Effect of Pretreatment on a Copper Concentrate with High Arsenic Content

Abstract

Chilean mining faces challenges associated with the depletion of oxidized copper ore and the environmental complexity of treating concentrates with high arsenic content. Given this, hydrometallurgy emerges as an alternative for the treatment of these concentrates. This research analyzes the interaction of sulfuric acid (0, 70, 140, and 210 kg/t), sodium chloride (0, 25, 50, and 100 kg/t), curing time (1, 5, 10, and 15 days), and temperature (25, 35, 50, and 75 °C) in the pretreatment of a copper concentrate with 35.57% total copper and 5.91% arsenic (enargite, 35.93%). In the pretreatment, a maximum copper extraction of 26.71% is achieved using 210 kg/t sulfuric acid at 50 °C over 15 days of curing. The experimental results are analyzed through an empirical model, where the interaction between sulfuric acid and curing time is identified as beneficial when the sulfuric acid addition is above 70 kg/t, leading to higher moisture content in the sample. In the absence of sulfuric acid, sodium chloride significantly influences the achievement of higher copper extractions. During curing at higher temperatures, the importance of maintaining a moisture level is emphasized to prevent solution evaporation and hinder diffusion through the particles, thereby ensuring reactivity in the sample.