Improving the utilization rate of wine steel resources from the development of mineral processing technology

I. Introduction

Minerals are non-renewable resources, with the rapid development of steel industry scale, China's iron ore available dwindling resources, rely on a large number of imports to maintain. According to statistics, as of the end of 2002, China has discovered 8,896 iron ore deposits (points), and has explored 2,034 sites. The accumulated proved reserves are 62.8 billion tons. After deducting the historical reserves and reserves, the reserves of reserves are 57.8 billion tons, but the economically recoverable reserves. It is only about 10 billion tons, and more than 80% of the iron ore reserves belong to the boundary economic reserves, sub-boundary economic reserves or prospective reserves with low exploration level, low grade, deep burial and poor mining and selection technology. In the past 20 years, the exploration of iron ore resources has been basically stagnant, and the recoverable reserves have experienced a large negative growth trend. Iron ore resources in our province is small, less than 2% of total reserves, but they belong to the majority poor, fine, miscellaneous hard mineral stone, so to improve resource utilization. Making full use of the resources already collected is of great significance to the sustainable development of the wine steel.

In recent years, with the continuous growth of China's economy and the adjustment of a new round of product structure, the sustainable development of resources has been recognized and valued by more and more people. China's mineral processing science and technology workers seize the opportunity and have sufficient resources. A lot of research and practice have been carried out on recycling and reducing cost and energy consumption. In just a few years, a batch of mineral processing scientific and technological achievements have been ranked among the international advanced, some of the results have been transformed into productivity, and production and application have achieved obvious results. . For example, some new high-efficiency beneficiation equipment applications, the application of new high-efficiency flotation reagents, and the application of new processes resulting in this have resulted in a significant increase in the concentrate grade of the application unit or a significant decrease in production costs. All have achieved certain economic benefits.

Jiuquan Iron and iron ore due to the unique nature of the ore, mineral composition is complex, disseminated fine grain size, low-grade theoretical characteristics, resulting in a highly refractory ore, metallurgical performance is poor, high impurity content, especially more metal recovery rate is low, The tailings have high grade and low resource utilization. After decades of unremitting efforts by technicians, the beneficiation index has been improved to a large extent, especially the application of anti-flotation and refining technology, which greatly optimized the roasting magnetic selection index. However, overall, the progress is still relatively slow. Many specialized research institutions in China have conducted special research on the wine steel ore, but have not achieved very obvious research results, and there are still many problems to be solved in the process. In the following years, in recent years, the development of new technologies, new equipment and new processes for domestic beneficiation, combined with the actual mineral processing of Jiuquan, will be briefly discussed from the perspective of improving resource utilization.

Second, implement the idea of ​​“breaking more and less grinding” and reduce the granularity of grinding

The purpose of crushing is to create conditions for grinding, reduce grinding energy consumption, improve grinding efficiency and increase processing capacity. Grinding operation is the most energy-consuming part of mineral processing, accounting for 50% to 60% of the total energy consumption of the ore dressing plant, and even higher. Minimizing the grinding time is an effective way to reduce energy consumption and improve grinding effect. The main method is to reduce the size of the ore into the mill by adopting a new type of crushing equipment with large size, large crushing ratio, high efficiency and low consumption. According to this need, crushing equipment at home and abroad has been rapidly developed. For example, HP type cone crusher produced by Nordberg Company of the United States can achieve a particle size of 12~7 mm or less. There are more than 100 different types of crushing equipment in production in China, such as Baotou Steel in the mine 0-100 Under the particle size of mm, HP800 cone crusher is used , the content of -12mm in the product is over 95%; Wujiang Chengchao Iron Mine uses 3 HP500 cone crushers instead of φ2100 spring cone crusher, and the crushing capacity is improved from 2 million t/a. Up to 3.8 million t/a, the size of crushed ore reached 95%-10 mm, and the output of iron concentrate increased by more than 40%. The Qidanshan Concentrator and the Tuanjuntai Concentrator of Anshan Iron and Steel Co., Ltd. have also used this equipment for fine crushing, which has achieved significant energy saving. effect. The H series hydraulic cone crusher produced in Sweden also has the advantages of fine crushing size, high output and low energy consumption. The domestic application of the concentrator has also achieved satisfactory results.

