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Heap leaching technology is a relatively simple and economical technology for recovering gold from low-grade gold ores. This technology is currently mainly used to extract gold from low-grade ores, off-surface ores, old mine waste rock piles and old tailings. With the continuous application of heap leaching technology in actual production, the output of gold produced using this process is also increasing year by year. In order to meet the production needs of the heap leaching gold extraction process, it is necessary to understand the precautions during the heap leaching process to avoid other factors affecting the heap leaching efficiency and gold extraction efficiency. The following mainly discusses the precautions for gold extraction through heap leaching from the aspects of improving and perfecting the heap leaching process and the environment in which drugs act.
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In this regard, there are three main aspects to improve the heap leaching process: the correct application of granulation technology, the use of different heap leaching technologies, and the use of drip leaching technology.
(1) Correct granulation technology: Fine-grained materials and ores with too high clay content cannot be directly heap leached, and granulation pretreatment is required to improve the permeability of the ore pile. Granulation pretreatment can strengthen the leaching of gold to a great extent, speed up the leaching speed of gold, and also increase the leaching rate of gold. Therefore, granulation pretreatment can be used for gold ores containing a large amount of fine ore powder. Lime and cement are used as binders for ore granulation, and the dosage should be appropriate. With the development of technology, some new granulation auxiliaries can now be used for granulation.
(2) Use different heap leaching technologies: In addition to the heap leaching method of one pile and one unloading, there are also methods such as permanent pile yards, alternate pile building spraying and segmented pile building, cross spraying, multi-stage countercurrent leaching, etc. . Permanent stockpiles are mainly selected in places with a large bottom area, such as valleys. The stacking method is divided into layered and partitioned alternating stacking or segmented stacking, and spray processing is used, which can greatly improve the economic benefits of the mineral processing plant. The layered and partitioned alternating heaping and spraying method can greatly improve the operation rate of mining, heaping equipment and spraying equipment, and at the same time ensure that the taste of your liquid is in a relatively stable state. No matter which heap building method is adopted, the air permeability of the ore pile and the permeability of the solution are the key factors affecting the heap leaching effect. In addition, the heap leaching reaction should be carried out at a slightly higher temperature. Therefore, in the cold season, the main problem of heap leaching lies in the temperature of the solution. To overcome this problem, the heap leach time can be extended and the solution heated before being sent to the ore pile for processing.
(3) Use dripping technology: There are two different liquid distribution methods commonly used in the spray and dripping wet heap leaching processes, both of which can produce a uniform liquid distribution effect. Uniform liquid distribution is one of the key factors to improve the gold leaching rate. The spray equipment commonly used at home and abroad is the rotating swing spray equipment. This equipment has a large spray area, uniform spray liquid, is not easy to atomize, is not easy to be blocked, and is easy to load and unload. However, this type of equipment has a strong impact on the surface of the ore pile, resulting in increased evaporation losses of the solution, and at the same time, wind entrainment losses will also increase. The dripping method is mainly suitable for the desert area next door. Heap leaching production under natural conditions of drought, high temperature, strong wind and water shortage can improve the efficiency of gold extraction by drip leaching. Due to the unique advantages of drip leaching equipment, it has been widely used.
Oxygen plays a very important role in the heap leaching gold extraction process, and the use of oxidants is an important technical measure to improve heap leaching of gold mines. An appropriate amount of soaking agent or wetting agent is added to the solution to facilitate the penetration of the solution and react with the wrapped gold. Before heap leaching, it can be treated with alkali to reduce the adverse effects of harmful metal ions on leaching. It can also increase the dosage of drugs and increase the gold leaching rate. Multi-stage leaching is used during leaching. Compared with single-stage heap leaching, the leaching rate is higher.
The above are two aspects that should be paid attention to when extracting gold through heap leaching technology. In actual production, many types of refractory ores require biological oxidation pretreatment before heap leaching to shorten the leaching time and increase the leaching rate. Therefore, with the extensive development and utilization of gold mines, the dilution of gold mine resources has become increasingly serious, and the heap leaching process has become more widely used. According to the characteristics of the specific ore, choosing the appropriate heap leaching method and paying attention to each link can improve the efficiency of gold extraction and the utilization rate of gold ore resources.