Thermal Pressure Oxidation Pretreatment for Cyanide Gold Leaching

Among pretreatment technologies for cyanide leaching gold extraction, thermal pressure oxidation pretreatment is a highly targeted and efficient technique primarily used for processing refractory gold ores. It achieves gold liberation by decomposing the gangue minerals encapsulating gold through oxidation reactions under high-temperature, high-pressure conditions. This process stands alongside oxidation roasting as a fundamental processing technology for refractory gold ores. Based on the pH of the reaction system, it can be categorized into acidic hot-press oxidation and alkaline hot-press oxidation, with significant differences in their applicable scenarios and performance outcomes.

The alkaline hot-press oxidation process has a relatively narrow scope of application, being suitable only for refractory gold ores with high carbonate content and low sulfide content (below 20%). When treating such ores, this process effectively decomposes associated minerals without generating substantial harmful impurities. However, when applied to high-sulfur, high-arsenic gold concentrates, it exhibits significant drawbacks: the reaction readily produces large amounts of sulfates. These sulfates complicate slurry solid-liquid separation, increasing subsequent processing difficulty. Additionally, the process consumes substantial materials and incurs relatively high treatment costs, limiting its applicability in high-sulfur, high-arsenic gold ore processing.

The acid hot-press oxidation process addresses the shortcomings of alkaline methods in treating high-sulfur, high-arsenic ores. Its primary advantage lies in achieving higher gold recovery rates. It effectively decomposes gangue minerals in high-sulfur, high-arsenic gold concentrates, fully liberates gold particles, and significantly enhances the efficiency of subsequent cyanide leaching. However, this process also has significant limitations: it demands extremely high levels of operational and maintenance expertise, requiring specialized technical personnel for oversight; it involves substantial equipment investment and high initial construction costs; and energy consumption and chemical usage during production keep operating costs elevated. Furthermore, resources like arsenic and sulfur generated during the process are not effectively recovered, leading to resource waste and low resource utilization rates. These factors collectively limit its widespread adoption.