A method for recovering sodium tungstate from tungsten wire alkaline washing solution

Abstract

The present application belongs to the field of tungsten alloy wire manufacturing, and specifically relates to a method for recovering sodium tungstate from tungsten wire alkaline washing liquid, comprising the following steps: obtaining tungsten wire alkaline washing liquid, adding activated carbon to the tungsten wire alkaline washing liquid, and filtering to obtain a filtrate; adding an organic phosphate solvent to the filtrate to separate an organic phase and an aqueous phase; dehydrating the aqueous phase to obtain a solid phase; washing the solid phase with an alcohol solvent, and drying to obtain sodium tungstate. The present application utilizes the strong adsorption properties of activated carbon to effectively remove oil stains and emulsifiers in waste alkaline liquid; utilizes the difference in solubility of metal ions in organic solvents and water to achieve the separation of tungstate and Co. 2+ 、Ni 2+ 、Fe 3+ The process effectively separates metal ions such as tungstate and sodium tungstate; obtains relatively pure sodium tungstate crystals; and achieves efficient recovery of tungsten through simple filtration, extraction and vacuum distillation processes, thus optimizing resource utilization efficiency.

Description

Technical Field

[0001] The present invention relates to the field of tungsten alloy wire manufacturing, and specifically relates to a method for recovering sodium tungstate from tungsten wire alkaline washing solution. Background Art

[0002] In the production process of tungsten wire, graphite emulsion is often used as a lubricant, but impurities such as emulsifiers and oils in the graphite emulsion are easily attached to the surface of the tungsten wire. If these impurities are not removed in time, they may enter the tungsten matrix during the deformation and drawing process, thereby affecting the surface quality and performance of the tungsten wire. In order to ensure the quality of the tungsten wire, the surface of the tungsten wire must be electrolytically cleaned with alkaline solution many times during the production process to remove the attached impurities. During the electrolytic cleaning process, organic matter such as emulsifiers and oils attached to the surface of the tungsten wire are removed. 2+ 、Ni 2+ 、Fe 3+ Metal ions such as tungsten oxide and tungsten will dissolve into the alkali solution. As the scale of tungsten wire production expands, the amount of sodium tungstate contained in the waste alkali solution will also increase. If these waste alkali solutions are directly discharged as wastewater, it will not only waste tungsten resources, but also cause environmental pollution. Therefore, if the tungstate and Co in the tungsten wire alkali solution can be 2+ 、Ni 2+ 、Fe 3+ If metal ions such as tungsten can be effectively separated, the separated tungsten can be recovered, thus realizing resource recycling. However, traditional technologies generally have problems such as narrow applicability, secondary pollution risks, and difficulty in balancing multi-component separation. In particular, the recovery efficiency of low-concentration, complex waste liquids is low. Summary of the Invention

[0003] The present invention provides a method for recovering sodium tungstate from tungsten wire alkaline washing solution, which can efficiently separate tungstate and Co in tungsten wire alkaline washing solution. 2+ 、Ni 2+ 、Fe 3+ This method can recover the tungsten dissolved in the alkali solution in the form of sodium tungstate, thus realizing the reuse of tungsten resources.

[0004] The method for recovering sodium tungstate from tungsten wire alkaline washing solution of the present application comprises the following steps:

[0005] S1. Obtaining a tungsten filament alkaline washing solution, adding activated carbon to the tungsten filament alkaline washing solution, and filtering to obtain a filtrate;

[0006] S2, adding an organophosphate solvent to the filtrate to separate the organic phase and the aqueous phase;

[0007] S3, removing water from the aqueous phase to obtain a solid phase;

[0008] S4. Wash the solid phase with an alcohol solvent and obtain sodium tungstate after drying.

[0009] In the above technical solution, step S1 utilizes the strong adsorption of activated carbon to remove the oil and emulsifier in the tungsten wire alkaline washing solution, so that the addition of the organic phosphate solvent in step S2 will not be difficult to extract due to emulsification; step S2 utilizes tungstate and Co 2+ 、Ni 2+ 、Fe 3+ The difference in solubility of metal ions in organophosphate solvents effectively removed Co by extraction. 2+ 、Ni 2+ 、Fe 3+ and other metal ions; step S3 removes water from the aqueous phase, and sodium tungstate and alkali are precipitated in solid form; step S4 utilizes the different solubility of sodium tungstate and alkali in alcohol solvents, and uses alcohol solvents to wash away excess alkali, thereby collecting sodium tungstate with higher purity.

