Process for the recovery of tungsten from a tungsten-containing waste material

Abstract

The application discloses a tungsten recovery method from tungsten-containing waste, and relates to the technical field of tungsten-containing waste recovery. A manganese-containing compound is used as an additive to calcine the tungsten-containing waste, and selectively converts the difficultly leached tungsten-containing substances (tungsten, tungsten carbide, etc.) in the tungsten-containing waste into easily leached manganese tungstate, so that the tungsten-containing substances are leached in the form of sodium tungstate in the subsequent alkali leaching process, and the tungsten content of the alkali leaching tungsten residue is effectively reduced. At the same time, in the calcination process, the problem of equipment coking is avoided, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling tungsten-containing waste materials, and in particular to a method for recycling tungsten from tungsten-containing waste materials. Background Art

[0002] At present, the main methods for recovering tungsten from tungsten-containing waste are saltpeter smelting and oxidation roasting alkaline leaching, but both methods have certain problems:

[0003] (1) The saltpeter smelting method uses saltpeter as an oxidant to convert tungsten carbide in tungsten-containing waste into sodium tungstate at high temperature, while other impurity elements are oxidized into their metal oxides that are insoluble in water, thereby achieving the purpose of recovering tungsten. This method has a long industrial process, uses expensive raw and auxiliary materials, has high production costs, and emits exhaust gases that pollute the environment. In addition, the saltpeter smelting method has a low recovery rate.

[0004] (2) Oxidation roasting and alkaline leaching: tungsten-containing waste is converted into tungsten oxide through oxidation roasting. During the alkaline leaching process, the tungsten oxide reacts to form sodium tungstate, which enters the solution, thereby achieving the purpose of tungsten recovery. This method causes serious furnace congestion in the roasting equipment, resulting in a high tungsten content in the waste slag, a low recovery rate, and high secondary slag treatment costs.

[0005] It can be seen from this that the existing methods for leaching sodium tungstate from tungsten-containing waste generally have problems such as complex process flow, low recovery rate, high tungsten content in slag, and high processing cost.

[0006] In addition, the prior art also reports methods of introducing additive treatment, such as introducing magnesium-containing additives to improve the recovery rate of tungsten. However, the amount of magnesium-containing additives used in this process is 1.1-4 times that of tungsten-containing waste. The high amount of magnesium-containing additives used leads to low production efficiency.

[0007] Therefore, there is an urgent need to develop a method for leaching sodium tungstate from tungsten-containing waste with a short process, high efficiency, cleanliness and low cost, so as to achieve the purpose of secondary efficient recycling of tungsten resources.

[0008] In view of this, the present invention is proposed. Summary of the Invention

[0009] The object of the present invention is to provide a method for recovering tungsten from tungsten-containing waste, aiming to achieve efficient recovery of tungsten under the premise of low additive dosage and improve the recovery rate of tungsten.

[0010] The present invention is achieved in that:

[0011] In a first aspect, the present invention provides a method for recovering tungsten from tungsten-containing waste, comprising:

[0012] The tungsten-containing waste material is mixed with an additive to obtain a mixture, the mixture is calcined to obtain a calcined material, and the calcined material is mixed with a sodium hydroxide solution for reaction;

[0013] The additive is a manganese-containing compound, and the mass ratio of the manganese-containing compound to the tungsten-containing waste is 1:(10-100).

[0014] In an optional embodiment, the manganese-containing compound is selected from at least one of manganese carbonate, manganese sulfate and manganese chloride.

[0015] In an optional embodiment, the mass ratio of the manganese-containing compound to the tungsten-containing waste is 1:(10-20).

[0016] In an optional embodiment, the mass fraction of tungsten in the tungsten-containing waste is 40%-98%;

[0017] Preferably, the tungsten-containing waste is powdered tungsten-containing waste with a particle size of 44 μm-149 μm.

