Mineral resources are the material basis for human survival and development, an important material guarantee for the sustainable development of economy and society, and a huge supporting force for China's rapid development. Phosphorus is an important strategic mineral resources in China, it is both the preparation and production of important chemical fertilizer mineral raw material of yellow phosphorus, phosphoric acid and a variety of other phosphorus products, as well as food safety is an important material, but also the material basis of Fine Chemical phosphorus, in It plays an important role and role in national economic and social development.
Phosphate mines in China are mainly distributed in 27 provinces and autonomous regions. Hubei, Hunan, Sichuan, Guizhou and Yunnan are phosphate-rich areas. Five provinces have identified phosphate reserves of about 3/4 of the country. China's phosphate rock resources are abundant and not rich. Compared with the countries in the world, China's phosphate rock has great differences in ore quality and selectivity. China's phosphate rock is rich in minerals, and there are many medium and low grade ore deposits. Most of the phosphate mines must be subjected to beneficiation and enrichment to meet the requirements of phosphoric acid and high-concentration phosphate compound fertilizer production. Among the proven reserves, sedimentary phosphate rock (glylite mine) accounts for 85% of China's total reserves, and most of them are medium and low grade ore. The mineral particles are fine, the inlay is tight, and there are many harmful impurities. The mineral processing is very difficult. Large, it has brought certain difficulties to the development and utilization of phosphate rock in China. Especially in recent years, with the continuous development and utilization of phosphate rock resources, the resources of rich phosphate rock and easy-selected phosphate rock are decreasing day by day. The research on the beneficiation technology of medium and low grade phosphate rock, especially the medium and low grade refractory phosphate rock has been studied. It is imminent. Facing the challenges of the scarcity of phosphate rock resources in the world, a comprehensive analysis of the current status of phosphate ore dressing technology , focusing on the progress of refractory phosphate rock flotation reagents is of great significance to the sustainable development of phosphate rock resources in China.
1 Status and progress of phosphate ore beneficiation technology
2. 1 Mineral processing technology
At present, the ore dressing process of phosphate rock mainly includes flotation method, rubbing and eluting mud process, gravity beneficiation, roasting) digestion method, chemical leaching technology, photoelectric beneficiation and joint beneficiation process.
2. 1. 1 flotation process
Flotation has always been considered the most effective method for phosphate ore dressing. The phosphate rock flotation method includes direct flotation, reverse flotation, positive and negative flotation, reverse flotation and double reverse flotation. In 1986, Hubei Jingjing Wangji built a 1.5 million t / a sedimentary phosphorite ore dressing plant, using direct flotation process to select colloidal phosphate rock, but the industrial production effect is not very satisfactory, especially for MgO, Al2O3 and Fe2O3 content. High phosphate ore dressing is difficult to achieve the desired index. Luo Huihua, Zhong Kangnian, etc., according to the nature of the ç“®ç¦æŸèƒ¶ç£·çŸ¿, using a reverse flotation process, combined with a new type of phosphate ore inhibitor, in the case of the ore P2O5 grade of 27.33%, MgO of 6.19%, A phosphorus concentrate having a P2O5 grade of 37.34%, a MgO0. 73%, and a recovery rate of 92.39% was obtained. A phosphate ore Liaoning P2O5 grade of 19.41%, Ge Yingyong, Wang Kai Jin et al., For the low-grade phosphate rock ore, the high magnesium content of silicon, embedded in the fine particle size distribution characteristics, the - reverse flotation process, The new medicaments MG and SR were used as positive and negative flotation collectors respectively. The closed-circuit test index of the mixed concentrate P2O5 grade of 32.07% and the recovery rate of 89.63% was obtained, which was effective for the purpose of minerals and gangue. Separation. The Lianyungang Design and Research Institute of the Ministry of Chemical Industry conducted a continuous expansion test on the lower mine of Haikou Phosphorus Mine. The main chemical composition of the mine is: P2O5 22. 31%, CaO34. 89%, MgO 3.29%, SiO222. 37%, trans-positive Flotation, finally obtained P2O532. 46%, phosphorus concentrate containing MgO1. 28%, phosphorus recovery rate of 73.40%. Ge Yingyong, Ji Rong, Yuan Wupu and others aimed at the properties of low-grade collophane ore in Yuan'an, and the P2O5 grade was 18.21% of the phosphate rock. The double reverse flotation process was adopted to obtain the P2O5 grade of phosphate concentrate. 13%, the recovery rate of 80. 74%, the MgO content of 0.93% of the ore dressing index.