[0010] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, the organic phosphate solvent includes at least one of dibutyl methyl phosphate or tributyl phosphate.

[0011] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, the alcohol solvent includes at least one of methanol or ethanol.

[0012] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, the tungsten wire alkaline washing solution comprises: cobalt ions, nickel ions, iron ions, oil and emulsifier; wherein the total content of cobalt ions, nickel ions and iron ions does not exceed 10wt%, and the total content of oil and emulsifier does not exceed 2wt%.

[0013] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, the mass ratio of activated carbon to tungsten wire alkaline washing solution is 1:80 to 1:100.

[0014] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, the mass ratio of the organophosphate solvent to the filtrate is 1:65 to 1:75.

[0015] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, the mass ratio of the alcohol solvent to the solid phase is 40:1 to 50:1.

[0016] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, step S4 further includes: performing a washing operation 3 to 5 times; this step can further remove the remaining alkali and improve the purity of the recovered sodium tungstate.

[0017] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, in step S2, the organic phase and the aqueous phase are separated by high-speed centrifugation, the centrifugation time is 2-3 minutes, and the rotation speed is 3800-4000 r / min.

[0018] As a preferred embodiment of the method for recovering sodium tungstate from tungsten wire alkaline washing solution described in the present application, in step S3, water is removed from the aqueous phase by vacuum distillation, and the heating temperature of the vacuum distillation is 50-60°C.

[0019] This application proposes a method for recovering sodium tungstate from tungsten wire alkaline washing solution, which realizes the recovery of sodium tungstate from tungsten wire. 2+ 、Ni 2 + 、Fe 3+ The effective separation of metal ions such as tungstate and sodium tungstate can obtain relatively pure sodium tungstate crystals, realize the efficient recovery of tungsten, and optimize the efficiency of resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0021] Figure 1 This is the XRD pattern of the sodium tungstate crystals obtained in Example 1.

[0022] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] 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.

[0024] The technical solution proposed in this application includes the following steps:

[0025] S1. Obtaining a tungsten filament alkaline washing solution, adding activated carbon to the tungsten filament alkaline washing solution, and filtering to obtain a filtrate;

[0026] Specifically, activated carbon is added to the tungsten wire alkaline washing solution, stirred, and filtered, and the strong adsorption performance of the activated carbon is used to remove oil and emulsifier to obtain a transparent filtrate; wherein, Co in the tungsten wire alkaline washing solution 2+ 、Ni2+ 、Fe 3+ The total content does not exceed 10wt%, the total content of oil and emulsifier does not exceed 2wt%, the mass ratio of activated carbon to tungsten wire alkaline washing solution is 1:80~1:100, and the stirring speed is 100~120r / min; specifically, the mass ratio of activated carbon to tungsten wire alkaline washing solution can be any one of 1:80, 1:85, 1:90, 1:95, 1:100 or a range between any two of them, and the stirring speed can be any one of 100r / min, 105r / min, 110r / min, 115r / min, 120r / min or a range between any two of them; in other embodiments, the mass ratio of activated carbon to waste alkaline solution, and the mass ratio of organic phosphate solvent to filtrate can also be other ratios, which can be adjusted according to actual conditions. For example, if the impurity content in the tungsten wire alkaline washing solution is too high, the amount of activated carbon can be appropriately increased; if the tungsten content in the tungsten wire alkaline washing solution is high, the amount of organic phosphate solvent can be appropriately increased;

[0027] S2, adding an organophosphate solvent to the filtrate to separate the organic phase and the aqueous phase;

[0028] Specifically, add the organic phosphate solvent to the filtrate and shake it thoroughly. Since different ions have different solubility in the organic phosphate solvent and water, Co 2+ 、Ni 2+ 、Fe 3+ The metal ions will be extracted into the organic phase, while the sodium tungstate and the alkali will remain in the aqueous phase, and then the organic phase and the aqueous phase are separated; wherein the organic phosphate includes at least one of dibutyl methyl phosphate or tributyl phosphate; the mass ratio of the organic phosphate solvent to the filtrate is 1:65-1:75, specifically, the mass ratio of the organic phosphate solvent to the filtrate can be any one of 1:65, 1:68, 1:70, 1:72, 1:75, or a range between any two of them; the preferred separation method is high-speed centrifugation, with a centrifugation time of 2-3 minutes and a rotation speed of 3800-4000 r / min; specifically, the rotation speed can be any one of 3800 r / min, 3850 r / min, 3900 r / min, 3950 r / min, 4000 r / min, or a range between any two of them;

