A method for recovering tungsten extraction residue

Abstract

The application relates to a tungsten extraction residue recovery method, which comprises the following steps: S1, tungsten extraction residue and water are mixed to prepare a slurry, sodium hydroxide is added, heating reaction is carried out, solid-liquid separation is carried out after reaction, a first filtrate and a first solid phase are obtained, the first filtrate contains an organic metal compound, and the organic metal compound is recovered; S2, the first solid phase is mixed with sodium hydroxide and phosphoric acid, heating reaction is carried out, solid-liquid separation is carried out after reaction, a second filtrate and a second solid phase are obtained, the second filtrate contains sodium tungstate, and the sodium tungstate is recovered; S3, the second solid phase is mixed with acid, the acidity is controlled to make the second solid phase completely dissolve, a post-reaction liquid is obtained, the post-reaction liquid contains tungsten, and tungsten recovery is carried out. By adopting the method, tungsten in the extraction residue can be completely recovered, and the recovery cost is relatively low.

Description

Technical Field

[0001] This invention relates to tungsten extraction and recovery processes, specifically to a method for recovering tungsten extraction residue. Background Technology

[0002] With the gradual development of tungsten smelting technology and the gradual mining of tungsten ore, the reserves of tungsten are becoming increasingly scarce. Therefore, it is of great significance to recover tungsten as much as possible, especially in hydrometallurgical tungsten smelting. The slag precipitated from the extraction and impurity removal stage contains a certain amount of tungsten, as well as organic matter. The crystals contain a lot of impurities, and the crystalline slag has many hard lumps, requiring multiple treatments. The auxiliary materials used for treatment are costly. These extraction slags are generally treated under high temperature and high alkalinity conditions, which destroys the organic molecules. The small organic molecules formed are not completely separated from the feed liquid and are easily carried into the feed liquid in the later stages, causing tungsten loss and making it inconvenient for subsequent tungsten recovery and separation.

[0003] Chinese patent application CN111573734A discloses a novel extractant and a method for extracting tungsten from a phosphotungstic heteropolyacid solution. The novel extractant is composed of 0.1-0.4 parts by volume of butyl acetate, 0.2-0.4 parts by volume of n-butanol, and 0.3-0.6 parts by volume of sulfonated kerosene. It can rapidly extract tungsten from phosphotungstic heteropolyacid under acidic conditions and convert it into an ammonium tungstate / sodium tungstate solution, providing a new pathway for the conversion of tungsten to ammonium tungstate / sodium tungstate. Simultaneously, this method can extract a high concentration of phosphotungstic heteropolyacid, with an extraction efficiency exceeding 90%. However, the extraction residue formed by this method contains 2%-3% tungsten. Using conventional methods, on the one hand, the tungsten recovery rate is only about 97%, making it difficult to completely recover the tungsten from the residue; on the other hand, the processing cost of the extraction residue is high, as the crystals are hard and require multiple processing steps, resulting in high auxiliary material costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the difficulty of completely recovering tungsten from the extraction solid phase generated in the tungsten extraction process, and to provide a method for recovering tungsten extraction residue.

[0005] The specific plan is as follows:

[0006] A method for recovering tungsten extraction residue includes the following steps:

[0007] S1, mix tungsten extraction residue and water to form a slurry, add sodium hydroxide, heat to react, and then perform solid-liquid separation to obtain a primary filtrate and a primary solid phase. The primary filtrate contains organometallic compounds, which are then recovered.

[0008] S2, the primary solid phase is mixed with sodium hydroxide and phosphoric acid, heated to react, and then the solid and liquid are separated to obtain a secondary filtrate and a secondary solid phase. The secondary filtrate contains sodium tungstate, and the sodium tungstate is recovered.

[0009] S3, the secondary solid phase is mixed with acid, and the acidity is controlled to completely dissolve the secondary solid phase to obtain a reaction liquid containing tungsten, and tungsten is recovered.

[0010] Furthermore, the tungsten extraction residue is the remaining solid phase after tungsten is extracted from scheelite and / or wolframite using an extraction process. Preferably, the tungsten extraction residue is formed by crystallizing impurities in the remaining material after extraction from scheelite and / or wolframite using an extractant composed of 0.1-0.4 parts by volume of butyl acetate, 0.2-0.4 parts by volume of n-butanol, and 0.3-0.6 parts by volume of sulfonated kerosene.

[0011] Furthermore, the tungsten extraction residue contains, by weight percentage, 50-70% calcium sulfate, 10-30% calcium tungstate, 1-10% phosphotungstic heteropoly acid, and 1-10% calcium phosphate.

