Optimizing leaching parameters can increase recovery by 5–15% and reduce reagent costs by 10–30%.
1. Grinding Fineness Test
Proper grinding liberates gold particles, essential for cyanide or non-cyanide leaching. Over-grinding increases costs and soluble impurities.
Key finding: Every 10% increase in fineness improves recovery by approx. 3%.
2. Pre-treatment Reagent Selection
Compare calcium peroxide, sodium hypochlorite, sodium peroxide, hydrogen peroxide, citric acid, lead nitrate, vs. no pre-treatment.
Key finding: Hydrogen peroxide + lead nitrate combination increases recovery by 8%.
3. Protective Alkali (Lime) Dosage Test
Maintains cyanide or alternative lixiviant stability. Lime is commonly used.
Recommendations:
- Optimal pH: 10.0–10.5
- Lime addition: 0.5–3 kg/t ore
- Excess alkali reduces recovery by up to 5%
4. Lixiviant Dosage Test
Higher dosage improves recovery up to a point, beyond which costs increase with little gain.
Recommended parameters:
- Low-grade ore: 0.01–0.03% NaCN
- High-grade ore: 0.05–0.1% NaCN
5. Leaching Time Test
Longer time increases recovery but allows impurity accumulation.
Suggested schedule:
- Pre-leach: 4–8 hours
- Main leach: 12–24 hours
- Adsorption: 4–6 hours
Note: Beyond 24 hours, impurity accumulation increases by 15%.
Post time: Apr-13-2026
