Pressure Cyanidation

Abstract

Although the effect of high oxygen pressure at elevated slurry temperatures on gold recoveries was previously investigated, the sole effect of the pressure at ambient temperature on cyanide leaching with the presence of nearly enough oxygen for the cyanide reactions to occur has not been found to be studied.This research work carried out with the objective of investigating the effect of pressure on the recovery of gold from an oxide gold ore and flotation tailings sample the during cyanide leaching process at room temperature. Pressure cyanidation experiments were run in a laboratory scale autoclave under different oxygen and nitrogen gas pressures and pH conditions. Results showed that, gold recoveries of the pressure cyanidation experiments conducted at room temperature were as much as two times higher than the atmospheric leaching conditions for the same leaching times. Oxide ore samples leached at ninety (90) psi nitrogen pressure had thirty-six percent (36%) better recovery, carbon in leach (CIL) feed (flotation tailings samples) leached at the same nitrogen pressure had seventy-seven percent (77%) better recovery compared to atmospheric leaching conditions at the same period of leaching time.