[0029] S3, removing water from the aqueous phase to obtain a solid phase;

[0030] Specifically, the water phase is dehydrated by vacuum distillation until the water is completely removed; the heating temperature is 50-60°C and the rotation speed is 80-105r / min;

[0031] S4, washing the solid phase with an alcohol solvent and drying to obtain sodium tungstate;

[0032] Specifically, the solid phase obtained in step S3 is washed out with a small amount of ethanol or methanol, and the solid phase is further washed 3 to 5 times with ethanol or methanol. The mass ratio of the alcohol solvent to the solid phase during washing is 40:1 to 50:1, and the excess alkali is removed. After drying, sodium tungstate with higher purity is obtained.

[0033] The tungsten wire alkaline washing solution used in each embodiment and comparative example of the present application is the alkaline washing waste liquid generated during the electrolytic cleaning of tungsten wire. 2+ 、Ni 2+ 、Fe 3+ The total content is 3.5wt%, and the total content of oil and emulsifier is 2wt%. The technical solution of this application is further explained below with reference to specific examples.

[0034] Example 1

[0035] Add activated carbon to the tungsten wire alkaline washing solution, stir, and filter to obtain a transparent filtrate, wherein the mass ratio of activated carbon to tungsten wire alkaline washing solution is 1:100, and the stirring speed is 115r / min; add dibutyl methyl phosphate to the filtrate, the mass ratio of dibutyl methyl phosphate to filtrate is 1:70, fully shake, and centrifuge at high speed for 2 minutes at a speed of 4000r / min to separate the organic phase and the aqueous phase; pour the aqueous phase into a flask and connect it to a rotary evaporator, adjust the temperature to 55°C and the speed to 80r / min, evaporate the solvent water, and precipitate the solid phase; wash the solid phase with ethanol, at a mass ratio of ethanol to solid phase of 15:1 during washing, continue to use ethanol to wash the solid phase three times, maintaining the mass ratio of ethanol to solid phase of 50:1 during washing, and dry to obtain sodium tungstate. After testing, the purity of the sodium tungstate powder is 99.87%, and no sodium tungstate is detected in the organic phase. Figure 1 This is the XRD pattern of the sodium tungstate crystals obtained in Example 1. The characteristic peaks in the XRD pattern completely overlap with the characteristic peaks of the standard spectrum of sodium tungstate PDF#12-0772, and there is no other phase. It can be determined that the recovered solid powder is sodium tungstate.

[0036] Example 2

[0037] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate. The mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:80, and the stirring speed was 105 r / min. Dibutyl methyl phosphate was added to the filtrate at a mass ratio of dibutyl methyl phosphate to filtrate of 1:75. The mixture was thoroughly shaken and centrifuged at 4000 r / min for 3 minutes to separate the organic phase from the aqueous phase. The aqueous phase was poured into a flask and connected to a rotary evaporator. The temperature was adjusted to 60°C and the speed was adjusted to 95 r / min. The solvent water was evaporated to precipitate a solid phase. The solid phase was washed with ethanol at a mass ratio of 16:1. The solid phase was washed with ethanol five times, maintaining a mass ratio of 45:1 during the washing process. The sodium tungstate powder was dried to obtain sodium tungstate. Testing showed that the purity of the sodium tungstate powder was 99.56%, and no sodium tungstate was detected in the organic phase.

[0038] Example 3

[0039] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate. The mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:90, and the stirring speed was 100 r / min. Dibutyl methyl phosphate was added to the filtrate at a mass ratio of dibutyl methyl phosphate to filtrate of 1:65. The mixture was thoroughly shaken and centrifuged at 3900 r / min for 2.5 minutes to separate the organic phase from the aqueous phase. The aqueous phase was poured into a flask and connected to a rotary evaporator. The temperature was adjusted to 50°C and the speed was adjusted to 105 r / min. The solvent water was evaporated to precipitate a solid phase. The solid phase was washed with ethanol at a mass ratio of 17:1. The solid phase was washed with ethanol four times, maintaining a mass ratio of 45:1 during the washing process. The sodium tungstate powder was dried to obtain sodium tungstate. Testing showed that the purity of the sodium tungstate powder was 99.63%, and no sodium tungstate was detected in the organic phase.

