Tungsten ore beneficiation process

This article describes the status of the black mineral processing technology, scheelite, and carried out a detailed review of its flotation collectors, the status quo adjusters and beneficiation process and progress, and to conduct research black, white tungsten ore beneficiation Looking forward. The collectors and inhibitors of high-efficiency black and scheelite should be developed; the combined process of smelting and smelting should be carried out; the regularity of the combination of the agents, the synergistic effect between the combined agents and the mechanism of action of the agents and minerals should be studied in depth; grade tungsten efficient recovery of flotation devices, and solve black, white tungsten multi-metal ore beneficiation process long status quo.
Tungsten minerals have been found in nature and contain tungsten minerals are more than 20 species, but have only wolframite (tungsten, manganese iron ore) and scheelite (calcium tungsten ore) mining economic value. Hematite (Fe, Mn) WO4, containing WO3 76%; scheelite CaWO4, containing WO3 80.6%. Others, such as tungsten China WO3 · H2O, copper tungsten China CuWO4 · H2O, tungsten, molybdenum and tungsten PbWO4 lead ore galena (Pb, Mo) WO4 etc. and there is not much commercial value.
Tungsten mine is China's dominant mineral resource. China's tungsten ore reserves rank first in the world, more than three times the total reserves of more than 30 foreign countries. Although the reserves of tungsten ore in China are large, the grade is low, and the refractory ore accounts for a considerable proportion. Among them, scheelite and black and white tungsten mixed ore are mostly ore with complex composition and fine mineral inclusions. The sorting is difficult, and it is associated with other metals, which is more difficult to develop and utilize.
1 Research status of black and white tungsten ore dressing chemicals
1.1 Black and scheelite collectors It is very difficult to study the separation of scheelite from calcium-bearing gangue minerals such as calcite and fluorite minerals. Therefore, research on scheelite flotation reagents and flotation equipment is essential. . The scheelite collectors can be divided into four categories: anion collectors, cation collectors, amphoteric collectors, and non-polar collectors, the most commonly used of which are anion collectors. In addition, the combined use of collectors is also a research hotspot. Anionic collectors mainly include fatty acids, sulfonic acids, phosphonic acids, hydroxamic acids and chelating collectors. Cationic collectors mainly refer to amine collectors, and amphoteric collectors, ie, amino acid collection. Agent.
Cheng Xinchao's pharmaceutical system with a combination of chelator collector and water glass, finally obtained a white tungsten concentrate containing 71.83% of WO3, a recovery rate of 56.23%, and a black tungsten concentrate containing WO3 66.61% and a recovery rate of 27.30%. Mine, the total tungsten recovery rate reached 83.53%. Meng Xianyu used modified water glass and fatty acid for rough selection of white tungsten, and improved the white tungsten addition by the modified “Peterlow method”. The ore contained 0.413% of WO3, and obtained white with WO67 67.87% and recovery rate of 85.99%. Tungsten concentrate. Zhang Zhonghan et al. used the chelation collector GYN and the auxiliary collector GYE to obtain 45.2% of the white tungsten concentrate containing WO3, and the recovery rate was 89.58%. Ye Xuejun and others added 731 oxidized paraffin soap with a ratio of 5:1 and Tal oil as a combined collector. Compared with 731 oxidized paraffin soap alone, the WO3 grade decreased by 0.24%, and the recovery rate increased by 2.26%. Yu Jun et al. used flocculating agent CKY and sodium oleate to conduct flotation separation of hematite, scheelite, fluorite, calcite single mineral and actual mineral, which can effectively separate tungsten mineral from fluorite and calcite. Zhou Yu et al. used K to capture the flotation of Yaogangxian scheelite, and obtained a white tungsten coarse concentrate containing WO3 64.76% and a recovery rate of 87.76% from the ore containing 0.33% WO3. Zhou Xiaotong et al. used the first flotation sulfide ore, and then added Na2CO3, Na2SiO3 and high-efficiency composite collector TA for rough white tungsten, white tungsten coarse concentrate with