A method for preparing ammonium paratungstate
Patent Information
- Application Number
- CN202611495727.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-24
- Publication Date
- 2026-11-03
AI Technical Summary
Existing technologies for treating tungsten slag result in low tungsten conversion and recovery rates. Traditional fluxes have limited effectiveness, and water leaching and desorption agents are limited and difficult to adapt to solutions of different concentrations, leading to low tungsten resource recovery rates and high costs.
Borax was introduced as a new fluxing agent and mixed with traditional sodium-containing reagents. The mixture was then calcined using a staged addition method. By combining ion exchange resins and different desorbents, the fluxing agent ratio and addition method were optimized to achieve impurity solidification and efficient tungsten extraction.
It improves the conversion and recovery rate of tungsten, reduces processing costs, enhances the adaptability of the method, and enables efficient recovery of tungsten resources under different production conditions.
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Abstract
Description
Technical Field
[0001] This application belongs to the field of tungsten resource recycling technology, specifically a method for preparing ammonium paratungstate. Background Technology
[0002] Tungsten, as an important strategic metal resource, has wide applications in industrial production. China, as a major global tungsten resource country and a major exporter of tungsten products, holds approximately 60% of the world's total tungsten reserves, ranking first globally. Currently, China's tungsten smelting mainly employs the alkaline decomposition process, extracting tungsten from the ore through ball milling and alkaline pressure leaching. However, the alkaline pressure leaching process generates a large amount of tungsten slag. For every ton of ammonium paratungstate produced, tungsten smelting enterprises generate approximately 0.8 tons of tungsten slag. Based on this, it is estimated that domestic tungsten smelting enterprises generate approximately 100,000 tons of tungsten slag annually. With the continuous development of the tungsten industry, the consumption of metallic tungsten raw materials is increasing, recoverable tungsten resources are gradually decreasing, and tungsten ore reserves are declining sharply. Some mines are already facing or are about to face the severe situation of resource depletion.
[0003] Currently, to improve the recovery rate of tungsten resources, the main measures adopted for tungsten slag recovery and extraction include pyrometallurgical roasting using a single flux, simple water leaching treatment, and extraction using a single desorbent. These technologies have improved the recovery efficiency of tungsten resources to some extent, but some problems and shortcomings remain. First, in the traditional pyrometallurgical roasting process, only sodium carbonate and sodium hydroxide are typically used as fluxes. These single fluxes have limited effectiveness in treating tungsten slag with complex compositions, and cannot effectively improve the conversion rate of tungsten and the solidification effect of impurities. Second, existing water leaching treatment and desorbent extraction methods are limited and cannot adapt to solutions of different concentrations, resulting in low tungsten extraction efficiency and low recovery rate. Furthermore, existing technical solutions have certain limitations in practical applications and are difficult to meet the tungsten resource recovery needs under different production conditions.
[0004] Therefore, developing a novel method for optimizing pyrometallurgical calcination fluxes has significant practical implications and application value. Summary of the Invention
[0005] To address the aforementioned issues, this application provides a method for preparing ammonium paratungstate. By introducing borax as a new fluxing agent on the basis of traditional fluxing agents, the efficiency of pyrometallurgical roasting can be improved while solidifying impurities. Subsequently, different solutions are used for analysis, which can further separate impurities and more effectively analyze tungsten in the solution, thereby improving the extraction efficiency and recovery rate of tungsten.
[0006] This application discloses a method for preparing ammonium paratungstate, comprising the following steps: S1. Obtain tungsten slag, sodium-containing reagent and borax, and mix the sodium-containing reagent and the borax to obtain a flux; S2. The flux is mixed with the tungsten slag and calcined to obtain the calcined product; S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid; S4. The water-immersed liquid is adsorbed using an ion exchange resin. After the adsorption is saturated, it is first rinsed with sodium chloride solution and then desorbed with sodium hydroxide solution to obtain the eluent. S5. The solution is processed by traditional process to obtain national standard grade zero ammonium paratungstate product.