[0040] Example 4

[0041] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate. The mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:95, and the stirring speed was 120 r / min. Dibutyl methyl phosphate was added to the filtrate at a mass ratio of dibutyl methyl phosphate to filtrate of 1:68. The mixture was thoroughly shaken and centrifuged at 4000 r / min for 2 minutes to separate the organic phase from the aqueous phase. The aqueous phase was poured into a flask and connected to a rotary evaporator. The temperature was adjusted to 60°C and the speed was adjusted to 90 r / min. The solvent water was evaporated to precipitate a solid phase. The solid phase was washed with ethanol at a mass ratio of 16:1. The filter residue was washed with ethanol four times, maintaining a mass ratio of 40:1 during the washing process. The sodium tungstate powder was dried to obtain sodium tungstate. Testing showed that the purity of the sodium tungstate powder was 99.48%, and no sodium tungstate was detected in the organic phase.

[0042] Example 5

[0043] Activated carbon was added to the tungsten filament alkaline wash solution, stirred, and filtered to obtain a transparent filtrate. The mass ratio of activated carbon to tungsten filament alkaline wash solution was 1:100, and the stirring speed was 115 r / min. Tributyl phosphate was added to the filtrate at a mass ratio of tributyl phosphate to filtrate of 1:70. The mixture was thoroughly shaken and centrifuged at 3800 r / min for 2 minutes to separate the organic phase from the aqueous phase. The aqueous phase was poured into a flask and connected to a rotary evaporator. The temperature was adjusted to 55°C and the speed was adjusted to 80 r / min. The solvent water was evaporated to precipitate a solid phase. The solid phase was washed with ethanol at a mass ratio of 15:1. The solid phase was washed with ethanol three times, maintaining a mass ratio of 50:1 during the wash. The sodium tungstate powder was dried to obtain sodium tungstate. Testing showed that the purity of the sodium tungstate powder was 98.59%, and no sodium tungstate was detected in the organic phase.

[0044] Example 6

[0045] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate. The mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:100, and the stirring speed was 115 r / min. Dibutyl methyl phosphate was added to the filtrate at a mass ratio of dibutyl methyl phosphate to filtrate of 1:70. The mixture was shaken thoroughly and allowed to stand for 30 hours to allow the organic and aqueous phases to separate. The organic phase was poured into a flask and connected to a rotary evaporator at a temperature of 55°C and a speed of 80 r / min. The solvent was evaporated to precipitate a solid phase. The solid phase was washed with ethanol at a mass ratio of 15:1. The solid phase was washed with ethanol three times, maintaining a mass ratio of 50:1 during the washes, and dried to obtain sodium tungstate. Testing showed that the sodium tungstate powder had a purity of 98.56%, and no sodium tungstate was detected in the organic phase.

[0046] Comparative Example 1

[0047] Activated carbon was added to the tungsten wire alkaline washing solution, stirred, and filtered to obtain a transparent filtrate, wherein the mass ratio of activated carbon to tungsten wire alkaline washing solution was 1:100, and the stirring speed was 115 r / min; ethyl acetate was added to the filtrate, and the mass ratio of ethyl acetate to filtrate was 1:70. The mixture was fully shaken and centrifuged at high speed for 2 minutes at a speed of 4000 r / min to separate the organic phase and the aqueous phase; the aqueous phase was poured into a flask, connected to a rotary evaporator, and the temperature was adjusted to 55°C and the speed was 80 r / min. The solvent water was evaporated to precipitate a solid phase; the solid phase was washed out with ethanol, and the mass ratio of ethanol to the solid phase during washing was 15:1. The solid phase was washed with ethanol for 3 times, and the mass ratio of ethanol to the solid phase during washing was maintained at 50:1. The sodium tungstate was obtained by drying.

[0048] This comparative example is consistent with Example 1 except that ethyl acetate is used as the extractant. The purity of the recovered sodium tungstate is 93.89%, which is lower than that of Example 1. This comparative example shows that the extraction effect of the organophosphate solvent is better than that of ethyl acetate.

[0049] Comparative Example 2

[0050] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate, wherein the mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:100, and the stirring speed was 115 r / min; dibutyl methyl phosphate was added to the filtrate, and the mass ratio of dibutyl methyl phosphate to the filtrate was 1:90. The mixture was fully shaken and centrifuged at high speed for 2 minutes at a speed of 4000 r / min to separate the organic phase and the aqueous phase; the aqueous phase was poured into a flask, connected to a rotary evaporator, adjusted to a temperature of 55°C and a speed of 80 r / min, the solvent water was evaporated, and a solid phase was precipitated; the solid phase was washed out with ethanol, and the mass ratio of ethanol to the solid phase during washing was 15:1. The solid phase was continuously washed with ethanol for 3 times, maintaining the mass ratio of ethanol to the solid phase during washing at 50:1, and dried to obtain sodium tungstate.