[0018] In an optional embodiment, preferably, the tungsten-containing waste material is derived from at least one of a cemented carbide production process, a tungsten carbide powder production process, and a tungsten powder production process;

[0019] Preferably, the tungsten-containing waste material is selected from at least one of floor material, dust collection material, grinding material and waste material.

[0020] In an optional embodiment, during the calcination process, the calcination temperature is controlled to be 300° C.-1000° C., and the calcination time is 1 h-24 h;

[0021] Preferably, the calcination temperature is controlled to be 400° C.-600° C., and the calcination time is controlled to be 1 h-3 h.

[0022] In an optional embodiment, the calcination process is carried out in an oxygen-containing atmosphere, and the container is turned over during the calcination process, with the container being turned over every 20 minutes to 40 minutes.

[0023] In an optional embodiment, the calcined material is mixed with a sodium hydroxide solution and reacted for 60 minutes to 180 minutes to obtain a solid-liquid mixture, and the solid-liquid mixture is subjected to solid-liquid separation to obtain a sodium tungstate solution.

[0024] In an optional embodiment, the concentration of the sodium hydroxide solution is 50 g / L-300 g / L;

[0025] Preferably, the mass ratio of the sodium hydroxide content in the sodium hydroxide solution to the tungsten-containing waste is 1:(1-6).

[0026] In an optional embodiment, the method further comprises: subjecting the sodium tungstate solution to evaporation and crystallization to obtain a sodium tungstate product;

[0027] And / or, extracting or ion-exchanging the sodium tungstate solution to obtain an ammonium tungstate solution, and then evaporating and crystallizing the ammonium tungstate solution to obtain an ammonium paratungstate product;

[0028] And / or, the sodium tungstate solution is extracted or ion-exchanged to obtain an ammonium tungstate solution, and then the ammonium tungstate solution is evaporated and crystallized to obtain an ammonium paratungstate product, and the ammonium paratungstate product is calcined to obtain a tungsten oxide product.

[0029] The present invention has the following beneficial effects: calcining tungsten-containing waste with a manganese-containing compound as an additive selectively converts difficult-to-leach tungsten-containing substances (tungsten, tungsten carbide, etc.) in the tungsten-containing waste into easily leached manganese tungstate. In the subsequent alkaline leaching process, the tungsten-containing substances are leached as sodium tungstate, effectively reducing the tungsten content of the alkaline leached tungsten slag and the amount of additives used. Furthermore, during the calcination process, equipment stagnation is avoided, improving production efficiency and reducing production costs. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0031] An embodiment of the present invention provides a method for recovering tungsten from tungsten-containing waste, comprising the following steps:

[0032] S1, mixed

[0033] The tungsten-containing waste is mixed with an additive, wherein the additive is a manganese-containing compound. The inventors have creatively used the manganese-containing compound as an additive to convert difficult-to-leach tungsten-containing substances (tungsten, tungsten carbide, etc.) in the tungsten-containing waste into manganese tungstate during the calcination process, while using a relatively low additive dosage.

[0034] In some embodiments, the manganese-containing compound is selected from at least one of manganese carbonate, manganese sulfate, and manganese chloride, and the manganese-containing compound can be any one or more of the above. The mass ratio of the manganese-containing compound to the tungsten-containing waste is 1:(10-100), preferably 1:(10-20). When the amount of the manganese-containing compound is within the above range, the difficult-to-leach tungsten-containing substances (tungsten, tungsten carbide, etc.) in the tungsten-containing waste can be converted into manganese tungstate during the calcination process.

[0035] Specifically, the mass ratio of the manganese-containing compound to the tungsten-containing waste can be 1:10, 1:15, 1:20, 1:30, 1:50, 1:80, 1:100, etc.

[0036] In some embodiments, the mass fraction of tungsten in the tungsten-containing waste is 40%-98%. Any tungsten content within this range is suitable for recovering tungsten from the tungsten-containing waste using the methods provided in embodiments of the present invention. The tungsten-containing waste can be powdered tungsten-containing waste with a particle size of 44 μm-149 μm.

