Our iron ore reserves, poor quality iron ore beneficiation plays a vital role in improving the market competitiveness of the steel industry. For a long time, the technical and economic indicators of China's mineral processing industry are not high. For this reason, as early as during the "Seventh Five-Year Plan" period, the state took the iron ore produced by the Qidashan Iron Mine, the largest iron ore mine in the country with a reserve of 6 Rillion tons, as the research object, and issued the "Qidashan Iron Mine". The “Research on Reasonable Mineral Processing Technology†requires that the process test indicators reach the international advanced level, the iron concentrate grade reaches 65%, and the recovery rate is over 80%. Changsha Research Institute of Mining and Metallurgy, Anshan Iron and Steel Group Anshan Mining Research Institute and Maanshan Mine Research Institute and other scientific research units have cooperated with each other to complete a number of process demonstration projects from January 1984 to May 1987. Research and expand continuous experimental research; completed industrial processes of three optimized processes from June 1987 to December 1990 (including process test, verification test, concentrate dewatering filtration test, backwater utilization test) ) and other work. On the basis of these research work, the process of “continuous grinding, weak magnetic-strong magnetic-anion reverse flotation†was selected as the process flow of the newly-built Qishanshan iron ore beneficiation branch of Anshan Iron and Steel Co., Ltd. From March 1998, the plant began to operate until the end of 2002, and the mineral processing technical indicators continued to increase. By the end of 2002, with an ore grade of 29.69%, it achieved an ideal annual average of 66.80% of iron concentrate grade, 7.47% of tailings grade and 84.28% recovery rate, which can generate an economy of more than 400 million yuan per year. Benefits, with international leading level. The influence of the ideal selection index after the process of “continuous grinding, weak magnetic-strong magnetic-anion reverse flotation†was adopted by the Qishanshan Iron Ore Dressing Plant of Anshan Iron and Steel Co., Ltd., starting from 1998, one pass to pass the process. The core process "magnetic separation - anion reverse flotation" sorting process to improve the beneficiation index research work, in the national red iron ore concentrator and magnetite ore dressing plant in full swing. On the basis of the research results, since 2000, technical transformation has been carried out in some concentrating plants, so that the red iron ore concentrator represented by Qidashan concentrator and the magnetite concentrator represented by Jianshan iron ore beneficiation plant While the mineral processing technical indicators have been greatly improved, huge benefits have been generated, which have had a major impact in the domestic mineral processing industry. Therefore, based on the research process of the related process flow with the magnetic separation-anion reverse flotation process as the core, the characteristics of the magnetic separation-anion reverse flotation process are analyzed. How to make the "magnetic separation-anion reverse flotation" sorting process work better and put forward opinions, further promote the role of "magnetic separation-anion reverse flotation" sorting process, and promote the progress of China's mineral processing technology, it will certainly start To positive promotion.
I. Status and utilization of iron ore resources at home and abroad
(1) Iron ore reserves at home and abroad
In order to further clarify the resources of iron ore at home and abroad, the iron ore resources of the world's major iron ore production as of the end of 2001 were counted. The results are shown in Table 1.
Table 1 Iron ore reserves of major iron ore producers in the world
From Table 1, China's iron ore accounted for 16.20% of the world total), ferrous metals accounted for 9.23 percent of the world total, with an average iron grade of 56.99% is the world average iron grade, relatively large reserves of iron ore resources , but the quality is poor.
(II) The situation of rich reserves of China and the world's major iron ore producers In order to further clarify the reserves of China and the world's other major iron ore-rich mines, this was investigated. The results are shown in Table 2.
Table 2 The reserves and quality of rich ore in the world's major iron ore producing countries
It can be seen from Table 2 that China has a small proportion of rich ore reserves and a low iron grade compared with the world's major iron ore producing countries. The iron content of iron ore in different countries is also different. Brazil's iron ore has low silica content and is a good iron ore resource.
(III) Technical indicators of iron concentrates in China and the United States for iron ore beneficiation
Compared with the United States, the average iron content of total resources in China is very close, at 30.00% and -30.67% respectively; the proportion of rich ore is also the least among the world's major iron ore producers, respectively 2.80% and 12.06%. Obviously, the tasks of China's and the United States facing the progress of mineral processing technology are relatively heavy and comparable. This is also the case. The level of mineral processing technology in China and the United States is relatively high in the world. Therefore, the iron ore concentrate technical indicators of poor iron ore beneficiation in China and the United States are compared. The results are shown in Table 3.
