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With the continuous development and progress of the gold production industry, the amount of gold resources and the number of high-quality gold ores are decreasing year by year, but the price of gold is rising. In order to make full use of gold resources, it is necessary to strengthen the utilization of low-grade gold ores and other gold-containing minerals. Heap leaching is one of the main methods for gold ore beneficiation. This method can not only improve the grade of gold ore, but also process the residues, tailings and other materials produced by low-grade minerals. Therefore, it is also a method of gold ore recycling. The following article will explain in detail the impact of different factors on the heap leaching process of gold extraction, hoping to have a certain reference for the practice of gold heap leaching production.
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The heap leaching gold extraction process mainly includes two processes: cyanide leaching of gold in gold ore and recovery of gold in gold-containing leaching solution. The effect of cyanide leaching directly affects the success or failure of the gold heap leaching production process. During the heap leaching process, cyanide solution with a certain alkalinity is used as a gold leaching agent to react with the gold exposed on the surface of the ore block and the cracks and holes inside the ore. The gold will be oxidized and complexed with cyanide ions to form easily soluble gold-cyanide complex ions that enter the solution, and the gold in the ore can be leached by the cyanide agent.
After gold ore or other gold-containing materials are crushed and ground to a suitable particle size, they are piled up at a certain level and height using appropriate methods. The ore pile needs to be laid on a heap leaching site that does not leak solution and can automatically drain the lining. A cyanide solution with a certain pH value is intermittently sprayed on the ore pile evenly and cyanide leached to dissolve the gold. The leached gold-containing solution is recovered using a certain method.
1. Influence of leaching solution
The influence of leaching solution on heap leaching gold extraction process is mainly reflected in the selection of reagents, cyanide concentration, oxygen concentration and pH value of leaching solution. Because different reagents have different dissolution rates for gold, the selection of leaching reagents is crucial. The concentration of cyanide will affect the leaching efficiency of gold. If the concentration is too high, it will lead to waste of reagents and cause environmental pollution. The appropriate oxygen concentration during heap leaching can promote the dissolution process of gold. Keeping the leaching solution within the appropriate pH range can also improve the recovery rate of gold.
2. Influence of ore
The structure, physicochemical properties, occurrence state of gold in the ore and other components of the gold ore will affect the efficiency of the heap leaching process. The structure and physicochemical properties of the gold ore determine the permeability of the leaching solution and the contact between cyanide and gold particles. If the structure of the gold ore is dense, the leaching solution is difficult to penetrate, resulting in low gold leaching efficiency. The occurrence state of gold particles in the ore determines the difficulty of gold dissolution. Other ore components in the gold ore will react with cyanide, resulting in the consumption of reagents, which will inhibit the cyanidation reaction.
3. Impact of heap leaching
The impact of heap leaching on gold ore is mainly reflected in the particle size of the ore entering the leaching process and the permeability of the heap. The particle size of the ore will directly affect the leaching efficiency. Smaller ore particle size will help the cyanide solution to penetrate and contact with the gold ore, thereby increasing the dissolution rate of gold. Larger ore particle size will affect the penetration of the cyanide solution and reduce the gold recovery rate. The permeability of the heap mainly affects the fluidity and leaching uniformity of the leaching solution. The permeability of the heap is mainly affected by factors such as ore particle size, heap structure, and water content.
4. Influence of spraying method
In the process of heap leaching gold, the choice of spraying method determines the contact uniformity and efficiency between the leaching solution and the ore. Common spraying methods include dripping, spraying and circulating spraying. The appropriate spraying method can ensure that the leaching solution evenly penetrates the entire ore pile and improves the leaching rate of gold. In addition, factors such as spraying intensity, spraying time and spray particle size will directly affect the coverage of the reagent and the reaction speed of the ore. Therefore, continuous optimization of the spraying process can effectively improve the overall effect and economic benefits of the cyanidation process.
5. Environmental impact
The environmental impact on gold extraction through heap leaching is mainly reflected in temperature and weather. Temperature has a significant impact on the rate and effect of the cyanidation reaction. Higher temperatures can speed up the dissolution of gold and increase the leaching rate of gold, but temperature It should not be too high, otherwise side reactions will occur and affect the recovery rate of gold. Meteorological factors such as precipitation, humidity and wind speed will affect the heap leaching process. Higher humidity and increased precipitation will lead to an increase in moisture in the heap leaching ore body, affecting the concentration and permeability of the leachate. Wind speed mainly affects the supply of oxygen. Therefore, reasonable control of environmental conditions is crucial to improve the gold recovery efficiency of heap leaching.
The above is a brief introduction to the mechanism, process and influencing factors of heap leaching gold extraction. Although the process flow of heap leaching gold extraction is relatively simple, the process will be affected to varying degrees by different factors. In order to improve the leaching rate of gold and achieve good leaching effects, it is necessary to comprehensively consider various influencing factors, conduct careful analysis and take effective measures to ensure the efficiency of heap leaching of gold mines.
