Method for recovering tungsten in lepidolite concentrate

Abstract

The invention discloses a method for recovering tungsten in lepidolite concentrate, which comprises the following steps: S1, mixing the lepidolite concentrate and a roasting additive to obtain a mixture A; the roasting additive comprises a lithium extraction additive and a tungsten extraction additive; s2, grinding the mixture A to obtain a mixture B, and granulating to obtain lepidolite concentrate particles; s3, roasting the lepidolite concentrate particles to obtain a mixture C; and S4, the mixture C is subjected to water leaching, and leaching residues and leaching liquid are obtained after filtering. According to the method, synergistic leaching of lithium and tungsten can be effectively achieved, and the tungsten recovery rate can reach 80% or above on the premise that the lithium extraction technology is not affected.

Description

Technical Field

[0001] The invention belongs to the field of tungsten extraction and relates to a method for recovering tungsten in lepidolite concentrate. Background Art

[0002] As an important metal element, tungsten has the physical characteristics of high melting point, high hardness and high density. Its chemical properties are stable and it can play the role of many elements and compounds. Its unique physical and chemical properties make tungsten and its compounds occupy an important position in many fields such as alloys, chemical industry, aerospace, etc. With the increasing mining year by year, the high-grade and easy-to-handle tungsten ore resources in China have been basically exhausted. The tungsten ores used in current industrial production are mostly low-grade and difficult-to-handle tungsten ores, or tungsten ore resources associated with other metal ores are recovered. Traditional industrial production technology uses high temperature, high pressure and high alkali wet treatment to achieve a good decomposition rate. The impurity composition and impurity content in the leaching solution are complex, which greatly increases the subsequent evolution and impurity removal technology requirements and treatment costs, and also produces a large amount of saline industrial wastewater. At present, the factors affecting tungsten recovery in industrial production are mainly the transformation and decomposition of insoluble or insoluble tungsten in tungsten ore resources. The decomposition methods of tungsten mineral raw materials mainly include acid decomposition and alkali decomposition.

[0003] According to literature and industrial practice, the decomposition process of tungsten minerals, whether it is wet high-pressure leaching, caustic soda leaching, sodium fluoride leaching or pyrometallurgical NaOH roasting-water leaching, direct smelting, is not suitable for treating low-grade tungsten-containing minerals from the perspective of economic benefits and environmental protection.

[0004] The grade of lithium mica concentrate is generally low, but it is accompanied by a variety of valuable metals. The lithium mica concentrate obtained by beneficiation contains a small amount of tungsten resources. According to the current industry status, it is necessary to recycle as much as possible to obtain higher economic benefits. At present, there is no clear roasting transformation method for tungsten extraction in the process of pyrometallurgical roasting of lithium mica concentrate. The tungsten yield is very low (<10%). If tungsten needs to be decomposed during leaching, a large amount of acid or alkali is required. While increasing the tungsten leaching rate, a large amount of impurities will also be dissolved in the leachate. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings and defects mentioned in the above background technology and provide a method for recovering tungsten in lithium mica concentrate, which has good roasting transformation effect on tungsten in lithium mica concentrate and high tungsten leaching rate, and does not affect the main lithium extraction process.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for recovering tungsten from lithium mica concentrate comprises the following steps: S1, mixing the lepidolite concentrate and the roasting additive to obtain a mixture A; The roasting additives include lithium extraction additives and tungsten extraction additives; The lithium extraction additive includes a lithium extraction additive a and a lithium extraction additive b, wherein the lithium extraction additive a is sodium sulfate or potassium sulfate, and the lithium extraction additive b includes one or more of calcium carbonate, calcium sulfate, and calcium oxide; The tungsten extraction additive is sodium carbonate or potassium carbonate; The mass ratio of the lepidolite concentrate to the lithium extraction additive is 1:0.1-0.6, and the amount of the tungsten extraction additive added is 0.1%-5% of the total mass of the lepidolite concentrate and the lithium extraction additive; S2, grinding the mixture A to obtain a mixture B, and then granulating it to obtain lithium mica concentrate particles; S3, roasting the lepidolite concentrate particles to obtain a mixture C; S4, soaking the mixed material C in water, and obtaining the leached residue and the leached liquid after filtering.