Table 3 Technical Index of Iron Concentrates in Lean ore Ore Dressing in China and the United States
It can be seen from Table 3 that China's mineral processing technical indicators have a certain distance from the US mineral processing technical indicators. Since the iron ore resources of the two countries are similar, it is necessary and speedy for China to accelerate the progress of mineral processing technology.
Second, the magnetic separation-anion reverse flotation process related process research
In view of the current poor quality of iron ore in China, the state attaches great importance to the research of mineral processing technology. In particular, during the “Seventh Five-Year Plan†period, the “Study on the Rational Mineral Processing Technology of Qi Dashan Iron Ore†was issued, which put forward higher requirements for Chinese mineral processing workers. After nearly 10 years of struggle, the process of “continuous grinding, weak magnetic-strong magnetic-anion reverse flotation†with world-class level was finally introduced in the Qidashan Iron Ore Dressing Plant of Anshan Iron and Steel Group. Then, Anshan Iron and Steel Group Qidashan Concentrator, Taigang Group Jianshan Iron Mine, Laigang Group Hanwang Iron Mine, Anshan Iron and Steel Group Donganshan Sintering Plant and other units have begun to "continuous grinding, weak magnetic! Strong magnetic! Anion anti In the flotation process, the core selection process “magnetic separation-anion reverse flotation†is the main content of the research work, and both have achieved good results.
(1) Magnetic separation! Anion reverse flotation separation process
The "magnetic separation-anion reverse flotation" sorting process includes a "weak magnetic-anion reverse flotation" sorting process and a "weak magnetic-strong magnetic-anion reverse flotation" sorting process. The former is mainly used for sorting magnetite; the latter is mainly used for sorting red iron ore. However, the principle flow of the two is consistent. See below.
Principle of magnetic separation-anion reverse flotation process
(II) Study on rational beneficiation process of Qidashan Iron Mine
1. Basic research work of Changsha Research Institute of Mining and Metallurgy
The research on the rational beneficiation process of Qidashan Iron Mine began in 1984 and completed the final plan in 1990, and it took nearly 10 years. Among them, the Changsha Research Institute of Mining and Metallurgy has made the most innovative steps in the previous research work, and it is the most meaningful. It has achieved new breakthroughs in mineral processing methods and new breakthroughs in pharmaceuticals. On the basis of completing a large number of preliminary laboratory work, the "weak magnetic-strong magnetic-yin (yang) ion reverse flotation" and "continuous grinding" method were carried out from March 10 to May 10, 1987. Weak magnetic-strong magnetic-spiral chute-anion reverse flotation" was extended to a total of four programs. The results are shown in Table 4.
Table 4 Four schemes expand the continuous test results
(The grinding method is continuous grinding)%
As can be seen from Table 4, regardless of the structure of the process, the selection method, or the type of pharmaceutical, the Changsha Research Institute of Mining and Metallurgy has carried out a lot of work and achieved good selection indicators. Finally, the Changsha Institute of Mining and Metallurgy recommended industrial testing in accordance with the “continuous grinding, weak magnetic-strong magnetic-anion (RA-315) reverse flotation process scheme.
2. The industrial test of the rational beneficiation process of Qidashan Iron Mine is based on the optimization of the process provided by the participating units, according to the “Continuous Grinding, Weak Magnetic-Strong Magnetic-Anion Reverse Flotation†provided by Changsha Research Institute of Mining and Metallurgy. “Process flow, “stage grinding, re-election-magnetic selection-acid positive flotation†process and “continuous grinding, weak magnetic-strong magnetic-cation reverse flotation†process provided by Anshan Mining Company Research Institute of Anshan Iron and Steel Group Co., Ltd. And the industrial process of "continuous grinding, weak magnetic-strong magnetic-acidic positive flotation" provided by Maanshan Mine Research Institute was carried out. The results are shown in Table 5.