[0051] This comparative example is consistent with Example 1 except that the mass ratio of dibutyl methyl phosphate to filtrate is 1:90. The purity of the recovered sodium tungstate is 62.72%, which is significantly lower than that of Example 1. This shows that insufficient amount of extractant will also affect the reaction between tungstate and Co during extraction. 2+ 、Ni 2+ 、Fe 3+ Separation effect of metal ions.

[0052] Comparative Example 3

[0053] When dibutyl methyl phosphate was added to the tungsten wire alkaline washing solution that had not been treated with activated carbon, the organic phase and the aqueous phase were emulsified after shaking and centrifugation, and extraction could not be performed. This is because the emulsifier affected the extraction effect, making it impossible to separate the tungstate and Co in the tungsten wire alkaline washing solution. 2+ 、Ni 2+ 、Fe 3+ Other metal ions.

[0054] Comparative Example 4

[0055] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate, wherein the mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:125, and the stirring speed was 115 r / min; dibutyl methyl phosphate was added to the filtrate, and the mass ratio of dibutyl methyl phosphate to the filtrate was 1:70. The mixture was fully shaken and centrifuged at high speed for 2 minutes at a speed of 4000 r / min to separate the organic phase and the aqueous phase; the aqueous phase was poured into a flask, connected to a rotary evaporator, adjusted to a temperature of 55°C and a speed of 80 r / min, the solvent water was evaporated, and a solid phase was precipitated; the solid phase was washed out with ethanol, and the mass ratio of ethanol to the solid phase during washing was 15:1. The solid phase was continuously washed with ethanol for 3 times, maintaining the mass ratio of ethanol to the solid phase during washing at 50:1, and dried to obtain sodium tungstate.

[0056] This comparative example is consistent with Example 1 except that the mass ratio of activated carbon to waste alkali solution is 1:125. The purity of the recovered sodium tungstate is 83.72%, which is lower than that of Example 1.

[0057] It can be seen from Comparative Examples 3 and 4 that insufficient amount of activated carbon will reduce the effect of adsorbing oil and emulsifier, thereby affecting the reaction between tungstate and Co during extraction. 2+ 、Ni 2+ 、Fe 3+ Separation effect of metal ions.

[0058] Comparative Example 5

[0059] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate, wherein the mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:100, and the stirring speed was 115 r / min. Dibutyl methyl phosphate was added to the filtrate, and the mass ratio of dibutyl methyl phosphate to filtrate was 1:70. The mixture was fully shaken and centrifuged at a high speed of 4000 r / min for 2 minutes to separate the organic phase and the aqueous phase. The aqueous phase was poured into a flask and connected to a rotary evaporator. The temperature was adjusted to 55°C and the speed was 80 r / min. The solvent water was evaporated to precipitate a solid phase, which included sodium tungstate.

[0060] This comparative example is consistent with Example 1 except that ethanol washing is not used. The purity of the recovered sodium tungstate is 64.91%, which is significantly lower than that of Example 1.

[0061] Comparative Example 6

[0062] Activated carbon was added to the tungsten filament alkaline washing solution, stirred, and filtered to obtain a transparent filtrate, wherein the mass ratio of activated carbon to tungsten filament alkaline washing solution was 1:100, and the stirring speed was 115 r / min; dibutyl methyl phosphate was added to the filtrate, and the mass ratio of dibutyl methyl phosphate to the filtrate was 1:70. The mixture was fully shaken and centrifuged at high speed for 2 minutes at a speed of 4000 r / min to separate the organic phase and the aqueous phase; the aqueous phase was poured into a flask, connected to a rotary evaporator, adjusted to a temperature of 55°C and a speed of 80 r / min, the solvent water was evaporated, and a solid phase was precipitated; the solid phase was washed out with ethanol, and the mass ratio of ethanol to the solid phase during washing was 15:1. The solid phase was continuously washed with ethanol for 3 times, and the mass ratio of ethanol to the solid phase during washing was maintained at 20:1, and dried to obtain sodium tungstate.

[0063] This comparative example is consistent with Example 1 except that the mass ratio of ethanol to filter residue during washing is 20:1. The purity of the recovered sodium tungstate is 78.85%, which is significantly lower than that of Example 1.

[0064] Comparative Examples 5 and 6 show that washing with ethanol of appropriate quality can efficiently remove residual alkali, thereby greatly improving the purity of the recovered sodium tungstate.

