A method for recovering tungsten from an acidic tungsten-containing solution

Abstract

This application belongs to the technical field of tungsten smelting resource utilization, specifically to a method for recovering tungsten from an acidic tungsten-containing solution, comprising the following steps: obtaining an acidic tungsten-containing solution and an alkaline sodium tungstate solution; forming a mixed system with the alkaline sodium tungstate solution, reacting to precipitate tungstic acid crystals, continuing the crystallization, filtering to obtain a filtrate, and recovering the tungstic acid. The tungsten recovery method of this application solves the problem of the difficulty in efficiently recovering tungsten resources from acidic tungsten-containing solutions, achieving efficient tungsten recovery and reducing wastewater treatment costs. This method provides a new technical option for companies in the tungsten industry, with significant economic and social benefits.

Description

Technical Field

[0001] The present application belongs to the technical field of tungsten smelting resource utilization, and specifically relates to a method for recovering tungsten from an acidic tungsten-containing solution. Background Art

[0002] Scheelite is currently the most important tungsten resource. Its smelting processes primarily include alkaline and acid processes. To reduce acid and alkali consumption and lower production costs, many companies combine the acid and high-alkali processes. Specifically, the main process uses a high-alkali decomposition of scheelite followed by ion exchange and evaporation crystallization to produce APT. This process produces sodium tungstate with a high alkaline concentration, requiring significant acid consumption during neutralization in wastewater treatment. Alternatively, a portion of the scheelite is decomposed with hydrochloric acid to produce tungstic acid, which is then neutralized with high-alkali sodium tungstate. This reduces acid consumption in wastewater treatment and reduces production costs. However, due to the solubility of tungstic acid in hydrochloric acid and the extremely fine particles produced by scheelite decomposition, a small amount of tungstic acid can pass through the filter cloth and enter the acid filtrate during filtration, resulting in a WO3 concentration as high as 3-6 g / L in the acid filtrate, representing 1%-3% of the total metal content. If not recycled, this represents a significant waste of tungsten resources, negating the advantages of the combined process. If the acid filtrate is directly mixed with a high-alkali sodium tungstate solution to produce sodium tungstate, while the tungsten in the acid filtrate can be effectively recovered, the acid filtrate contains a large amount of calcium chloride. The calcium ions react with the tungstate ions to form calcium tungstate, causing severe tungsten loss. Furthermore, the extremely high concentration of chloride ions severely reduces the exchange capacity of the resin, clearly failing to meet the requirements of the ion exchange process. Therefore, how to achieve efficient recovery of tungsten resources from the acid filtrate has become a focus of industry attention.

[0003] Currently, adding sulfuric acid to the acid decomposition solution to react and form calcium sulfate precipitation is a relatively good method. This not only allows the calcium in the acid decomposition solution to precipitate primarily as calcium sulfate, but also allows the acid to be regenerated and returned to secondary decomposition. However, this method results in the loss of fine particles of tungstic acid along with the calcium sulfate, and the recovery of large amounts of calcium sulfate is difficult to handle. Another method is to adjust the pH of the acid filtrate to 3-6 with lime, then adsorb and recover tungsten using a weak-base anion exchange resin. Finally, the recovered solution is adjusted to a neutral pH with lime before discharge. This method is theoretically feasible, but the weak-base resin's tungsten recovery efficiency is very low, perhaps due to the high chloride ion concentration in the solution, at only 30-40% of its normal adsorption capacity. Therefore, the development of technologies for the efficient utilization of tungsten resources in acid filtrates is of great significance. Summary of the Invention

[0004] The present application provides a method for recovering tungsten from an acidic tungsten-containing solution. A technical solution is developed for reacting an acidic tungsten-containing solution with an alkaline sodium tungstate solution to produce tungstic acid and simultaneously recovering the tungstic acid in the acidic tungsten-containing solution. The obtained tungstic acid can be added to an alkaline sodium tungstate solution for dissolution, and APT can be prepared through processes such as ion exchange-evaporation crystallization.

[0005] The method for recovering tungsten from an acidic tungsten-containing solution of the present application comprises the following steps:

[0006] S1. Obtain an acidic tungsten-containing solution and an alkaline sodium tungstate solution;

[0007] S2. Adding the alkaline sodium tungstate solution into the acidic tungsten-containing solution to form a mixed system, reacting to precipitate tungstic acid crystals, and continuing to crystallize, filtering to obtain a filtrate, and recovering the tungstic acid.

