1) Flotation method The main method of selection of spodumene is flotation. The stirring strength, slurry temperature and ratio of adjusting agent in the flotation operation are the three important factors affecting the flotation of spodumene. Nowadays, the flotation method of spodumene in China is carried out by adding "tri-alkali two soaps". "Tri-alkali", namely sodium hydroxide, sodium carbonate and sodium sulfide, their use, the location of addition, and the concentration of Ca2+ in the water used in the selection process all have an important influence on the flotation of spodumene. The key factor affecting the flotation index is the concentration ratio of carbonate ion, hydroxide ion and calcium ion in the slurry. Therefore, the amount of the modifier varies with the softness and hardness of the water used. In the pulp environment where the optimum pH is weakly alkaline, it is easy to float the surface spodumene with oleic acid and its soap. "Two soaps", namely naphthenic acid soaps and oxidized paraffin soaps, are commonly used collectors for spodumene flotation, and their amounts also vary with the softness and hardness of water. In the case of hard water, naphthenic acid soap is not conducive to flotation. When the water quality is soft, the use of naphthenic acid soap can significantly increase the recovery rate of spodumene. Because the mineral surface is often subjected to weathering and mica contamination in the slurry during flotation, the floatability of spodumene is deteriorated, and some of the dissolved salt ions in the slurry, such as magnesium ions, iron ions and calcium ions, not only make The spodumene is activated, and the gangue mineral is also activated, so that the difference in the planktonic properties of spodumene and gangue minerals is not obvious. Therefore, for various spodumene ore, the physical and chemical properties should be studied and analyzed before selecting suitable collectors and beneficiation processes. The two processes of positive flotation and reverse flotation are currently the main methods used in industry to select spodumene. 1 flotation method Positive flotation generally uses an anionic collector. By adding the ore that has been ground to a strongly alkaline alkaline medium, a high concentration of strong agitation is performed. After multiple scrubbing and deliming, the anionic collector is finally added. Conduct a direct selection of spodumene. Due to the reaction of the added sodium hydroxide and the silicate in the slurry to form sodium silicate - "autogenous water glass", which is an inorganic inhibitor, can effectively inhibit silicate gangue minerals, therefore, in flotation The process does not require the addition of an inhibitor. The alkaline activation of spodumene is a key step in the selection process. By NaOH treatment of raw slurry at a high concentration, then the effect of the product ore fluids and minerals with a base prolapse, this time spodumene since the surface extrusive SiO2 is activated, and gangue minerals due to its activating cation (Cu2 + surface, Ca2+, Fe3+, etc.) are inhibited by the formation of poorly soluble compounds that are excluded from the mineral surface. After washing and de-slurry, an anion collector is used to float the spodumene. In order to better inhibit gangue minerals, water glass, silicone, lignin and lactic acid can be added. Xinjiang Keketuohai noble metal ore spodumene, stirred by a high strength in the flotation machine, thereafter the mineral surface for scrubbing off the mud, tailings desliming cationic collector preferentially at neutral weak alkaline environment Flotation mica, floating mica tailings with Na2CO3 and NaOH as a combination adjuster to adjust the slurry, in the slurry pH = 10.5 ~ 11.5, using oxidized paraffin soap as a collector flotation spodumene, containing Li2O 1.76% in the ore in the case of obtaining containing Li2O 5.65% ~ 6.38% of spodumene concentrate, recovery of 80.78%. Sun Wei et al. conducted a small laboratory test on a spodumene ore, through the fineness of grinding, the stirring strength of the flotation machine, the ratio of the adjusting agent, and the flotation of the amount of the adjusting agent and the collector during the sorting process. The relationship between all the different water quality and the location of the flotation agent was compared to determine the best conditions. In the case of 1.42% of the original ore Li2O grade, the spodumene concentrate with a Li2O content of 6.05% and a recovery rate of 85.92% was obtained. . The test results show that the stirring operation is related to sodium hydroxide. With