China has also carried out a lot of research and improvement on crushing equipment and technology. The high-pressure roller mill developed by Beijing Research Institute of Mining and Metallurgy can achieve the effect of ultra-fine crushing and coarse grinding. The final crushing particle size can be reduced to below 3 mm (not yet Used in production), which greatly reduces the grinding energy consumption of the ball mill. In addition, the column mill developed by Changsha, the crushing king series produced in Guizhou and other types of cone crushers have high crushing efficiency.

The Jiugang concentrator was designed in the 1950s. Its crushing and grinding process has been applied to this day, and there has been no major technical improvement, especially in terms of crushing. The ore produced by the company is divided into lump ore (greater than 15 mm) and fine ore (less than 15 mm) after being coarsely crushed and crushed in the Jingtieshan Mine. It is transported to the concentrator, and the lump ore enters the shaft furnace for roasting. The mine directly enters the grinding. After roasting, the ore directly enters the ball mill for grinding without any processing. Although some of the ore is crushed into two or several pieces along the crack after roasting, the grain size of the grinding is still very high. In China, no large-scale concentrator has achieved this. The coarse grinding grain size is trying to take the road of “multiple crushing and less grinding”. Although the ore becomes more abrasive than that before calcination, the excessive particle size still results in low grinding efficiency, low grinding treatment capacity and high grinding energy consumption. The use of advanced fine crushing equipment to further crush the ore after roasting to 12mm or less will inevitably greatly increase the production capacity of the ball mill and greatly reduce energy consumption. For fine ore, although the particle size is already fine, from the development trend, the grain size of -15 mm will also become backward. Without crushing, the grinding index of the powder ore system will still be at a domestic backward level. . Studies have shown that the subsequent crushing particle size will meet the requirements of directly extracting some qualified concentrates, that is, it will reach 3 mm or less, or even below 0.1 mm, directly reaching a grinding effect. Therefore, from the overall consideration, it is recommended to increase the fine grinding operation in the beneficiation process to improve the grinding effect, improve the grinding efficiency and increase the output.

Third, optimize the grinding and grading process. Improve grinding results and reduce the production of coarse-grained and fine-grained products

The role of grinding operations is to separate the target minerals from the gangue mineral package to the maximum extent, and create conditions for the next step of beneficiation and purification. For a specific ore, it has its own most suitable grinding fineness. When the grinding particle size is coarse, the target mineral and gangue minerals are not fully dissociated, so that a large number of gangue minerals enter the concentrate with the target mineral in the form of continuum. It also allows some of the target minerals to enter the tailings in the form of lean organisms. When the grinding grain size is fine, not only the grinding energy consumption is increased, but also some of the target minerals are over-grinded, and the resulting fine-grained grade enters the tailings due to the efficiency of the beneficiation equipment. Both of these conditions will affect the selection of indicators and reduce the recovery rate. Therefore, optimizing the grinding and grading process and minimizing the production of coarse-grained and fine-grained products are important guarantees for improving the selection index and increasing the recovery rate.

From the current grinding and grading equipment and process development technology, the development of grinding equipment at home and abroad is relatively slow. At present, only the grinding mill has been successfully developed. Compared with the ball mill, this type of mill can reduce energy consumption by 30% to 50%. . The basic trend of the development of grinding equipment is large-scale, and the power consumption, steel ball consumption and lining consumption are greatly reduced after the equipment is enlarged. At present, relatively more research is still on the quality of the steel ball and the improvement of the quality of the lining and the improvement of the grinding machine transmission, and the purpose is still to further reduce the energy consumption. Grading equipment has achieved rapid development in recent years. The United States Derek derrick high-frequency vibration fine screen, China Tangshan MVS Lukai high-frequency vibration mesh screen, Weihai Haiwang cyclone, etc. have high classification efficiency. The advent of these high-efficiency grading equipments has led to the transformation of traditional grinding processes. The traditional grinding process forms closed-circuit grinding for ball mills and spiral classifiers. Due to the low classification efficiency of spiral classifiers (generally only 20% to 30%), The grinding energy consumption is high, the grinding effect is poor, and the over-grinding phenomenon and the insufficient grinding phenomenon coexist. The use of the above classification equipment instead of the spiral classifier or in series with the spiral classifier can greatly improve the classification efficiency, reduce the grinding energy consumption, and improve the grinding effect. At present, many concentrators have already achieved industrial applications or are about to be retrofitted.

