World phosphorus ore resources are mainly located in Africa, China, the United States, the Middle East, Russia, as of 2007, the world apatite reserves of 18 billion t, based on reserves of 50 billion t, the world's major countries phosphate reserves in Table 1.
As can be seen from Table 1, China's phosphate resources are very rich, and reserves rank first in the world, but this data contains low-grade ore. China's phosphate rock resources have the following characteristics: sedimentary phosphate rock is dominant in phosphate rock resources; phosphate rock resources are concentrated, mainly distributed in Yunnan, Guizhou, Sichuan and Hubei, accounting for 92.5% of total reserves, which is conducive to mining; The grade of phosphate rock resources accounts for a large proportion, accounting for more than 80% of the total reserves. Therefore, how to use the low-grade phosphate resources has become our current difficult task [1] .
First, the current status of flotation process
China's phosphate rock composition is complex, different types of ore, due to differences in metallogenic conditions, mineral types and content, inlaid grain size, structural structure, etc., the difficulty of sorting and the process flow are quite different. Phosphate ore is classified into siliceous phosphate rock, calcareous phosphate rock and siliceous calcium phosphate rock according to the chemical composition of minerals. The sorting process is different for different ore types. At present, the process of sorting phosphate rock applied at home and abroad is relatively perfect, but each has its own advantages and disadvantages. The following is a brief introduction to the more common processes.
(1) Positive flotation process
The process is generally used for sorting low grade phosphate rock, silica and silicon processing including calcium phosphate, calcium and magnesium phosphate quality. The process must have a combination of inhibitory inhibitors to achieve satisfactory results, mainly for the minerals in which the phosphorus minerals and gangue minerals are finely embedded. In recent years, L series and S series high-efficiency inhibitors have been successfully developed, and can obtain better flotation effect on sedimentary metamorphic limestone [2] , but only for ore with low MgO content, and direct filtration of products. Difficulties, which limit the application and promotion of the process in the production of phosphate rock in China.
(2) Reverse flotation process
The process is mainly applied to the separation of phosphate rock and dolomite. The fatty acid is used as a collector in a weakly acidic medium, and the dolomite is floated. The product in the tank is a phosphate concentrate. The discharge rate of dolomite is generally up to 70% to 80%. The ratio of the dolomite discharge rate to the P2O5 loss rate is generally (6 to 10): 1. However, it can not separate the siliceous gangue. At the same time, there are shortcomings such as fine particle size, difficult transportation and handling of foam products. At present, there are still problems in finding suitable collectors with good collection performance and excellent inhibitors [3]. . Wu Yanni et al [4] adopted a reverse flotation process with three-stage dosing and three sweeps, and obtained a satisfactory selection index. When the ore P 2 O 5 grade is 27.07%, the MgO content is 4.22%, and the grinding fineness is -0.071 mm (-200 mesh) 66.4%, P 2 O 5 grade can be obtained by using phosphoric acid as a reverse flotation inhibitor. The high-quality phosphate concentrate with 32.91% and 0.90% MgO has a P 2 O 5 recovery rate of 92.88% and a MgO removal rate of 83.33%.
(3) Combined process of positive and negative flotation
In order to overcome the shortcomings of the positive flotation and reverse flotation processes, the siliceous calcium phosphate ore can be treated by a combination of positive and negative flotation processes. The process is to first float the carbonate in a weakly acidic medium, and then float the silicate in an alkaline medium (regrind or not), since the hardness of the carbonate is lower than the hardness of the phosphorus mineral, In the process of mining, it is easy to break and is preferentially dissociated. The purpose of the second stage of the reverse flotation process is to improve the subsequent processing properties of the phosphate concentrate (ie, reduce the content of MgO), rather than to improve the concentrate grade as the main purpose [5] . Another advantage of the positive and negative flotation process compared to other flotation processes is that its final concentrate is in the tank, has a coarser particle size, and is easier to dewater than a foam product.
Deng Wei et al [6] used the persulfate positive and negative flotation process for the refractory Qingping low-grade silicon-calcium phosphate rock mine. In the original ore P 2 O 5 22.22%, MgO 2.91%, and ground to -200 Under the condition of 93%±, continuous operation for 72h, the process technical index of concentrate grade P 2 O 5 30.37%, MgO 0.53%, concentrate yield 60.71%, I recovery rate 82.99% can be obtained. Selected, and the type of flotation agent is small, and the cost of the drug is low.
