Copper recovery from a leach residue: CCD washing + hydroxide precipitation — a BRINE process flowsheet
A leach residue leaves a heap/tank-leach circuit as a slurry — insoluble gangue solids carrying entrained copper-sulfate pregnant liquor that would be lost to tailings if simply thickened. A counter-current-decantation (CCD) wash train recovers it: the residue is washed with clean water flowing counter-current to the solids across a chain of thickeners, so the dissolved copper is displaced into a pregnant-liquor overflow while the washed solids go to tailings. The new ccd_washer unit op models the whole train in one block via the classic counter-current washing equation f = (R-1)/(R^(N+1)-1) (Perry's §18; Coulson & Richardson Vol. 2): five stages at a wash ratio near 4 recover ~99.9% of the dissolved copper, leaving only ~0.08% with the tailings. The pregnant liquor is then dosed to pH 8, where the copper drops as Cu(OH)2 sludge (the precipitator op on the CRC-cited solubility-product chemistry), leaving a barren raffinate for recycle.
Modeling assumptions & limitations
- 1Ideal equilibrium washing (perfect mixing + constant underflow at every stage; no settling-flux / thickener-area sizing, wash-water short-circuiting or solute adsorption on the solids) and equilibrium Ksp precipitation at a dosed pH (B-dot activity, a dilute-liquor solution-volume estimate) — a screening process-design starting point, the metallurgical-balance level, not a certified settling/reagent deliverable.
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- Rigorous BRINE thermodynamics, solved by the same engine every simulation runs on.
- 2 unit operations modeled: CCD, Precip.
- Focus areas: Hydrometallurgy, Copper, CCD washing, Counter-current decantation, Precipitation.
- Verified fast convergence — a real, measured solve time, not an estimate.
- Thermodynamics
- BRINE
- Components
- water, cu, so4, gangue
- Unit operations
- CCDPrecip
Opens in a new tab, loaded straight into the app — no setup.
Read the step-by-step guideReproduce this exact result from Python — the real client.get_example() → run_and_wait() path, not a mockup.
from flowsim.sdk import FlowSimClient
client = FlowSimClient()
example = client.get_example("copper-ccd-wash-recovery")
sim = client.create_simulation(example["title"], example["flowsheet"])
result = client.run_and_wait(sim["id"])
print(result["status"]) # "converged"
streams = client.streams(sim["id"])Related models
Acid-mine-drainage neutralization: staged lime precipitation
Acidic, metal-laden mine water (dissolved ferric iron, aluminium, nickel and zinc over a sulfate background) is cleaned in a two-stage lime-neutralization circuit — the classic hydrometallurgy / water-treatment precipitation train. Stage 1 doses to pH 4.5, where ferric iron (Fe(OH)3, pKsp 38.6) and aluminium (Al(OH)3, pKsp 33.0) drop out as a sludge while the base metals stay dissolved; stage 2 raises the liquor to pH 9.5, where nickel (Ni(OH)2) and zinc (Zn(OH)2) precipitate, leaving a clarified effluent. Both stages are the new precipitator unit op wrapping the codebase's CRC-cited metal-hydroxide solubility-product chemistry (thermo/electrolytes.hydroxide_precipitation) — dose to a pH setpoint, read off what drops out — the same selective-precipitation workflow a real neutralization plant runs.
Cobalt/nickel solvent extraction (D2EHPA)
A laterite leach liquor (Co/Ni/Mg in dilute sulfate solution) meets a D2EHPA-in-kerosene organic phase across a 20-stage countercurrent extraction circuit run at pH 5.2 — the real industrial operating window (e.g. Bulong, Murrin Murrin, Western Australia) that exploits the ~1 pH-unit gap between Co and Ni's D2EHPA extraction isotherms: Co extracts into the organic while Ni (and Mg gangue) are rejected to the raffinate. The loaded organic then meets fresh dilute-acid strip liquor across a 10-stage strip circuit at pH 1.0 (well below Co's isotherm), reversing the equilibrium to recover a concentrated cobalt strip liquor and regenerate barren organic. Real pH-isotherm chemistry throughout, not a fitted shortcut K_D.
Battery black-mass recycling: leach -> SX -> BPED -> LiOH crystallization
Spent-battery black mass (an NMC111-like LiNi1/3Mn1/3Co1/3O2 lump, sulfuric acid-leached at a screening-level yield/stoichiometry — see the stated scope) dissolves into a pregnant leach solution carrying Li/Co/Ni/Mn. A 15-stage D2EHPA solvent-extraction circuit (the same real pH-isotherm chemistry the co-ni-solvent-extraction example uses, operated at pH 7.5 — above every curated Co/Ni/Mn pH50 — so all three transition metals extract into the kerosene organic phase while Li, which has no curated D2EHPA isotherm, stays in the aqueous raffinate untouched) purifies the liquor before it ever reaches the lithium-recovery chemistry. A Faraday's-law bipolar-membrane electrodialysis (BPED) cell (the same real electrochemistry as the direct-lithium-extraction example, sized up for this liquor's larger Li flow) converts Li+ to LiOH, which an MSMPR crystallizer takes to battery-grade LiOH solid. Every step reuses an already-real, independently-tested unit op (,,,) chained into the one train none of them had been assembled into before.