The grinding grain size of the Jiugang concentrator has also been greatly improved in recent years. For example, the spiral classifier is changed to the cyclone closed circuit classification, the classification efficiency is improved, and the grinding fineness is obviously improved, but it is still not ideal. According to the embedded characteristics of the wine ore, when the fineness of the grinding reaches 95% or more, the iron mineral can obtain sufficient monomer dissociation, and the current grinding fineness is only 80%-85%, which has not yet reached The ideal fineness is an important factor affecting the quality of the concentrate. At the same time, there are a large number of fine-grained grades (below 30μm) in the grinding products. This part of the grinding products often has a low recovery rate due to exceeding the recycling range of the sorting equipment, especially the SHP strong magnetic used in the wine steel. Through the machine, the recovery effect on the -30 micron size is very poor. Therefore, in the grinding and grading process, the Jiugang concentrator has more work and needs technical personnel to do it. First, in the grinding production, high-quality wear-resistant consumable materials should also be used to reduce the grinding cost. At the same time, a more reasonable steel ball addition system should be studied to improve the grinding effect. Second, further study on efficient grinding. The grading process selects the grading equipment suitable for the wine ore, and the grinding and grading are effectively matched to increase the fineness of the grinding. Even if the mineral is fully dissociated, the segregation is timely and the over-grinding is reduced. The third is to explore the rationality of multi-stage grinding, increase the number of grinding sections, reduce the grinding time of each section, in order to ensure that the grinding fineness is evenly maintained in the required size range.

At present, the use of hydrocyclone and grinding to form a closed-circuit grinding process has been promoted, and the high-frequency vibrating fine screen and the matching technology of the mill have achieved more obvious results. For example, Laiwu Laiwu Mining Company used Derrick high-frequency vibrating fine screen to replace the original cyclone and nylon fine screen in the second stage of grinding. The screening efficiency is as high as 85%-90%. The capacity of the new-200 target has been increased from the original 1.1 t/(h·m 3 ) to 1.6 t/(h·m 3 ), and the classification efficiency has been improved, which has greatly improved the processing capacity of a section of grinding, with an annual benefit of more than 3,000. Ten thousand yuan. The effect of the application of another mining company in Laiwu Steel is also very obvious.

4. Select high-efficiency beneficiation equipment and beneficiation process to reduce the loss of target minerals

The mineral processing equipment is the focus of the development of mineral processing technology . In China's mineral processing equipment, the magnetic separation equipment is developed rapidly. Such as permanent magnet medium field magnetic separator, dry permanent magnet strong magnetic separator, high gradient magnetic separator, wet permanent magnetic pulse magnetic separator, multi-magnetic magnetic separator, magnetic separation column, new magnetic gathering machine, magnetic field screening The magnetic weight sorter used for the separation of fine-grained magnetites, which is invented by the machine and the retired high-tech workers, has a variety of magnetic separation equipment for different properties, different fineness and different uses. The sorting is performed, and the efficiency of the sorting is higher than that of the old magnetic sorting equipment. At present, these equipments have been widely used in different concentrating plants, and the indicators have been significantly improved, resulting in great economic benefits. For example, in 2002, the Jiugang concentrator renewed the old magnetic separator to a multi-magnetic magnetic separator. The sorting efficiency was significantly improved. The final concentrate grade increased by more than 0.5 percentage points, and the recovery rate also increased to some extent. The disc magnetic separator is used for tailings recovery and also produces better results. In recent years, China's strong magnetic separation equipment and flotation equipment have also developed rapidly, and a large number of domestic concentrating plants have been put into production and application.

Since the establishment of the Jiugang Concentrator, the roasting magnetic separation process has undergone some technical transformations. However, before the flotation process was put into production, the overall process change was small. The overall view was mainly due to the low iron recovery rate and high tailings grade. (Up to 18% to 20%), which is basically the worst indicator in domestic large-scale concentrators, which greatly affects the recovery rate of iron minerals. Therefore, researching a reasonable process, developing and introducing efficient beneficiation equipment is the main work content for improving the quality and resource utilization of concentrates in the future.