(4) Double reverse flotation process
Double reverse flotation is the first reverse flotation of dolomite, and then reverse flotation of silicate, the product in the tank is the final phosphate concentrate. The process can be carried out under normal temperature and coarser particle size conditions. Compared with the positive and negative flotation combined process, the conditions of flotation silicate gangue are different. The positive and negative floating combined process is to make the surface of the silicate positively charged under alkaline conditions and to separate from the target mineral by an anion collector, and the double reverse float overcomes the shortcomings of the difference between the acidity and alkalinity of the positive and negative floating combined process. . Zeng Xiaobo [7] used the de-magnesium collector SR agent, a coarse two-sweeping agent and a de-siliconization agent GE-609, a coarse-sweep double-reverse float process flotation, and obtained a satisfactory indicator: P 2 O 5 27.27% When the original ore is milled to -0.074mm for 75%±, the SR concentrate and GE-609 double reverse float flotation, the comprehensive concentrate yield is 72.69%, P 2 O 5 grade is 32.87 %, and the recovery rate is 86.93%; Magnesium, aluminum and iron were all significantly reduced: the ore contained 2.2% of MgO, 1.87% of Fe 2 O 3 and 3.11% of A1 2 O 3 , and the concentrate contained 0.93% of MgO, 1.17% of Fe 2 O3 and 1.45% of A1 2 O 3 .
Shen Jing et al. [8] obtained ore with P 2 O 5 24.69%, MgO 3.173%, and SiO 2 14.57%. Under the condition of grinding fineness -200 mesh 85%, the double reverse flotation process can be used. P 2 O 5 32.48%, MgO 0.42% phosphorus concentrate, concentrate yield 65.28%, P 2 O 5 recovery rate 85.88%, magnesium removal rate 91.36% process index, the process drug system is simple, less pesticides required The sorting efficiency is high, the process index is excellent, and the final concentrate is the product in the tank, which is easy to dehydrate.
In addition to the above several flotation processes, there are also phosphorus phosphorus combined process [9] , heavy media separation process [10] , photovoltaic selective flotation [11] , roasting-digestion-flotation [12] And other processes.
Second, the research status of phosphate ore flotation reagent
The flotation method is one of the effective sorting methods for phosphate rock sorting. In the flotation process, flotation reagent plays a decisive role in the technical index of beneficiation . Therefore, a large amount of research work is focused on finding flotation agents with good selectivity, good performance and low cost in order to make better use of low-grade phosphate resources.
(1) Collecting agent
In the flotation of phosphate rock, phosphate and carbonate are recovered from fatty acid collectors such as oxidized paraffin soap and tar oil at home and abroad. Due to its poor selectivity, it has poor applicability to hard water and low temperature flotation. Since the 1980s, some effective phosphate rock collectors have been developed at home and abroad, such as cationic collectors and amphoteric collectors.
1, cationic collector
Cationic collector after leaving the solution, to produce an amine having a hydrophobic hydrocarbon group, colored metal oxide ore, quartz, feldspar aluminosilicate effective collector. Since the 1980s, many researchers have reported the use of cationic collectors to capture apatite and anti-floatation. Studies have shown that cationic amine collectors have properties for siliceous, calcareous, and silicic phosphates. Sorting. Zeng Xiaobo [7] used a cationic collector GE-609 to select phosphate rock containing P 2 O 5 27.27%, MgO 2.25%, Fe 2 O 3 1.87%, and A1 2 O 3 3.11% in Yichang. Float flotation, the comprehensive concentrate P 2 O 5 grade reached 32.87%, the impurity content decreased significantly: MgO 0.93%, Fe 2 O 3 1.1%, A1 2 O 3 1.45%.
2. Amphiphilic collector
In recent years, amphiphilic collectors have made great progress in flotation of phosphate minerals. According to reports [13] , Finland successfully used the amphoteric collector alkyl-N-methylglycine to float apatite from calcite , dolomite and mica , to P 2 O 5 4%, MgO 14.7% The ore is obtained by three times to obtain a concentrate containing P 2 O 5 35.0% and MgO 1.6%, and the dosage of the agent is 32.5 g/L.
Houot. Rc [14] et al. studied various amphoteric collectors and found that such collectors were well selected. In general, only one collector was used during the sorting process. Compared with fatty acid collectors, it has strong adaptability, especially in siliceous minerals, because the removal process in the traditional double reverse flotation process is removed, and the process is simple. In addition, there are other novel collectors such as alkyl phosphates, alkylamine propionic acid, alkylamine propylamine propionic acid, oxyethylene collectors, and the like.
