Introduction
Placer gold is generally found in rivers, lakes, valley alluvial layers, etc. The beneficiation process mainly relies on gravity separation, which is widely used in the African market because of its simple operation, low investment, environmental protection and pollution-free.
Placer gold beneficiation process is mainly used in seaside placer, riverside placer or alluvial placer. The placer gold beneficiation process includes cracking, screening, desludging stage, separation operation, etc.
Main process of placer gold beneficiation
Screening & Classifying
Goal: Remove large pieces of waste rock and improve subsequent beneficiation efficiency.
Trommel Screen: Screen out large particles of waste rock, usually with a sieve hole of 5-10mm.
Vibrating Screen: Further screen gold sand of different particle sizes to improve recovery rate.
Gold Separation
Goal: To use the high specific gravity of gold (specific gravity of about 19.3) for gravity separation.
Main methods
| Method | Scope of application | Advantages |
| Sluice Box | Suitable for small miners | Low investment, simple operation |
| Jig Machine | Suitable for medium-sized gold particles (0.2-5mm) | Strong processing capacity, high recovery rate |
| Centrifugal Concentrator | Suitable for fine gold (0.02-0.5mm) | Recovery rate up to 90%+, suitable for fine gold recovery |
| Shaking Table | Selected heavy gold minerals, suitable for fine gold (0.037-2mm) | High sorting accuracy, can recover extremely fine particles |
Gold refining
Amalgamation: Use mercury to recover gold (but the environmental protection requirements are strict, and it is not recommended to promote).
Gravity Refining: Smelting the selected gold concentrate.
Electrolytic Refining: Large-scale gold ore purification process, suitable for industrial production.
Key points of placer gold beneficiation
Adequate water resources: Most of the placer gold beneficiation relies on hydraulic power, and it is necessary to ensure a stable water supply.
Reasonable equipment matching: roughing (chute, jig) + fine selection (centrifuge, shaking table) to improve gold recovery rate.
Reduce losses: Reasonably control the screening and chute slope to avoid the loss of fine gold.
Environmental protection requirements: Avoid the use of mercury, promote gravity separation technology, and reduce pollution.
