/day ≈ 70,000 m³/year.
Feed enters a vacuum chamber held under deep vacuum. Under this pressure water evaporates at ambient temperature and condenses as clean water, while the dissolved load concentrates in the residual liquor. No heat is supplied to the process: the process temperature equals the temperature of the incoming stream and of the surroundings. Efficient heat recuperation reduces net energy demand. The core process employs no membranes, no electrodes and no added chemical reagents, and discharges no liquid effluent.
Why cobalt escapes into water in the first place. In the oxide and mixed ores of the Copperbelt, copper and cobalt are leached simultaneously in sulphuric acid, with a reducing agent — typically sulphur dioxide added as sodium metabisulphite — required to reduce Co(III) minerals to the soluble divalent state. Cobalt therefore enters solution as Co²⁺ and, in most DRC flowsheets, is recovered from the raffinate of the low-grade copper solvent-extraction circuit rather than from a dedicated cobalt leach. Recovery from raffinate is incomplete and grade-sensitive; heap and dump leach solutions are never fully collected; sulphide minerals in tailings and waste rock generate sulphuric acid on exposure to air and water and mobilise metals into acid mine drainage. Cobalt is unusually mobile under these conditions — more so than copper — because Co²⁺ remains soluble across a wide pH range and does not readily precipitate until neutralisation is deliberately imposed. The operator therefore pays twice: the metal is lost from the product stream, and the same stream must then be neutralised with lime or equivalent reagents at typically $1–3 per m³ treated.
Three platform characteristics specific to cobalt-bearing mine waters:
Cobalt-specific step. As water is removed, Co²⁺ concentrates in the residual liquor; product grade is reached by a secondary pass through the same separation stage rather than by a distinct chemical circuit. Copper and nickel accompanying cobalt are recovered from the same stream, so a single installation produces several saleable fractions plus water.
Limitations stated in the source. Design depends almost entirely on feed concentration, and reported cobalt concentrations in the Katanga region span four orders of magnitude — from approximately 0.003 g/L in near-neutral environmental discharge waters, through mixed mine and process waters, to raffinate grade of 1–3 g/L, with extreme mine-water values reaching tens of g/L. A recovery project therefore does not face a single "average" feed but a choice of tie-in point. Module sizing, cobalt output and revenue scale approximately linearly with feed concentration. The figures below constitute a module-level model built on platform parameters; project-level output is set by site conditions and is established from site assay.
| Parameter | Value |
|---|---|
| Vacuum in chamber | deep vacuum |
| Process temperature | ambient — no heat supplied; equals the temperature of the feed and the surrounding environment |
| Specific energy consumption (water-base processing) | very low specific energy consumption, among the lowest reported for the sector |
| Heat recuperation | efficient heat recuperation, reducing net energy demand |
| Water return | near-complete water return by volume, zero liquid discharge |
| Membranes / electrodes / reagents | none |
| Reference module throughput | 200 m³/day ≈ 70,000 m³/year |
| Conservative design basis, Co in feed | 0.2 g/L |
| Reported Co range, Katanga region | 0.003 g/L (environmental discharge) to tens of g/L (mine water); raffinate 1–3 g/L |
| Cu in feed (model assumption) | 0.5 g/L |
| Cobalt output at 0.2 g/L | approximately 14 t/year per module |
| Cobalt output at raffinate grade 1 g/L | approximately 70 t/year per module |
| Co²⁺ upgrading to product grade | secondary pass through the same separation stage |
| Ballast removed | iron, aluminium, calcium, sulphate — by density, as valorised fraction |
| As, U | report to immobilised fraction; acidity neutralised in the same operation |
| Deployment form | container-class modules, single or multi-unit cascade on one water circuit |
| TRL | 9 |
| ARBOK-AVD (solid spent cells) | mercury amalgamation at near-ambient temperature; distillation under vacuum at elevated temperature; mercury recovered and recycled at a very high rate; strong recovery for Co, Ni, Cu |
Vacuum chamber operating under deep vacuum with ambient-temperature evaporation and condensate collection; heat recuperation loop reducing net energy demand; density-based separation of ballast salts as a valorised fraction; immobilisation route for arsenic and uranium with simultaneous neutralisation of drainage acidity; secondary pass through the same separation stage for Co²⁺ upgrading to product grade; co-product recovery of copper and nickel from the same stream. No membranes, no electrodes, no reagent dosing, no furnaces, no consumables. Container-class, automated modules, configured as single units or as multi-unit cascades on one water circuit.
