Chalcopyrite Leaching with Hydrogen Peroxide in Formic Acid Medium

Abstract

This study is concerned with the leaching process of copper with hydrogen peroxide (H2O2) and formic acid (HCOOH) from the Kure chalcopyrite concentrate. All experiments were carried out in a leaching system equipped with an adjustable temperature shaker under atmospheric pressure. The needed oxygen was provided by H2O2 decomposition to achieve the oxidizing leaching medium. The parameters affecting leaching process, H2O2 concentration, HCOOH concentration, sulfuric acid (H2SO4) concentration, leaching time, liquid/solid ratio and stirring speed, were studied. The optimum experimental conditions were determined as leaching temperature 40 degrees C, leaching time 120 min, H2O2 concentration 1.2 M, HCOOH concentration 3 M and stirring speed 500 rpm. It was observed that there was no positive effect of sulfuric acid (H2SO4) concentration on the metal extraction. In addition, the percentage of copper passing to solution was increased from 7.83 to 62.37% as a result of the liquid/solid ratio increasing from 2.0 to 100, respectively. Consequently, formic acid could be used as an alternative and organic leaching agent in the selective leaching of chalcopyrite and even for leaching processes of the other oxidized and sulfured ores containing precious metals. [GRAPHICS] .