VAT LEACHING OPTIMIZATION IN GOLD PROCESSINGVAT optimization in gold processing refers to improving the efficiency of VAT leaching, a method used to extract gold from ore using cyanide solution in large, sealed tanks (vats). It’s commonly used for low to medium grade ores.
Key Areas of VAT Optimization in Gold Processing
❖ Ore Preparation:
- Crush ore to optimal size for leaching (usually <10mm).
- Ensure uniform particle size to allow better cyanide penetration.
❖ Leaching Efficiency:
- Control cyanide concentration (typically 0.05–0.1% NaCN).
- Optimize pH (10.5–11.5) to prevent cyanide loss and reduce toxic gas formation.
- Use proper aeration (oxygen improves gold dissolution).
❖ Retention Time:
- Adjust how long ore stays in the vat to balance recovery and throughput.
- Over-leaching wastes cyanide; under-leaching reduces recovery.
❖ Solution Flow:
- Improve solution distribution and drainage.
- Prevent channelling or dead zones in the vat.
❖ Recovery & Detoxification:
- Optimize gold recovery from pregnant solution using zinc precipitation or activated carbon.
- Treat tailings to detoxify cyanide before disposal (e.g., SO2/air, peroxide methods).
❖ Water & Reagent Recycling:
- Reuse cyanide solution and process water to cut costs.
- Monitor build-up of impurities in recycled solution.
Benefits of VAT Optimization
- Higher gold recovery rates.
- Lower reagent (cyanide, lime) consumption.
- Reduced environmental impact.
- Lower operating costs.
- Improved safety and process control.
NOTE
Optimization depends on ore type, mineralogy and site specific conditions.
Also, Pilot testing and lab analysis are often used before scaling improvements