Table 5 4 kinds of process flow industrial test results%
It can be seen from Table 5 that the “continuous grinding, weak magnetic-strong magnetic-anion reverse flotation†provided by the Changsha Research Institute of Mining and Metallurgy has the characteristics of high mineral processing technical index. And its alkaline pulp is conducive to the transportation of more economical concentrate pipelines. Then, in order to be safe, the industrial verification test, concentrate dewatering filtration test and backwater utilization test were carried out according to the process of “continuous grinding, weak magnetic-strong magnetic-anion reverse flotationâ€. Effect.
According to the process of “continuous grinding, weak magnetic-strong magnetic-anion reverse flotationâ€, the Anshan Steel Qidashan Iron Ore Dressing Plant has shown strong vitality once it is put into production. In 2002, the whole plant's beneficiation index achieved an ideal index of 66.80% of iron concentrate grade, 7.47% of tailings grade and 84.28% metal recovery rate when the original ore grade was 29.69%. The economic benefit is taken as an example in 2002. The annual benefit of mineral processing itself is 124 million yuan, and the annual profit of the process after mineral processing is 280 million yuan.
(III) Experimental study on process optimization of Qidashan Concentrator
The original process adopted in the first workshop of Qidashan Concentrator was “stage grinding, re-election-magnetic separation-acid positive flotationâ€. The technical index is 28.49% of the original ore grade and 63.60% of the iron concentrate grade. The grade is 11.36% and the metal recovery rate is 73.20%. Influenced by the better beneficiation index of the Anshan Iron and Steel Qidashan Iron Ore Dressing Plant, Anshan Iron and Steel Group Anshan Mining Co., Ltd. began in 1998, around the Qi Dashan Concentrator "stage grinding, re-election - magnetic separation - acid positive flotation" process The research on the process of “stage grinding, re-election-magnetic separation-anion reverse flotation†was carried out. On the basis of the small test and single system industrial test, in mid-September 2000, half-field industrial test was carried out, and the original ore grade was 28.58%, the iron concentrate grade was 65.10%, the tailings grade was 12.35%, and the metal recovery rate was 70.09. % of the ideal beneficiation indicators. At the end of 2000 and the end of 2001, the two beneficiation workshops of the first and second selection workshops of the Qidashan Concentrator of Anshan Iron and Steel Co., Ltd. were technically modified according to this process. Although the ore conditions are deviated during the process test, and the factors such as the unsuitable impact indicators of the equipment, the beneficiation index after the transformation has been greatly improved. In the first half of 2003, with an ore grade of 29.50%, the iron concentrate grade was over 67.40% and the tailings grade was below 11.00%. The process transformation of Qidashan Concentrator will bring about 80 million yuan of benefits per year to the beneficiation plant, which will bring huge benefits to the ore dressing plant. This is rare in the transformation of the old ore dressing plant.
The "magnetic separation-acidic positive flotation" selection process in the original "stage grinding, re-election-magnetic separation-acidic flotation" process in the first workshop of Qidashan Concentrator was changed to "magnetic separation-anion anti-floating" The selection of the "selection process" has enabled such a large improvement in the mineral processing technical indicators, which was unexpected. This in itself reflects the strong vitality of the "magnetic separation - anion reverse flotation" selection process.
(IV) Research on the application of "magnetic separation-anion reverse flotation" process in other mineral processing plants
Taiyuan Jianshan Iron Ore Dressing Plant is one of the domestic manufacturers of “magnetic separation-anion reverse flotationâ€. The main practice is to carry out anion reverse flotation after the process, and the anion reverse flotation operation has an ideal experimental research index of 69.08% iron concentrate grade and 98.24% recovery rate when the input grade is 65.75%. According to this plan, after the completion of industrial transformation at the end of 2002, the mineral processing technical indicators have been greatly improved, and the benefits are remarkable.
Anshan Iron and Steel Donganshan Sintering Plant carried out industrial tests according to the principle process of the reformation of Qishanshan Concentrator in Anshan Iron and Steel Co., Ltd., which made the original process grade 32.47%, the iron concentrate grade 59.98%, the tailings grade 14.72%, and the metal recovery rate 72.94%. The mineral processing index was raised to 31.38% of the original ore grade, 64.08% of the iron concentrate grade, 13.77% of the tailings grade, and the ideal sorting index of the metal recovery rate of 71.47%. After the industrial transformation, although the process is relatively difficult to reduce tailings in Donganshan iron ore. However, the process has a strong vitality for the large improvement of the Donganshan iron ore.