[0007] As a further improvement, the tungsten content in the lithium mica concentrate is less than 1000 ppm.

[0008] As a further improvement, the lithium extraction additives are sodium sulfate, calcium carbonate and calcium sulfate, and the mass ratio is lithium mica concentrate: calcium sulfate: sodium sulfate: calcium carbonate = 1: 0.2~0.5: 0.1~0.2: 0.1~0.2.

[0009] As a further improvement, the S2 is ground until the particle size is above 100 mesh, and water is added and mixed to perform granulation.

[0010] As a further improvement, the calcination temperature of S3 is between 600°C and 900°C.

[0011] As a further improvement, the calcination temperature of S3 is between 800°C and 900°C.

[0012] As a further improvement, the liquid-to-solid ratio of the water immersion in S4 is 0.8~4:1.

[0013] As a further improvement, the liquid-to-solid ratio of the water immersion in S4 is 1:1.

[0014] As a further improvement, the S4 water immersion temperature is 20°C~80°C.

[0015] As a further improvement, the S4 water immersion temperature is 20°C.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The invention obtains a tungsten-rich leachate by granulating, roasting and leaching the lepidolite concentrate, wherein the lepidolite concentrate is mixed with an auxiliary material roasting additive and ground, and then granulated so that the lepidolite concentrate and the auxiliary material have a larger contact area, the reaction rate is increased, the material transformation rate in the roasting stage is greatly increased, and the leaching effect is further improved.

[0017] There is no chemical reaction between the tungsten extraction additive and the lithium extraction additive added in the present invention, the tungsten extraction reaction and the lithium extraction reaction do not interfere with each other, and have no influence on the transformation of lithium during the roasting process, and can effectively achieve the coordinated leaching of lithium and tungsten.

[0018] In addition, during leaching, the present invention directly uses the roasted mica particles to carry out leaching with clean water at normal temperature and pressure, and can ensure a high leaching rate without stirring or adding other substances.

[0019] In the present invention, up to 90% of the tungsten in the tungsten-containing lithium mica concentrate is leached into the leaching solution, which greatly improves the tungsten recovery effect. The recovery effect can reach more than 80% without affecting the lithium extraction process.

[0020] The process of the present invention avoids the problem of using a large amount of acid and alkali in the treatment of low-grade tungsten-containing materials in the traditional process. In the treatment of tungsten-containing lithium mica concentrate, lithium and tungsten can be effectively converted and leached simultaneously. The low solid ratio of the leaching liquid makes the concentration in the leaching liquid high, reducing the difficulty and cost of recovery, and at the same time reducing the amount of wastewater generated and the treatment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the process flow in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0024] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0026] like Figure 1 In some specific embodiments, the method for recovering tungsten from lithium mica concentrate of the present invention comprises the following steps: S1. Mixing the lepidolite concentrate and the roasting additive (lithium extraction additive and tungsten extraction additive) to obtain a mixture A.

[0027] In some embodiments, the tungsten content in the lithium mica concentrate is less than 1000 ppm.

[0028] In some embodiments, the lithium extraction additive includes a lithium extraction additive a and a lithium extraction additive b, wherein the lithium extraction additive a is sodium sulfate or potassium sulfate, and the lithium extraction additive b includes one or more of calcium carbonate, calcium sulfate, and calcium oxide, and the lithium extraction additive does not react with tungsten during roasting. The mass ratio of lithium mica concentrate to lithium extraction additive is 1:0.1~0.6. Preferably, the lithium extraction additive a is sodium sulfate, and the lithium extraction additive b is calcium carbonate and calcium sulfate, and the mass ratio is lithium mica concentrate: calcium sulfate: sodium sulfate: calcium carbonate = 1:0.2~0.5:0.1~0.2:0.1~0.2.