3. Modified fatty acid collector
Sulfation of fatty acids, water solubility, temperature resistance, capture and selectivity can be improved. For example, for the polyvinyl alkyl sulfate R(OCH 2 CH 2 ) nO-SO 3 —M+n, other groups and isomerization are introduced. Some researchers [15] compared the isomers of C12-16, α-sulfonate carboxylic acid and Tal oil, and found that the former showed strong flotation activity, and better for hard water and low temperature pulp. Adaptability. Refined Tal oil is a mixture of fatty acid and rosin acid, which is the acidified product of the acid waste paper. The Soviet Union [16] used LMR-25 (light Tar oil) to select apatite, which is better than ordinary chemicals, and generally can obtain more than 36% of high-quality phosphate concentrate.
4, mixed collector
The combination of phosphate rock collectors is characterized by the combination of fatty acids and their derivatives or other pharmaceutical agents. Lianyungang Chemical Design and Research Institute has many reports. Fatty acids are classic collectors for phosphate rock flotation. They are rarely used alone and are used in combination with neutral oils. In the early 1940s, India reported the composition of oleic acid and kerosene as phosphate rock flotation collectors, silicon-containing phosphate in the election, she won the high-quality phosphate concentrates.
It was reported [17], a combination of sodium oleate and ammonium oleate as phosphorus collector, from P 2 O 5 27.6%-containing ore, to obtain P 2 O 5 38.1%, 85.2% recovery of phosphorous Concentrate. In addition, there are many reports on the combination of phosphate collectors, such as petroleum sulfonic acid and sodium oleate combination, fatty acid and hexafluorobutadiene combination, hydroxylamine and alkyl sulfonate combination, fatty acid and fractionation. Acid residue combination, Acritol FA-18 neutral oil combination, fatty acid and amine combination.
(2) Inhibitors
Separation of phosphate rock from calcite and dolomite is the main problem of phosphate ore dressing. Because they are the same type of salt minerals, they have similar physical and chemical properties, whether they are cationic collectors or anionic collectors, phosphate rock and white clouds. The floatability of the stones is very similar. Therefore, under the general pharmaceutical system, a good flotation index cannot be obtained without using an excellent inhibitor.
There are many researches on inhibitors at home and abroad, which can be divided into the following two categories.
1. Inorganic acid inhibitors
The inorganic acid inhibitors are mainly phosphoric acid, sulfuric acid, silicic acid, phosphate, and the like. L. Xiao [18] and so on, when pH=9, alizarin red S is a potent inhibitor of dolomite in Florida phosphate rock, because the adsorption of alizarin red S on dolomite is more than that on fine-grained apatite. . Studies have shown that alizarin red S has a similar structure to S808 developed in China. It inhibits apatite and dolomite respectively when sorting calcite system and apatite-calcite system. There are also reports using phosphoric acid and sulfuric acid as anti-flotation inhibitors.
2, organic acid plus metal salt combined inhibition
The combination of inorganic metal salts ( cobalt , copper , iron, aluminum, lead , nickel heavy metal inorganic salts) and organic complexes such as oxalic acid and tartaric acid, using the principle that phosphate minerals have stronger adsorption power to these metal salts than carbonates. The surface of the phosphate mineral is positively charged and then complexed by the organic complex to exhibit hydrophilicity. It can be sorted under normal pH conditions (nearly neutral) using a general fatty acid collector.
There are many researches on inhibitors in China, especially inhibitors of carbonate minerals. In recent years, domestic new types of inhibitors mainly include: S series, BS-33, L-339, sodium nitro-humate. The performance of these agents has been validated in extended or small trials. Among them, S808 is currently recognized as a better inhibitor and has been successfully used in the reverse flotation process of Wangji Phosphate Mine. However, the toxicity of the agent is too large [19] , resulting in high cost and difficulty in wastewater treatment. Now it has introduced its substitute S711 and applied it to beneficiation production. It has obtained the beneficiation index similar to S808, and the wastewater treatment cost is also low.
BS-33 is made of papermaking waste liquid as the main raw material, and the price is low. The use of BS-33 instead of lignosulfonate can obtain similar indicators to the use of lignosulfonate alone. BS-33 has a degree of sulfonation of 16 to 12 and a pH of 11 to 12. Flotation Jinjiasha Phosphate Mine can obtain concentrate with P2O529.51% and recovery rate of 85.41%, but its inhibition effect on dolomite is not as good as S808 [20] .
L-339 is prepared by reacting calcium lignin sulfonate, a by-product of acid method, with acid and decalcification, and reacting with formaldehyde and sodium sulfite adduct sodium hydroxymethanesulfonate. It is a potent inhibitor of magnesium minerals and is used for the flotation of metamorphic calcareous phosphate ore to obtain high-grade and high-recovery phosphate concentrates [21] .