[0037] The source of tungsten-containing waste is not limited and can come from at least one of the following processes: cemented carbide production, tungsten carbide powder production, and tungsten powder production. In other words, the tungsten-containing waste can come from any one of these processes, or a mixture of wastes from these processes.

[0038] Furthermore, the tungsten-containing waste is selected from at least one of floor materials, dust collection materials, grinding materials and waste materials. The tungsten-containing waste can be a mixture of any one or more of the above waste forms.

[0039] S2. Calcination

[0040] The mixed material is calcined to obtain a calcined material for later use. During the calcination process, the difficult-to-leach tungsten-containing substances (tungsten, tungsten carbide, etc.) in the tungsten-containing waste are selectively converted into easily leached manganese tungstate with a high conversion rate, which can significantly improve the recovery rate of tungsten.

[0041] In some embodiments, the calcination process is controlled at a temperature of 300°C to 1000°C for a time of 1 to 24 hours; preferably, the calcination temperature is controlled at 400°C to 600°C for a time of 1 to 3 hours. By optimizing the calcination temperature and time, the difficult-to-leach tungsten-containing substances (tungsten, tungsten carbide, etc.) in the tungsten-containing waste are converted into easily leached manganese tungstate, further improving the tungsten recovery rate.

[0042] Specifically, the calcination temperature can be 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, etc.; the calcination time can be 1h, 2h, 3h, 5h, 10h, 15h, 20h, 24h, etc.

[0043] In some embodiments, the calcination process is carried out in an oxygen-containing atmosphere, such as an air-enriched atmosphere. During the calcination process, the material can be stirred to ensure sufficient contact with air. In actual operation, the material can be stirred every 20-40 minutes (e.g., 20 minutes, 30 minutes, 40 minutes, etc.) to ensure an air-enriched atmosphere during the calcination process.

[0044] S3, alkali leaching

[0045] The calcined material is mixed with sodium hydroxide solution for reaction. During the alkaline leaching process, tungsten-containing substances such as manganese tungstate are leached in the form of sodium tungstate, which effectively reduces the tungsten content of the alkaline leached tungsten slag and improves the tungsten recovery rate.

[0046] In some embodiments, the calcined material is mixed with a sodium hydroxide solution and reacted for 60-180 minutes to obtain a solid-liquid mixture, which is then subjected to solid-liquid separation to obtain a sodium tungstate solution, thereby achieving efficient recovery of tungsten. The solid-liquid separation method is not limited, and common filtration methods can be used.

[0047] In some embodiments, the concentration of the sodium hydroxide solution is 50 g / L-300 g / L, such as 50 g / L, 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, etc. The mass ratio of the sodium hydroxide content in the sodium hydroxide solution to the tungsten-containing waste is 1:(1-6), such as 1:6, 1:3, 1:2, 1:1.5, 1:1.2, 1:1, etc. By further adjusting the concentration and amount of the sodium hydroxide solution, tungsten can be more fully leached.

[0048] In some embodiments, the method for recovering tungsten further includes: subjecting the sodium tungstate solution to evaporative crystallization to obtain a sodium tungstate product. Evaporative crystallization of the sodium tungstate solution can produce a sodium tungstate product, thereby increasing the added value of the product. It should be noted that the temperature and other conditions for evaporative crystallization are conventional in the art and can be selected by those skilled in the art based on actual needs. These conditions will not be further elaborated here.