[0007] In the above technical solution, borax, due to its excellent fluxing properties and low melting point, is introduced into a fluxing agent prepared by mixing borax with traditional sodium-containing reagents. When mixed with tungsten slag for roasting, borax can form water-insoluble substances with impurities such as iron, silicon, calcium, and aluminum, thereby solidifying the impurities and achieving separation of tungsten and these impurities during water leaching. Simultaneously, the low-melting-point melt formed by borax and impurities allows the sodium-containing reagents to react better with the tungsten slag, making tungsten extraction more efficient. The main component of the leaching solution is sodium tungstate solution. After adsorption by ion exchange resin, it is first leached with sodium chloride solution. Because of the high melting point, the sodium chloride solution... - Compared to WO4 2- It is more easily adsorbed by the resin column, therefore some of the Cl... - It can be used to wash away impurities of tungsten, and another part can replace some impurities to pre-separate some impurities; then, sodium hydroxide solution is used to completely precipitate the adsorbed tungsten. First, borax is used to melt and solidify the impurities, and then different solutions are used to separate the impurities. The resulting precipitate can be processed by traditional processes to obtain the national standard grade zero ammonium paratungstate product.
[0008] Furthermore, in step S1, the sodium-containing reagent includes sodium carbonate, sodium hydroxide, or sodium nitrate.
[0009] Furthermore, in step S1, the WO3 content in the tungsten slag is 0.8wt%~1.5wt%.
[0010] Furthermore, in step S1, the mass ratio of the tungsten slag, the sodium-containing reagent, and the borax is 100:(40~60):(15~35); By optimizing the flux ratio, the complex composition of tungsten slag can be effectively addressed, improving the efficiency of pyrometallurgical roasting and the solidification effect of impurities, thereby significantly increasing the conversion and recovery rate of tungsten. At the same time, it can also reduce the amount of flux used and lower the processing cost.
[0011] Furthermore, in step S2, the calcination temperature is 800~900℃ and the time is 2~4h.
[0012] Further, step S2 specifically involves: heating the tungsten slag to a first temperature, adding 60wt%~70wt% of the flux and holding it at the first temperature, then heating it to a second temperature, adding the remaining flux and holding it at the second temperature, and finally heating it to 800~900℃ for calcination for 2~4 hours to obtain the calcined product.
[0013] Furthermore, the first temperature is 300~400℃, and the first heat preservation time is 0.5~1h; the second temperature is 700~750℃, and the second heat preservation time is 2~4h.
[0014] By altering the flux addition method and employing a staged addition approach, the flux can play a better role at different reaction stages, improving the solidification effect of impurities and the conversion rate of tungsten. Within the 300–400℃ range, low-valent tungsten and tungsten sulfide undergo oxidation, readily soluble tungsten is converted to Na₂WO₄, and iron-manganese hydroxides are dehydrated; silicon-aluminum undergoes only a dehydration phase transition, avoiding the formation of large amounts of molten silicates; calcium-magnesium minerals undergo a preliminary phase transition. Within the 700–750℃ range, sparingly soluble tungstates such as calcium tungstate and iron tungstate are decomposed by the added sodium-containing reagent, releasing the encapsulated tungsten, and borax produces a suitable liquid phase. The staged addition of flux and the stepwise heating method also allow for strict control of prolonged high-temperature contact between silicon, aluminum, and sodium-containing reagents, reducing the large-scale formation of sodium aluminosilicate.
[0015] Furthermore, before step S4, the pH of the water-immersed solution is adjusted to 4-6.
[0016] Furthermore, in step S3, the liquid-to-solid ratio of the water immersion is (2~4) mL / 1g.
[0017] Furthermore, step S4 specifically includes: The water-immersed liquid was adsorbed using an ion exchange resin. After adsorption saturation, it was first rinsed with sodium chloride solution until the concentration of WO3 in the collected leaching solution was 0.7~1g / L. Then, it was desorbed with sodium hydroxide solution to obtain the eluent.
[0018] Furthermore, in step S4, the concentration of the sodium chloride solution is 0.5~1 mol / L.
[0019] Furthermore, in step S4, the concentration of the sodium hydroxide solution is 16~18 mol / L.
[0020] Furthermore, in step S4, the ion exchange resin is D314 resin.
