Removal of mercury from cyanide leach solution using potassium amyl xanthate (PAX)

Abstract

The dissolution of mercury during cyanide leaching of Hg-containing gold ores and amalgamation tailings cause many environmental, health and operational problems. For this reason, mercury removal is a very important factor in the economic and environmental selection of the separation method. In this study, the use of potassium amyl xanthate (PAX) as precipitation reagents in the removal of mercury -cyanide complexes from synthetic solutions containing gold, silver and mercury has been investigated. The effect of reaction time, PAX:Hg molar ratio, pH, temperature, CN concentration and Cu concentration on the precip-itation of mercury was explored using synthetic mercury-cyanide solutions. Detailed characterization of pre-cipitates was performed using SEM EDS, XRD, FT-IR and particle size analysis. The results of this study illustrate that the precipitant dosage, initial concentrations, pH and temperature were quite effective on the Hg removal efficiency. The best Hg removal efficiency was obtained of 99.2 % at 44.7 degrees C. The Hg concentration was reduced from 10000 ppb to 72 ppb. As a result of characterization tests, it has been determined that highly stable metacinnabar (beta-HgS) is formed as precipitate. The findings showed that PAX is an effective reagent for the selective precipitation of mercury from cyanide leaching solutions.