[0008] Furthermore, the acidic tungsten-containing solution includes hydrochloric acid and the first tungstic acid; the alkaline sodium tungstate solution includes sodium hydroxide and the first sodium tungstate; with the addition of the alkaline sodium tungstate solution, the pH of the mixed solution increases, the solubility of tungstic acid in the acid solution decreases, and the generated tungstic acid uses the first tungstic acid in the acid filtrate as a seed crystal, which can enable the tungstic acid crystals in the mixed system to continue to grow, thereby making the tungstic acid crystals more thoroughly filtered and greatly reducing tungsten loss.

[0009] Furthermore, in step S2: in order to improve the recovery rate of tungstic acid, the alkaline sodium tungstate solution is added to the acidic tungsten-containing solution at a constant rate to form a mixed system, and tungstic acid crystals are precipitated by reaction. When the hydrochloric acid in the mixed system reaches a preset concentration, the addition of the alkaline sodium tungstate solution is stopped, and crystallization is continued. The filtrate is filtered to recover the tungstic acid.

[0010] Furthermore, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 100-250 g / L, and the concentration of the first tungstic acid in the acidic tungsten-containing solution measured as WO3 is 3-6 g / L.

[0011] Furthermore, the concentration of sodium hydroxide in the alkali-containing sodium tungstate solution is 2-5 mol / L, and the concentration of the first sodium tungstate in the alkali-containing sodium tungstate solution measured as WO3 is 150-300 g / L.

[0012] Furthermore, in order to further improve the recovery rate of tungstic acid, the temperature is controlled at 60~95℃ to precipitate tungstic acid crystals and continue crystallization.

[0013] Furthermore, the crystallization time is continued for 30 to 60 minutes.

[0014] Furthermore, the filtrate contains a second sodium tungstate, and the concentration of the second sodium tungstate measured as WO3 is 0.05-0.3 g / L.

[0015] Furthermore, the acidic tungsten-containing solution also contains calcium ions; in order to further improve the recovery rate of tungstic acid, the constant rate is set to 0.5~3m 3 / h; When calcium ions exist, the addition rate of the alkaline sodium tungstate solution should be properly controlled so that local alkaline conditions will not be formed in the mixed system, thereby reducing the formation of insoluble calcium tungstate and improving the recovery rate of tungstic acid.

[0016] Furthermore, in order to further improve the recovery rate of tungstic acid, the concentration of hydrochloric acid in the mixed system is preset to 20~40g / L; as the concentration of hydrochloric acid increases, the solubility of tungstic acid continues to increase; controlling the hydrochloric acid concentration of the mixed system to 20~40g / L can not only better control the solubility of tungstic acid in the solution, but also maintain an acidic environment, avoiding local over-alkalinity to form calcium tungstate and cause tungsten loss.

[0017] The above technical solution is used to recover tungsten from the acidic tungsten-containing solution in the form of tungstic acid, and the recovery rate of tungsten is ≥75%. Preferably, the recovery rate of tungsten is ≥85%.

[0018] The present application provides a method for recovering tungsten from an acidic tungsten-containing solution. By controlling the addition rate of alkaline sodium tungstate, the reaction temperature, and the acid concentration in the reaction system, the method solves the problem of difficult efficient recovery of tungsten resources in the acidic tungsten-containing solution, achieves efficient recovery of tungsten, and can also reduce wastewater treatment costs, providing a new technical option for companies related to the tungsten industry, with significant economic and social benefits. DETAILED DESCRIPTION

[0019] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0020] The technical solution proposed in this application includes the following steps:

[0021] S1. Obtain an acidic tungsten-containing solution and an alkaline sodium tungstate solution;

[0022] Specifically, scheelite is decomposed with hydrochloric acid and filtered to obtain tungstic acid and an acidic tungsten-containing solution, the acidic tungsten-containing solution comprises hydrochloric acid and a first tungstic acid, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 100-250 g / L, and the concentration of the first tungstic acid measured as WO3 is 3-6 g / L, and the acidic tungsten-containing solution is heated to 60-95° C. Specifically, the concentration of hydrochloric acid in the acidic tungsten-containing solution is any one of 100 g / L, 125 g / L, 150 g / L, 170 g / L, 200 g / L, 225 g / L, and 250 g / L, or in the range between any two of them, and the concentration of the first tungstic acid measured as WO3 is any one of 3 g / L, 3.5 g / L, 4 g / L, 4.5 g / L, 5 g / L, 5.5 g / L, and 6 g / L, or in the range between any two of them; Scheelite is decomposed with sodium hydroxide to obtain an alkali-containing sodium tungstate solution, the alkali-containing sodium tungstate solution comprising sodium hydroxide and a first sodium tungstate, the concentration of the sodium hydroxide in the alkali-containing sodium tungstate solution being 2-5 mol / L, and the concentration of the first sodium tungstate measured as WO3 being 150-300 g / L; specifically, the concentration of the sodium hydroxide in the alkali-containing sodium tungstate solution being in the range of any one of 2 mol / L, 2.5 mol / L, 3 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, and 5 mol / L, or in the range between any two thereof, and the concentration of the first sodium tungstate measured as WO3 being in the range of any one of 150 g / L, 175 g / L, 200 g / L, 225 g / L, 250 g / L, 275 g / L, and 300 g / L, or in the range between any two thereof;