[0021] This application proposes a method for preparing ammonium paratungstate, which produces the following beneficial effects: 1. Improve tungsten resource recovery rate: By introducing borax as a new fluxing agent and optimizing the fluxing agent ratio, the efficiency of pyrometallurgical roasting and the effect of impurity solidification can be improved, while the conversion rate and recovery rate of tungsten can be increased. 2. Reduce tungsten slag treatment costs: By optimizing the flux addition method, the flux can play a better role in different reaction stages, improve the solidification effect of impurities and the conversion rate of tungsten, reduce the amount of flux used, and reduce treatment costs; 3. Improve the efficiency of tungsten slag treatment: By using different desorption agents in stages, tungsten in solutions of different concentrations can be extracted more effectively, improving the extraction efficiency and recovery rate of tungsten, thereby improving the overall efficiency of tungsten slag treatment; 4. High adaptability: The ratio and addition method of flux, as well as the concentration and desorption steps of the desorbent, can be flexibly adjusted according to different production conditions and tungsten slag composition. It has strong adaptability and flexibility and can meet the needs of tungsten resource recovery under different conditions. Detailed Implementation
[0022] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0023] This application discloses a method for preparing ammonium paratungstate, comprising the following steps: S1. Obtain tungsten slag, sodium-containing reagent and borax, and mix the sodium-containing reagent and borax to obtain a flux; Preferably, the sodium-containing reagent includes sodium carbonate, sodium hydroxide, or sodium nitrate; the WO3 content in the tungsten slag is 0.8wt%~1.5wt%; and the mass ratio of tungsten slag, sodium-containing reagent, and borax is 100:(40~60):(15~35).
[0024] S2. The flux is mixed with tungsten slag and then roasted to obtain the roasted product; Preferably, the calcination temperature is 800-900℃ and the time is 2-4 hours; specifically, the calcination temperature can be any one or a range between 800℃, 820℃, 840℃, 860℃, 880℃, and 900℃, and the time can be any one or a range between 2 hours, 2.5 hours, 3 hours, 3.5 hours, and 4 hours. In some preferred embodiments of this application, the tungsten slag can be first heated to a first temperature, 60wt%-70wt% of flux can be added and the temperature can be held for a first time, then the temperature can be raised to a second temperature, the remaining flux can be added and the temperature can be held for a second time, and finally the temperature can be raised to 800-900℃ for calcination for 2-4 hours to obtain the calcined product. The first temperature can be 300-400℃ and the first holding time can be 0.5-1 hour; the second temperature can be 700-750℃ and the second holding time can be 2-4 hours.
[0025] S3. The roasted product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid. Preferably, the liquid-to-solid ratio of the water immersion is (2~4) mL / 1g; in some preferred embodiments of this application, the pH of the water immersion solution can be adjusted to 4~6 before step S4.
[0026] S4. The water-immersed liquid is adsorbed using ion exchange resin. After adsorption saturation, it is first rinsed with sodium chloride solution and then desorbed with sodium hydroxide solution to obtain the eluent. Preferably, the concentration of the sodium chloride solution is 0.5~1 mol / L, and the concentration of the sodium hydroxide solution is 16~18 mol / L. Specifically, the concentration of the sodium chloride solution can be any one or a range between any two of 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, and 1 mol / L, and the concentration of the sodium hydroxide solution can be any one or a range between any two of 16 mol / L, 16.5 mol / L, 17 mol / L, 17.5 mol / L, and 18 mol / L. In some preferred embodiments of this application, D314 resin can be used to adsorb the water-immersed liquid. After adsorption saturation, the liquid is first rinsed with sodium chloride solution until the concentration of WO3 in the collected leaching solution is 0.7~1 g / L, and then eluted with sodium hydroxide solution to obtain an eluent, which is a sodium tungstate solution.
[0027] S5. The eluent is processed by traditional process to obtain national standard grade zero ammonium paratungstate product. In some preferred embodiments of this application, the eluent can be processed to obtain ammonium paratungstate product by: first removing impurities from the eluent, then adsorbing it using a resin column, followed by eluenting it with ammonia water to obtain ammonium tungstate, and then evaporating and crystallizing it to obtain the ammonium paratungstate product.
[0028] Calculations show that the tungsten recovery rate in this application is no less than 70%. By flexibly adjusting the flux ratio and addition method, as well as adjusting the concentration of the eluent and the eluent steps, the tungsten recovery rate can be increased to over 95%. The tungsten recovery rate in this application is calculated as follows: Tungsten recovery rate = (c1V1 + c2V2) / mω × 100%, where c1 is the concentration of WO3 in the eluent, V1 is the volume of the eluent, c2 is the concentration of WO3 in the eluent, V2 is the volume of the eluent, m is the mass of the tungsten slag, and ω is the mass fraction of WO3 in the tungsten slag.