Battery cobalt recovery: leach, neutralize, D2EHPA Mn SX, Cyanex 272 Co SX, electrowinning
Spent NMC111 black mass is leached in sulfuric acid with the acid consumption tracked (lithium as Li₂SO₄, each transition metal as its sulfate), so the pregnant leach solution carries the residual free acid a real leach leaves. A neutralizer then titrates that liquor with 20 wt% caustic to pH 4.0 on the aqueous speciation: the caustic dose is solved, not assumed, and the heat of neutralization (55.8 kJ per mole of acid neutralized) warms the liquor; the caustic header is the supply, and what the titration does not take is returned. Two solvent-extraction circuits on the pH-isotherm chemistry follow, the common NMC arrangement: D2EHPA at pH 4.0 takes manganese into the organic while cobalt and nickel stay behind, and Cyanex 272 at pH 5.0 then takes cobalt and rejects nickel and lithium to the raffinate. The Cyanex 272 isotherms are one published measurement (Liu et al., Metals 11 (2021) 401: 0.4 M in ShellSol D70, 40 C, sulfate; pH50 cobalt 4.15, nickel 6.06), and the 1.9 pH-unit gap between them is why the cobalt organic carries about 0.6% of the nickel, against about 3% with D2EHPA at the same cobalt recovery. The loaded cobalt organic is stripped into a dilute sulfuric strip liquor, and that advance electrolyte goes to cobalt electrowinning: Faraday's law at a 90% current efficiency, 90% of the cobalt plated as cathode cobalt, the anode's oxygen and the 10% of the charge that evolves hydrogen reported as cell gas, and one mole of sulfuric acid regenerated per mole of cobalt plated.
Produced-water scale removal: precipitation + thickener dewatering
Oilfield produced water carries the classic mineral-scale ions — barium and strontium against sulfate (barite BaSO₄ / celestine SrSO₄, the notorious hard sulfate scales that plug tubing and need milling to remove) plus calcium against carbonate and sulfate (calcite / gypsum). A precipitation stage throws every over-saturated scale mineral at once — the precipitator unit op keyed on its CRC-cited solubility-product table, with each mineral removing BOTH its metal cation and its anion from the water — and a gravity thickener then dewaters the slurry into a dense underflow sludge and a clarified overflow. The barium (the worst offender) comes out essentially completely as barite.
Cooling-tower blowdown treatment — lime dosing and what it will not remove
The stream cooling-water-utility-circuit sends to effluent, treated. Concentrated blowdown (4 cycles on a hard makeup, plus zinc from a corrosion-inhibitor programme) is dosed with lime to pH 10.5, and the metals that can drop as hydroxides do. A separate flowsheet on purpose. This runs on the brine electrolyte package with the ions as real components; the cooling loop runs on steam with water alone. Carrying hardness as flowsheet components changes the thermodynamics of every stream it touches, so the loop keeps its water model and the treatment plant gets the one it needs — which is also how the two are engineered and operated in a real plant. The result is mostly a lesson in what hydroxide precipitation cannot do. Magnesium goes from 2100 to 10 ppm-equivalent (99.5% removed) and zinc is essentially complete, leaving a sludge that is 91% Mg(OH)2 and 9% Zn(OH)2. Calcium does not move at all — it enters at 0.0042 mole fraction and leaves at 0.0042. That is correct, not a failure to converge: Ca(OH)2 is far too soluble to precipitate at this pH, and removing calcium needs carbonate — soda-ash softening — which is a different reagent and a different chemistry from the one dosed here. A treatment report claiming lime alone softens a blowdown is describing something this model will not reproduce. Sulfate likewise passes straight through: it leaves with the clarified water, which is why blowdown salinity is a discharge-consent question rather than something a precipitation stage fixes. Bounded: equilibrium Ksp at a dosed pH (see), with no self-consistent pH from the metal hydrolysis itself, a dilute-liquor volume estimate, and B-dot activities. The lime reagent is a circuit condition rather than a tracked feed, and the gypsum a real lime circuit throws is not modelled. Sludge dewatering is absent deliberately: the precipitator's solid outlet carries no entrained water, so a thickener placed after it would be splitting a dry stream and reporting a 'recovered water' that is 100% hydroxide.