Cyanide Recovery from Barren Leach Solution

TECHNICAL SUMMARY

In gold processing operations, cyanide recovery from barren leach solution is critical to controlling operating costs and maintaining process efficiency. The presence of cyanide-soluble copper significantly increases cyanide consumption and interferes with gold recovery, leading to both economic and operational challenges. :contentReference[oaicite:0]{index=0}

This paper evaluates the application of the SART (Sulphidization-Acidification-Recycling-Thickening) process combined with AVR (Acidification-Volatilization-Recycling) to address these challenges. The SART process breaks copper-cyanide complexes under acidic conditions and precipitates copper as a copper sulphide concentrate, allowing for its removal from solution.

Following copper removal, the AVR process is used to recover cyanide by volatilizing hydrogen cyanide gas and capturing it in a scrubber system for reuse in the leaching circuit. This enables regeneration of free cyanide and reduces the need for fresh reagent addition.

Bench-scale testing demonstrated that SART reaction kinetics are rapid, with copper precipitation occurring within minutes. The process operates effectively at controlled pH and oxidation-reduction conditions, producing a stable sulphide precipitate that can be filtered and handled as a saleable product.

The integration of SART and AVR into the existing process flow sheet provides a closed-loop approach to cyanide management, improving resource efficiency and reducing environmental impact. The approach also enhances downstream gold recovery by reducing copper interference in adsorption and electrowinning stages.