2. 1. 2 "wipe off the mud" process
This technology is mainly used for weathering or phosphate rock containing more muddy materials. This technology can be used in phosphate rock in the Dianchi area of ​​Yunnan and other areas of the weathered phosphate rock, and can obtain good economic benefits. This technique scrubs the phosphate rock, removes the slime, and then sifts and grades. “Erasing mud†is a physical beneficiation method. It is simple in process, can be produced in the open air, and does not consume chemicals, so it will not pollute the environment.
This technology is widely used in foreign phosphate mines. For example, the Huliba plant in Morocco has a processing capacity of 1 million t/a. The process is to wash and classify with an impeller type washing machine, then concentrate with a hydrocyclone, and dewater the centrifuge.
The weathered phosphate ore around the Dianchi Lake in Yunnan Province can obtain high-quality phosphate concentrate by rubbing and eluting mud, which is an ideal raw material for producing high-concentration phosphate fertilizer. The region's scouring plant, which has been put into operation at the end of 1993, has a capacity of 300-3.5 million t/a for processing raw ore. It is an important phosphate mine base in China.
2. 1. 3 heavy medium beneficiation process
Heavy medium sorting is a phosphate rock re-election technique. Hubei Yichang Huaguoshu Phosphorus Heavy Medium Concentrator is the first phosphate ore heavy medium selection plant built in China. The plant is in a heavy medium cyclone separation device, the medium is a magnetic iron ore weighting agent, use some washing desliming a fine and a coarse heavy medium beneficiation processes, the process in the tape width than 2mm, of which 30% 20mm The above phosphate rock, which is mainly composed of strip structure, laid the foundation for comprehensive development and utilization of phosphorus resources in Yichang area. Subsequently, based on years of research on heavy medium separation technology, Tiandi Technology Co., Ltd. Tangshan Branch successfully applied the three-product heavy medium cyclone to the phosphate rock sorting after continuous scientific research. Good economic and social benefits. At present, Hubei Yichang flower fruit processing plant, Guangyuan Chemical Co., Ltd. concentrator and concentrator gem Hill Mines Ltd., dense medium cyclone phosphorus election has been widely used.
2. 1. 4 roasting-digestion process
The process is suitable for calcareous phosphate rock, that is, phosphate rock with high carbonate content and low silicate content. Using the roasting-digesting process, the lower the S iO2 content, the better, the highest should not exceed 5%. The process usually calcines carbonate-containing phosphate rock at 900e. The carbonate minerals liberate CO2 at high temperature, and then water digested to hydrate CaO and MgO into fine-grained Ca(OH)2 and Mg(OH). 2) Re-depositing and classifying operations to remove calcium and magnesium hydroxides to enrich phosphate rock. The Guizhou Yanfu Phosphate Mine expanded test to obtain phosphorus concentrate with P2O5 grade of 37.43%, MgO1. 27% and recovery rate of 88.89% after calcination, digestion and removal of impurities. 1%。 The removal rate of MgO was 72.1%. Roasting) Although the digestion process is simple, it requires high operation technology, high energy cost for roasting, and difficulty in removing lime milk. Therefore, it is difficult to promote and apply it in large quantities.
2. 1. 5 Chemical leaching technology
Chemical beneficiation is a beneficiation method that uses chemical methods to reduce the impurity content and improve the purity of useful minerals. The method is mainly applicable to calcium phosphate rock with low carbonate content and fine grain size and impurities in the separation flotation concentrate. The leachant may be ferric chloride, sulfuric acid or sulfur dioxide, and the like, and sulfuric acid is commonly used. Sulfuric acid leaching technology has been extensively studied and reported at home and abroad. The common defect is that when using sulfuric acid as a leaching agent, the loss rate of phosphorus minerals is as high as 15% to 30%, which is economically difficult to accept and requires high equipment. Processing costs are expensive.