[0023] S2. Adding the alkaline sodium tungstate solution to the acidic tungsten-containing solution to form a mixed system, reacting to precipitate tungstic acid crystals, and continuing the crystallization, filtering to obtain a filtrate, and recovering the tungstic acid;

[0024] Specifically, slowly add the alkaline sodium tungstate solution into the acidic tungsten-containing solution to form a mixed system. In order to improve the recovery rate of tungstic acid, keep the temperature of the mixed system at 60~95℃ and control the addition speed to 0.5~3m 3 / h, tungstic acid crystals are precipitated by reaction. When the concentration of hydrochloric acid in the mixed system is 20~40g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for tungstic acid to continue to crystallize for 30~60min. After filtering, the filtrate is obtained and the tungstic acid is recovered. Specifically, the addition speed is 0.5m 3 / h、1m 3 / h、1.5m 3 / h、2m 3 / h、2.5m 3 / h、3m 3 / h or any one thereof, and the concentration of hydrochloric acid in the mixed system is any one of 20g / L, 25g / L, 30g / L, 35g / L, 40g / L or any two thereof; at this time, the test filtrate also contains very little second sodium tungstate, and the concentration of the second sodium tungstate measured as WO3 is 0.05-0.3g / L.

[0025] In addition, the tungstic acid recovered by the technical solution of the present application can be added to an alkali-containing sodium tungstate solution to dissolve it until the concentration of sodium hydroxide in the solution is 4-20 g / L, and the reaction is continued to obtain a sodium tungstate solution, and then the APT product is prepared through ion exchange, evaporation crystallization and other steps.

[0026] The technical solution of this application is further described below with reference to specific examples. Each example and comparative example is based on an acidic tungsten-containing solution and an alkaline sodium tungstate solution from a domestic company. The hydrochloric acid concentration in the acidic tungsten-containing solution is 208 g / L, and the concentration of the first tungstic acid, measured as WO3, is 3 g / L. The sodium hydroxide concentration in the alkaline sodium tungstate solution is 140 g / L, and the concentration of the first sodium tungstate, measured as WO3, is 250 g / L.

[0027] Example 1

[0028] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 85℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 1.8m 3 / h, when the concentration of hydrochloric acid in the reactor is 29g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.8m 3 The WO3 concentration in the filtrate was detected to be 0.07 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 97.2%.

[0029] Example 2

[0030] Take 4m 3 Add the acidic tungsten solution to 10m 3In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat to 60℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 1.8m 3 / h, when the concentration of hydrochloric acid in the reactor is 29g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.8m 3 The WO3 concentration in the filtrate was detected to be 0.28 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 88.8%.

[0031] Example 3

[0032] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 95℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 1.8m 3 / h, when the concentration of hydrochloric acid in the reactor is 29g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.8m 3 The WO3 concentration in the filtrate was detected to be 0.06 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 97.6%.

[0033] Example 4

[0034] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 85℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 0.5m 3 / h, when the concentration of hydrochloric acid in the reactor is 25g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.9m 3The WO3 concentration in the filtrate was detected to be 0.05 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 98%.

[0035] Example 5

[0036] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 85℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 3m 3 / h, when the concentration of hydrochloric acid in the reactor is 31g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 30 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.7m 3 The WO3 concentration in the filtrate was detected to be 0.29 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 88.6%.

[0037] Example 6

[0038] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 85℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 1.8m 3 / h, when the concentration of hydrochloric acid in the reactor is 20g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 60min to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 5.0m 3 The WO3 concentration in the filtrate was detected to be 0.07 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 97.1%.

[0039] Example 7

[0040] Take 4m 3 Add the acidic tungsten solution to 10m 3In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 85℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 1.8m 3 / h, when the concentration of hydrochloric acid in the reactor is 40g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.5m 3 The WO3 concentration in the filtrate was detected to be 0.1 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 96.3%.