[0049] In another embodiment, the sodium tungstate solution is subjected to extraction or ion exchange to obtain an ammonium tungstate solution, and then the ammonium tungstate solution is subjected to evaporation and crystallization to obtain an ammonium paratungstate product. The sodium tungstate solution is subjected to extraction or ion exchange to obtain an ammonium tungstate solution, and then the ammonium tungstate solution is subjected to evaporation and crystallization to obtain an ammonium paratungstate product, thereby increasing the added value of the product. The extractant used in the extraction can be selected from at least one of N235, TOA, Alamine-336, a quaternary ammonium salt, etc., and the ion exchange resin used in the ion exchange can be a strong basic anion exchange resin such as D201×7, Amberlite IRA-400, AB-17Π, Amberlite IRA-4200, or a weak basic anion exchange resin such as AH-80Π. It should be noted that the specific operation process of extracting or ion exchanging the sodium tungstate solution to obtain the ammonium tungstate solution is conventional in the art under evaporation and crystallization conditions and will not be repeated here.

[0050] In another embodiment, a sodium tungstate solution is subjected to extraction or ion exchange to obtain an ammonium tungstate solution, which is then evaporated and crystallized to obtain an ammonium paratungstate product. The ammonium paratungstate product is then calcined to obtain a tungsten oxide product. The detailed instructions for obtaining the ammonium paratungstate product can be found above and are not repeated here. Further calcination of the ammonium paratungstate product can produce a tungsten oxide product, thereby increasing the added value of the product.

[0051] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0052] It should be noted that in the following embodiments and comparative examples, the tungsten-containing waste is conventional commercially available tungsten-containing waste, and its composition includes: a tungsten mass content of 40% to 98%, and also contains other elements M, wherein M is selected from one or more of Fe, Cu, Ca, Zn, Ni, Mg, C, Ta, Co, Ti, Nb, Mn, Sn, Cr, V, K, Na, Zr, Pb, Mo, P, S, Al, and Si.

[0053] Example 1

[0054] This embodiment provides a method for recovering tungsten from tungsten-containing waste, comprising the following steps:

[0055] (1) Mixing: 300 g of tungsten-containing waste was added with manganese carbonate and mixed uniformly to obtain a mixture. The mass ratio of manganese carbonate to tungsten-containing waste was 1:10. The tungsten-containing waste was composed of 81 wt% tungsten, with the remainder being M. The particle size of the tungsten-containing waste was 44 μm to 149 μm.

[0056] (2) Calcination: The mixed material prepared in step (1) was calcined at 500° C. in an air atmosphere for 2 h, and was continuously turned over during the calcination process at a frequency of 30 min / time to obtain a calcined material.

[0057] (3) Alkali leaching: The calcined material obtained in step (2) was added to 1 L of a sodium hydroxide solution having a concentration of 200 g / L, and the mixture was stirred for 120 min to obtain a solid-liquid mixture. After solid-liquid separation, a sodium tungstate solution was obtained. The residue was dried, weighed, and analyzed for residual tungsten content.

[0058] According to the test, the residual slag obtained in this embodiment contains 3.23% tungsten, and the recovery rate of tungsten is calculated to be 98.81%.

[0059] Example 2

[0060] This embodiment provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that manganese carbonate is replaced with manganese sulfate of equal mass. The rest is the same as Example 1.

[0061] According to the test, the residual slag obtained in this embodiment contains 4.40% tungsten, and the tungsten recovery rate is calculated to be 98.31%.

[0062] Example 3

[0063] This embodiment provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that manganese carbonate is replaced with manganese chloride of equal mass. The rest is the same as Example 1.

[0064] According to the test, the residual slag obtained in this embodiment contains 5.49% tungsten, and the tungsten recovery rate is calculated to be 97.83%.

[0065] Example 4

[0066] This embodiment provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that the mass ratio of manganese carbonate to tungsten-containing waste is replaced from 1:10 to 1:20, and the rest is the same as Example 1.

[0067] According to the test, the residual slag obtained in this embodiment contains 3.94% tungsten, and the recovery rate of tungsten is calculated to be 98.52%.

[0068] Example 5

[0069] This embodiment provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that the mass ratio of manganese carbonate to tungsten-containing waste is replaced from 1:10 to 1:50, and the rest is the same as Example 1.

[0070] According to the test, the residual slag obtained in this embodiment contains 5.48% tungsten, and the tungsten recovery rate is calculated to be 97.81%.