[0029] The technical solution of this application will be further described below with reference to specific embodiments. In the following embodiments and comparative examples, the WO3 content in the tungsten slag is 1.2 wt%. In step S5, the eluent is first purified, then adsorbed using a resin column, followed by ammonia water for elution to obtain ammonium tungstate, and subsequently evaporated and crystallized to obtain ammonium paratungstate product.
[0030] Example 1
[0031] A method for preparing ammonium paratungstate includes the following steps: S1. Obtain 1000g of tungsten slag, sodium carbonate, and borax. Mix the sodium carbonate and borax to obtain a flux. The mass ratio of tungsten slag, sodium carbonate, and borax is 100:40:15. S2. Heat the tungsten slag to 300℃, add 60wt% flux and keep it at that temperature for 0.5h, then heat it to 750℃, add the remaining flux and keep it at that temperature for 2h, and finally heat it to 800℃ for calcination for 2h to obtain the calcined product. S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid. The pH of the water-soaked liquid is adjusted to 4. S4. D314 resin was used to adsorb the water-immersed liquid. After adsorption saturation, the liquid was first rinsed with 0.5 mol / L sodium chloride solution until the concentration of WO3 in the collected 20 mL rinsing solution was 1 g / L. Then, 16 mol / L sodium hydroxide solution was used for analysis to obtain 380 mL of eluent with a concentration of 30 g / L of WO3. S5. After treatment, the eluent yields the national standard grade zero ammonium paratungstate product. The content of each impurity element is shown in Table 1. The calculated tungsten recovery rate is 95.2%.
[0032] Table 1. Impurity element content (ppm) of the ammonium paratungstate product prepared in Example 1
[0033] Example 2
[0034] A method for preparing ammonium paratungstate includes the following steps: S1. Obtain 1000g of tungsten slag, sodium carbonate, and borax. Mix the sodium carbonate and borax to obtain a flux. The mass ratio of tungsten slag, sodium carbonate, and borax is 100:50:20. S2. Heat the tungsten slag to 350℃, add 65wt% flux and keep it at that temperature for 0.6h, then heat it to 730℃, add the remaining flux and keep it at that temperature for 3h, and finally heat it to 850℃ for calcination for 3h to obtain the calcined product. S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid. The pH of the water-soaked liquid is adjusted to 5. S4. D314 resin was used to adsorb the water-immersed liquid. After adsorption saturation, the liquid was first rinsed with 0.75 mol / L sodium chloride solution until the concentration of WO3 in the collected 20 mL of rinsing solution was 1 g / L. Then, 17 mol / L sodium hydroxide solution was used for analysis to obtain 361 mL of eluent, in which the concentration of WO3 was 32 g / L. S5. After treatment, the eluent yields the national standard grade zero ammonium paratungstate product. The content of each impurity element is shown in Table 2. The calculated tungsten recovery rate is 96.4%.
[0035] Table 2. Impurity element content (ppm) of the ammonium paratungstate product prepared in Example 2.
[0036] Example 3
[0037] A method for preparing ammonium paratungstate includes the following steps: S1. Obtain 1000g of tungsten slag, sodium carbonate, and borax. Mix the sodium carbonate and borax to obtain a flux. The mass ratio of tungsten slag, sodium carbonate, and borax is 100:60:35. S2. Heat the tungsten slag to 400℃, add 70wt% flux and keep it at that temperature for 1 hour. Then heat it to 700℃, add the remaining flux and keep it at that temperature for 4 hours. Finally, heat it to 900℃ and calcine it for 4 hours to obtain the calcined product. S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid. The pH of the water-soaked liquid is adjusted to 6. S4. D314 resin was used to adsorb the water-immersed liquid. After adsorption saturation, the liquid was first rinsed with 1 mol / L sodium chloride solution until the concentration of WO3 in the collected 20 mL rinsing solution was 1 g / L. Then, 18 mol / L sodium hydroxide solution was used for analysis to obtain 332 mL of eluent with a concentration of 35 g / L of WO3. S5. After treatment, the eluent yields the national standard grade zero ammonium paratungstate product. The content of each impurity element is shown in Table 3. The calculated tungsten recovery rate is 97.0%.
[0038] Table 3. Impurity element content (ppm) of the ammonium paratungstate product prepared in Example 3.