(1) Mineral processing equipment

Magnetic dewatering tank equipment. The magnetic dewatering tank that has been applied since the establishment of the Jiugang Concentrator has been designed to remove fine mudstones and create favorable conditions for subsequent magnetic separation operations. However, from today’s perspective, it was produced in the 1950s and 1960s. Is the equipment still a highly efficient de-sludge equipment? As a sorting operation, can the beneficiation efficiency be adapted to the high-efficiency and low-cost development needs? In fact, the dewatering tank is far less efficient than magnetic separation. Machine, and the dewatering tank needs stable water supply pressure and feed, and the fluctuation of water pressure and ore supply will directly affect the selection index. (When the dewatering tank operation parameters are adjusted, the ore and feed water need to be stable, water pressure When the ore is changed, the amount of mud removal is reduced or even disappeared. When the amount of water and the ore is increased, it is “running black” and the iron mineral is lost), so it needs to be adjusted at any time. After decades of practice, there have been many improvements in the domestic magnetic dewatering tank, such as the patented high-efficiency magnetic dewatering tank, and there are already more efficient alternatives. We should choose more suitable and more efficient equipment. If magnetic separation is used instead.

Multi-pole magnetic separator. The equipment is a highly efficient equipment for new applications, but even after this three-stage magnetic separation, the silicon content in the final concentrate is still as high as 10% or more, indicating that only the magnetic separator is used to improve the concentrate grade and the silicon content. It is difficult to reduce below 10%. According to analysis, a part of the silicon in the concentrate is a fine-grained gangue which has become a monomer, and a part is a coarse continuous body. The equipment for sorting fine-grained gangue has a magnetic separation column and a magnetic weight sorter (the industrial test has been completed in the Jiugang concentrator, and the effect of removing the fine-grained gangue is obvious), while the equipment for the continuum has high-frequency vibration. Fine sieve (laboratory research shows that the sieve grade of 0.1mm or more can be screened out, the concentrate grade can be increased by more than 1%. The sieved product is returned to the mill for regrind) and the magnetic field screening machine (applied by the existing concentrator) Etc., research should be strengthened to introduce equipment suitable for the improvement of wine steel indicators.

SHP wet magnetic separator. The equipment was developed in the 1970s and put into production in the early 1980s. It has made important contributions to the utilization of our company's fine ore resources for more than 20 years. With the development of mineral processing technology, from the current point of view, the equipment selection index is not ideal, the concentrate grade is low, the silicon content is high, and the iron recovery rate is low. The magnetic separator has poor recovery effect on the particle size below 30 μm, so that many fine-grained iron minerals which have been dissociated from the monomer enter the tailings, greatly reducing resource utilization. How to improve and optimize the strong magnetic separator, so that the sorting efficiency is greatly improved, and research needs to be carried out. SHP strong magnetic machine has a single magnetic magnetic medium, fast tooth tip wear and easy scaling. It is an important reason for the selection of indicators. As the main mineral processing equipment of our company, researching high-efficiency magnetic magnetic medium is also one of the ways to improve the index.

Slom vertical ring pulsation high gradient magnetic separator. The strong magnetic machine runs smoothly, consumes less power, and is easy to maintain. However, the grade of tailings has been high for more than 23% in the past few years, which has seriously affected the recovery rate of strong magnetic and reduced resource utilization. From the current operation, due to the weak magnetic properties of the Jiugang ore, the gradient of the high gradient is not high, and the magnetic field is insufficient to cause insufficient magnetic field force, thus affecting the recovery of weak magnetic minerals, such as thin rods and mesh media can improve the selection index. Therefore, high-gradient magnetic separators also need to conduct research and research on magnetic media.