Third, the conclusion
In short, China's existing reserves of phosphate resources account for a large advantage, but the medium and low grade phosphate resources have not been widely exploited. In order to seize the favorable opportunity for the price of phosphate concentrate to rise significantly, and the opportunity for phosphorus chemical industry to increase the demand for phosphate rock, it is necessary to increase efforts to develop and utilize low-grade phosphate rock resources to meet the needs of production and life. But we also need to realize that the use of low-grade phosphate rock is more complicated and difficult. Since the utilization of low-grade phosphate rock is mainly realized by the positive flotation process, the process requires that the collector has better collection performance and the requirement for the inhibitor is also high, so it is necessary to increase the flotation agent. Research and development. As long as the problem of phosphate collectors and inhibitors is solved, it will definitely lead to better and faster development of the utilization of phosphate resources in China.
references
[1] Lu Rukun. Phosphate Resources and Phosphate Fertilizer Production and Consumption in China[J]. Soil, 2004, (1): 1-4.
[2] Wu Caibin, Duan Xixiang. Research on Treatment Process of Phosphate Ore in China[J].Yunnan Metallurgy,2000,(8);19-22.
[3] Wu Liangguo, Zhu Weicheng. Study on the removal of magnesium oxide by reverse flotation[J]. Chemical Mining Technology, 1986, (3): 33-34.
[4] Wu Yanni, Chen Nan, Hua Liyan. Research on reverse flotation process of carbonate type phosphate rock [J]. Chemical Mineral Geology, 2008, (9): 169-173.
[5] Tang Yun. Application of flotation agent TS in flotation of phosphate rock (Master's thesis) [D].2003:2-3.
[6] Deng Wei, et al. Application of new normal temperature and reverse flotation process in difficult selection of Qingping Phosphate Mine [J]. Chemical Minerals and Processing, 2009, (1): 6-8.
[7] Zeng Xiaobo. Double reverse flotation process and foam behavior regulation of colloidal phosphate ore (Master's thesis)[J].2006:16-35.
[8] Shen Jing, et al. Study on double-reverse flotation process of a full-layer ore in a phosphate mine in Hubei Province [J]. Chemical Minerals and Processing, 2007, (6): 5-6.
[9] Tang Deshen. Semi-industrial test and results of the combined process of heavy medium ore dressing in Yichang Phosphorus Mine[J]. Comprehensive Utilization of Mineral Resources, 1995, (1).
[10] Xu Huaqing, Current status of heavy medium ore dressing and application prospects in phosphate ore dressing [J]. Chemical Mining Technology.
[11] Li Huada. Photoelectric sorting machine picking Kaiyang Phosphate Ore [J]. Chemical Mining Technology, 1984, (5): 37-39.
[12] Yang Guo. Application of reverse flotation process in phosphate ore dressing[J]. Comprehensive Utilization of Mineral Resources, 1998, (6): 48-49.
[13] BMMondgy, the progress of phosphate ore [J]. Chemical translation, 1988, (2): 25-30.
[14] Houot.R and Poilayaire, Inversflotation beneficiation of phosphate ores, Proceeding compounds, Apr. 2 1 25, 1980, 231-246.
[15] Brit. PI, 355091 (1974).
[16] CA104, 36241 (1986).
[17] Banejee.USK, et a1.J.Sci.Ind.Res. (India), 1955, (14): 242.
[18] L. Xiao and P. somaundaran, Interactions Between anionic collector and modifier in dolomite francolite flotation system [J]. Society of mining engineer preprint number. 88-189.
[19] Yin Yiwei, Zhang Yuying, S-808 is a flotation agent of phosphate rock tailings water on the sublethal effect of fish [J]. Environmental Science and Technology, 1990, (4): 5-9.
[20] Zhang Xiangdong. Study on Synthetic Process of Glutamate Gangue Inhibitor BS-33[J].Applied chemical industry,2001,(1):24-26.
[21] Yang Zuwu. Application of a New Type of Gangue Inhibitor L-339 Re-deposited Metamorphic Phosphorite Ore Flotation[J].化工化工技术,1988,(6):19-22.
(Author: Changyu book Gong Wenqi Unit: School of Resource and Environment Engineering, Wuhan University of Technology)
(Author: Chen Changyu book of Units: Institute of Chinese Academy of Geological Sciences Utilization of Mineral Resources)
British Car Brake Pads,Auto Brake Pads For Mini Car,Wva 23915 Brake Pads,Wva 23916 Brake Pads
DONGYING BORUI BRAKE SYSTEM CO.,LTD. , https://www.boruiauto.com