modified Na2SiO3 and heating and selection process, and obtained WO3 grade 65.41%. , recovery rate of 81.12% of scheelite concentrate. Han Zhaoyuan used a combination of GYB and ZL to carry out mixed flotation of wolframite and scheelite containing WO3 0.81% ore, and obtained a coarse concentrate containing 30.07% of WO3 and a recovery rate of 88.79%. The WO3 grade in tungsten concentrate is 68.24%, and the recovery rate is 60.02%. The selected tailings are selected by shaker to obtain black tungsten concentrate with WO3 grade of 66.17% and recovery rate of 13.74%; WO3 grade of hypotungite concentrate The recovery rate was 10.27%, the total recovery rate of WO3 in tungsten concentrate was 84.55%, and a good beneficiation index was obtained. Zeng Qingjun [9] used ZL as a collector to obtain tungsten concentrate grade and recovery rate higher than 731 oxidized paraffin soap, and the amount of ZL collector is less. When the ore grade is WO3 0.58%, the industrial test index of tungsten concentrate grade 66.82% and recovery rate 90.98% can be obtained. Zhang Shuhong [10] used GYW ​​new oxidized ore collector to perform scheelite ore dressing in Na2CO3 and Na2SiO3 alkaline medium. When the ore contains WO30.58%, it obtains WO3 grade 65.70% and recovery rate of 75.90% scheelite concentrate. . Deng Lihong used R31 as collector, Na2CO3 as regulator, Na2SiO3 as inhibitor for white tungsten rough selection, white tungsten for Na2SiO3 heating floatation process, and obtained white tungsten concentrate in the ore containing WO30.28%. The grade is 73.10% and the recovery rate is 81.67%. R31 is a suitable collector for scheelite.
1.2 Study of scheelite inhibitors The scheelite flotation is generally carried out under high alkalinity conditions. Usually, sodium carbonate, sodium hydroxide and water glass are required to adjust the pH value of the slurry. Gangue inhibitors can be divided into two major categories of organic inhibitors and inorganic inhibitors. In addition, the combined use of the inhibitors can also significantly enhance the inhibitory effect. The addition of polyvalent metal cations such as metal salts such as Al3+, Cr3+, Mg2+, Cu2+, Zn2+ and Pb2+ can improve the selective inhibition performance of water glass.
In addition to sodium silicate, also conventional inorganic inhibitors and acid phosphate and sodium fluosilicate. Cheng Xinchao et al [12] used phosphate as a regulator to preferentially float scheelite from calcite, fluorite, quartz and garnet . Studies have shown that sodium hexametaphosphate and sodium pyrophosphate are also preferred flotation of scheelite. Effective adjuster. Organic inhibitors commonly used are tannins and white bark bark juice. Cheng Xinchao uses water glass and BLR as a combination inhibitor. Compared with single water glass, it can greatly improve the grade of tungsten coarse concentrate. The recovery rate is similar and the selectivity is better. Ye Xuejun uses water glass + metaphosphate as a combination inhibitor in the selection of scheelite at room temperature, which not only eliminates the complicated process of slurry concentration and heating, reduces the cost of ore dressing, but also has obvious effect of reducing phosphorus, so as to avoid the production. The acid leaching and phosphorus removal process provides a basis. Sodium carbonate and water glass were added as a combined inhibitor. When the raw ore WO3 was 0.37%, a white tungsten coarse concentrate containing a WO3 grade of 9.11% and a recovery rate of 85.68% was obtained. Chen Wensheng believes that in the selection of black and scheelite mixed coarse concentrates in Shizhuyuan, the addition of sodium sulfide and water glass mixture can better separate the feldspar and fluorite and other calcium-containing minerals and gangue minerals. And can reduce the amount of water glass to a certain extent, saving costs. Wang Qiulin et al [16] used the combination inhibitor Y88 to effectively inhibit the gangue minerals during the normal temperature selection process of scheelite, achieving the effective separation of scheelite and calcium-containing gangue minerals, and obtaining a tungsten-containing grade of 72.18%. The high-quality white tungsten concentrate with a recovery rate of 84.85%. Zeng Qingjun and others used Na2SiO3 and YN as gangue inhibitors in the flotation of scheelite, which can effectively separate scheelite from gangue.