[0071] Example 6

[0072] This embodiment provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that the mass ratio of manganese carbonate to tungsten-containing waste is replaced from 1:10 to 1:100, and the rest is the same as Example 1.

[0073] According to the test, the residual slag obtained in this embodiment contains 7.78% tungsten, and the tungsten recovery rate is calculated to be 97.15%.

[0074] Example 7

[0075] This embodiment provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that the tungsten-containing waste is composed of 40 wt% tungsten and the balance is M. The rest is the same as Example 1.

[0076] According to the test, the residual slag obtained in this embodiment contains 3.87% tungsten, and the recovery rate of tungsten is calculated to be 98.39%.

[0077] Example 8

[0078] This embodiment provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that the tungsten-containing waste is composed of 98 wt% tungsten, with the remainder being M. The rest is the same as Example 1.

[0079] According to the test, the residual slag obtained in this embodiment contains 3.83% tungsten, and the recovery rate of tungsten is calculated to be 98.63%.

[0080] Comparative Example 1

[0081] This comparative example provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that step (1) is not performed, i.e., no additive is added. The specific steps are as follows:

[0082] (1) Calcination: 300 g of tungsten-containing waste was calcined at 500° C. in an air atmosphere for 2 h, and the waste was continuously turned over during the calcination process at a frequency of 30 min / time to obtain a calcined material.

[0083] (2) Alkali leaching: The calcined material obtained in step (1) was added to 1 L of a sodium hydroxide solution having a concentration of 200 g / L, and the mixture was stirred for 120 min to obtain a solid-liquid mixture. After solid-liquid separation, a sodium tungstate solution was obtained. The residue was dried, weighed, and analyzed for residual tungsten content.

[0084] According to the test, the residual slag obtained in this embodiment contains 31.17% tungsten, and the recovery rate of tungsten is calculated to be 80.41%.

[0085] Comparative Example 2

[0086] This comparative example provides a method for recovering tungsten from tungsten-containing waste, which differs from Example 1 only in that manganese carbonate is replaced with manganese dioxide of equal mass, and the rest is the same as Example 1.

[0087] According to the test, the residual slag obtained in this comparative example contains 26.76% of tungsten, and the recovery rate of tungsten is calculated to be 86.47%.

[0088] Comparative Example 3

[0089] This comparative example provides a method for recovering tungsten from tungsten-containing waste, which differs from Example 1 only in that manganese carbonate is replaced with potassium permanganate of equal mass, and the rest is the same as Example 1.

[0090] According to the test, the residual slag obtained in this comparative example contains 23.14% tungsten, and the recovery rate of tungsten is calculated to be 87.65%.

[0091] Comparative Example 4

[0092] This comparative example provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that the mass ratio of manganese carbonate to tungsten-containing waste is replaced from 1:10 to 1:200, and the rest is the same as Example 1.

[0093] According to the test, the residual slag obtained in this embodiment contains 19.12% tungsten, and the recovery rate of tungsten is calculated to be 91.44%.

[0094] Comparative Example 5

[0095] This comparative example provides a method for recovering tungsten from tungsten-containing waste. The only difference from Example 1 is that the mass ratio of manganese carbonate to tungsten-containing waste is replaced from 1:10 to 1:5, and the rest is the same as Example 1.

[0096] According to the test, the residual slag obtained in this comparative example contains 26.38% of tungsten, and the recovery rate of tungsten is calculated to be 86.27%.

[0097] The results are analyzed as follows:

[0098] From the comparison results of the tungsten recovery rates in Comparative Example 1 and Examples 1, 2, and 3, it can be seen that when calcination is performed without adding an additive, the tungsten recovery rate is only 80.41%. When manganese carbonate, manganese sulfate, and manganese chloride among the manganese-containing compounds are used as additives for calcination, the tungsten-containing substances (tungsten, tungsten carbide, etc.) that are difficult to leach in the tungsten-containing waste can be selectively converted into manganese tungstate that is easy to leach. In the subsequent alkaline leaching process, the tungsten-containing substances are leached in the form of sodium tungstate, which can increase the tungsten recovery rate to more than 95%.