[0029] In some embodiments, the tungsten extraction additive is sodium carbonate or potassium carbonate. The amount of the tungsten extraction additive added is 0.1% to 5% of the total mass of the lepidolite concentrate and the lithium extraction additive, preferably 1% to 5%.

[0030] In some embodiments, the preparation method of mixture A comprises the following steps: (1) Mixing lepidolite concentrate and lithium extraction additive to obtain mixed material A 1 ; (2) Mixture A 1 Mixed with tungsten extracting additives to obtain mixed material A.

[0031] S2, grinding the mixed material A to obtain a mixed material B, and then granulating the mixed material to obtain lepidolite concentrate particles.

[0032] In some embodiments, the grinding is performed until the particle size is above 100 mesh, preferably 200 mesh to 1000 mesh.

[0033] In some embodiments, S2 includes the following steps: (1) Mixture B is mixed with water to obtain mixture B. 1 ; (2) Mixture B 1 Granulation is performed to obtain lithium mica concentrate particles.

[0034] S3, roasting the lepidolite concentrate particles to obtain a mixture C.

[0035] In some embodiments, the calcination temperature is between 600°C and 900°C, preferably between 800°C and 900°C.

[0036] S4. Leaching the mixed material C in water, and obtaining the leaching residue D and the leaching solution E (tungsten-rich and lithium-rich leaching solution) after filtering.

[0037] In some embodiments, the liquid-to-solid ratio of the mixture C in water is 0.8-4:1, preferably 1:1, and the water immersion temperature is room temperature (20°C)-80°C, preferably room temperature (20°C).

[0038] The liquid-to-solid ratio in the present invention refers to the mass ratio of liquid to solid in the material.

[0039] During roasting, the mechanism of action of tungsten extracting additives is: Na 2 CO 3 +CaWO 4 =Na 2 WO 4 +CaO+CO 2 Tungsten in lithium mica concentrate is mostly in the form of water-insoluble CaWO 4 In the form of Na 2 CO 3 Calcination is performed to make CaWO 4 Transformed into Na2O3 which is easily soluble in water 2 WO 4 , making tungsten WO 4 2- In the form of Na 2 CO 3 Transform the tungsten in the concentrate, improve the recovery rate and recovery effect of tungsten in subsequent water leaching, and do not affect the main lithium extraction process.

[0040] Reaction mechanism of lithium extraction additives: Li 2 O.Al 2 O 3 ·4SiO 2 +Na 2 SO 4 →Li 2 SO 4 +Na 2 O.Al 2 O 3 ·4SiO 2 The lithium in lepidolite concentrate is mainly in the form of water-insoluble Li 2 O form, by adding Na2 SO 4 Roasting makes Li 2 O is converted into Li which is easily soluble in water. 2 SO 4 , so that lithium is Li + into the solution for recovery.

[0041] The main function of calcium sulfate in lithium extraction additives is to increase the melting point of materials and fix fluorine, the function of calcium carbonate is to fix fluorine, decompose to produce pores and increase porosity, and calcium oxide is mainly used for fixing fluorine. The fixing fluorine effect makes a large amount of fluorine in lithium mica concentrate remain in the roasting product, reducing the fluorine content in the flue gas and reducing the cost of flue gas treatment. At the same time, the carbon dioxide generated by the decomposition of calcium carbonate and the reaction of sodium carbonate and calcium tungstate is beneficial to the porosity of the roasted product after granulation and roasting in this process, and improves the leaching effect.

[0042] Except Na 2 SO 4 All other lithium extraction additives do not participate in the main reaction of lithium recovery process. All lithium extraction additives do not react with CaWO in lithium mica concentrate. 4 Therefore, the tungsten recovery rate is low without the addition of other additives. 2 CO 3 The addition of Na has no effect on the main lithium extraction process. 2 CO 3 The invention can effectively carry out transformation roasting of tungsten in lithium mica concentrate, thereby improving the recovery effect of tungsten in lithium mica concentrate.