1.3 Research on black tungsten ore dressing agent The black tungsten ore flotation mainly refers to the flotation of black tungsten fine mud. Fine-grain flotation requires highly selective collectors, mainly including tannins, phosphonic acids, chelating agents, amphoteric collectors, and a few fatty acid collectors. The pH adjuster and the inhibitor of gangue minerals during the flotation of the black tungsten ore are basically the same as the flotation of scheelite, and commonly used activators such as lead nitrate and ferrous sulfate. Studies have shown that metal cations such as Mn2+ and Fe2+ have an activation effect on the flotation of wolframite. Mixed drugs are widely used not only for collectors, but also for regulators. The development of new chelating agents has become the development trend of black tungsten ore flotation agents.
2 Research Status of Beneficiation Process of Black and White Tungsten Ore
2.1 Study on the beneficiation process of scheelite The coarse-grained scheelite is still recovered by re-election method, and the fine-grained scheelite is generally recovered by flotation. The flotation of scheelite is generally divided into rough selection section and selected section. The rough selection section aims to maximize the grade of coarse concentrate, and the selected section aims to meet the market demand of tungsten concentrate. Therefore, in order to obtain a qualified tungsten concentrate, it is often necessary to adopt a relatively complicated process flow and multiple selections to achieve the goal. In the flotation research and practice of scheelite, the rough selection process includes lime + sodium carbonate method and sodium carbonate method, generally adopting short rough selection and long sweep selection. The key to the white tungsten selected section is to separate the calcium-containing gangue mineral from the scheelite. The selection process of white tungsten coarse concentrate has normal temperature method and heating method. The normal temperature method is not suitable for ore, and the selection index has large fluctuation. The WO3 grade of flotation smectite concentrate is generally 55% ~ 60%. Containing high impurities, usually by the method of leaching with hydrochloric acid, the purpose of recovering more than 65% of tungsten concentrate of WO3 is finally achieved. The normal temperature method is more commonly used in quartz vein mines and mines with low calcium mineral content. Mines with high calcium mineral content, especially high fluorite content and low tungsten content, generally use heating method.
In the normal temperature selection process of scheelite, Deng Lihong obtained a white tungsten concentrate containing WO365.17% by adding TC combination inhibitor and a small amount of TA-3 agent, and the recovery rate was 70.16%. Ye Xuejun et al. used white tungsten at room temperature flotation process, obtained molybdenum concentrate containing 17.56% Mo, recovery rate was 71.84%, scheelite concentrate containing WO3 27.34%, recovery rate was 76.96%. Using 731 oxidized paraffin soap white tungsten at room temperature flotation process, high quality molybdenum and tungsten, molybdenum concentrate grade 46.20%, recovery rate 76.87%; scheelite concentrate containing WO3 70.18%, recovery rate 85.31%. Zeng Qingjun et al used Na2CO3 as a pH adjuster, Na2SiO3 and YN as gangue inhibitors, and ZL as a collector. After heating and selection, when the ore grade (WO3) was 2.83%, the grade (WO3) was obtained. 75.01% The first class of bismuth sulphur concentrate, WO3 recovery rate of 91.89%. Cheng Qiong selected a certain white tungsten coarse concentrate with a grade of 10.50%, and obtained a ore dressing with a tungsten concentrate yield of 15.12%, a tungsten concentrate (WO3) grade of 65.37%, and a tungsten recovery rate of 95.10%. Technical indicators. Xu Xiaoping et al. used the process of “priority float copper desulfurization – white tungsten rough selection – coarse concentrate heating and stirring without decontamination selection” to test the tungsten concentrate containing tungsten (WO3) 0.75%. It is 1.03%, the tungsten concentrate (WO3) grade is 65.37%, and the tungsten recovery rate is 86.31%.
2.2 Study on the preparation process of black tungsten ore The most important sorting process for the preparation of black tungsten ore is re-election. Multi-stage jigging, multi-stage shaker, medium-mine re-grinding and fine mud treatment are the processes of black tungsten beneficiation. The jigging early harvest and the shaker tail are the core of re-election. The black and white tungsten symbiotic ore also uses a strong magnetic separation and flotation process.