the increase of the amount of sodium hydroxide, the stirring time can be shortened accordingly, and the recovery rate is gradually increased. To a certain extent, the operation intensity of the flotation machine is improved, and the grade and recovery rate of the spodumene concentrate can also be improved to some extent. The experiment of adjusting agent under different water quality shows that NaOH should not be added into the mill when the concentration of Ca2+ in water is high, and the amount of NaOH in the mixing operation is not suitable. In the case of soft water, NaOH is added to the slurry to activate. obvious. At the same time, the Na2CO3 test showed that the grade of the spodumene concentrate increased significantly with the increase of the amount of Na2CO3. When the amount of Na2CO3 exceeded a certain range, the recovery rate of the spodumene concentrate decreased. Yan Gengsheng and others pointed out that it is difficult to select the spodumene in the spodumene plant after the completion of the project. By strengthening the mixing and scrubbing of the pre-lithium pulp, adding the spodumene activator calcium chloride and changing the collector, etc. The method to improve the floatation of spodumene has finally achieved a good selection index. The laboratory small test uses a combination of collectors, namely sodium oleate: 731 is 7:3, Na2CO3, NaOH is used as a regulator, and diesel stabilized foam is used. When the fineness of grinding is -0.074mm, the average content of spodumene is 80%. In the case of 16.00%, the final obtained spodumene has a spodumene content of 72.65% and a recovery rate of 76.00%. Better indicator. 2 reverse flotation The reverse flotation process uses lime and dextrin to adjust the slurry, and uses a cationic collector to reverse flotation of silicate-like gangue minerals such as quartz , feldspar and mica at a pH of 10.5 to 11.0. In order to obtain the qualified spodumene concentrate, the in-tank product containing some iron minerals is thickened and then treated with hydrofluoric acid, and then the fatty acid collector-resin acid soap is used for the selection, and the obtained in-tank product is obtained. It is a spodumene concentrate. In the US Jinsishan spodumene concentrator, the reverse flotation process was adopted. They used lime as a pH adjuster, added a spodumene inhibitor to the spodumene mineral in an alkaline medium, and selected a cationic collector for reverse flotation. Out of the gangue mineral, the obtained spodumene concentrate is the product in the tank, and the product meets the standard of chemical grade products. In order to improve the quality of the spodumene concentrate product, the above-mentioned concentrate products can be selected, in order to reduce the content of Fe in the lithium concentrate, by adding HF, resin acid salt, and finally adding a foaming agent to remove iron minerals. The soda limestone concentrate thus obtained reaches the ceramic spodumene standard and can be used as a raw material for the ceramic industry. The foam concentrate obtained by preferentially removing the gangue minerals can be further separated to obtain concentrate products such as mica, feldspar and quartz, respectively, and the obtained spodumene concentrate is contained in the case where the ore contains Li2O about 1.5%. Li2O is higher than 6.00%, and the recovery rate is 70.00% to 75.00%. 2) Hand selection method The method of separating from the silicate-like gangue mineral according to external features such as the shape or color of the mineral itself is a hand selection method. For the coarse-grained crystal combination, namely spodumene and lithium mica, a good spodumene concentrate can be obtained by hand selection. Currently, the spodumene ore of the Etite deposit in South Dakota, USA, is still selected by this method. The Lijiagou lithium pyroxene mine in Jinchuan County, Sichuan Province uses the hand selection method to pretreat the ore, that is, after the coarse crushing, part of the waste rock is removed by hand selection. Manual hand selection is relatively simple. Hand selection not only improves the grade of ore selected, but also reduces the cost of mineral processing. It also helps to improve the lithium flotation index. However, this method is inefficient and not suitable for fine-grained ore. 3) Thermal cracking Some minerals can be selectively destroyed by heating, cooling, etc. This is the thermal cracking method. The spodumene mineral undergoes a transformation during the heating process, ie the transformation of allotropes. Some gangue minerals have different properties from