(2) Mineral processing technology

Compared with the domestic large-scale concentrator beneficiation process, the strong magnetic separation process of Jiuquan Steel can be described in two words: simple. Simple process can reduce the cost of beneficiation processing, but for complex ore properties, a simple process will inevitably result in poor selection criteria. At present, the content of silicon in the strong magnetic separation concentrate of Jiuquan is as high as 10%, and the recovery rate of strong magnetic separation is only about 67%. Compared with domestic large-scale concentrators, it is a very backward indicator. In order to improve the selection index and improve the resource utilization rate as much as possible, many large-scale concentrating plants at home and abroad have carried out the “fine grinding and deep selection” transformation. Some factories have only reached more than a dozen segments, and the indicators have been greatly improved. Jiuquan Steel should carry out a lot of work in the selection process to research, introduce and improve the process suitable for the nature of its own ore.

5. Explore new processes to increase recycling rates

(1) Application of flotation process

In the previous iron ore beneficiation, flotation was only used in the red ore. For example, the Anshan Iron and Steel Concentrator in Anshan Iron and Steel Co., Ltd. directly produced iron ore concentrate with a grade of about 60% by cation positive flotation. With the rapid development of equipment and technology such as magnetic separation and re-election, the position of flotation in iron ore beneficiation has declined, and there are few application manufacturers. Until recently, with the implementation of the national “fine material policy” and the proposal of “lifting iron and reducing phosphorus ” in recent years, the role of flotation in iron ore selection has become more and more obvious, and it has become the most important means of silicon reduction. The technology was first used in the Anshan Iron and Steel Plant Concentrator in 1997. At the initial stage of production, the iron concentrate grade was around 64% to 65%. In recent years, in order to meet the market demand for iron concentrate quality, it has been continuously researched and adjusted. At present, the grade of concentrate has reached 67.5%. The success of using the strong magnetic tailing-anion reverse flotation process to treat the Anshan-type red iron ore has greatly promoted the production and application of the process, and then the Qidashan Concentrator, The Donganshan Concentrator has been transformed, the concentrate has been greatly improved (up 3.5 to 4.5 percentage points), the silicon content has also decreased, creating huge economic benefits. The Gongchangling iron ore has adopted cationic reverse flotation. It also effectively reduces the silicon content in the concentrate, the concentrate grade is increased from 65% to 68%, the silica content is reduced to below 4%, and the technical indicators have reached the advanced level of domestic and international mineral processing.

In view of the great success of the above manufacturers, the new development of anti-flotation and silicon reduction process has been opened up. Various ore dressing research institutions have studied high-efficiency flotation reagents for different iron ores, such as Beijing Research Institute of Mining and Metallurgy, Maanshan Mine Research Institute, Changsha Research Institute of Mining and Metallurgy, Anshan Iron and Steel Research Institute and Metallurgical Institute. Production of cation and anion reverse flotation reagents. Anion reverse flotation has relatively high application efficiency due to its high efficiency (high-grade iron concentrate and low-grade qualified tailings), fragile flotation foam (easy to follow-up operation), and many types of chemicals. This has also greatly promoted the development of anion reverse flotation technology.

The roasting magnetic separation-reverse flotation process that has been put into production by Jiugang has achieved great success and achieved remarkable results. The concentrate grade has been greatly improved, and the silicon content has decreased significantly. After the flotation of the magnetic separation concentrate The grade can reach more than 60%, and the silicon content falls below 7%. The strong magnetic separation system is still a single magnetic separation process with a low concentrate grade. The test results of the strong magnetic-flotation process carried out in the laboratory are that the concentrate grade can reach more than 50% and the silicon content falls below 7%. The application of the reverse flotation process guarantees the quality of our company's concentrate. Our next goal is to improve the magnetic separation process before flotation, to maintain high iron recovery rate at this stage and maximize the use of the company's mineral resources.

(2) Exploring the powder ore roasting process

From the selection index, the magnetic separation process of our company's concentrator is obviously superior to the strong magnetic separation process, mainly in the iron recovery rate, which is nearly 15% difference. If our company's fine ore can also successfully use the roasting magnetic separation process, it will greatly improve our company's resource utilization.

From the domestic point of view, the iron ore roasting magnetic separation process is currently only practical in the application of wine steel, so the domestic research on roasting equipment and processes is rare. In the 1970s, domestic research institutes conducted a large amount of roasting magnetic separation research on our company's fine ore, which was unable to achieve production due to equipment and process reasons. In recent years, the Changsha Mining Research Institute has carried out research on roasting technology. The technology of roasting kiln roasting iron ore has been converted into production, and the scintillation roasting technology has also achieved good indicators in the laboratory. Both roastings are suitable for fine ore. The technology, their successful research, provides the possibility for the application of our company's powder ore roasting magnetic separation process. As a technician, we will also strengthen the experimental research, such as the experimental research on the ball-making process after grinding, which will benefit early.