Black tungsten has weak magnetic properties and is also widely used in magnetic separation processes. The Hunan Persimmon Garden 380 Plant adopted a similar process, which not only recovered the magnet concentrate, but also improved the quality of the tungsten concentrate and achieved good economic benefits. Zhang Indium is a separation study of black and white tungsten for the problem that black and white tungsten affect each other's concentrate quality. The magnetic selection is SQC-2-1100 wet magnetic separator, which has obtained special grade black and white tungsten concentrate. The Slon-1000 vertical ring pulsating high gradient magnetic separator has obtained good results in the fine dust tungsten dust collected by ventilation and dust collection. The sample has a fine particle size (-0.074 mm for 80%), black tungsten for 74%, and white tungsten for 26%. When the ore grade is 4.6%, the tungsten concentrate grade is 59.55%, the recovery rate is 77.88%, and the black tungsten recovery rate is 89.08%. The tungsten fine mud of the Yaogangxian tungsten mine in Hunan Province was tested by a high-gradient magnetic separator for the rough selection, primary selection and secondary sweeping. When the ore grade was 0.43%, the concentrate grade was 21.89%. The recovery rate of tungsten fine mud was 77.11%. The Shizhuyuan Mine was subjected to flotation by CF method to obtain black and white tungsten mixed concentrate containing WO362.41%. The black and white tungsten separation was carried out by weak magnetic-high gradient magnetic separation process, and the magnetic separation black tungsten concentrate grade was obtained as WO366. .16%, the total recovery rate of wolframite is 81.06%.
2.3 Status of black tungsten fines beneficiation process Hematite is brittle and easy to crush. The recovery rate of tungsten in fine mud is below 45%. In the black tungsten fine mud flotation, toluic acid, mixed toluic acid, styrenephosphonic acid is used to increase the black tungsten with a collector such as hydroxy (oxy) citric acid. The recovery rate of fine mud. For simple ore, the main process uses “sulfurization ore flotation – wolframite flotation – black tungsten selection”, in the weakly alkaline or neutral pulp, adding oleic acid, toluic acid or styrenephosphonic acid for collection. Agent, sometimes oleic acid as a rough collector, toluic acid as a selective collector; for more complex ores, the main process uses "mixed flotation - sulfide ore flotation - re-election - black tungsten flotation ", rough selection in weakly alkaline or neutral pulp; for complex refractory ores (such as separation from rare earth metal phosphate ore), the main process uses "sulfide ore flotation - wolframite flotation - black tungsten "Select", in the strong acidic medium, sodium silicate is used.
Gao Yude uses a combination of water-based glass inhibitors, BD single inhibitors and benzoic acid-based mixed collectors to treat the Shizhuyuan polymetallic ore scheelite and warm tailings, including WO3. The grade was 1.74%, and the results of closed-circuit test with WO3>65% and recovery rate >90% were obtained. In the slurry with pH 6.5 ~ 7.0, lead nitrate is used as the activator, water glass and aluminum sulfate are combined inhibitors, and the combined collectors such as benzoic acid and tal soap are used in one rough selection. The process of three-time selection and three-time sweeping can obtain 66.04% of WO3 and a recovery rate of 90.36%.
Zhou Xiaotong and others used the heavy-floating-heavy combined process to recover tungsten. When the tungsten fine grade was 0.33%, the white tungsten concentrate with a grade of 55.38% and a recovery rate of 29.82% was obtained, with a grade of 38.76% and a recovery of 32.55%. Black tungsten concentrate, the average tungsten grade is 45.26%, and the total tungsten recovery is 62.37%. Dai Zilin and other mixed reagents BH, which is mainly composed of benzoic acid, combined with the combination inhibitor AD, can effectively separate fine-grained wolframite from calcium-containing minerals such as fluorite and calcite. For WO3 1.94%, CaF2 60.35% and CaCO39.77% of the ore supply can obtain 52.77% flotation concentrate containing WO3, and the recovery rate is 68.32%. Deng Lihong and others used the re-election pre-enrichment-flotation-re-election combined process to treat the tungsten secondary fine mud to obtain better beneficiation index. Zhou Xiaotong et al. used Na2CO3, modified Na2SiO3 and Pb(WO3)2 as regulators, TA-24 