spodumene minerals, and the crystals do not change during heating. Therefore, it is feasible to use this method to select spodumene. However, this method is limited to the case where the ore composition is good. For example, if there are a large number of gangue minerals having the same crystal properties as spodumene, such as albite, calcite and mica, it is difficult to obtain qualified lithium by this method. Pyroxene concentrate. The sphalerite test of the spodumene was carried out by the thermal cracking method in the methyl strontium pyroxene mine in Ganjiang County, Sichuan Province. The test results showed that the ore particle size was -55 to ±0.2 mm, the temperature was 1050±50 °C, and the constant temperature time was obtained. The furnace is calcined under the process conditions of 30 to 40 minutes. When the ore contains Li2O of about 2.0%, the Li2O grade in the concentrate can be 6 to 8%, and the recovery rate is 80%. However, the calcination of the process needs to be carried out at a very high temperature, and it is not possible to comprehensively recover other useful metal components, and therefore, there are certain limitations in actual production. 4) Resuspension method Since the density of spodumene minerals and gangue minerals is different, this property is used to select them. This method is a resuspension or heavy liquid beneficiation method. The spodumene single mineral density is 3.10 to 3.20 g/cm3, and the density of gangue minerals (feldspar, quartz, muscovite, etc.) coexisting with spodumene minerals is about 2.6 g/cm3, although this density difference is Sorting with a shaker and a jig cannot be done, but it is feasible for certain types of lithium ore. Magnetite suspension used, tribromo methane, ferrosilicon. While ensuring that the viscosity of the suspension is kept to a minimum, the specific gravity of the suspension can be kept constant, and the resulting spodumene concentrate is of high quality. Tao Jiarong et al. conducted a beneficiation industry test on a spodumene ore by heavy medium method. The results showed that when the medium density of the heavy medium system was 2.95-3.0 kg/L and the size of the spodumene sample was -3+1 mm. A lint-fine process is used to obtain a spodumene concentrate with a grade of 7.06% and a total recovery of 87.47% in the case of a raw ore containing 2.95% Li2O. Liao Minghe and others believe that the resuspension method is not only simple and practical but also intuitive and effective. It is a pre-selectability test method for the effective sorting of spodumene. Using this method, we can understand the monomer dissociation of spodumene minerals under different particle size conditions and the precision of separation of spodumene minerals from gangue minerals, and then quickly make a preliminary evaluation of the optionality of the ore. The next step is to expand the basis of the beneficiation test. The xenophosite deposit in Jixian County, Jiangxi Province is invaded into the quartz mica schist. More than ten veins have been controlled. Each vein is between 150 and 300 meters long and 3 to 15 meters thick. It is a typical granite. Pegmatite-type spodumene deposit. Spodumene, quartz, muscovite, sericite and coarse crystalline potassium sodium feldspar ore is the main component and containing trace amounts of niobium tantalite, spodumene content is typically ten percent to thirty percent, wherein The rich ore section is more than 45 percent, the lowest Li2O content is 0.7%, and the highest is 3.44%. According to the characteristics of this deposit, sampling is carried out in three veins of V10, V25 and V26. The samples of V10 and V25 veins are native to weakly weathered ore. In addition, V26 is a native rich ore (single weight is about 5kg). At the same time, the +0.125mm fractions were selected, and the yields were 86.0%, 88.8%, and 92.6%, respectively, and this fraction was used as a sample for heavy liquid sorting. The heavy liquid used in this test is analytically pure tribromomethane with a density between 2.891 and 2.889 g/cm3. It is used for gangue minerals (potassium feldspar, quartz, muscovite, sericite, density) associated with spodumene. Separated to about 2.6 g/cm3). The sorting procedure is as follows: first, pour a heavy liquid (about 170 mL) into a 250 mL glass beaker at room temperature, then put about 50 g of the ore sample into the heavy liquid, stir it with a glass rod for about 1 min, and let the solution stand and stratify. After that, it is screened with 140 mesh stainless steel, and the sediment (concentrate) and floating matter (tailing) are taken out. The