At the same time, Laigang Hanwang Iron Mine, Angang Dagushan Concentrator, Zhejiang Yantie Mine, Wuhan Iron and Steel Daye Iron Mine and Chengchao Iron Mine have all adopted the "magnetic separation-anion reverse flotation" selection process to improve The research work of mineral processing technical indicators has a relatively good effect. And some have made significant progress.
Third, the magnetic separation - anion reverse flotation selection process characteristics
1. Better adapt to the process mineralogy characteristics of iron ore in China. From the overall situation of China's iron ore, it has the characteristics of large reserves and poor quality. This feature indicates that China's iron ore must strengthen the pre-tailing and coarse concentrate re-election work. At present, magnetic separation (including weak magnetic and strong magnetic) operations is one of the effective means of pre-spinning; anion reverse flotation operation is one of the effective means to improve the grade of iron concentrate. In particular, in the process of beneficiation, both of them are selected from the useful or gangue minerals with less content in the mineral materials, and both use the most different aspects of mineral selectivity. It works well in the entire process flow. For most of the red iron ore mines in China, there is a tendency from the shallow part to the deep part of the mine to change from red iron ore to magnetite, which makes the change of FeO more frequent and has an increasing trend. This trend has led to many unsuitable problems in the "magnetic separation - acid positive flotation" sorting process in the original process of the Qidashan Concentrator. For the magnetic separation-acidic positive flotation in the original process of Qidashan Concentrator, when the FeO is low, the amount of concentrate in the weak magnetic separation is relatively small, the sorting effect is better, and the concentrate grade is relatively high. In the "strong magnetic-acidic positive flotation" part, the amount of inclusion is increased, and the selection effect is poor. When FeO is high, the amount of concentrate in the weak magnetic separation part is large, the sorting effect is relatively poor, and the concentrate grade is relatively low. In the "strong magnetic-acidic positive flotation" section, the amount of inclusion is reduced, and the sorting effect is better. The change in the amount of concentrate in the weak magnetic separation due to the change in FeO and the change in the amount of "strong magnetic-acidic positive flotation" are the qualitative changes in the selection. This is also the case, the original process of the Qidashan Concentrator, the concentrate, especially the concentrate grade has been poor. After adopting the "strong magnetic-anion reverse flotation" sorting process instead of the "strong magnetic-acidic positive flotation" sorting process, on the basis of strong magnetic tailing, the amount and grade of entering the reverse flotation are basically the same, avoiding The original process of Qidashan Concentrator caused fluctuations in the index due to fluctuations in flotation volume, thus making the indicators more advanced.
2, magnetic separation job tailing is an ideal job to provide ideal conditions for the next section of work. Magnetic separation is an ideal finishing operation. For magnetite, magnetic separation is economical and the efficiency of sorting is high, especially in the tailing. Due to the large room for field strength adjustment, the tailing is adjustable, and its operation has been widely used in magnetic separation plants. Magnetic separation operations are widely used in magnetite ore dressing plants, not because of their upgrading, mainly because of their tailing effect. On the contrary, in the case of higher grades, it is often not effective to rely on magnetic separation to improve the quality; for red iron ore, strong magnetic separation is not only an effective means of tailing, but also effective by tailing. A sorting operation that provides ideal working conditions for the next stage of work. At present, the current situation of strong magnetic separation widely used at home and abroad red iron ore dressing plant tailings illustrates this point.
3. The anion reverse flotation process has an efficient sorting effect. Once applied, the anion reverse flotation process shows great vitality. This powerful support of vitality is a good selection mechanism for the anion reverse flotation process. On the one hand, reverse flotation takes full advantage of the gravity properties of minerals. Generally, the density of quartz is about 2.65 g/cm 3 , the density of iron mineral is about 5.0 g/cm 3 , and the density of pulp is between (1 and 2) g/cm 3 , making quartz effective in pulp. The gravity is much lower than the effective gravity of the iron mineral in the slurry. This suggests that quartz is better in flotation than the effective pharmaceutical system from the gravity feature. Anionic reverse flotation operation, a total of sodium, 4 kinds of agent acting starch, calcium oxide, and other collectors in the pulp occurs, many kinds of agents, control can be achieved by a plurality of flotation in the process variables. The increase in the variety of drugs makes the flotation process more targeted. Among them, only the sodium hydroxide therein has the effect of adjusting the pH value of the slurry, changing the surface potential of the slurry, and affecting the occurrence state and effect of other agents.
