Alluvial gold deposits are gold-bearing mixed sand deposits formed by long-term weathering of vein gold deposits. Due to long-term river water transportation, three natural types of residual placer gold deposits, slope deposit placer gold deposits and alluvial placer gold deposits have naturally formed. Among them, alluvial placer gold mines have the most industrial mining value, and can be subdivided into shore alluvial gold mines and river valley alluvial gold mines. River beach placer gold mines and river bed placer gold mines.
Placer Gold Ore Beneficiation Process
According to the nature of the placer gold ore, the beneficiation process of the placer gold ore can be divided into the crushing and screening of the alluvial gold ore, the gravity beneficiation of the alluvial gold ore, and the selection of the placer gold ore.
Crushing and Screening Equipment
Placer gold mines can be divided into easy (mud content <10%), medium (mud content 10%-15%), difficult (15%-30%) and difficult degree of beneficiation according to different mud content. The most difficult (mud content>30%). At the same time, it contains different impurities such as boulders (+100-200mm), pebbles (-100+25mm), gravel (-25+0.2mm) and sand mud (-01~0.2mm). The disintegration and screening equipment should be reasonably configured according to the specific conditions of the alluvial gold mine. Commonly used crushing and screening equipment are: cylinder washing machine, trough washing machine, drum screen, vibrating screen.
Gravity Beneficiation Equipment for Placer Gold Mine
After disintegrating, washing and grading the alluvial gold ore, the granular placer gold ore can be recovered with sluice box, jig, spiral concentrator, shaker and gravity separation equipment of different structures.
Use a Sluice Box to Extract Gold from a Placer Gold Mine
The sluice box is the simplest gravity beneficiation equipment for a alluvial gold mine. The sluice box has 4 advantages:
- Large processing capacity.
- The enrichment ratio is high.
- Wide range of particle size.
- No electricity is needed, and the production cost is low.
The effect of the sluice box on the beneficiation of placer gold ore is often related to the following conditions:
- 1 meter long sluice box width, or processing capacity of 1 square meter collection area.
- The inclination of the sluice box.
- Slurry concentration and flow rate.
- Mineral grain size and shape of placer gold ore.
- The content of heavy sand.
- Number of rinses.
When the sluice box extracts gold from the placer gold mine, its length is of little significance, because the specific gravity difference between gold and gangue is greater than 16, and most of the gold is recovered at the head of the sluice box. For coarse-grained gold, the length of its filling in the sluice box is 15-20 meters, sometimes as long as 100 meters. For fine-grained gold, the length of its filling in the sluice box is greater than 5 to 6 meters.
Use a Jig to Extract Gold from a Alluvial Gold Mine
The use of jigs to extract gold from placer gold mines has the characteristics of large processing capacity and high recovery rate, and the recovery rate of gold in fine-grained alluvial gold mines can reach 90-94%. The jig machine’s gold ore selection index is often closely related to the water consumption, the type and shape of the ore, the particle size and shape of the placer gold ore, and the mud content of the alluvial gold ore.
Use a Shaker to Extract Gold from a Placer Gold Mine
The processing capacity of the shaker is small, but the concentrated ore enrichment ratio it obtains is high. It is suitable for the beneficiation of placer gold mines, and it is often used in conjunction with jigs, sluice boxes and spiral concentrators. The recovery rate of the shaker selection operation can reach 98-99%.
There are two types of shakers: coarse sand shakers and mud shakers. For coarse-grained alluvial gold mines, the recovery rate of gold from the shaker is relatively high.
Gongyi Forui Machinery Factory is a professional manufacturer of beneficiation equipment. Our factory has designed alluvial gold beneficiation technology and equipment configuration for multiple alluvial gold beneficiation plants and has a complete test platform. It can conduct beneficiation tests and design processes for customers free of charge.
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