obtained fine tailings are washed and dried, weighed, and finally the fine tailings are ground and tested. The test obtained a Li2O grade between 6.1% and 6.9% with the lowest recovery rate. 66.7%, up to 94% of spodumene concentrate. Under the condition of optimal sorting size (0.28~1mm), the lithium semenite concentrate Li2O grade is 6.72%~7.0%, and the recovery rate is 83%~95%. Subsequently, an expanded flotation test was carried out, and the recovery rate of the qualified spodumene concentrate obtained finally reached over 70%. AB Sosa et al. treated the northern Portuguese granite spodumene ore in the form of fine-grained pegmatite and carried out flotation and heavy medium sorting tests to obtain qualified spodumene concentrate and feldspar concentrate. They used bromoform as a heavy liquid, and the ore samples (having a particle size of 2.00 to 6.70 mm) were divided into four non-granular grades. The resulting spodumene concentrate contained about 5.00% of Li2O, and the recovery was 39.0%. ~ 61.0%, reaching the glass quality standard. Although this method is not affected by temperature and can be carried out under a relatively coarse particle size, the current re-suspension beneficiation is limited to the problems of complicated process and high cost, and cannot be practically applied. 5) Magnetic separation method Magnetic separation is commonly used to improve the quality of the spodumene concentrate, which is commonly used to remove weakly magnetic iron-lithium mica or other impurities containing Fe in ore minerals. Since the content of Fe is sometimes high in the spodumene concentrate obtained by the flotation method, the spodumene concentrate can be treated by magnetic separation to obtain low-iron spodumene to improve the spodumene concentrate. grade. This method can be used to remove weak magnetic impurities from spodumene coarse concentrate. 6) Joint beneficiation method At present, it is difficult to obtain qualified spodumene concentrate from lean, fine and miscellaneous spodumene minerals by a single beneficiation method. The combined beneficiation method and the combined metallurgy process are produced, such as: flotation-magnetic separation process ( a spodumene mine in a certain area of ​​Sichuan, a rare metal spodumene mine in the Cocoa Sea in Xinjiang); a flotation-re-election-magnetic separation process (Grincipush Lithofia mine in Kiwary, Australia) Metal ore); beneficiation-chemical treatment combined process (Danke pegmatite mine of Canada Minmetals Mining); selective-smelting joint process (North Carolina lithium feldspar pegmatite deposit owned by Ford, USA). Xinjiang Coco-Taihai spodumene ore, after crushing and de-slurry, using oxidized paraffin soap and naphthenic acid soap as a combination collector, NaOH as a pH adjuster, and a coarse-fine flotation in alkaline pulp The process flow is selected. The flotation of spodumene coarse concentrate is de-ironed by a wet strong magnetic separator. In the case of Li2O containing 1.14%, a ceramic grade spodumene containing 6.44% Li2O and 0.39% Fe2O3 is obtained. Concentrate. A spodumene mine in Sichuan Province, experts at the Sichuan Metallurgical Research Institute Great progress has been made in the research. At room temperature spodumene flotation, flotation spodumene using reverse flotation rougher concentrate off gangue minerals, concentrate obtained Li2O grade of 5.91%, Fe2O3 1.44%, thereafter by high gradient magnetic separator Removal of iron-bearing minerals, in the case of a raw ore containing Li2O of 1.33% and Fe2O3 of 1.02%, the resulting low-iron spodumene in the spodumene concentrate obtained with a Li2O grade of 6.15% and a Fe2O3 content of 0.24% mine. Australian slang group Wa (Cwalia) Pushi Lin's grid (Greenbusbse) spodumene ore, raw ore containing Li2O 4.01%, the impurities in the iron ore tourmaline, and the mineral composition simply by using gravity and magnetic floating Combined Technology In the process, two glass-grade spodumene concentrates are finally obtained, and their indexes are: 4.8% of Li2O, 0.4% of Fe2O3, and more than 7.5% of Li2O, and less than 0.1% of Fe2O3. 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The selection of spodumene is affected by many factors, such as ore type, mineral symbiosis combination, inlaid characteristics and ore grade, etc., and different beneficiation processes are required. In the practice of spodumene ore dressing, the current selection methods of spodumene mainly include flotation method, hand selection method, thermal cracking method, resuspension method, magnetic separation method and joint beneficiation method.