Summary of research and application of leaching mining technology (1)

Leaching mining technology and new methods of mining mining, mineral processing, in one of the metallurgical, mining is multidisciplinary, geology, hydrodynamics, geochemistry, and other hydrometallurgical intersecting edge science [1-2] . Leaching mining can be divided into three main methods: in-situ leaching method, in-situ leaching method and heap leaching method.
In-situ leaching refers to the process of casting the leaching solution into the ore body by artificial drilling, selectively leaching the useful mineral components, and pumping the leaching solution to the surface processing by drilling [3]. Situ leaching technology has developed rapidly in recent decades, mainly for large-scale mining of uranium ore and copper ore. In 1984, the leaching uranium test of the Tengchong 381 deposit in Yunnan was successful. In 1992, the Xinjiang 512 deposit was built as the first in-situ uranium mine in China, which indicates that China's in-situ uranium mining technology has been realized from the experimental research stage to the industrial scale production stage. Leap.
In situ crushing and leaching is to first break the ore body in the natural state to a certain degree by means of blasting, and then use the leaching solution to leaching. The difference from the in situ leaching is that the former ore has a certain displacement through blasting and crushing. Heap leaching method refers to spraying a chemical solution directly onto an ore or low-grade ore heap. During the diafiltration process, selectively dissolves and leaches the useful mineral components, dissolves them in the solution, and further extracts them. a way. At present, heap leaching has gradually become an economically reasonable and effective method for reclaiming resources such as tailings, lean ore, waste rock minerals and extracting metals such as uranium, gold, copper and silver [4].
Leaching and mining has the advantages of simple process, low investment, low cost, green environmental protection, etc., especially for the development and recovery of low-grade metal ore or tailings, and has obvious economic and social benefits.
1 Research Status at Home and Abroad 1.1 Domestic Research and Application Status Currently, leaching and mining is widely used in China. From the perspective of leaching methods, surface heap leaching, borehole leaching, underground in-situ leaching and leaching have all been industrialized in China; from the perspective of metal types, leaching of uranium, copper and gold has been industrialized. The technology is very mature. Many institutions are conducting research on the leaching of metals such as nickel , diamond, lead and zinc , which is expected to achieve breakthroughs. From the geographical location of leaching mining applications, mining companies using leaching mining have spread all over the country. From this point of view, leaching mining technology has been fully applied under various environmental conditions throughout the country. Control of leaching range of in-situ leaching and mining in China, formulation and use of leaching solution, mobile processing device for product solution, heap leaching system, anti-leakage and bottom structure of heap leaching field, and gold granulation Dipping and other aspects have developed rapidly. However, in theory, new process research and process technology, equipment development and production, there is still a big gap compared with advanced countries [5]. In the experimental research of leaching mining method, China has done a lot of work and achieved fruitful results [6].
(1) In-situ borehole leaching test [7]. The Wushan Copper Mine has been conducting research in this area since 1993, and has achieved certain results in cup immersion, mineralogy, column leaching and leaching agent optimization. At the end of 1998, the project was identified as an internationally advanced level by the National Nonferrous Metals Industry Bureau.
(2) Low-grade sulfide ore surface bacterial heap leaching test [7]. Every year, more than 20 million tons of poor ore-poor mines in the Dexing Copper Mine are discharged to the dumping site. Now the amount of waste rock has reached several billion tons, including more than 2 million tons of copper. Dexing Copper Mine cooperated with Beijing Nonferrous Metallurgy Design and Research Institute to establish a surface heap leaching copper system with an annual output of 2000t electric copper using bacterial leaching technology. The heap leaching plant area is 75,000 m2 and the pile height is 80 m. The processing capacity was 320m2/h, which was put into operation in May 1997, and the electrolytic copper produced reached Grade A.
The geological reserves of low-grade copper ore above 810m elevation in Zhongtiaoshan Copper Mine are more than 10 million tons, the average grade of copper is 0.59%, and the oxidation rate is ≥50%. If mining is carried out by general mining method, it is economically not. reasonable. In order to improve the utilization rate of resources, the mine was listed as a pilot mine for the underground leaching test study of the low-grade copper ore in the “Ninth Five-Year” scientific and technological research project, and the Zhongtiaoshan Nonferrous Metals Corporation and the Beijing Research Institute of Mining and Metallurgy. In the joint research cooperation, a demonstration system of 500t/a electrolytic copper underground leaching and mining was completed in March 2000. In August 2000, the project passed the appraisal and acceptance of the national “Ninth Five-Year Plan” project, and the technical level reached the world advanced level, making China For the first time, tens of thousands of tons of underground crushing were realized in situ leaching. The content of copper in the leaching solution reached 2.189~5.78g/L. The quality of electric copper was equivalent to the international first-class standard, and the cost of electric copper ton was 8754. 31 yuan, only half the cost of traditional mining law. In view of the good economic benefits, the mine has expanded the underground leaching mining system to expand the scale to 2,500 tons of copper.

