gold ore gravity separation process

The reselection method is a process that utilizes the differences in mineral density and particle size, and utilizes the combined action of medium fluid and various hydraulic forces to create suitable loose layering and separation conditions, in order to obtain products with different densities or particle sizes. Due to the presence of a certain amount of coarse free gold (+0.1mm) in most gold bearing ores, it is difficult to recover them through flotation and hydrometallurgy. Therefore, the reselection method is often used to separate placer gold and vein gold, and to recover coarse-grained gold from monomer dissociation before and after flotation and leaching. Generally, the minimum particle size of gold that can be recovered by the reselection method is 0.01mm.

Gold gravity concentration process flow

  • 1. Ore preparation: Crush and screen the raw ore to remove large blocks and impurities, and divide it into different particle size grades.
  • 2. Gravity beneficiation:
  • The main equipment for jigging gold selection is a jigger, which mixes mineral particles with different densities and stratifies them according to their densities in a vertically moving variable speed medium flow. Minerals with lower densities are located in the upper layer, while minerals with higher densities are located in the lower layer. By utilizing the action of machinery and water flow, the layered materials are discharged separately. Jigging gold separation is suitable for separating coarse-grained mineral particles (mineral raw materials of any particle size except for fine materials). The particle size range of its metal minerals is 0.074-50mm. For placer gold beneficiation, the lower particle size can reach 0.04mm under the premise of a specific gravity difference of ≥ 1.25 and the dissociation of ore monomers. The process operation is simple, the equipment processing capacity is large, and the application effect in coarse gold beneficiation is very good.
  • The main equipment for shaking table gold selection is a shaking table, which is a selection equipment in a horizontal medium flow. It uses a transmission mechanism to drive the bed surface to perform longitudinal reciprocating motion, perform flushing and differential motion on the bed surface. During the reciprocating motion, the ore particles undergo a layering effect perpendicular to the bed surface and a separation effect parallel to the bed surface, allowing materials of different particle sizes to be discharged from different sections of the bed surface and achieve sorting.
    Shake bed gold selection is suitable for processing minerals with finer particle sizes, and can be divided into three types based on the different particle sizes of the ore: coarse sand bed, fine sand bed, and mud bed. Among them, coarse sand beds are suitable for sorting mineral particles with a particle size between 0.5 and 2.0mm, fine sand beds are suitable for processing mineral particles with a particle size range of 0.074 to 0.5mm, and mud beds are suitable for processing mineral particles with a particle size range of 0.037 to 0.074mm.
  • The main equipment for gold selection in the chute is the spiral chute, which is a device that uses inclined water flow for sorting. The material uses the combined force of water flow, mineral gravity, and friction between the ore particles and the bottom of the chute to settle the ore particles in different areas of the chute according to their specific gravity. The ore particles with smaller specific gravity are carried away by the water flow, leaving behind larger ones, completing the sorting process. Spiral chutes are suitable for processing fine-grained materials with low mud content, with a particle size range of 0.03-0.6mm. They have a simple structure, large processing capacity, and low overall cost.
  • 3. Concentrate processing: Further processing of the re selected gold concentrate, such as washing, filtering, and drying, is carried out to remove impurities and improve the purity of gold.
  • 4. Tailings treatment:The re selected tailings are treated to reduce their impact on the environment. Tailings can be treated chemically to remove heavy metals and other harmful substances.

Combining gravity beneficiation with other processes

  • Gravity beneficiation cyanide combined process:This gold ore beneficiation process is suitable for processing quartz vein gold containing oxidized ores. The raw ore is first subjected to gravity separation, and the concentrate obtained from gravity separation is subjected to cyanide gold extraction; Alternatively, the raw ore can be directly subjected to gravity separation, and the tailings and graded ore can be cyanide treated separately.
  • Gravity flotation combined process:This gold ore beneficiation process first uses gravity separation to recover coarse-grained gold from the ore, and gravity separation tailings are used for flotation. The gold ore beneficiation process flow is suitable for processing single flotation treated ores, gold containing oxidized ores, and ores associated with free gold, and can achieve higher recovery rates than a single flotation process.
  • Flotation gravity separation combined process:The beneficiation process of this gold mine is mainly based on flotation, which is suitable for ores with close symbiosis between gold and sulfides and can only be recovered by smelting. It is also suitable for gold bearing quartz vein ores with uneven coarse accumulation and distribution, and can achieve higher recovery rates than single flotation.
    Taking the ore dressing process of rock gold ore as an example, in a closed circuit grinding system, coarse-grained gold is easily enriched in the circulating material or embedded in the mill liner (or medium), causing gold loss. Moreover, gold particles have great toughness and are not easy to grind during the grinding process. The cyanide leaching process belongs to the diffusion control process, and this part of the gold dissolves slowly, which can easily cause incomplete leaching and remain in the cyanide tailings. Therefore, in the grinding process, most of the coarse gold particles are pre recovered using the gravity separation method.
    For the gold ore re selection method, placer gold mines generally use the re selection method to separate gold from heavy sand minerals; And vein gold mines often use combined beneficiation processes such as flotation, gravity separation, and cyanide, and try to use stage grinding and stage separation processes as much as possible, implementing the principle of early recovery and timely recovery of coarse gold.
    Regardless of the type of gold beneficiation process, in order to select gold from gold ore more reasonably, economically, and environmentally friendly, it is necessary to first conduct beneficiation tests, comprehensively analyze the properties of the ore, and obtain scientific beneficiation test reports to determine which gold beneficiation process method to use. Then, after comprehensively considering the actual situation of the gold beneficiation plant, investment and other factors, the beneficiation plan should be determined to achieve the ideal return on investment.
  • Gold ore resources are extremely precious, and in order to select ores more reasonably, the gold ore beneficiation process is crucial. To select gold from gold ore in a more economical and environmentally friendly way, it is necessary to first conduct beneficiation tests, comprehensively analyze the properties of the ore, and obtain a scientific beneficiation test report to determine which gold ore beneficiation process to use. After considering the actual situation of the gold ore beneficiation plant, investment and other factors, the beneficiation plan should be determined to achieve the ideal investment return rate.

Typical beneficiation plant

Hanihe Gold Mine Dressing Plant

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