[0043] The chemical composition (%) of the lithium mica concentrate in the following examples and comparative examples is as follows: Li 2 O 2.02%, WO 3 0.16%, SiO 2 48.3%, F 4.03%, Al 2 O 3 20.34%, Rb 2 O 0.62%, Cs 2 O 0.05%.

[0044] Example 1 The method for recovering tungsten and lithium from the lithium mica concentrate of the present embodiment is specifically to add auxiliary materials to the lithium mica concentrate raw material and then granulate-roast-water soak, comprising the following steps: S1. Mix the lepidolite concentrate with a lithium extraction additive (composed of calcium sulfate, sodium sulfate and calcium carbonate, concentrate: calcium sulfate: sodium sulfate: calcium carbonate = 1:0.2:0.1:0.1) to obtain a mixture A. 1 .

[0045] According to Mix A 1Sodium carbonate as a tungsten extraction additive is added at a ratio of 0.1% by mass, mixed evenly, and fully contacted to obtain a mixture A.

[0046] S2. Finely grind the mixture A until the particle size reaches 300 mesh or more to obtain the mixture B.

[0047] Mixture B is added with water at a ratio of 10% to obtain mixture B. 1 Mixture B 1 Granulation is performed to obtain lithium mica concentrate particles.

[0048] S3. The lithium mica concentrate particles are roasted at 900° C. to obtain a mixture C (lithium mica particle clinker).

[0049] S4. The mixed material C is immersed in water at a liquid-to-solid ratio of 1:1 to obtain leached residue D and leaching liquid E.

[0050] The leached residue and leaching solution obtained in Example 1 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 1.

[0051] Example 2 The method for recovering tungsten from the lithium mica concentrate of the present embodiment is specifically to add auxiliary materials to the lithium mica concentrate raw material and then granulate-roast-water soak, comprising the following steps: S1. Mix the lepidolite concentrate with a lithium extraction additive (composed of calcium sulfate, sodium sulfate and calcium carbonate, concentrate: calcium sulfate: sodium sulfate: calcium carbonate = 1:0.2:0.1:0.1) to obtain a mixture A. 1 .

[0052] According to Mix A 1 Sodium carbonate as a tungsten extraction additive is added at a ratio of 1% by mass, mixed evenly, and fully contacted to obtain a mixture A.

[0053] S2. Finely grind the mixture A until the particle size reaches 300 mesh or more to obtain the mixture B.

[0054] Mixture B is added with water at a ratio of 10% to obtain mixture B. 1 Mixture B 1 Granulation is performed to obtain lithium mica concentrate particles.

[0055] S3. The lithium mica concentrate particles are roasted at 900° C. to obtain a mixture C.

[0056] S4. The mixed material C is immersed in water at a liquid-to-solid ratio of 1:1 to obtain leached residue D and leaching liquid E.

[0057] The leached residue and leaching solution obtained in Example 2 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 1.

[0058] Example 3 The method for recovering tungsten from lithium mica concentrate in this embodiment is basically the same as that in Example 2, except that the amount of sodium carbonate is increased to 2% in step S1.

[0059] The leached residue and leaching solution obtained in Example 3 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 1.

[0060] Example 4 The method for recovering tungsten from lithium mica concentrate in this embodiment is basically the same as that in Example 2, except that the amount of sodium carbonate is increased to 5% in step S1.

[0061] The leached residue and leaching solution obtained in Example 4 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 1.

[0062] Comparative Example 1 The method for recovering tungsten from the lithium mica concentrate in this comparative example is basically the same as that in Example 2, except that sodium carbonate is not added in step S1.

[0063] The leaching residue and leaching liquid obtained in Comparative Example 1 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 1.

[0064] Comparative Example 2 The method for recovering tungsten from the lepidolite concentrate of this comparative example is substantially the same as that of Example 2, except that sodium hydroxide is added in place of sodium carbonate in step S1.

[0065] The leached residue and leaching solution obtained in Comparative Example 2 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 1.