[0041] Example 8

[0042] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Alkaline sodium tungstate solution is added to the reactor at room temperature. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Alkaline sodium tungstate solution is continuously added at a rate of 1.8m 3 / h, when the concentration of hydrochloric acid in the reactor is 29g / L, stop adding the alkali-containing sodium tungstate solution, wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.8m 3 The WO3 concentration in the filtrate was detected to be 0.5 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 80%.

[0043] Example 9

[0044] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 85℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 5m 3 / h, when the concentration of hydrochloric acid in the reactor is 29g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.8m 3The WO3 concentration in the filtrate was detected to be 0.07 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 76%.

[0045] Although the tungsten concentration in the filtrate of this embodiment is low, a certain amount of precipitate is produced when the obtained tungstic acid is dissolved in the alkaline sodium tungstate solution. XRD analysis shows that the precipitate is CaWO4. This is because when the feeding speed is fast, local alkaline conditions are formed. At this time, tungstate radicals combine with calcium ions present in the solution to form insoluble CaWO4, thereby reducing the recovery rate of tungsten.

[0046] Example 10

[0047] Take 4m 3 Add the acidic tungsten solution to 10m 3 In the reactor, the concentration of hydrochloric acid in the acidic tungsten-containing solution is 208g / L, and the concentration of WO3 is 3g / L. Heat it to 85℃ and maintain the temperature. Then add the alkaline sodium tungstate solution to the reactor. The concentration of sodium hydroxide in the alkaline sodium tungstate solution is 140g / L, and the concentration of WO3 is 250g / L. The acidic tungsten-containing solution reacts with the alkaline sodium tungstate solution to produce tungstic acid crystals. Continue to add the alkaline sodium tungstate solution at a rate of 1.8m 3 / h, when the concentration of hydrochloric acid in the reactor is 60g / L, stop adding the alkaline sodium tungstate solution, maintain the temperature, and wait for another 45 minutes to allow tungstic acid to continue to crystallize, and filter to obtain tungstic acid and 4.3m 3 The WO3 concentration in the filtrate was detected to be 0.5 g / L, and the recovery rate of tungsten in the acidic tungsten-containing solution was calculated to be 82.1%.

[0048] Please refer to Table 1, which is a summary of the process flow of each embodiment:

[0049] Table 1

[0050]

[0051] The above description is only a preferred embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application specification under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for recovering tungsten from an acidic tungsten-containing solution, characterized in that: The following steps are involved: S1. Obtain an acidic tungsten-containing solution and an alkaline sodium tungstate solution; S2. Adding the alkaline sodium tungstate solution to the acidic tungsten-containing solution to form a mixed system, reacting to precipitate tungstic acid crystals, and continuing the crystallization, filtering to obtain a filtrate, and recovering the tungstic acid.

2. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 1, characterized in that: The acidic tungsten-containing solution comprises hydrochloric acid and a first tungstic acid; the alkaline sodium tungstate solution comprises sodium hydroxide and a first sodium tungstate.

3. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 2, characterized in that: In step S2, the alkaline sodium tungstate solution is added to the acidic tungsten-containing solution at a constant rate to form a mixed system, and tungstic acid crystals are precipitated by reaction. When the hydrochloric acid in the mixed system reaches a preset concentration, the addition of the alkaline sodium tungstate solution is stopped, and crystallization is continued. The filtrate is filtered to obtain the filtrate, and the tungstic acid is recovered.

4. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 2, characterized in that: The concentration of the hydrochloric acid in the acidic tungsten-containing solution is 100-250 g / L, and the concentration of the first tungstic acid in the acidic tungsten-containing solution measured as WO3 is 3-6 g / L.

5. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 2, characterized in that: The concentration of the sodium hydroxide in the alkali-containing sodium tungstate solution is 2-5 mol / L, and the concentration of the first sodium tungstate in the alkali-containing sodium tungstate solution measured as WO3 is 150-300 g / L.

6. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 1, characterized in that: Tungstic acid crystals precipitate at 60~95℃ and continue to crystallize.

7. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 1, characterized in that: The continued crystallization time is 30 to 60 minutes.

8. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 2, characterized in that: The filtrate contains a second sodium tungstate, and the concentration of the second sodium tungstate measured as WO3 is 0.05-0.3 g / L.

9. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 3, characterized in that: The acidic tungsten-containing solution also contains calcium ions; the constant rate is 0.5~3m 3 / h.

10. The method for recovering tungsten from an acidic tungsten-containing solution according to claim 3, characterized in that: The preset concentration is 20~40g / L.

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