Gold ore processing technology plays a key role in the full utilization of gold ore resources, and the appropriate ore processing technology can improve the yield of gold mine and the quality of concentrate. According to the types and characteristics of ore, the dressing technology is also different. In the actual production, there are a variety of gold ore mineral processing methods. The following will introduce the mineral processing technology of gold mine from physical mineral processing, chemical leaching mineral processing, microbial ore processing and pretreatment technology of difficult gold mine selection.
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Gold ore gravity separation is a technique based on the density difference of gold mine from other gangue minerals. The available gold ore gravity separation equipment includes jig machine, shaker and spiral chute. When the spiral chute is used to recover the gold, the material will be carried down by the water flow through the chute, and the transverse lattice bar in the chute is used to recover the gold. Gravity separation can be used to recover gold from raw ore or for pre-enrichment of gold or gold-containing compounds. Then use other methods such as mercury mixing method or cyanide method for treatment. When the gold mine is treated by gravity separation method, it will be combined with flotation technology, and the selected concentrate will be recovered by mercury mixing method.
By flotation, the gold mines will rise together with the bubbles to the liquid surface and then fall off. Flotation methods can be used to treat base metal ores or sulfide ores, such as pyrite, chalcopyrite, etc. During gold ore flotation, if gold is associated with a certain product, it can be recovered in the subsequent sulfide concentrate smelting or refining of metal products, and it can also be recovered by cyanide roasting concentrate. When the gold mine is associated with the sulfide mineral, the flotation gold mine such as the sulfur mine collector can be used to recover the sulfur-containing concentrate. In the actual production, the single flotation index is not as good as the combined mineral processing process index. Flotation method is not very good to recover coarse grain free gold, this part of the gold can be recovered by mixed mercury method.
The process of extracting gold in the gold ore heap leaching is to break the low-grade ore to a certain extent and then build a heap, to spray the solution containing cyanide. The cyanide contacts with the useful part of the deposit, so that the gold is dissolved into the solution, for recovery. Backup leaching technology is generally used to treat low-grade gold mines. However, with the grade of gold ore getting lower and lower, the combined beneficiation method can not meet the requirements of full utilization of resources, so the process should be adjusted according to the nature of the ore to ensure the recovery rate of gold mine.
The method is similar to the heap leaching method in principle, but the method can make the mineral better contact with cyanide, and improve the leaching rate and the recovery rate of gold concentrate. This method is usually used to treat gold deposits that are more difficult to leach. When stirring for leaching, the ore should be ground to the required particle size to expose the wrapping gold and improve the leaching speed. There are other methods to improve the leaching rate, such as pressurized leaching, warmed leaching, and enhanced agitation.
Microbial leaching method has the advantages of simple process, low investment, low cost and small impact on the environment, and is receiving more and less attention on the concentrator. It mainly uses microorganisms such as bacteria or fungi to decompose sulfide and release metals. This technology is generally used in the pretreatment stage of cyanide gold, mainly for the treatment of refractory gold deposits that can not be most of the gold extracted by the cyanide process, such as gold deposits containing sulfide, such as pyrite, chalcopyrite, etc.
The physical pretreatment methods mainly include fine grinding and screening, mainly to refine the ore particles, expose the gold, and improve the efficiency of subsequent gold ore processing. The commonly used grinding equipment is ball mill, autogenous mill, rod mill and so on.
Chemical oxidation pretreatment uses a chemical reaction to oxidize sulfide into a dissolved form, thus making the metal easier to leach. Commonly used oxidants include oxygen, hydrogen peroxide, etc.
The roasting oxidation pretreatment destroys the sulfide by heating and dissociates the gold. Under high temperature and aerobic conditions, sulfide oxidation improves the mineral processing effect of gold mine. The processing speed of this process is fast, strong adaptation, and the by-products produced in the process can also be recycled.
Thermal pressure oxidation method is to use air or oxygen rich in the autoclave for high temperature oxidation, heating and oxidation will destroy the crystals of sulfide ore and some gangue minerals, make the wrapped gold exposed, improve the efficiency of cyanide leaching. This process can be performed in acidic or alkaline media.
The above contents are various methods of gold ore processing, from traditional physical mineral processing and chemical leaching to innovative microbial mineral processing and pretreatment technology of difficult gold mine, which provide rich technical choices for gold mining. Due to the different ore types and properties, the specific ore processing process should be determined according to the specific ore properties and production requirements. Xinhai Mining suggests to conduct beneficiation tests to determine the properties and characteristics of the ore, and customize the gold ore mineral processing process according to customer needs to improve economic benefits.