4. It is more suitable for the development requirements of China's steel industry. In the new century, on the one hand, after joining the World Trade Organization, the competition in the iron concentrate market will become more and more fierce; on the other hand, China's steel industry has accelerated the pace of moving from a steel power to a steel power. These two aspects require China's mineral processing industry to continuously improve the concentrate grade while requiring iron concentrate to reduce costs. The "magnetic separation-anion reverse flotation" sorting process is the best sorting process to reflect this requirement and is one of the most vital sorting processes under today's conditions.
Fourth, the application of magnetic separation - anion reverse flotation selection process recommendations
1. Strengthen the promotion and application of magnetic separation-anion reverse flotation separation process. From the application of magnetic separation-anion reverse flotation sorting process in China, whether it is Qidashan Iron Ore Dressing Plant, Qidashan Concentrator, or Jianshan Iron Ore Dressing Plant; whether it is magnetite ore dressing plant, The red iron ore concentrator has achieved good sorting results in the magnetic separation-anion reverse flotation separation process. In today's increasingly fierce competition in the iron concentrate market and the steel industry is increasingly demanding the quality of iron concentrates, China's iron ore should be in an invincible position in the competition under the condition of poor quality, and continuously meet the steel. Industry needs to accelerate technological progress in the quality requirements of iron concentrates. There is no doubt that the magnetic separation-anion reverse flotation separation process is one of the most worthwhile studies.
2. Enhance the optimization of the magnetic separation-anion reverse flotation separation process. For the red iron ore concentrator, the main problem is to solve two problems. One is to shorten the number of segments of the magnetic separation operation as much as possible. In the past, red iron ore required weak magnetic, medium magnetic and strong magnetic before anion reverse flotation. New magnetic separation equipment , including the SLon vertical ring pulsating high gradient magnetic separator, has made it possible to simplify the magnetic separation due to improved performance. At the same time, there are differences in ore conditions in each mine. Therefore, it is necessary to strengthen the research work on the simplified selection process of the magnetic separation part. The second is to study and improve the anion reverse flotation process. As a result of the return of the sweeping essence, it is traditionally believed that the sweeping essence should return to the concentration tank before the rough selection. However, at present, some concentrating plants will return to the rough selection directly, and the effect is good, which should attract attention. For the magnetic separation plant, it is necessary to strengthen the reasonable magnetic separation and tailing work, so that the functions of magnetic separation and anion reverse flotation can be mutually coordinated, and better in the case of shorter process flow and lower operating cost. effect. This point is the shortcoming of some magnetite ore dressing plants to increase the anion reverse flotation process after the original process.
3. Strengthen the research work of new equipment. In terms of magnetic separation, it is necessary to strengthen the research work of a strong magnetic separator that has strong compatibility and is conducive to shortening the number of magnetic separation sections. And relying on the continuous development of new materials, accelerate the research work of permanent magnet magnetic separator. For the flotation machine, there is not only a problem of selection, but also what should be paid attention to: to better distinguish the difference between the flotation machine selected by the concentrate and the flotation machine with the lower grade. The problem has not attracted attention and has caused inconvenience to some concentrators.
4. Strengthen the research work of new pharmaceuticals. For different concentrators, there should be different pharmacy systems. At present, the research work of pharmaceuticals is progressing rapidly. However, by studying the compounding agent, the agent has the characteristics of simultaneous preparation and simultaneous addition. Although some progress has been made, there is no industrial application yet, and it needs to be strengthened. At the same time, research on green non-toxic, non-polluting and degradable agents should be strengthened.
Author unit
Changsha Research Institute of Mining and Metallurgy (Zhang Yusheng)
Anshan Iron and Steel Group Anshan Mining Company (Dunk)
Anshan Iron and Steel Group Anshan Mining Company Research Institute (Li Weibing)
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