(National Committee for Philosophy of Geological Sciences)
This paper illustrates the importance and necessity of comprehensive utilization of tailings through examples.
Keywords comprehensive utilization of tailings
Tailings usually refer to the residue after mineral processing under certain technical conditions. The residue may contain low-grade "useful metal substances" and "surrounding rocks". Broadly speaking, tailings, waste rocks, coal gangue, fly ash and blast furnace slag can all be called "tailings".
Tailings have attracted people's attention because they occupy a lot of land, pollute the environment and endanger ecology, society and people's health.
The annual amount of tailings discharged by countries all over the world is about 5 billion tons, and the annual amount of mining solid waste residue discharged by China is more than 65.438+0.2 billion tons, and the cumulative amount has reached 20 billion tons, covering an area of 55,000 hectares. Moreover, with the improvement of the comprehensive utilization level of mineral resources, the recoverable grade of ore will decrease correspondingly and the amount of tailings will increase. A large number of tailings and waste rocks are discharged and accumulated, which pollutes the environment and occupies land, causing economic losses as high as 30 billion yuan every year.
Tailings, on the surface, belong to abandoned waste. However, with the progress of science and technology and the deepening of people's understanding, tailings have become available material resources, or called "secondary resources". There are no useless substances in the world, only substances that are misplaced.
The comprehensive utilization of tailings can be divided into at least the following aspects: first, the continuous extraction and application of useful elements; The second is to make new materials; Third, it is used for ecological restoration of mines and land; The fourth is something else. Here are just some examples of the above applications.
First, continue to extract and apply useful elements.
Comprehensive recovery of (1) molybdenum mine tailings
After multi-element analysis, the tailings of a molybdenum mine concentrator contain many elements, as shown in table 1.
Table 1 Element Content in Tailings of a Molybdenum Ore Dressing Plant
Based on the above data analysis, only the grade of iron in tailings is high, reaching 2.34%, which has potential recovery value. The results of phase analysis of iron in tailings by School of Chemistry and Environmental Engineering of Shandong University of Science and Technology are shown in Table 2.
Table 2 Phase analysis results of iron in tailings of a molybdenum ore concentrator
The analysis shows that the occurrence state of iron minerals is complex, and the iron in magnetic iron should be comprehensively considered as the recovery object. Through the direct magnetic separation test of tailings, about 43% iron concentrate was obtained. The regrinding and re-concentration test of iron concentrate was carried out, and the iron concentrate with yield of 0.38%, grade of 63.93% and recovery rate of 10.29% was obtained.
(2) Recovering low-grade scheelite from Bi-Zn-Fe tailings
A large skarn-type metal mine mainly recovers bismuth, zinc, copper and iron, and processes 2,400 tons of ore every day, resulting in tailings 1.700 tons. It contains about WO30. 12%, and the relative content of minerals in tailings is shown in Table 3.
Table 3 Table of relative contents of minerals in tailings
Guangzhou Institute of Nonferrous Metals adopted the flowsheet of medium magnetic-high magnetic-flotation-optimization, and obtained magnetite containing 48.59% iron, sulfur concentrate containing 42.57%, scheelite concentrate containing Zn 13. 13%, garnet concentrate containing WO3 67.92% and garnet concentrate containing 92% from tailings. The recovery rate of tungsten is 64.04%.
(3) the structure and comprehensive utilization of copper mine tailings resources
Not all mines in history have tailings ponds, so a considerable part of metals, including copper tailings, are directly discharged into rivers, lakes and seas. According to the investigation of tailings of some key mines in Jiangxi, Anhui, Hubei, Yunnan and other large copper bases by China Geo University (Beijing), it is judged that the recoverable copper tailings are about 200 million tons (Table 4).
Table 4 List of recyclable copper tailings in some provinces (regions) of China.
sequential
The research on the above tailings shows that under the current technical and economic conditions, 25% of copper tailings resources have the economic value of re-election, and 75% of copper tailings do not have the economic value of re-election. Those with economic value of gravity separation are outstanding in old mine tailings, as shown in Table 5.
Table 5 Examples of Economic Value of Old Copper Mine Tailings Re-concentration
(4) Other comprehensive recycling.