[0012] Furthermore, in step S1, the solid-liquid ratio of the slurry is 1:2-5, preferably 1:2-4; sodium hydroxide is added to make the pH 8-9; the heating reaction temperature is 35-55℃, and the reaction time is 1-10h.

[0013] Furthermore, the tungsten content of the primary solid phase obtained in step S1 is 30-35 wt%.

[0014] Furthermore, the tungsten content of the primary filtrate obtained in step S1, calculated as WO3, is 5-15 g / L.

[0015] Furthermore, in step S2, the primary solid phase is mixed with sodium hydroxide and phosphoric acid, and the concentration of sodium hydroxide in the solution is controlled to be 30-40 g / L and the concentration of phosphoric acid is 1-6 g / L; the heating reaction temperature is 70-100℃ and the reaction time is 0.5-10 h.

[0016] Furthermore, the tungsten content of the secondary solid phase obtained in step S2 is 2-3 wt%.

[0017] Furthermore, the tungsten content of the secondary filtrate obtained in step S2, calculated as WO3, is 30-45 g / L.

[0018] Furthermore, the acid mentioned in step S3 is hydrochloric acid, and the residual acidity of the solution after the reaction is controlled to be 5-10 g / L.

[0019] Beneficial effects:

[0020] In this invention, atmospheric pressure operation is adopted, the process is simple, the energy consumption cost is low, and the obtained primary filtrate, secondary filtrate, and post-reaction liquid have good connectivity with conventional tungsten recovery sections. They can be directly transported to the original tungsten recovery section for tungsten extraction, making it highly feasible.

[0021] Furthermore, by using the method of the present invention, the tungsten recovery rate is increased from 97% to 100%, all tungsten is recovered, and production costs are reduced, which has good prospects for industrial application. Attached Figure Description

[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0023] Figure 1 This is a schematic diagram of the process flow provided in one embodiment of the present invention. Detailed Implementation

[0024] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. In the following embodiments, unless otherwise specified, "%" refers to weight percentage.

[0025] Comparative Example 1

[0026] A novel extractant (see CN111573734A) is used to extract more than 90% of the tungsten from a phosphotungstic heteropoly acid solution. The remaining 10% of the tungsten solution contains a large number of other impurities, which crystallize out to obtain the extraction residue.

[0027] The main components of the extraction residue are shown in Table 1.

[0028] Table 1 Composition of Extraction Residue

[0029] Extraction residue components content(%) Calcium sulfate 60 Calcium tungstate 20 Phosphotungstic heteropolyacid crystals 5 Calcium phosphate 5 other 10

[0030] Take the extraction residue, add water to make a slurry with a solid-liquid volume ratio of 1:5, then add caustic soda flakes and phosphoric acid, heat to 80℃, reaction time: 60min, alkalinity (mass concentration of sodium hydroxide): 30-60g / l, phosphorus concentration (mass concentration of phosphoric acid): 2-5g / l. If the alkalinity and phosphorus concentration do not meet the requirements, continue to add them. After the reaction, filter under pressure to separate the solid and liquid. The results are shown in Table 2.

[0031] Table 2 Reaction Results

[0032]

[0033] As can be seen, the average processing cost using the above process is 6.38 yuan / kg / WO3, and the residue after solid-liquid separation still contains tungsten, so the tungsten recovery rate is less than 100%.

[0034] Therefore, the residue after solid-liquid separation needs to be further processed by adding water and acid to carry out secondary treatment. The increased consumption of auxiliary materials in the secondary treatment will further increase the cost, resulting in a higher overall processing cost.

[0035] Example 1

[0036] Take the extraction residue from Comparative Example 1, and follow... Figure 1 The steps shown mainly include:

[0037] S1, tungsten extraction residue and water are mixed and slurried, with a residue to water volume ratio of 1:3. Sodium hydroxide flakes are added, and the mixture is heated to 45°C for 60 minutes. After the reaction, solid-liquid separation is performed to obtain a primary filtrate and a primary solid phase, as shown in Table 3. The primary filtrate contains organometallic compounds. The organometallic compounds can be recovered by static separation, i.e., allowing the organometallic compounds to precipitate before solid-liquid separation.

