Gold Processing Solution

The gold ore challenge

No two gold deposits behave the same way. The single biggest decision is whether your ore is free-milling or refractory, because that sets the entire flowsheet. Free-milling ore releases gold to cyanide once it is ground; refractory ore locks gold inside sulfides or carbon, so leaching alone leaves money in the tailings. Xinhai begins every project with a bench and pilot test at its 3,000 m² mineral test center to confirm gold deportment, grind size and reagent demand before any equipment is sized.

The recommended flowsheet

For most free-milling ores we combine gravity and cyanidation. After three-stage crushing and closed-circuit grinding to roughly 75-80% passing 200 mesh, a gold centrifugal concentrator and shaking table recover coarse free gold first. This gravity stage reduces the gold that must be dissolved downstream, lowering cyanide and carbon consumption. The remaining gold is leached in agitation leaching tanks using a carbon-in-leach or carbon-in-pulp circuit.

CIL leaches and adsorbs gold simultaneously and suits ores with preg-robbing tendencies or moderate grades; CIP adsorbs after leaching and can be more economical on clean, fast-leaching ore. Our turnkey CIP gold processing plant packages tanks, screens, carbon transfer and the full reagent system. Whichever route fits, see our breakdown of CIL vs CIP vs heap leach to understand the trade-offs.

Reagent regime and residence time are set by testwork. A typical cyanidation circuit holds the pulp at 40-45% solids and pH 10.5-11 with lime, dosing sodium cyanide to a residual concentration that the leach kinetics demand, over a residence time of roughly 24-36 hours across a tank train. Activated carbon at around 10-25 g/L scrubs the dissolved gold from solution as it forms. Right-sizing cyanide and carbon is the largest single lever on operating cost, which is why we measure it rather than assume it.

Refractory ore

When gold is sulfide-locked, carbonaceous or arsenical, a flotation step on a flotation circuit concentrates the gold-bearing sulfides, which are then oxidized (roasting, pressure or bacterial oxidation) before cyanidation. Skipping pretreatment on refractory ore is the most common cause of poor recovery.

Recovering the gold and closing the circuit

Loaded carbon passes to a gold elution and electrowinning system, where it is stripped at elevated temperature and pressure, gold is electrowon onto cathodes, and barren carbon is regenerated and returned. Thickeners and filters recover process water and dewater tailings for safe storage. Browse the full gold extraction equipment range to see how the units fit together.

Typical recoveries are 90-96% on free-milling ore and 80-90% on refractory ore after flotation and pretreatment, always framed against your specific testwork rather than promised in advance. For a representative build, review our 6,000 t/d gold CIL plant in Guinea. As an EPC+M+O contractor, Xinhai delivers the engineering, in-house manufacturing, construction and operator training as a single source. To size a plant to your deposit, contact us for an ore test.