Gold beneficiation plants employ a series of processes to extract and refine gold from ore, with the flowsheet tailored to the specific characteristics of the deposit. The typical flowsheet begins with crushing and grinding to liberate gold particles from the host rock. Primary crushing reduces large ore fragments, followed by secondary and tertiary crushing to achieve finer particle sizes. The ground ore is then subjected to gravity separation, which exploits the high density of gold to concentrate it using equipment like jigs, spirals, or shaking tables.
For ores with fine-grained gold, cyanidation is often employed. The ground ore is mixed with a dilute cyanide solution in leaching tanks, where gold dissolves into the solution. Activated carbon is then used to adsorb the gold from the pregnant solution in a process called carbon-in-pulp (CIP) or carbon-in-leach (CIL). The loaded carbon undergoes elution to strip the gold, which is subsequently electrowon or precipitated to produce doré bars.
Flotation may be incorporated for sulfide-associated gold ores. Here, reagents are added to make gold-bearing sulfides hydrophobic, allowing them to attach to air bubbles and float to the surface. The concentrate is then reground and subjected to further processing, such as pressure oxidation or roasting, to liberate encapsulated gold before cyanidation.
Refractory ores, where gold is locked within sulfide minerals or organic carbon, require pretreatment like bio-oxidation or autoclaving to break down the host matrix. Tailings management is critical, with detoxification of cyanide residues and proper storage in engineered facilities to mitigate environmental risks.
The flowsheet’s design hinges on ore mineralogy, grade, and economic considerations. Advanced technologies like sensor-based sorting or modular plants are increasingly adopted for efficiency. Each stage is optimized to maximize recovery while minimizing costs and environmental impact.