as collector to coarsely select black and white tungsten ore, then selected and separated by heating, and selected tailings were selected by shaker. Do not get black tungsten concentrate. When the tungsten fines feed grade (WO3) is 0.2%, obtain a white tungsten concentrate with a grade of 59.55% and a recovery rate of 47.21%, a black tungsten concentrate with a grade of 36.62% and a recovery rate of 19.53%, and an average grade of tungsten concentrate. It is 50.60% and the total recovery rate is 66.74%. Gao Yude started from the study of the working principle of black tungsten fine mud flotation inhibitors, and carried out research on black tungsten fine mud and mineral flotation separation inhibitors such as fluorite, calcite and quartz. In the pulp with a pH of 6.5-7.0, lead nitrate is used as the activator, and benzoic acid is used as the collector. The combination of water glass, carboxymethyl cellulose and a small amount of aluminum sulfate is used. Inhibitor AD, single inhibitor BD Flotation of Shizhuyuan Mine black tungsten fine mud, when the ore grade WO3 1.62%, calcium mineral content greater than 70%, can obtain 66.04% WO3, recovery rate of 90.36% flotation Concentrate. Chang Zhuchun and others used the new process of magnetic-floating-heavy black tungsten fines beneficiation for industrial trials, which solved the problem of flotation technology and beneficiation process for recovering fine-grained wolframite from heated fine tailings. Zhu Jianguang discussed the synergistic effect of several groups of mixed collectors in flotation of black tungsten and cassiterite . When the mixed collector molecules form a composite hemi-micule, a synergistic effect occurs. Zhu Yimin floats black tungsten fine mud with naphthohydroxamic acid. When the black tungsten grade of the ore is 1.34%, and the material of the -10 μm is 30%, the black tungsten grade can be obtained by flotation and enrichment. 19.91%, recovery rate It is 87.17%. Chen Wanxiong believes that lead nitrate has a significant activation effect on the flotation of wolframite. The use of lead nitrate as an activator for flotation of WO31.62% of Shizhuyuan black tungsten fine mud is carried out to obtain black tungsten concentrate containing WO3 66.04%. The recovery rate was 90.36%. The components after hydrolysis of lead nitrate were analyzed from the chemical point of the flotation solution. At pH <9.5, Pb2+ and Pb(OH)+ were the main components of activation. Lead nitrate can change the F potential of the surface of the wolframite from negative to positive, and the characteristic adsorption of lead ions on the surface of the wolframite enhances the action of the collector.
3 Status of beneficiation process of black and white tungsten mixed ore
For simple stellite and black tungsten ore, the separation process is relatively simple. For the symbiotic ore of black and white tungsten, especially the fine-grained black and scheelite symbiotic polymetallic ore, it is usually used. A mixed flotation process is used to recover the tungsten therein. There are two main types of main processes:
(1) Sulfide ore mixed flotation - black and white tungsten mixed float - white tungsten heating selected - white tungsten tailings strong magnetic separation - reselection of black tungsten;
(2) Sulfide ore mixed flotation - strong magnetic separation black and white tungsten separation - white tungsten flotation - black tungsten flotation.
Zhang Zhonghan of Guangzhou Nonferrous Metals Research Institute proposed a new GY method for floating tungsten, the development of a new chelate collector GY and the improvement of the traditional inhibitor water glass. In the case of 0.47% of the original ore grade (WO3), the industry The test obtained 70.07% of tungsten concentrate, and the recovery rate of tungsten reached 81.62%.
Sun Wei et al. studied the capture performance of the new chelation agent F-305 on wolframite and scheelite by single mineral test and actual ore test. The test results show that F-305 has a strong ability to capture tungsten ore, especially for wolframite, and can obtain good flotation indexes at room temperature. Zhou Xiaotong uses a modified activator ZP of modified water glass and tungsten minerals and a chelate collector GY to treat complex tungsten ore containing 0.599% WO3. The grade of scheelite concentrate is 73.26%, and the recovery rate is 73.20%. Black tungsten concentrate The grade is 66.25%, the recovery rate is 13.53%, and the total tungsten recovery rate is 86.73%.