2. 1. 6 elective technology
Electrification is a beneficiation method in which different minerals have different electrical properties, and the minerals are separated by electric and mechanical forces acting on the minerals as they pass through the electric field. The electric selection is dry operation, no waste water and environmental pollution, simple equipment structure, easy operation and maintenance, low production cost, good sorting effect, and foreign electricity has been successfully used in the production of phosphate rock. I. Phosphate concentrate with a P2O5 ratio of 29.4% and a recovery of 83.4%, with a P2O5 grade of 24.9%. The United States of America with P2O5 15.50% of the ore tailings after electrification, P2O5 grade can be increased to 34%, the recovery rate of 80%; Duan Xixiang, Gong Guisheng and others in the laboratory using electrical selection method to select Jiangchuan Qingshuigou phosphorus The mine has achieved good selection indicators and provided a new research direction for China's low-grade phosphate ore dressing.
2. 1. 7 joint beneficiation process
With the continuous exploitation of resources, phosphate resources are increasingly lean, fine, miscellaneous and difficult. It is difficult to obtain high-quality concentrate products by a single beneficiation process, and the joint beneficiation process can be a new way to solve such phosphate ore beneficiation. . Based on the mineral characteristics of the medium-low grade colloidal phosphates in Jinning, Kunyang and Haikou, Yang Maozhen determined the use of the heavy-floating combined process. The results show that the process can not only obtain better concentrate indicators, but also reduce the selection by re-election pre-selection. The floating amount reduces the cost of beneficiation to a certain extent, and provides a practical technical route for the development and utilization of low-grade colloidal phosphate rock in Dianchi area. The Institute of Mineral Resources Comprehensive Utilization of the Chinese Academy of Geological Sciences used a magnetic separation-re-election-flotation combined process to treat low-grade phosphate rock in Brontu, Inner Mongolia, and selected P2O5 grade from the P2O5 grade of 8.33% of the original ore to be 31.39%. Phosphate concentrate.
In addition to the above several phosphorus selection processes, there are also photoelectric picking technology, magnetic cover method and so on. In general, flotation is the most effective and widely used beneficiation method in phosphate ore dressing.
2. 2 flotation reagent
The flotation reagent is directly related to the quality of the phosphate rock flotation. To this end, the majority of mineral processing science and technology workers have devoted a lot of time and energy to the development of new phosphorus-selecting agents. At present, some research results have been achieved, and some new drugs have been successfully used in production.
Phosphate ore collectors are mainly divided into modified fatty acids, cationic collectors, amphoteric collectors, mixed collectors, etc. Phosphate ore dressing inhibitors mainly include carbonate inhibitors and phosphorus-containing mineral inhibitors. The following is a brief introduction to some of the new phosphorus-selecting agents developed in recent years.
OT-8 is a phosphate mineral collector obtained by compounding cotton oil soap. Added a small amount of surface activity when compounding OT-8
These surfactants can promote the adsorption of fatty acid collectors on the surface of apatite, improve the chemical environment of calcium and magnesium ions on the surface of minerals, and increase the dispersion of fatty acids at low temperatures. The use of OT-8 collector can increase the hydrophobicity of the mineral, reduce the flotation temperature of the slurry, and achieve low temperature flotation. OT-8 is used in the Susong phosphate mine and the Haizhou phosphate mine at low temperature of 3~8 °C, and has obtained good beneficiation index.
GE-609 is a new type of high-efficiency cationic desiliconization collector developed by Wuhan University of Technology. The collector has the characteristics of good selectivity, strong harvesting ability, low temperature resistance, and fragile flotation. Ge Yingyong et al [5] found that the use of anion collector MG anti-floating magnesium, cationic collector GE- 609 anti-floating silicon double reverse flotation process to treat low-grade colloidal phosphate is better, can be greatly improved Phosphate concentrate P2O5 grade.
