With the rapid economic and social development, the demand for resources has increased rapidly, and the development of mineral resources has gradually increased, resulting in many tailing ponds. On the one hand, the construction and maintenance costs of the tailings dam body are relatively high, which brings environmental, safety and economic restrictions to the development of mining enterprises. The governance of the surrounding environment of mine waste rock and tailings cannot be delayed; another In terms of mine tailings, there is also a wealth of valuable metals. How to properly dispose of the tailings, reduce safety risks, restore the ecological environment of the mining area, and develop secondary resource development and utilization is currently an urgent problem to be solved.
Secondary Resource Recovery of Copper Mine Tailings Pond
The secondary resource recovery of the copper mine tailings reservoir can be divided into hydraulic mining, dry mining and ship mining. Hydraulic mining uses the energy of water and the gravity of the tailings to impact the tailings, and separate mineral resources that can be used for secondary use in the broken dam.
According to the power source, hydraulic mining can be divided into natural hydraulic mining and mechanical hydraulic mining. Natural hydraulic mining is the use of natural water to scour the layered tailings, and transport the formed tailings slurry back to the concentrator; mechanical hydraulic mining is the use of water pumps to pressurize, forming a high-pressure gun to the tailings Scour. Dry mining is the use of excavators and other equipment to mine the tailings, and then use loading machinery or conveyor belts to send the reusable part back to the concentrator. Under normal circumstances, dry mining is divided into three methods in order, one-time mining, step layering and bottom-up layering methods. Ship mining is to use a sand mining ship with mining function to mine in a certain order within a preset range. After the tailings are washed by high-pressure water, they are transported to the conveying pipeline through the ship-mounted sand pump. . Comparing the three methods, hydraulic mining has the advantages of simple facilities, large production capacity and relatively low cost, so it is more suitable for mining tailings that have been deposited for a certain period of time and are more cemented. However, the technical requirements of hydraulic mining methods are relatively high, so in the mining process, we must strengthen the attention to production efficiency and production safety [2].
Before the secondary resource recovery of the tailings pond, it is necessary to carry out engineering geological survey work on the tailings pond being mined, to clarify the specific layering of the accumulation in the tailing pond, and the corresponding physical and mechanical properties and location of the tailing pond Geological characteristics of the mining area. The use of scientific and reasonable beneficiation technology can effectively improve the recovery efficiency, complete the recovery of valuable minerals at one time, and avoid multiple repetitions. After completing the basic operations, the safety of the tailings pond must be determined in detail, and the mining process shall be formulated in strict accordance with the relevant standards, and various factors shall be considered comprehensively to ensure the safety of the dam during the mining phase.
Copper mine valuable metal recovery
The recovery of secondary copper metal in copper mines can use agitation leaching process, which mainly includes agitation leaching, solid-liquid separation, extraction, stripping, and electrowinning. Stirring leaching is mainly to screen the materials in the tailings pond, and add water washing, slurry preparation and other processes in the screening process, and the slurry is stirred for leaching operation. The solid-liquid separation is to send the stirred slurry to the thickener, and use the thickener and other equipment for solid-liquid separation. The leaching residue needs to be washed twice and the solid content in the separated leaching liquid should be as low as possible. The leaching residue is sent to the magnetic separation process to select the mixed iron concentrate, and then the leaching liquid is sent to the extraction equipment, and the appropriate extractant is added to complete the two-stage countercurrent extraction of copper metal.
The washed organic phase is sent to the stripping equipment for operation. The stripping solution enters the electrolytic cell to complete the electrolysis. The cathode is made of insoluble alloy materials. After the electrode is energized, the copper ions will be obtained on the cathode Relevant electrons are deposited to obtain electrowinning copper and complete the recovery of copper metal.
Safe disposal of tailings leaching waste residue
The safe disposal of waste slag leached from copper mine tailings is mainly to use certain engineering methods to change the physical, chemical and toxic properties of the waste slag, so as to promote the stabilization and solidification of the waste slag, thereby reducing, reducing or eliminating the harm of leaching waste slag Sex.
Methods for safe disposal of leaching waste residues include phytoremediation, chemical leaching, and microbial detoxification. Phytoremediation methods can be used for waste residues with low soil pollution concentration, which can be applied to soil that has been contaminated by heavy metals to complete the in-situ soil restoration, but this method takes a relatively long time. The safe disposal of leaching waste residues by chemical leaching method can be done by spraying chemical liquids on the waste slag piles, and forming a precipitable form through the reaction of the spraying liquid with the valuable metals in the waste residues, and rinsing together with the spraying liquid come out. This method is more suitable for use in the presence of valuable metals in waste slag. The microbial detoxification method can be used to detoxify the leaching waste residue through biological culture and screening of microorganisms with heavy metal tolerance.
For example, the reduction of microorganisms can reduce high-priced heavy metals in waste residues, thereby changing the analytical performance of heavy metals, thereby achieving the purpose of detoxification. The microbiological method is suitable for the reduction and detoxification of waste residues in a certain type of high-priced heavy metals, but this method is not suitable for the safe disposal of waste residues when multiple heavy metals coexist, and it is also subject to temperature and seasons during actual operation. It is relatively difficult to operate and manage.
Copper mine tailings reclamation
The tailings vegetation reclamation of copper mines includes: Dachonggou tailings reclamation and stripping of rock and soil to fill pits and other methods. The first method is to reclaim the places where the rocks are discharged and the tailings are discharged, and the stripped rock and soil are discharged into the gullies and dams in a planned way to form an artificial tailings sedimentation pond. And then in the copper mine
The tailings are filled in the sedimentation tank, and subclay is laid on it. The characteristic of this technique is that it uses rocks to build the dam in sections. The advantage is that the soil quality of the stripped rock and soil is relatively loose and the porosity is relatively large, so water can seep out through the pores, and there is no need to set up a tailings water overflow pipe, which saves costs. Another method is to use stripped rock and soil to reclaim the valley area. In the stripping process, first pile up the soil on the ground and the hillside soil, place hard rocks on the bottom of the pit, and place weathered rocks At the top, select plants that adapt to the surrounding environment and plant them on the surface, and choose an appropriate discharge thickness according to the depth of the plant.
Conclusion
The development of secondary resources for waste rock yards and tailings ponds is the focus of environmental management in mines, and at the same time it turns waste into treasure. Based on the principle of reduction, resource utilization, and harmlessness and the concept of circular economy, under the condition of ensuring safe mining, the use of advanced technological processes improves the efficiency of mineral resource development and realizes the value of copper tailings The recovery and reuse of metal resources can extend the service life of mining enterprises and reduce the pressure on the environment caused by resource extraction.