[0066] The roasting of the above embodiments and comparative experiments was carried out in a rotary kiln, with specific process parameters: roasting temperature of 900°C, roasting time of 1h, the roasting product was used as the raw material for water leaching, no crushing and stirring were required during water leaching, the leaching temperature was room temperature, countercurrent leaching was adopted, the liquid-solid ratio was maintained at 1:1, the single leaching time was 8 hours, and the total time was 32 hours. Finally, the residual tungsten and lithium content in the leaching residue and the tungsten and lithium content in the leaching solution were determined, and the leaching rate of tungsten and lithium in water leaching was calculated in combination with the original content in the concentrate.

[0067]

[0068] As shown in Table 1, the feasibility of adding sodium carbonate to the lithium mica concentrate for roasting-water leaching to recover tungsten can achieve the coordinated leaching of lithium and tungsten when the addition amount is appropriate. 2 CO 3The test results show that the recovery of tungsten cannot be effectively improved under the test conditions. The reason is that the sodium hydroxide dissolves at 900℃, which is not conducive to the reaction and the transformation of tungsten. On the other hand, it causes adhesion between materials, thus affecting the leaching effect of tungsten and lithium.

[0069] Example 5 The method for recovering tungsten from lepidolite concentrate in this embodiment is substantially the same as that in Embodiment 2, except that the leaching liquid-solid ratio in step S4 is adjusted.

[0070] The leached residue and leaching solution obtained in Example 5 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 2.

[0071] Table 2 Lithium and tungsten leaching conditions at different leaching liquid-to-solid ratios in Example 5

[0072] It can be seen from Table 2 that the tungsten leaching rate in the present invention is different under different liquid-to-solid ratios, and the leaching rate increases with the increase of the liquid-to-solid ratio. Considering the concentration of the leaching solution and subsequent water treatment, a 1:1 liquid-to-solid ratio is more suitable for water leaching in the present invention.

[0073] Example 6 The method for recovering tungsten from lithium mica concentrate in this embodiment is basically the same as that in Embodiment 2, except that the roasting temperature is lowered in step S3, and the leaching effect after roasting at different roasting temperatures is investigated, and the leaching liquid-to-solid ratio is 1:1.

[0074] The leached residue and leaching solution obtained in Example 6 were analyzed and tested, and the relevant lithium and tungsten leaching rates were calculated. The results are shown in Table 3.

[0075] Table 3 Lithium and tungsten leaching at different roasting temperatures in Example 6

[0076] As shown in Table 3, the roasting temperature in the present invention has a great influence on the leaching effect of lithium and tungsten. A relatively low roasting temperature is more conducive to the successful transformation of tungsten, but it seriously restricts the transformation of lithium, and even no reaction occurs under this temperature condition. Therefore, it is necessary to select a suitable roasting temperature according to different lithium mica concentrates and their properties and the addition of auxiliary materials to achieve the purpose of recovery after the coordinated leaching of lithium and tungsten.

[0077] Example 7 The method for recovering tungsten from lithium mica concentrate in this embodiment uses the roasted material obtained in Example 6 for water leaching, with the difference that the leaching temperature of step S4 is adjusted, the leaching effect of tungsten under different leaching temperature conditions is investigated, and the raw material used is the roasted clinker obtained at 600°C in Example 6.

[0078] The leached residue and leaching solution obtained in Example 7 were analyzed and tested, and the correlation and leaching rate were calculated. The results are shown in Table 4.

[0079] Table 4 Tungsten leaching at different leaching temperatures in Example 7

[0080] It can be seen from Table 4 that in the present invention, the leaching temperature has little effect on the tungsten leaching effect, and the elevated temperature leaching cannot achieve a more ideal leaching effect compared with the normal temperature leaching.

[0081] Example 8 The method for recovering tungsten from lithium mica concentrate in this embodiment uses the roasted material obtained in Example 6 for water leaching, with the difference that the roasted clinker is ground, heated and stirred during leaching, and the leaching effect of tungsten under different leaching conditions is investigated. The raw material used is the roasted clinker obtained at 600°C in Example 6.

[0082] The leached residue and leaching liquid obtained in Example 8 were analyzed and tested, and the relevant leaching rates were calculated. The results are shown in Table 4.

