COPPER LEACHING FROM LOW GRADE COPPER ORES USING ALTERNATIVE LEACHING SYSTEMS

In this project, low grade copper ore samples were obtained from two mining sites in the US, which were chalcopyrite-rich (sample A) and conichalcite-rich (sample B) ores, with copper grades of 0.6% and 0.4%, respectively. Leaching experiments involving bottle roll tests for 24 hours were conducted using various lixiviant systems, including methanesulfonic acid (MSA) and glycine as alternatives to sulfuric acid. The study tested oxidants such as ferric ion and hydrogen peroxide. Results indicated that for sample A, adding 1 g/L ferric ion to the sulfuric acid and MSA solution enhanced copper extraction from 20% to 36%, while higher ferric ion concentrations did not further improve recovery. Significant increases in copper recovery were achieved with H2O2 concentrations, exceeding 80% recovery at 10% H2O2. In contrast, sample B exhibited rapid copper dissolution kinetics, achieving maximum extraction in five hours, where around 60% was extracted in both sulfuric acid and MSA solution. The recovery slightly improved with the addition of ferric ion and H2O2. Glycine proved to be a weaker lixiviant for both samples with extractions of 36% and 4%, respectively.