Bio-Oxidation Pretreatment Process for Gold Extraction

The bio-oxidation pretreatment process is an environmentally friendly technology in the field of cyanide leaching pretreatment for gold extraction. Utilizing bacteria as the core oxidizing agent, it employs bacterial metabolism to oxidize and decompose sulfide and arsenide minerals that encapsulate gold in ore. This process liberates and exposes the gold, thereby enhancing gold recovery rates in subsequent cyanide leaching stages. This process, alongside oxidation roasting and hot-press oxidation, constitutes a fundamental processing technology for refractory gold ores. Leveraging its unique advantages, it has found application in specific scenarios.

The core strengths of the biological oxidation pretreatment process lie in environmental sustainability and cost efficiency. Compared to traditional roasting and hot-press oxidation methods, it requires lower investment with reduced initial equipment costs. It operates under relatively benign conditions, eliminating the need for high-temperature or high-pressure environments. The mild reaction process generates minimal pollutants such as harmful gases or wastewater, minimizing environmental impact and aligning with green mining development trends. Additionally, the simplified operational workflow, free from complex high-temperature/high-pressure controls, makes it suitable for small-scale mines or scenarios with stringent environmental requirements.

Despite these advantages, the bio-oxidation pretreatment process faces notable limitations that restrict its widespread adoption. First, the process demands extremely strict operational control conditions. Bacterial growth and metabolism require precise parameters for temperature, acidity, and slurry environment, resulting in limited flexibility and difficulty adapting to gold ores of varying compositions and properties. Second, the bacterial oxidation process exhibits selectivity and adaptability toward ores, making it unsuitable for all refractory gold ores. Furthermore, the low slurry concentration and prolonged oxidation reaction time restrict equipment throughput and reduce production efficiency. Additionally, the bacterial oxidation process increases pulp acidity, necessitating the use of corrosion-resistant materials for equipment construction or retrofitting, significantly raising operational and maintenance costs. Finally, similar to the hot-press oxidation process, resources such as arsenic and sulfur generated during this process are not effectively recovered, resulting in low resource utilization rates and persistent resource wastage issues.