6. Develop a circular economy. Make full use of tailings resources

The traditional economic model is: resources - products - waste, with the reduction of resources and environmental protection requirements, the economic model has been transformed into: resources - products - secondary resources - products, this is the circular economy. It is characterized by high utilization of resources and low pollution. The wine steel beneficiation process is still in the traditional economic mode. More than 2 million tons of tailings are discharged into the tailings dam every year, which greatly reduces the utilization rate of the mineral resources of Jiuquan.

Since the production of non-waste technology has been promoted for many years, in recent years, there have been many new technologies and new processes in the utilization of tailings resources. The emergence of new technologies and new methods has made people have a new understanding of tailings. Recognize the resource nature of tailings, the dangers of the environment, and the importance of development and utilization. Tailings are a kind of renewable resources, but the treatment is really good, which will have a great impact on farmland and ecological environment. China's development and utilization of tailings is very rapid. In the field of materials, more than 80% of the tailings are non-metallic minerals. The composition is very similar to many non-metallic materials such as building materials, light industry and inorganic chemicals, as long as a small amount of other raw materials are added. It can be used as a raw material for many non-metallic materials by proper blending. At present, tailings are widely used in traditional industries such as ceramics, cement, glass, and paint.

(1) Recovering associated useful ingredients

The iron grade in Jiugang tailings is still high and should be recycled to increase the iron recovery rate. In addition, there is a large amount of barite minerals in the wine steel tailings, which is a non-metallic mineral rich in barium (component BaS0 4 ), and has a glass luster, a large specific gravity (4.3 to 4.7), and low hardness (2.5 ~3.5), chemically stable, non-toxic, non-magnetic, strong hiding rate, no chemical reaction in air and normal temperature, no discoloration in the air with hydrogen sulfide or toxic gases. It has good dispersibility, good weather resistance, flame retardancy and electrical insulation, and can absorb characteristics such as x-rays and gamma rays. Wide range of industrial applications in coatings, paints, paper, pharmaceuticals, glass, plastics, rubber, oil drilling, etc. Studies have shown that the use of flotation in the wine steel tailings can obtain a barite concentrate with a yield of 10% and a purity of more than 95% of barium sulfate, which can meet the quality requirements of many industries.

(II) Comprehensive utilization of tailings sand

Tailings is a kind of regenerative resource. After the minerals are extracted and the useful components are extracted, the slag is not treated in time and effectively. The accumulated accumulation of the slag has caused great damage to the environment and is also an extremely wasteful resource. Concentrator tailings discharged finer particle size, which can be reduced by as a raw material crushing, grinding cost, reduced coal consumption. Due to the close proximity of the inorganic materials such as glass, cement and ceramics in the silicate material, and the proper correction of the raw materials and the rare metal materials in the tailings, it is even better to produce better than conventional raw materials. The product. At present, tailings have successful application techniques in many fields such as cement production, production of glass-ceramics, ceramic tiles, lawn bricks, pavement bricks, manhole covers, hollow bricks, river sands, and ceramics. The application of tailings in building materials is accelerating and the scope of application is becoming wider and wider. The performance of tailings bricks can reach or exceed the common brick performance common in the market, and its cost is low, the production process is simple, the equipment is small, and the construction period is short, which provides an ideal raw material for the building materials industry, and also for beneficiation. The process has created conditions for the development of less tailings or tailings.

Conclusion

With the expansion of production scale, the contradiction between the shortage of wine and steel resources has become increasingly apparent. However, from the perspective of technological development, it is feasible to improve resource utilization. There are mature technologies already applied and mature equipment, and successful application will create considerable economic benefits for Jiuquan. Due to the special nature of the wine steel ore, the external successful technology cannot be completely copied. The technicians should conduct experimental research, research and improvement, and introduce equipment and process technology suitable for our own, so that the company should make full use of resources and take the road of sustainable development. Have contributed.

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