Complementary solid-feed unit ARBOK-AVD: shredded cell material contacted with liquid mercury at near-ambient temperature to form an amalgam, then distilled under vacuum at elevated temperature; mercury recovered and recycled at a very high rate; metals precipitate in density-stratified layers.
Technical: phase-change separation is indifferent to salinity, low pH, suspended solids and mixed metal loads that degrade membranes and ion exchange; ballast salts leave as a product instead of fouling the train; product grade reached by a secondary pass rather than a separate chemical circuit; no membranes, electrodes, reagents, furnaces or consumables.
Economic: the tie-in is to a stream the operator already pumps and already treats, so there is no new pit, no new tailings facility and no separate ore processing; copper and nickel arrive as co-products at no additional feed cost; recycled water and avoided neutralisation add value on streams currently booked as cost — approximately 42% of total module contribution comes from them.
Environmental: near-complete water return by volume with zero liquid discharge; arsenic and uranium immobilised; acid drainage neutralised in the same operation, eliminating the separate lime-treatment step; ambient-temperature, renewable-compatible operation.
Strategic: every tonne of cobalt obtained from water lies outside the DRC export quota and outside Chinese refining capacity, addressing both chokepoints of the cathode supply chain simultaneously.
Platform basis: ARBOK-VC (Vacuum Cracking). Complementary solid spent-cell route: ARBOK-AVD (Arbok-AVD addresses the solid cell fraction, the vacuum phase-separation platform addresses the water). Co-recovery of copper from the same mine-water streams links directly to ARBOK-Copper-Waters. Multi-metal cascades on one water circuit relate this case to the other critical-materials cases on the same platform: ARBOK-Indium, ARBOK-Rhenium, ARBOK-Germanium-Gallium, ARBOK-Scandium-REE. Salt and ballast fractions separated by density connect to ARBOK-CRYSTALLIZER.
Tie-in points at site: existing acid-mine-drainage treatment circuit, copper solvent-extraction raffinate line, heap/dump leach collection, tailings water circuit, hydrometallurgical battery-recycler effluent.
Implementation sequence: assay of the target water stream → selection of the recovery and secondary-pass configuration → module sizing → installation on the existing water circuit → commissioning.
Modules are container-class and automated, requiring minimal dedicated staffing, and operate at ambient temperature and pressure conditions compatible with renewable power. Because the tie-in is to a stream the operator already pumps and already treats, installation does not interfere with the primary mining or recycling flowsheet.
Two commercial structures are offered: outright purchase, or a build-own-operate-maintain arrangement under which the operator commits no capital and pays against recovered product and avoided treatment cost.
TRL 9. The platform is industrially validated in commercial ARBOK applications and is deployed in container-class modules. The cobalt-specific step — concentration of Co²⁺ in the residual liquor with a secondary pass to product grade — runs on the same separation stage and requires no distinct chemical circuit.
Illustrative module-level model: one container-class module treating 200 m³/day ≈ 70,000 m³/year at the conservative design basis of 0.2 g/L Co. Prices: approximately $60/kg for cobalt (April 2026) and approximately $13,300/t for copper (LME, July 2026). Copper assumed present at 0.5 g/L, a conservative figure for copper-belt waters.
| Line | Basis | Contribution |
|---|---|---|
| Cobalt | 70,000 m³/year at 0.2 g/L → approximately 14 t/year at $60/kg | approximately $0.84M/year |
| Copper and nickel co-products | same stream, no additional feed cost (0.5 g/L Cu, $13,300/t) | approximately $0.45M/year |
| Recycled water | 70,000 m³/year at $1/m³ in a water-constrained mining region | approximately $0.07M/year |
| Avoided acid-drainage neutralisation | elimination of separate lime treatment at $1–3/m³ | approximately $0.10M/year |
| Total per module | | approximately $1.45M/year |
The cobalt line is approximately 58% of the total; the remaining 42% derives from streams the operator currently treats as cost, before accounting for the removal of arsenic and uranium liabilities.
Sensitivity. Feed concentration dominates all other variables. On a raffinate-grade feed of 1 g/L Co, the cobalt line alone rises to approximately 70 t/year and approximately $4.2M/year, and the co-product and water credits are unchanged — the economics improve by roughly a factor of five relative to the 0.2 g/L basis.
ARBOK-VC (Vacuum Cracking) · ARBOK-AVD · ARBOK-Copper-Waters · ARBOK-Indium · ARBOK-Rhenium · ARBOK-Germanium-Gallium · ARBOK-Scandium-REE · ARBOK-CRYSTALLIZER
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