The process of coarse-grain re-election-fine flotation of low-grade fine vein type black and scheelite ore is carried out. In the case of ore containing WO3 23%, the re-selected tungsten concentrate contains WO3 63.54%, and tungsten recovery The rate is 70.11%; the fine mud flotation tungsten concentrate contains WO3 35.22%, the recovery rate of tungsten is 10.48%; the integrated tungsten concentrate contains tungsten WO3 57.53%, and the tungsten recovery rate is 80.59%. Zhang Zhonghan et al. Selectively inhibit fluorite and other gangue minerals with modified water glass according to the process mineralogical characteristics of Shizhuyuan tungsten-molybdenum- bismuth fluorite polymetallic ore, activate tungsten minerals with lead salt, and mix with new chelate collectors. Flotation of wolframite and scheelite, heating mixed fine concentrate to obtain scheelite concentrate; for selected tailings, flotation with GY collector to obtain black tungsten concentrate. For the ore containing 0.47% of WO3, the WO3 in the tungsten concentrate can reach 70.07%, and the total recovery of tungsten reaches 81.62%.
Cheng Xinchao studied the effects of various factors in the flotation process of tungsten minerals by CF method. The CF method can better achieve the flotation separation of tungsten minerals and calcium-containing gangue minerals in weak alkaline pulp. Guan Zezheng and other flotation experiments were carried out on the low-grade fine vein black and scheelite ore. When the ore contained WO3 0.23%, Mo 0.018% and Cu 0.013%, the tungsten concentrate grade was 63.31%. The recovery rate of tungsten is 86.64%; the grade of molybdenum containing molybdenum is 2.59%, the recovery rate of molybdenum is 66.19%; the technical index of copper grade 1.51% and copper recovery rate is 53.43%, which achieves the purpose of effectively recovering tungsten, molybdenum and copper.
4 Chemical dressing
Chemical beneficiation is mainly used to treat low-grade tungsten concentrate and medium ore. The advantage of this process is high recovery rate and high added value of the final product, especially suitable for fine-grained refractory ore. With the depletion of the black tungsten ore resources, the replacement of tungsten ore resources by scheelite has gradually become the development trend of tungsten smelting in the future. The simple and effective tungsten smelting technology has become the focus of many scholars.
Ding Zhiying et al studied the process of leaching scheelite from fluoride salt. Through thermodynamic calculation, the equilibrium concentration logarithm of each component in the leaching solution containing 0.10 mol/L and 0.12 mol/L was plotted, and the leaching of fluoride salt was carried out by using this graph. The scheelite process was subjected to thermodynamic analysis. Zhao Qinsheng introduced the application of microwave heating technology in the production of cemented carbide and its raw materials abroad, and introduced the new microwave soda treatment method of black tungsten concentrate. Under the conditions of soda content of 30%, sintering temperature of 800-850 °C, and constant temperature treatment time of 20-30 min, the leaching rate of W in the immersion of the sinter is 99%. Zhang Xiqing determined through experiments that it is feasible to increase the leaching rate and shorten the reaction time during the leaching process of tungsten ore by microwave radiation heating. The effect of various factors on the leaching rate during the leaching process was studied by microwave irradiation constant temperature heating. At a reaction temperature of 115 ° C, a reaction time of 2 h, a particle size of less than -300 mesh (-0.054 mm), a liquid-solid ratio of 20, and an alkali concentration of 500 g/L, the leaching rate of tungsten can reach over 96%. Under microwave power of 100 W, leaching time of 35 min, particle size of 250-300 mesh (0.065 ~ 0.054 mm), alkali concentration of 500 g / L, microwave heating alkali decomposition of low-grade black and white tungsten mixed ore, the leaching rate can reach 99.44%. Wu Jianguo et al. thermodynamically calculated and plotted the E-pH diagram and logW-pH diagram (25 °C) of the tungsten leaching system to conduct a thermodynamic analysis of the hydrometallurgical decomposition of scheelite, indicating that leaching white in alkaline solution Tungsten ore is difficult, and in the alkaline solution of caustic soda added with soluble phosphate, scheelite can be decomposed due to thermodynamic advantages. Long Yang discussed the current status of tungsten mineral caustic boiling process, and developed a process for deep extraction of tungsten in order to optimize the alkali decomposition production process. After adopting the corresponding technological measures, the content of WO3 in the discharged tungsten slag is 1.0% ~ 1.5%, and the comprehensive recovery rate of tungsten minerals is increased by 1% ~ 2%, so that the tungsten resources are effectively utilized.
