Extraction of gold from gravity-flotation concentrates via surfactant and oxidation reagents

Abstract

Abstract The focus of this work is to establish a hydrometallurgical technique for efficiently extracting gold from the aggregated gold-rich concentrate produced by a mining facility in one of Kazakhstan's deposits. The leaching techniques applied to gravity-flotation concentrates include hydrometallurgical gold recovery processes using the surfactant sulfanol and the oxidizing reagent trichloroisocyanuric acid (TCCA). The findings indicate the effectiveness of leaching gravity-flotation concentrates with oxidizing (accelerating) reagents. Gold extraction through cyanidation of the blended concentrate, ground to 89–90% passing 10 µm with TCCA, averaged 84.0%, compared to 65.76–67.8% with conventional direct cyanidation. The advantage of employing chlorine-based oxidants, such as TCCA, in hydrometallurgical processing lies in their applicability in both acidic and alkaline environments, whereas other oxidants are constrained by specific technological conditions. Technical trichloroisocyanuric acid (TCCA), a chlorine-containing oxidizer with the formula C3O3N3Cl3, containing 25–30% calcium hypochlorite as an impurity, proved to be the most effective in enhancing gold leaching techniques. Apart from improving the efficiency of the leaching process, the use of TCCA is economically viable. The wholesale cost of technical TCCA is ~ $700 per ton, significantly lower than many other oxidants commonly used in gold hydrometallurgical production. With its higher active chlorine content, TCCA consumption per ton of gold-bearing raw material is nearly half that of hypochlorite or peroxide. Additionally, TCCA use minimizes the formation of unwanted impurities in both the pulp and the productive solution.

Keywords

• Hydrometallurgy of gold
• Gold-containing concentrate
• Oxidation
• Trichloroisocyanuric acid