An Analysis of Gold Extraction Processes for Arsenic-Bearing Gold Ore

As easily mined, near-surface gold resources gradually deplete, arsenic-bearing gold ores—which are difficult to process—have become the core resources for gold mining development. Gold–arsenic co-occurrence presents a typical challenge in gold ore beneficiation. Arsenic and sulphide minerals are closely intergrown with and mutually encapsulated by gold; this not only significantly lowers the grade of gold concentrate but also substantially hinders the liberation of free gold, directly leading to low gold recovery rates and severe waste of resources, thereby constraining mining productivity. In response to the challenges posed by the co-occurrence of gold and arsenic in ores, the industry has now established four categories of mature and highly efficient processing technologies capable of specifically addressing the bottlenecks in gold extraction from arsenic-bearing gold ores.

The flotation process for arsenic suppression and gold flotation is a commonly used preliminary separation technique for treating arsenic-bearing gold ores. The core of this process lies in the scientific combination of specialised mineral processing reagents. By precisely regulating the floatability of mineral surfaces, it effectively suppresses the flotation of harmful minerals such as arsenic and sulphur, thereby achieving efficient separation of gold from arsenic-sulphide minerals. This allows gold to be effectively concentrated in the tailings, laying a solid foundation for subsequent gold extraction operations, and is suitable for the pre-treatment of most conventional disseminated arsenic-bearing gold ores.

The oxidation roasting–cyanidation process is a traditional, well-established and highly efficient gold extraction method. Through high-temperature roasting with air or oxygen, the sulphide and arsenide encapsulating structures on the ore surface are thoroughly destroyed, fully exposing the encapsulated gold and completely resolving the issue of gold being obscured and difficult to leach. Following arsenic and sulphur removal via roasting, cyanide leaching is carried out, which significantly improves gold leaching recovery rates and ensures stable and reliable beneficiation performance, making it suitable for complex gold ores with high arsenic and sulphur content.

The bacterial oxidation–cyanidation method is a green biological pre-treatment process. Relying on the oxidative decomposition action of specialised functional bacteria, it breaks down sulphides and arsenides in the ore, gently achieving desulphurisation and arsenic removal whilst exposing gold particles. Compared to high-temperature roasting, this process operates under milder conditions and causes less pollution; the pre-treated slurry, when combined with cyanide gold extraction, can stably improve the overall gold recovery rate.

Non-cyanide leaching is currently the mainstream development direction for environmentally friendly gold extraction. By replacing traditional cyanides with non-toxic leaching agents such as thiosulphates and thiocyanates, this method ensures effective gold extraction whilst completely eliminating the risk of highly toxic cyanide pollution. It is safe, environmentally friendly and highly compliant, making it ideally suited to mining projects subject to strict environmental regulations.

As a mining technology service provider with three decades of deep expertise in the mineral processing industry, Xinhai Mining has carried out projects in over 100 countries and regions worldwide. For arsenic-bearing gold ores with varying embedding characteristics and arsenic content, we can tailor bespoke mineral processing solutions and complete sets of equipment to precisely address the challenges of separating gold and arsenic. This ensures that mining processes are optimally adapted, operations remain stable, and profitability is maximised, thereby facilitating the efficient and environmentally friendly development of difficult-to-process gold ore resources.