Xu Zhichang et al. addressed the systematic engineering problems associated with the comprehensive recovery of scheelite from the Suichuan flotation molybdenum tailings in China, including conical spiral grading, re-election and flotation combined beneficiation, acid scrubbing, stirred AC field alkali decomposition and The process of evaporation-crystallization and ion exchange chemical separation has been carried out in a special and systematic study. Liang Dongwei used the secondary pressing process to increase the metal recovery rate of the tungsten smelting enterprise to over 97%, and the WO3 in the mixed slag was reduced to about 1%. Song Shanzhang invented a method for decomposing scheelite, which consists of three steps: one-time boiling, two-time boiling and phosphoric acid recovery. One-time boiling cooks the finely-milled scheelite and high-phosphoric sodium tungstate solution into a common agitating autoclave to control the solid-liquid ratio, boiling temperature and pressure, and after 0.5 to 1 h of heat preservation, the temperature is discharged and cooled and filtered. Obtaining low-phosphoric sodium tungstate product and one-time boiled filter residue; secondary press-cooking adds the first-time boiled filter residue to the autoclave and the alkali and phosphoric acid calculated by a certain multiple of the theoretical amount; the phosphoric acid recovery will be secondarily boiled The filter residue is leached with concentrated sulfuric acid.
Pan Enshu invented an atmospheric pressure alkaline cooking process to decompose high calcium and tungsten mineral raw materials. The method follows the current atmospheric pressure alkali cooking process, but the silica additive is added during the fine grinding process of the tungsten mineral, and the phosphate additive is added after the decomposition of caustic soda, and the process conditions of the traditional alkali cooking method are changed to decompose the tungsten. The rate is over 98%. This method not only changes the limit of Ca content of <5% for traditional soda cooking materials, but also applies to black, scheelite and mixed ore with WO3 content of 20% ~ 76% and Ca content of 0.2% ~ 20%. Li Honggui and others successfully studied the process of decomposing tungsten mineral raw materials by hot ball grinding, and organically combined ore crushing, mineral mechanical activation and leaching reaction, replacing the original pressing process. The process mechanically activates the material in a hot ball mill reactor to meet the thermodynamic and kinetic conditions required to decompose scheelite with sodium hydroxide.
Pu Chongen et al. invented a combined alkali decomposition process of scheelite and wolframite. The process separates the scheelite and the wolframite after grinding into alkali decomposition and decomposition, and the sulphuric acid is boiled and the filtered sodium tungstate solution is not separated by tungsten alkali, and is directly used for alkali decomposition of wolframite. The decomposition rate can reach about 99%, and the black sulphate concentrate, scheelite concentrate, black and white tungsten mixed ore, tungsten intermediate ore and waste tungsten slag can be simultaneously processed by the smelting plant's existing common pressing equipment. The white (black) tungsten mine invented by Professor Wan Linsheng of Jiangxi University of Science and Technology has cleaned and efficiently produced ultra-high-performance tungsten powder complete sets of technology and industrialization technology, using high-pressure low-alkali and low-phosphorization boiled and controlled crystallization process. Advanced, reliable and stable, high metal recovery rate and low cost, it has won the second prize of National Science and Technology Progress Award in 2008. Lin Haiqing carried out an experimental study on the comprehensive metallurgical recovery of the Tieshan Ridge tungsten ore by selective smelting and metallurgy. The flotation-leaching-replacement-flotation process was used to treat polymetallic sulphide ore, which contained 10.4% Cu and 8.9% Zn. , Cu 0.96%, Mo 0.277%, Pb 0.965% and WO30.24% of the sulfide ore obtained copper concentrate containing Cu25.23%, zinc concentrate containing Zn 45.17%, molybdenum concentrate containing Mo 57.25%, tungsten concentrate Containing WO357.25%, sponge bismuth containing Bi 40.3% and Ag 2010 g/t, greatly improving the recovery rate of various metals.
5 New progress in research and development of tungsten ore dressing equipment
(1) Centrifugal force field flotation machine This equipment can improve the momentum of fine-grained minerals. High-speed rotating ore particles collide with bubbles in the vicinity of the inner wall of the equipment to improve their collision chance and adhesion efficiency. The pulp rotates at high speed, and the layers are produced between layers. Strong shearing movement, while the slurry flow collides with the air bubbles, which is beneficial to overcome the non-selective agglomeration of fine ore particles and the inclusion of gangue particles in the bubbles, thereby improving the grade and recovery rate of useful minerals.