[0099] During the reaction, the generated gas agitates the materials, which facilitates the reaction. Comparison of the tungsten recovery rates in Comparative Examples 2 and 3 with those in Example 1 shows that when manganese carbonate is used as an additive for calcination, more carbon dioxide gas is generated during the reaction, agitating the materials and promoting the full progress of the reaction. Ultimately, the tungsten recovery rate is superior to that achieved when manganese dioxide or potassium permanganate are used as additives.

[0100] Comparing the tungsten recovery rates in Comparative Examples 4 and 5 with those in Example 1 shows that tungsten recovery rates decrease when the mass ratio of the additive to the tungsten-containing waste is too low or too high. Therefore, a mass ratio of the additive to the tungsten-containing waste of 1:100 to 1:10 is ideal.

[0101] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for recovering tungsten from tungsten-containing waste, characterized in that: include: mixing tungsten-containing waste with an additive to obtain a mixture, calcining the mixture to obtain a calcined material, and mixing the calcined material with a sodium hydroxide solution for reaction; Wherein, the additive is a manganese-containing compound, and the mass ratio of the manganese-containing compound to the tungsten-containing waste is 1:(10-100); The manganese-containing compound is selected from at least one of manganese carbonate, manganese sulfate and manganese chloride.

2. The method according to claim 1, characterized in that The mass ratio of the manganese-containing compound to the tungsten-containing waste is 1:(10-20).

3. The method according to claim 1, characterized in that The mass fraction of tungsten in the tungsten-containing waste is 40%-98%.

4. The method according to claim 3, characterized in that The tungsten-containing waste is powdered tungsten-containing waste with a particle size of 44 μm-149 μm.

5. The method according to claim 4, characterized in that The tungsten-containing waste material comes from at least one of a cemented carbide production process, a tungsten carbide powder production process and a tungsten powder production process.

6. The method according to claim 5, characterized in that The tungsten-containing waste material is selected from at least one of floor material, dust collection material and grinding material.

7. The method according to claim 1, characterized in that During the calcination process, the calcination temperature is controlled to be 300°C-1000°C, and the calcination time is 1h-24h.

8. The method according to claim 7, characterized in that The calcination temperature is controlled to be 400℃-600℃ and the calcination time is 1h-3h.

9. The method according to claim 7, characterized in that The calcination process is carried out in an oxygen-containing atmosphere, and the pellets are turned over during the calcination process, with each turning over occurring every 20 minutes to 40 minutes.

10. The method according to claim 1, characterized in that The calcined material and the sodium hydroxide solution are mixed and reacted for 60 minutes to 180 minutes to obtain a solid-liquid mixture, and the solid-liquid mixture is subjected to solid-liquid separation to obtain a sodium tungstate solution.

11. The method according to claim 10, characterized in that The concentration of the sodium hydroxide solution is 50g / L-300g / L.

12. The method according to claim 11, characterized in that The mass ratio of the sodium hydroxide content in the sodium hydroxide solution to the tungsten-containing waste is 1:(1-6).

13. The method according to claim 10, characterized in that Also includes: The sodium tungstate solution is evaporated and crystallized to obtain a sodium tungstate product.

14. The method according to claim 10, characterized in that Also includes: The sodium tungstate solution is extracted or ion-exchanged to obtain an ammonium tungstate solution, and then the ammonium tungstate solution is evaporated and crystallized to obtain an ammonium paratungstate product.

15. The method according to claim 10, characterized in that Also includes: The sodium tungstate solution is extracted or ion-exchanged to obtain an ammonium tungstate solution, and then the ammonium tungstate solution is evaporated and crystallized to obtain an ammonium paratungstate product, and the ammonium paratungstate product is calcined to obtain a tungsten oxide product.