[0039] Example 4
[0040] A method for preparing ammonium paratungstate includes the following steps: S1. Obtain 1000g of tungsten slag, sodium carbonate, and borax. Mix the sodium carbonate and borax to obtain a flux. The mass ratio of tungsten slag, sodium carbonate, and borax is 100:40:15. S2. Mix the flux with the tungsten slag and calcine at 800℃ for 2 hours to obtain the calcined product; S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid. The pH of the water-soaked liquid is adjusted to 4. S4. D314 resin was used to adsorb the water-immersed liquid. After adsorption saturation, the liquid was first rinsed with 0.5 mol / L sodium chloride solution until the concentration of WO3 in the collected 15 mL rinsing solution was 1 g / L. Then, 16 mol / L sodium hydroxide solution was used for analysis to obtain 370 mL of eluent with a concentration of WO3 of 28 g / L. S5. After treatment, the eluent yields the national standard grade zero ammonium paratungstate product. The content of each impurity element is shown in Table 4. The calculated tungsten recovery rate is 86.5%.
[0041] Table 4. Impurity element content (ppm) of the ammonium paratungstate product prepared in Example 4.
[0042] Example 5
[0043] A method for preparing ammonium paratungstate includes the following steps: S1. Obtain 1000g of tungsten slag, sodium carbonate, and borax. Mix the sodium carbonate and borax to obtain a flux. The mass ratio of tungsten slag, sodium carbonate, and borax is 100:40:55. S2. Heat the tungsten slag to 300℃, add 60wt% flux and keep it at that temperature for 1 hour. Then heat it to 750℃, add the remaining flux and keep it at that temperature for 2 hours. Finally, heat it to 800℃ and calcine it for 2 hours to obtain the calcined product. S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid. The pH of the water-soaked liquid is adjusted to 4. S4. D314 resin was used to adsorb the water-immersed liquid. After adsorption saturation, the liquid was first rinsed with 0.5 mol / L sodium chloride solution until the concentration of WO3 in the collected 20 mL rinsing solution was 1 g / L. Then, 16 mol / L sodium hydroxide solution was used for analysis to obtain 358 mL of eluent with a concentration of 30 g / L of WO3. S5. After treatment, the eluent yields the national standard grade zero ammonium paratungstate product. The content of each impurity element is shown in Table 5. The calculated tungsten recovery rate is 89.7%.
[0044] Table 5. Impurity element content (ppm) of the ammonium paratungstate product prepared in Example 5.
[0045] Example 6
[0046] A method for preparing ammonium paratungstate includes the following steps: S1. Obtain 1000g of tungsten slag, sodium carbonate, and borax. Mix the sodium carbonate and borax to obtain a flux. The mass ratio of tungsten slag, sodium carbonate, and borax is 100:40:15. S2. Heat the tungsten slag to 300℃, add 60wt% flux and keep it at that temperature for 0.5h, then heat it to 550℃, add the remaining flux and keep it at that temperature for 4h, and finally heat it to 600℃ for calcination for 2h to obtain the calcined product. S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid. The pH of the water-soaked liquid is adjusted to 4. S4. D314 resin was used to adsorb the water-immersed liquid. After adsorption saturation, the liquid was first rinsed with 0.5 mol / L sodium chloride solution until the concentration of WO3 in the collected 25 mL rinsing solution was 1 g / L. Then, 16 mol / L sodium hydroxide solution was used for analysis to obtain 372 mL of eluent, in which the concentration of WO3 was 24 g / L. S5. After treatment, the eluent yields the national standard grade zero ammonium paratungstate product. The content of each impurity element is shown in Table 6. The calculated tungsten recovery rate is 74.6%.
[0047] Table 6. Impurity element content (ppm) of the ammonium paratungstate product prepared in Example 6
[0048] Comparative Example 1 The only difference between this comparative example and Example 1 is that in step S4, instead of using sodium chloride solution for rinsing, a 16 mol / L sodium hydroxide solution is used directly for analysis, resulting in 379 mL of eluent with a WO3 concentration of 30 g / L. After treatment, the ammonium paratungstate product obtained from the eluent contained varying degrees of excessive As and P, which did not meet the requirements of the national standard grade zero product. The content of each impurity element is shown in Table 7, and the recovery rate of tungsten was 94.8%.
[0049] Table 7. Impurity element content (ppm) of the ammonium paratungstate product prepared in Comparative Example 1
[0050] Note: In the table, superscript 'a' indicates that impurities exceed the standard, and superscript 'b' indicates that the impurity level is too high.