Kang Yi, honorary president of China Nonferrous Metals Industry Association, pointed out that rare and precious elements such as platinum, palladium and gold recovered by Jinchuan Group have reached 18, and the comprehensive utilization rate of nickel and copper associated with * * * has reached 72%.
Shandong Xinfa Group 20 1 1 completed the comprehensive utilization project of 2 million tons of red mud. After treatment, the alkali content and alumina content in red mud decreased to below 1% and below 10%, and the alkali recovery rate was over 90% and the alumina recovery rate was over 40%.
Through the construction of "urban minerals" demonstration project, China has initially formed a recycling system for renewable non-ferrous metals. Compared with 2002, 20 1 1 year recycled copper increased from 880,000 tons to 2.6 million tons, recycled aluminum increased from 6.5438+0.3 million tons to 4.4 million tons, and recycled lead increased from 6.5438+0.7 million tons to 6.5438+0.3 million tons.
Zhang Jinqing, tailings comprehensive utilization technology center of Chinese Academy of Geological Sciences, pointed out that Shougang, Angang, Benxi Steel, Maanshan Iron and Steel Co., Ltd. have all recovered iron concentrate from tailings by gravity separation, and achieved good social and economic benefits. Xinjiang Rare Metals Mining Company comprehensively recovered muscovite from the tailings of Cocotohai, and established a joint venture with foreign investors with an annual output of 5,000 tons of mica powder, with an annual output value of 8 million yuan. Sulfur concentrate 1000 tons, 9.2 tons of copper and 33.4 kilograms of gold were recovered from Jiaxing copper mine tailings by gravity separation.
Two, the production of new building materials products, and the formation of industrial chain.
Using tailings to produce new series of products has become an important way to realize tailings reduction, harmlessness and resource utilization. Especially in recent years, tailings, as composite mineral raw materials, have been widely used in building materials, ceramics, glass industry and new material industry, with obvious results and broad prospects.
For example, as early as the early 1990s, Jiangxi Dexing copper mine tailings, Shougang iron tailings and Nanjing Meishan iron tailings were used to make purple sand fine arts ceramics and daily-use ceramics such as casseroles and wine vessels, and made into exterior wall tiles, brocade tiles, cement, sintered bricks and square tiles.
The tailings of Longtou Wangjin Mine in Shandong Province are treated in three parts: coarse slag is used as paving material, fine particles are sold, tailings are used to make bricks, and a brick factory with an annual output of 6.5438+0.7 million tons of bricks is built. Shandong Jiaojia Gold Mine has built four brick production lines in 1996, with an annual utilization of 60,000 tons of tailings.
1In September, 1999, Qian 'an Iron Mine of Shougang built the first domestic production line for hollow blocks, colored floor tiles and building sand, realizing industrialization.
Since the 20th century, Baiyin Copper Mine in Gansu, Shouwangfen Copper Mine in Chengde, Meishan Iron Mine in Nanjing, Hangang in Liaoning, Angang, Ling Gang and Xinggang in Hebei have successively set up factories with the technical support of the Chinese Academy of Geological Sciences to produce small hollow blocks, colored segmented blocks, perforated bricks, solid bricks, insulation partition boards, colored floor tiles and concrete additives.
In 2003, Shougang's project of "Industrialization of 654.38+0.5 million cubic meters of building sand and gravel with waste rock" and Beijing Weike Metallurgical Mining Company's project of "Industrialization of 3 million cubic meters of building sand and gravel with waste rock" were put into operation successively, which operated normally and achieved remarkable benefits, and achieved the goal of no waste rock accumulation in the mine dump that year.
In 2006, Anshan Iron and Steel Group built a production line with an annual output of 80 million standard solid bricks (perforated bricks and blocks) by using iron tailings and waste rocks, and the products were in short supply.
In 2008, the production line with an annual output of 60 million lime-sand bricks from iron mine tailings in Yixian, Hebei Province was put into operation, and 70% of the products were sold to Beijing.
In 2009, Nangou Mining Company of Lincheng County, Hebei Province used iron tailings to produce colored pavement bricks and load-bearing blocks, with an annual output value of 23 million yuan.