(2) The bubbles precipitated from the slurry by the microbubble precipitation flotation machine are selectively precipitated on the surface of the hydrophobic mineral. It is an active microbubble with small diameter, high dispersion and large volume per unit volume of pulp. The characteristics of the bubble surface area. The air flotation machine is produced by pumping gas from the slurry surface to generate negative pressure microbubbles; the pressurized slurry is sprayed into the flotation tank, so that the microbubbles which suddenly depressurize the slurry are precipitated by the jet cyclone flotation machine; A large number of microbubbles are electric microbubble precipitation flotation machines.
(3) New progress in research and development of scheelite fine flotation column Microbubble flotation column is a kind of flotation equipment capable of efficiently recovering fine particles. It has been widely used in fine-grained flotation and resource reuse. The microbubble flotation column uses microbubbles to enhance the recovery of fine-grain minerals to improve the recovery rate, and the use of the foaming area to reduce the gangue mineral inclusions to improve the concentrate grade. Huang Guangyao et al [78] developed a microbubble flotation column for flotation of the fine-grained grade of white tungsten in flotation tailings of Hunan Anhua Xiang'an Tungsten Company. The column is foamed with microporous material and the expert system is used to control the key operating parameters of the flotation column. The concentrate grade obtained by the test can reach 24.52%, the recovery rate is 43.41%, and the enrichment ratio is up to 35.03. The results of water analysis showed that the recoveries of 5 ~ 10 μm, 10 ~ 19 μm and 19 ~ 38 μm were all above 65%.
6 Conclusion
Black and white tungsten minerals must be recycled step by step and it is difficult to float and separate scheelite and calcium-containing minerals. It is recognized as the world's two major mineral processing problems. The main difficulty encountered in the tungsten ore flotation is that black tungsten is difficult to float and white tungsten is difficult (fine). The black and white tungsten mixed flotation has better recovery effect on fine-grained black and white tungsten symbiotic ore. However, the recovery of fine-grained black tungsten ore is a major difficulty. Therefore, research and development of efficient tungsten ore collectors, new technologies, new processes and new preparations are the top priority to solve these problems.
(1) Advances in smelting technology have made black and white tungsten do not need to be separated in the concentrator, and the development of low-pollution, low-cost black and scheelite high-efficiency collectors and corresponding modifiers has become the current tungsten dressing. One of the directions. Judging from the recent progress in tungsten flotation flotation, the combination of collectors is a direction of development.
(2) With the continuous development and utilization of scheelite resources, there are more and more “poor, fine and miscellaneous” scheelite resources. It is essential to research and develop flotation equipment for high recovery scheelite resources.
(3) With the depletion of Hetero-tungsten resources, there are more and more “poor, fine and miscellaneous” scheelite resources, and various mineral processing methods are combined with each other. The combined process of smelting and smelting has become the development trend of tungsten ore dressing, simple Effective tungsten hydrometallurgical technology has become the focus of many scholars.
(4) The research on drug selection mainly focuses on how to improve the performance of drugs, reduce costs and reduce pollution. The basic theoretical research on the effects of drugs and minerals in complex systems is still poor. In the case of tungsten ore flotation and mixing, theoretical research lags far behind practical application. Further research is needed on the regularity of the combination of agents, the synergistic effect between the combined agents, and the mechanism of action of the agents and minerals.
(5) For the current situation of long-term selection process of complex and difficult-to-select polymetallic black and scheelite, it is of great practical significance to develop a beneficiation equipment for fine-grained particle flotation to shorten the beneficiation process.
(6) High-efficiency recovery of tungsten from fine-grained black and white tungsten symbiotic ore is a difficult problem in tungsten ore dressing. It is necessary to conduct in-depth research on the mechanism of action of collectors, regulators and tungsten minerals and gangue minerals through flotation electrochemistry, flotation solution chemistry and interaction between particles, in order to find more efficient fine particles. The flotation method of the black tungsten ore is provided as a basis.

Uncoiling Flatting Cutting