Effect of hypophosphite during the recovery of copper and cyanide from high concentration copper-cyanide wastewater by electrodeposition

The recovery of copper and cyanide from high concentration wastewater was conducted by electrodeposition with high basicity. The effect of hypophosphite dosage and temperature on recycling copper and cyanide from wastewater was investigated. The linear cyclic voltammetry, potentiostatic electrolysis and X-ray diffraction analysis were used to research the anodic reaction and precipitate phase, the mechanisms of cyanide decomposition and hypophosphite inhibition were also analyzed. The experiment of cyanide leaching of gold was done in residual liquid after electrolysis. The results indicate that the damage of cyanide is effectively suppressed by hypophosphite. The inhibitory effect is enhanced gradually with increasing temperature. The Cu²⁺ forming on the anode surface is the main reason to degrade cyanide. Hypophosphite restrains cyanide from degradation by preferential oxidation. The tail liquid has no effect on leaching of gold, and the copper-cyanide wastewater can be comprehensively recovered the valuable metals and cyanide by electrodeposition.