Gao Huimin, Xu Hongfeng et al. used a new type of collector B-3 to conduct a reverse flotation study on a phosphate rock in Hubei. The results showed that the mass fraction of MgO was reduced from 10.83% to 1.30%. Below, and at room temperature, flotation can be carried out, which effectively reduces the cost of beneficiation. The final obtained P2O5 grade of phosphate concentrate is more than 37%, and the recovery rate is greater than 82%.
In order to improve the utilization of phosphorus resources in the Al-Jalam id phosphate mine in Saudi Arabia, Zhang Renzhong and Linghu Changjin used the WF-01 collector produced by the Yanfu Phosphorus Mine to conduct a beneficiation test on the Al-Jalam id phosphate rock. The research results show that the upper, middle and lower layer mixed ore can be selected by using the agent and a reverse flotation process without changing the design process. The P2O5 grade of the concentrate can reach more than 33%, and the recovery rate is over 80%. The effect is remarkable.
Tang Yun and Zhang Wei are the TS agents developed by phosphate ore flotation, which can reverse flotation of phosphate rock in weak acid medium, and the agent is cheap and non-toxic. Under the condition of grinding fineness of -200 mesh and 73.5%, using sulfuric acid as inhibitor and TS as collector, a rough selection and secondary selection process is used to reverse flotation of a phosphate mine in Guizhou. The technical index of phosphorus concentrate P2O5 grade 37%, MgO0. 5%, and P2O5 recovery rate 91.39% was obtained.
Liang Yongzhong and Luo Lianming's research group used plant extracts as raw materials to process an environmentally friendly carbonate inhibitor YY1. The agent not only has a significant inhibitory effect on carbonates such as dolomite, but also has a certain synergistic effect on the collector, which can improve the collection ability of the collector. A phosphate mine in Yunnan added a good selection index after adding YY1 in the positive flotation.
The highly effective reverse flotation inhibitor W-98 is a phosphoric acid derivative. Related studies have shown that it can be used as an inhibitor of reverse flotation in combination with sulfuric acid, which can effectively inhibit phosphate minerals and greatly reduce the amount of sulfuric acid. Luo Huihua and Cheng Jing conducted different inhibition experiments on carbonate-type phosphate rock in Mabian, Sichuan. The results showed that the sulfuric acid inhibition method, the phosphoric acid and sulfuric acid mixed acid inhibition method and the high-efficiency reverse flotation inhibitor W-98 combined with sulfuric acid suppression method. Among them, the high-efficiency reverse flotation inhibitor W-98 combined with the sulfuric acid suppression method has a better sorting effect and a high magnesium discharge rate.
2. 3 new mineral processing equipment
With the continuous development of mineral processing equipment, some new high-efficiency mineral processing equipment has been used for phosphate ore beneficiation. The successful development of the three-product heavy medium cyclone for phosphate rock and the effective application of the new process system have filled a gap in the field of high-density non-magnetic mineral sorting technology in China. The mediator cyclone can achieve efficient sorting of phosphate ore requiring high sorting density. The TDC1030P magnetic separator is a new type of magnetic separator for phosphate rock. It has been put into production in many domestic concentrators and has achieved good results. Xia Jingyuan and Yang Wenquan et al. conducted experimental research and concluded that the flotation column is feasible for the flotation of low-grade colloidal phosphate rock in Yunnan.
3 Conclusion
The beneficiation of low-grade colloidal phosphate rock is a major problem in domestic and international mineral processing research. In recent years, with the unremitting efforts of the majority of scientific research workers, China has made many achievements in the phosphate ore dressing process, pharmaceuticals and equipment, and successfully solved the mineral processing problems of some low-grade and difficult-to-select colloidal phosphate mines, but it must be fundamentally To solve this problem, further research is needed, especially the research on flotation reagents. Flotation agent is the key to phosphate flotation. Therefore, exploring the development of high-efficiency phosphate flotation new pharmacy is bound to become the research focus of phosphate ore dressing.
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