[0065] Comparative Example 7

[0066] Activated carbon was added to the tungsten wire alkaline washing solution, stirred, and filtered to obtain a transparent filtrate, wherein the mass ratio of activated carbon to tungsten wire alkaline washing solution was 1:100, and the stirring speed was 115 r / min; dibutyl methyl phosphate was added to the filtrate, and the mass ratio of dibutyl methyl phosphate to the filtrate was 1:70. The mixture was fully shaken and centrifuged at high speed for 2 minutes at a speed of 3000 r / min to separate the organic phase and the aqueous phase; the aqueous phase was poured into a flask, connected to a rotary evaporator, adjusted to a temperature of 55°C and a speed of 80 r / min, and the solvent water was evaporated to precipitate a solid phase; the solid phase was washed out with ethanol, and the mass ratio of ethanol to the solid phase during washing was 15:1. The solid phase was continuously washed with ethanol for 3 times, and the mass ratio of ethanol to the solid phase during washing was maintained at 50:1, and dried to obtain sodium tungstate.

[0067] This comparative example is consistent with Example 1 except that the centrifugal speed is 3000 r / min. The purity of the recovered sodium tungstate is 50.43%, which is significantly lower than that of Example 1. Comparative Example 7 shows that high-speed centrifugal separation can achieve better separation effect.

[0068] By comparing the above examples and comparative examples, it can be seen that the beneficial effects of the method for recovering sodium tungstate from tungsten wire alkaline washing liquid proposed in this application are as follows: the strong adsorption performance of activated carbon can effectively remove oil and emulsifier in the waste alkali solution; the difference in the solubility of metal ions in organic solvents and water is used to achieve the recovery of sodium tungstate from tungsten wire alkaline washing liquid. 2+ 、Ni 2+ 、Fe3+ The process effectively separates metal ions such as tungstate and sodium tungstate; obtains relatively pure sodium tungstate crystals; and achieves efficient recovery of tungsten through simple filtration, extraction and vacuum distillation processes, thus optimizing resource utilization efficiency.

[0069] 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 sodium tungstate from tungsten wire alkaline washing solution, characterized in that: The following steps are involved: S1. Obtaining a tungsten filament alkaline washing solution, adding activated carbon to the tungsten filament alkaline washing solution, and filtering to obtain a filtrate; The tungsten wire alkaline cleaning solution comprises: tungstate ions, cobalt ions, nickel ions, iron ions, oil stains and an emulsifier; wherein the total content of the cobalt ions, the nickel ions and the iron ions does not exceed 10wt%, and the total content of the oil stains and the emulsifier does not exceed 2wt%; The mass ratio of the activated carbon to the tungsten wire alkaline washing solution is 1:80 to 1:100; S2. Adding an organic phosphate solvent to the filtrate, separating the organic phase and the aqueous phase, and separating the tungstate ions from the cobalt ions, nickel ions, and iron ions by extraction using the difference in solubility between the tungstate ions and the cobalt ions, nickel ions, and iron ions in the organic phosphate solvent; S3, removing water from the aqueous phase to obtain a solid phase; S4, washing the solid phase with an alcohol solvent and drying to obtain sodium tungstate; The organic phosphate solvent includes at least one of dibutyl methyl phosphate or tributyl phosphate; The mass ratio of the organophosphate solvent to the filtrate is 1:65 to 1:

75.

2. The method for recovering sodium tungstate from tungsten wire alkaline washing solution according to claim 1, characterized in that: The alcohol solvent includes at least one of methanol or ethanol.

3. The method for recovering sodium tungstate from tungsten wire alkaline washing solution according to claim 1, characterized in that: The mass ratio of the alcohol solvent to the solid phase is 40:1 to 50:

1.

4. The method for recovering sodium tungstate from tungsten wire alkaline washing solution according to claim 1, characterized in that: The step S4 further includes: performing the washing operation 3 to 5 times.

5. The method for recovering sodium tungstate from tungsten wire alkaline washing solution according to claim 1, characterized in that: In step S2, the organic phase and the aqueous phase are separated by high-speed centrifugation, with a centrifugation time of 2 to 3 minutes and a rotation speed of 3800 to 4000 r / min.

6. The method for recovering sodium tungstate from tungsten wire alkaline washing solution according to claim 1, characterized in that: In step S3, water is removed from the aqueous phase by vacuum distillation; the heating temperature of the vacuum distillation is 50-60°C.

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