In 2000, the national “10th Five-Year” scientific and technological research project included the copper extraction project of Zijinshan Copper Mine, and in 2002, it built a 1000t/a copper metallurgical copper test plant, and accumulated leaching time of various leaching piles. For 1000h, the leaching rate is 40% to 60% [8], and all economic and technical indicators have achieved good results.
In addition, China has made some progress in the study of copper oxide leaching test and leaching of metals such as Ni, Co and Mo in high altitude areas [9].
(3) In terms of application, in the 1960s, Anhui Tongling Nonferrous Metals Corporation Songshushan Copper Mine took the lead in adopting the local crushing and leaching method; in the middle and late 1990s, Dexing Copper Mine built an annual output of 2000t. Copper heap leaching plant; in 2000, the Zhongtiaoshan copper mine was built to form an underground leaching and copper extraction demonstration system with an annual output of 500t of electrolytic copper; in 2003, Yunnan Guanfang copper mine was built to treat 0.9% copper-containing primary copper sulphide. And bio-dip leaching plant with secondary copper sulphide; in 2006, Fujian Zijinshan built a 10,000-ton biological copper leaching plant. The underground in-situ drilling and leaching technology of Wushan Copper Mine has also achieved good results. The leaching rate of copper ore is 68% leaching rate, 2.5g/L copper content, 95% extraction rate and 98% electrowinning rate. The comprehensive index of recycling is 41.15%, and the cost of electric copper is less than 1,000 yuan/t. In addition, during the “Eighth Five-Year Plan” period, the State also established a key scientific and technological research project “Study on New Technology of Ion-Type Rare Earth In-situ Leaching”. The in-situ leaching mining method of the southern ion-adsorbed rare earth ore also achieved obvious research results. During the fifteenth period, a certain degree of use has been obtained. The technical indicators that can be achieved by using this method are: mother liquor collection rate >90%, ion phase rare earth leaching rate >90%, and ionic phase rare earth comprehensive recovery rate >75% [10].
In terms of uranium mines, the uranium in-situ leaching of the Tengchong 381 deposit in Yunnan Province was carried out for the first time in 1985. The total metal recovery rate reached 65% and the production cost was reduced by 50%, making it the first in-situ leaching mine in China. In 1987, a 10,000-ton test of a uranium mine in Jiangxi was successful. The uranium leaching rate was ≥90%, and the metal production cost was reduced by 30%-40%. In 1989, it was changed to a full heap leaching mine. In 1992, Xinjiang 512 Mine expanded the in-situ leaching plant of 50t/d scale. In the mid-1980s, China achieved the success of in-situ leaching of ionic rare earth ore. So far, in-situ leaching of uranium has gone to scale production.
1.2 Status of foreign research and application In foreign countries, leaching mining technology has been used for the mining of various metals. At present, dozens of copper, uranium and gold mines have adopted this method on a large scale [11]. As early as the 16th century, the Harz region of Germany and the Rio Tinto mine in Spain used a leaching method to treat sulfide ore. 1947 Colmer and Hinkle separated out and from acidic waste water pit Thiobacillus ferrous oxide, people began to realize from bacterial leaching of sulfide minerals [12]. In the 1960s, the United States and the Soviet Union began experimenting with in-situ leaching to extract uranium ore and building the world's first leaching uranium mine in Wyoming. In the 1970s, the United States Kennecott Mining Company built the world's largest microbial heap leaching site, processing 3.6 billion tons of ore, with an annual output of 72,000 tons of copper metal. In 1986, the Fairview mine in South Africa was built into the world's first gold mining bioleaching plant, which processed 10 tons of gold concentrate daily. In the past 20 years, leaching technology has been widely promoted in the United States, Chile, Australia and other countries [13]. Currently, 25% of the world's copper and 20% of uranium are from leaching mining.
In the early 1970s, the US Bureau of Mines conducted a heap leaching test to solve the problem of refractory lean recovery [11]. Heap leaching has been widely used in gold mining in the United States [14]. As the world's third largest gold producing country in Nevada, most of the gold comes from heap leaching. In 2003, the output reached more than 7,000 ounces. The value is more than 2.5 billion 313 dollars, and the high yield period reaches 8.5 million ounces. The RoundMountainMine open-pit gold mine mainly uses the heap leaching method to extract metal. The ore is crushed and piled up on the reusable bottom pad, while the waste rock is directly on the waste rock pile. Heap dipping. About 30% of Chile's copper production comes from heap leaching, such as the Zaldivar mine, which is located in northern Chile and is a large-scale heap leaching company. In 2004, copper production was 14,800 tons, and cathode copper accounted for 98%. At 0.66 US dollars / lb, A grade copper accounted for 96%, after that, the mine has been working hard to study the leaching kinetics, improve the leaching mechanism, and make the oxidation reaction of sulphide ore faster, resulting in a leaching rate of about 20% higher, and the leaching process is reduced. 330d [15].
2 Problems in leaching mining The leaching mining technology has been widely used at home and abroad, and has made a series of progress in theoretical research, but the mine has poor permeability, uneven solution distribution, low bacterial activity, and internal temperature. The problem of uneven distribution still restricts the rapid development of leaching technology [16].
Downward Review of the Status Quo of Research and Application of Leaching Mining Technology (II)

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