20 1 1 year 1 1 month, the production line of new building materials series of Benxi Chiang Mai Tailings Comprehensive Utilization Co., Ltd. started construction. 20 12 The first phase of the project was put into operation in the first half of the year, and iron tailings were used to produce composite insulation blocks, aerated concrete blocks and dry powder mortar. 540 people are employed, the annual consumption of tailings is 1 10,000 tons, and the annual profit and tax is 32 million yuan.
In a word, the comprehensive utilization of tailings to produce new building materials series products has broad prospects and obvious benefits, which not only promotes employment, but also realizes ecological protection. It is a circular economy and a green industry.
Production of new material glass-ceramics from tailings.
Glass-ceramics is a new material developed internationally in recent years, which can be used in mechanical materials, optical materials, electronic and microelectronic materials, biomedical materials, chemical materials, building materials and other fields. Among them, foamed glass-ceramics have been widely studied and applied as structural materials, thermal insulation materials and fiber composite toughened glass-ceramics. Glass ceramics are also used to manufacture control rods of atomic reactors, reactor sealants, nuclear waste storage materials, etc. It has excellent properties such as acid and alkali resistance, wear resistance, thermal stability, electrical insulation, high compressive and impact strength, and no radioactive hazard.
The research project of "Tailings Glass-Ceramics" undertaken by Tailings Research Center of Chinese Academy of Geological Sciences won the patent of 1994 China for new invention, and its achievements have been successfully transformed in enterprise projects in Xinjiang, Shaanxi and Shanxi. In May 2007, the production line of "Tailings Glass-ceramics with an annual output of 200,000 square meters" of Xinjiang Jintai Glass-ceramics Co., Ltd. was completed and put into operation. Then, in August 2009, Junda (Fengxian) Company built the second tailing glass-ceramics production line with an annual output of 200,000 square meters in Baoji, Shaanxi. The above products are sold to Xi, Baoding, Ningbo, Italy, Japan and other places. Demand exceeds supply. At present, only China has realized the industrialization of tailings glass-ceramics technology.
Fourth, other applications.
Tailings can also be used as underground filling materials or filling pits to pave roads, and can also be used to reclaim tailings ponds, plant trees, improve soil with mineral fertilizers, or build ecological parks and sports and entertainment places.
For example, in Fankou lead-zinc mine, 50% of tailings are used for underground filling; Daye Iron Mine planted pear trees and holly on old tailings ponds such as Hongshan. Some gold mines in Zhaoyuan, Shandong Province, built terraces in old tailings ponds and planted sweet potatoes and peanuts.
In a word, after the harmless disposal of tailings, it will also produce certain economic and social benefits.
Five, strengthen planning, strengthen research, and strive to achieve comprehensive utilization of tailings.
Tailings Research Center of Chinese Academy of Geological Sciences, established in 1990, is a scientific and technological research institution specializing in the research and development of new technologies and new products for the comprehensive utilization of industrial solid waste resources such as mine waste rocks, tailings and coal gangue, and it is also the only one in China at present. From the initial research and production of building materials to the research of glass-ceramics series products, they have made great efforts and made outstanding contributions.
In order to realize the comprehensive utilization of tailings, their research and invention was listed as a guide for major high-tech industrialization projects in China's 11th Five-Year Plan by the National Development and Reform Commission, the Ministry of Science and Technology, the Ministry of Commerce and China National Intellectual Property Administration as early as 2007. The Ministry of Industry and Information Technology, the Ministry of Land and Resources, the Ministry of Science and Technology and the State Administration of Work Safety issued the Special Plan for Comprehensive Utilization of Metals and Tailings (2010-2015) in April 2065. The Ministry of Industry and Information Technology recently issued the Twelfth Five-Year Plan for Comprehensive Utilization of Bulk Industrial Solid Waste, which regards the comprehensive utilization of bulk industrial solid waste as an important content of strategic emerging industries of energy conservation and environmental protection. The planning target is that by 20 15, the comprehensive utilization of bulk industrial solid waste will reach 65,438.06 billion tons, the comprehensive utilization rate will reach 50%, the annual output value will be 500 billion yuan, and 2.5 million jobs will be provided. At present, according to statistics, by 20 10, the comprehensive utilization of bulk industrial solid waste in China has reached110 million tons, and the comprehensive utilization rate has reached 40%, with remarkable results.