[0038] Table 3. Reaction results of step S1 in Example 1

[0039]

[0040] S2, the primary solid phase is mixed with sodium hydroxide and phosphoric acid at a solid-liquid volume ratio of 1:5, alkalinity (mass concentration of sodium hydroxide) is 30-40 g / L, phosphorus concentration (concentration of phosphoric acid) is 3-6 g / L, temperature is 80℃, and the mixture is stirred for 1 hour. Calcium tungstate crystals are converted into sodium tungstate, and tungsten enters the solution. After the reaction, solid-liquid separation is performed to obtain a secondary filtrate and a secondary solid phase, as shown in Table 4. The secondary filtrate contains sodium tungstate. The sodium tungstate can be recovered by resin adsorption or chemical precipitation, both of which are conventional methods.

[0041] Table 4. Results of reaction in step S2 of Example 1

[0042]

[0043] S3, the secondary solid phase is mixed with hydrochloric acid, and the acidity after the reaction is controlled at 5-10 g / L. The secondary solid phase is completely dissolved to obtain the reaction liquid. The reaction liquid contains tungsten, as shown in Table 5. There is no solid residue after the reaction. The tungsten in the reaction liquid can be recovered by resin adsorption or chemical precipitation, which are both conventional methods.

[0044] Table 5. Results of reaction in step S3 of Example 1

[0045]

[0046] The treatment effects and costs using the above process are shown in Table 6.

[0047] Table 6. Processing Effects and Costs of Example 1

[0048]

[0049] As can be seen, by using the process in Example 1, the cost of auxiliary materials is reduced. The average cost of auxiliary materials in this process is 5.83 yuan, which is 0.55 yuan less than the cost of 6.38 yuan in Comparative Example 1. Based on the annual production of 1,000 tons of tungsten trioxide by the smelter, this can save about 550,000 yuan in production costs.

[0050] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0051] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0052] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method of recovering tungsten extraction residue, characterized by: The tungsten extraction residue is formed by impurities crystallization in the remaining material after extraction treatment of white tungsten ore and / or black tungsten ore with an extractant composed of 0.1-0.4 parts by volume of butyl acetate, 0.2-0.4 parts of n-butanol and 0.3-0.6 parts of sulfonated kerosene, and the tungsten extraction residue contains calcium sulfate 50-70%, calcium tungstate 10-30%, phosphotungstic heteropoly acid 1-10% and calcium phosphate 1-10% by weight percentage, and comprises the following steps: S1, mixing and slurrying the tungsten extraction residue with water, adding sodium hydroxide, heating and reacting, and then performing solid-liquid separation to obtain a first filtrate and a first solid phase, the first filtrate containing an organic metal compound, and the organic metal compound is recovered; S2, mixing the first solid phase with sodium hydroxide and phosphoric acid, heating and reacting, and then performing solid-liquid separation to obtain a second filtrate and a second solid phase, the second filtrate containing sodium tungstate, and the sodium tungstate is recovered; S3, mixing the second solid phase with acid, controlling the acidity to completely dissolve the second solid phase to obtain a post-reaction liquid containing tungsten, and recovering the tungsten.

2. The tungsten extraction residue recovery method according to claim 1, characterized by: In step S1, the solid-liquid ratio of the slurry is 1:2-5, and the pH is 8-9 after adding sodium hydroxide; the heating and reaction temperature is 35-55℃, and the reaction time is 1-10h.

3. The method of claim 2, wherein the tungsten extraction residue is characterized by: In step S1, the solid-liquid ratio of the slurry is 1:2-4.

4. The method of claim 2, wherein the tungsten extraction residue is recovered by: The tungsten content of the first solid phase obtained in step S1 is 30-35wt%.

5. The method of claim 2, wherein the tungsten extraction residue is recovered by: The tungsten content of the first filtrate obtained in step S1 is 5-15g / L as WO3.

6. The method of claim 4, wherein the tungsten extraction residue is recovered by: In step S2, the first solid phase is mixed with sodium hydroxide and phosphoric acid, and the concentration of sodium hydroxide in the solution is controlled to be 30-40g / l, and the concentration of phosphoric acid is 1-6g / l; the heating and reaction temperature is 70-100℃, and the reaction time is 0.5-10h.

7. The method of claim 6, wherein the tungsten extraction residue is recovered by: The tungsten content of the second solid phase obtained in step S2 is 2-3wt%.

8. The method of claim 7, wherein the tungsten extraction residue is recovered by: The tungsten content of the second filtrate obtained in step S2 is 30-45g / L as WO3.

9. The method of claim 7, wherein the tungsten extraction residue is recovered by: In step S3, the acid is hydrochloric acid, and the residual acidity of the post-reaction solution is controlled to be 5-10g / l.

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