Acid Leaching
Acid:ore ratios and recovery yields for hydrometallurgy.
How to use this tool
Estimate how much acid it takes to leach a target metal out of an ore, and how much concentrated product acid you'll need to buy to get there. A first-pass planning figure before bench testing.
What to enter
- Leach system: the metal-mineral + acid pairing (e.g. CuO + H₂SO₄). This fixes the reaction stoichiometry.
- Ore mass: kilograms of ore to be treated.
- Metal grade: percent of the ore that is the target metal.
- Target recovery: percent of that metal you expect to actually dissolve.
- Acid excess: percent above the stoichiometric minimum, to allow for gangue and kinetics.
- Acid concentration: % w/w of the acid product you'll buy, to convert the pure-acid figure into product mass.
Reading the result
The headline is acid required (with excess) on a pure-acid basis, alongside the same demand expressed as the concentrated product you'd order, the mass of metal leached, and the stoichiometric minimum. Real ores consume extra acid on gangue minerals, treat this as a lower bound and confirm by bench test.
Worked example
1000 kg ore at 25% Cu and 90% recovery via CuO + H₂SO₄ leaches 225 kg Cu, needing ≈ 347 kg pure H₂SO₄ (≈ 417 kg with 20% excess, ≈ 434 kg as 96% acid).
Acid demand
The headline is acid on a pure-acid basis with your excess already included; below it the same demand is restated as the concentrated product you'd actually buy, plus the metal leached and the stoichiometric minimum. Real ores also consume acid on gangue minerals, so treat every figure as a lower bound and confirm by bench test before scaling.
Stoichiometric acid demand
For a metal oxide/carbonate dissolving in acid, the acid required follows the balanced reaction (e.g. CuO + H₂SO₄ → CuSO₄ + H₂O; 1 mol acid per mol metal for divalent oxides in sulfuric). This tool computes the theoretical acid mass for a given ore mass, metal grade and recovery, then adds a practical excess. Real leaching also consumes acid on gangue, bench-test before scaling.
Sources
- Hydrometallurgy texts (Habashi); reaction stoichiometry.