[0083] Table 5 Tungsten leaching conditions in different leaching states in Example 8

[0084] As shown in Table 5, the use of powder leaching in the present invention can achieve a higher tungsten leaching rate, but from the perspective of process and economic benefits, it is more appropriate to directly leach without grinding.

[0085] Based on Example 2, the effects of different calcium carbonate addition amounts on lithium leaching rate and fluorine fixation effect were studied. The results are shown in Table 6.

[0086] Table 6

[0087] It can be seen from the above results that the present invention can effectively improve the recovery effect of tungsten in lithium mica, and can achieve a basically complete transformation of tungsten in lithium mica concentrate under appropriate process control conditions. The product after roasting can be directly leached at room temperature and pressure, with high leaching efficiency and high tungsten leaching rate. The water used for leaching can be reused repeatedly to avoid secondary pollution such as wastewater. At the same time, the roasted product does not need to be crushed or ground before leaching, and does not need to be stirred or added with other additives such as acid or alkali during leaching. It is more environmentally friendly while ensuring the leaching rate.

[0088] In addition, the present invention can effectively achieve the coordinated leaching of lithium and tungsten in the lithium extraction process of lithium mica concentrate, will not generate additional processes for the main lithium extraction process, and provides an effective method for recovering lithium and tungsten from tungsten-containing lithium mica concentrate.

[0089] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for recovering tungsten from lepidolite concentrate, characterized in that: The following steps are involved: S1, mixing the lepidolite concentrate and the roasting additive to obtain a mixture A; The roasting additives include lithium extraction additives and tungsten extraction additives; The lithium extraction additive includes a lithium extraction additive a and a lithium extraction additive b, wherein the lithium extraction additive a is sodium sulfate or potassium sulfate, and the lithium extraction additive b includes one or more of calcium carbonate, calcium sulfate, and calcium oxide; The tungsten extraction additive is sodium carbonate or potassium carbonate; The mass ratio of the lepidolite concentrate to the lithium extraction additive is 1:0.1-0.6, and the amount of the tungsten extraction additive added is 0.1%-5% of the total mass of the lepidolite concentrate and the lithium extraction additive; S2, grinding the mixture A to obtain a mixture B, and then granulating it to obtain lithium mica concentrate particles; S3, roasting the lepidolite concentrate particles to obtain a mixture C; S4, soaking the mixed material C in water, and obtaining the leached residue and the leached liquid after filtering.

2. The method for recovering tungsten in lepidolite concentrate according to claim 1, characterized in that: The tungsten content in the lithium mica concentrate is less than 1000ppm.

3. The method for recovering tungsten in lepidolite concentrate according to claim 1 or 2, characterized in that: The lithium extraction additives are sodium sulfate, calcium carbonate and calcium sulfate, and the mass ratio is lithium mica concentrate: calcium sulfate: sodium sulfate: calcium carbonate = 1: 0.2-0.5: 0.1-0.2: 0.1-0.

2.

4. The method for recovering tungsten in lepidolite concentrate according to claim 1 or 2, characterized in that: The S2 is ground until the particle size is above 100 mesh, and water is added and mixed to granulate.

5. The method for recovering tungsten in lepidolite concentrate according to claim 1 or 2, characterized in that: The S3 calcination temperature is between 600°C and 900°C.

6. The method for recovering tungsten in lepidolite concentrate according to claim 5, characterized in that: The S3 calcination temperature is between 800°C and 900°C.

7. The method for recovering tungsten in lepidolite concentrate according to claim 1 or 2, characterized in that: The liquid-to-solid ratio of the water in S4 is 0.8-4:

1.

8. The method for recovering tungsten in lepidolite concentrate according to claim 7, characterized in that: The liquid-to-solid ratio of the water in S4 is 1:

1.

9. The method for recovering tungsten in lepidolite concentrate according to claim 1 or 2, characterized in that: The S4 water immersion temperature is 20°C to 80°C.

10. The method for recovering tungsten in lepidolite concentrate according to claim 9, characterized in that: The S4 water immersion temperature is 20°C.

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