[0051] Comparative Example 2 The only difference between this comparative example and Example 1 is that in step S1, the flux is only sodium carbonate and no borax is added, and the mass ratio of tungsten slag to sodium carbonate is 100:40. 20 mL of 1 g / L WO3 eluent and 352 mL of 28 g / L WO3 eluent were obtained. The ammonium paratungstate product obtained after treatment of the eluent contained varying degrees of excessive Ca, Si, As and P, which did not meet the requirements of the national standard grade 0 product. The content of each impurity element is shown in Table 8. The tungsten recovery rate was 82.3%.
[0052] Table 8. Impurity element content (ppm) of the ammonium paratungstate product prepared in Comparative Example 2
[0053] Note: In the table, superscript 'a' indicates that impurities exceed the standard, and superscript 'b' indicates that the impurity level is too high.
[0054] Comparative Example 3 The only difference between this comparative example and Example 1 is that in step S4, a mixed solution containing 0.5 mol / L sodium chloride and 16 mol / L sodium hydroxide is used for analysis to obtain 360 mL of eluent, in which the concentration of WO3 is 30 g / L. After treatment, the ammonium paratungstate product obtained from the eluent contained varying degrees of excessive As and P, which did not meet the national standard requirements for grade zero products. The content of each impurity element is shown in Table 9. The tungsten recovery rate was 90.0%.
[0055] Table 9. Impurity element content (ppm) of the ammonium paratungstate product prepared in Comparative Example 3.
[0056] Note: The superscript 'a' in the table indicates that the impurities exceed the standard.
[0057] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the inventive concept of this application and using the content of this application specification, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.
Claims
1. A method for preparing ammonium paratungstate, characterized in that, Includes the following steps: S1. Obtain tungsten slag, sodium-containing reagent and borax, and mix the sodium-containing reagent and the borax to obtain a flux; S2. The flux is mixed with the tungsten slag and calcined to obtain the calcined product; S3. The calcined product is soaked in water, and the solid and liquid are separated to obtain the water-soaked liquid; S4. The water-immersed liquid is adsorbed using an ion exchange resin. After the adsorption is saturated, it is first rinsed with sodium chloride solution and then desorbed with sodium hydroxide solution to obtain the eluent. S5. The solution is processed by traditional process to obtain national standard grade zero ammonium paratungstate product.
2. The method for preparing ammonium paratungstate according to claim 1, characterized in that, In step S1, the sodium-containing reagent includes sodium carbonate, sodium hydroxide, or sodium nitrate.
3. The method for preparing ammonium paratungstate according to claim 1, characterized in that, In step S1, the mass ratio of the tungsten slag, the sodium-containing reagent, and the borax is 100:(40~60):(15~35).
4. The method for preparing ammonium paratungstate according to claim 1, characterized in that, In step S2, the roasting temperature is 800~900℃ and the time is 2~4h.
5. The method for preparing ammonium paratungstate according to claim 1, characterized in that, Step S2 specifically involves: The tungsten slag is heated to a first temperature, 60wt%~70wt% of the flux is added and the temperature is held for a first time, then the temperature is raised to a second temperature, the remaining flux is added and the temperature is held for a second time, and finally the temperature is raised to 800~900℃ for calcination for 2~4 hours to obtain the calcined product.
6. The method for preparing ammonium paratungstate according to claim 5, characterized in that, The first temperature is 300~400℃, and the first heat preservation time is 0.5~1h; the second temperature is 700~750℃, and the second heat preservation time is 2~4h.
7. The method for preparing ammonium paratungstate according to claim 1, characterized in that, Before step S4, the pH of the water-immersed solution is adjusted to 4-6.
8. The method for preparing ammonium paratungstate according to claim 1, characterized in that, Step S4 specifically involves: The water-immersed liquid was adsorbed using an ion exchange resin. After adsorption saturation, it was first rinsed with sodium chloride solution until the concentration of WO3 in the collected leaching solution was 0.7~1g / L. Then, it was desorbed with sodium hydroxide solution to obtain the eluent.
9. The method for preparing ammonium paratungstate according to claim 1, characterized in that, In step S4, the concentration of the sodium chloride solution is 0.5~1 mol / L.
10. The method for preparing ammonium paratungstate according to claim 1, characterized in that, In step S4, the concentration of the sodium hydroxide solution is 16~18 mol / L.