Sixth, it is suggested to control the related problems of tailings from the source.
In order to reduce the production of tailings, we must start from each link, that is, improve the recovery rate of mineral resources to reduce slag, ore, waste rock and so on; Strive to improve the recovery rate of mineral processing and reduce the waste of useful minerals; Efforts should be made to improve the comprehensive utilization rate of mineral resources and recover as many useful metals and elements as possible. Of course, no matter how high the recovery rate, recovery rate and comprehensive utilization rate are, there are still inexhaustible problems and tailings can not be comprehensively utilized for the time being, so it is necessary to increase investment and efforts in tailings research, development and utilization.
In recent years, with the attention of the state and all sides, the recovery rate of some key large and medium-sized coal mining areas has reached more than 80%, the recovery rate of open-pit mining in metal mines has exceeded 85%, and the recovery rate of underground mining has also exceeded 80%. The coal recovery rate is increased by 2% ~ 1 1%, and the iron ore recovery rate is increased by 3% ~ 13%. This shows that it is entirely possible to improve the recovery rate of the mine.
In terms of mineral processing recovery, some iron ores are increased to about 85%, non-ferrous metals are 80%, and phosphorus and sulfur are 60%. The concentrate grade and resource recovery level have been effectively improved.
From the comprehensive utilization of mineral resources, according to statistics, at present, more than 50% of vanadium, more than 22% of gold, and more than 50% of rare metals such as platinum, palladium, tellurium, gallium, indium and germanium come from comprehensive utilization. Under the special arrangement of the central government, 40 demonstration bases for comprehensive utilization of mineral resources were established in the first batch of 201/kloc-0, and the efficiency of resources is being transformed efficiently.
In a word, controlling tailings from the source is fundamental to reduce tailings, and increasing the research, development and utilization of tailings is an effective way to turn waste into treasure.
refer to
Magnesite: breakthrough in mineral utilization research. China Land and Resources News, 2012-1-16.
Proceedings of the conference on tungsten geology. Beijing: Geological Publishing House, 198 1.43.
Cao Jincheng, Guo Wei. Policy research and demand analysis of comprehensive utilization of mineral resources. China mining industry, 20 12(9)
Chen Jiabin, Wang Haijun. Study on resource structure and comprehensive utilization policy of copper mine tailings. China Mining Industry, 20 12( 1).
Deng Lijiang is from Zhou Xiaotong. Study on recovering low-grade scheelite from Bi-Zn-Fe tailings by high gradient magnetic separator. China Mining Industry, 20 12( 1).
Guo Wei. Preliminary study on the green development model of "coal gangue for coal" China mining industry, 20 12(5)
Kang yi. China's comprehensive utilization of non-ferrous metals has made great achievements and great potential. China Land and Resources News, 2012-1-17.
Lin Li, Lv Xianjun, Qiu Jun, Peng Li. Experimental study on comprehensive recovery of molybdenum tailings. China Mining Industry, 20 12( 1).
Liu Wei. On the left is hidden danger, and on the right is wealth: pay attention to the development and utilization of tailings. Guide to Geology and Minerals, 2011-12-28.
Selected Works of Mao Zedong and Mao Zedong: Volume 1. Beijing: People's Publishing House, 199 1.296 ~ 297.
Qu Zhao Li. Research on standard step development theory. China standardization, 1994(9).
Wu Yun. Characteristics and enlightenment of "four-step" training mode for German civil servants. Journal of Qingdao Administration College of Party School of Qingdao Municipal Committee, 20 10(3)
Xu Dao. The policy has a great effect, and the waste residue turns into gold residue. China Environment News, 20 12- 1- 19.
Yang Ruilong, Yang. Gradual institutional change model: Re-discussion on the role of local government in institutional change in China. Economic Research, 2000(3)
Zhu Xun Introduction to prospecting philosophy. Beijing: Geological Publishing House, 2008.399.