Method for preparing tungstic acid from hard alloy waste tungsten grinding material

Abstract

One or more embodiments of the invention relate to the field of industrial solid waste recycling, in particular to a method for preparing tungstic acid from a hard alloy waste tungsten grinding material, and the method comprises the following steps: S1, carrying out roasting pretreatment on the waste tungsten grinding material to obtain a roasted material; s2, mixing the roasted material obtained in S1 with an acidic solution, and stirring to obtain a solid-liquid mixture; s3, putting the solid-liquid mixture obtained in S2 into a high-pressure kettle; s3-1, oxidizing gas is introduced into the high-pressure kettle, and a stirring leaching reaction is carried out; s3-2, after the reaction is completed, carrying out liquid-solid separation; and S3-3, after liquid-solid separation, washing the leaching residues with hot water for 3-5 times to obtain the leaching residues which are tungstic acid solid phases and a leaching solution which is a cobalt salt solution. The problems that in the prior art, various hard alloy waste tungsten grinding material regeneration treatment technologies are tedious in technological process, large in tungsten loss, high in treatment cost and the like are solved.

Description

Technical Field

[0001] One or more embodiments of the present specification relate to the field of industrial solid waste recycling, and in particular, to a method for preparing tungstic acid from cemented carbide waste tungsten grinding material. Background Art

[0002] Tungsten carbide-based cemented carbide will produce a large amount of waste tungsten grinding materials during the grinding process. With the widespread application of cemented carbide and the increase in demand, the amount of waste tungsten grinding materials generated has also increased. In recent years, many countries have regarded cemented carbide waste as a valuable second resource to solve the problem of the lack of tungsten ore raw materials and to reduce the production cost of cemented carbide. Therefore, how to efficiently recycle and utilize these cemented carbide waste has become one of the urgent problems to be solved for the high-quality development of the tungsten industry.

[0003] The existing production technology methods for recycling and treating cemented carbide waste mainly include "zinc melting method", "saltpeter smelting method", "roasting-alkali leaching method", "electrochemical dissolution method" and so on. These current production technologies have various defects. For example, the zinc melting method is only suitable for treating cemented carbide with a cobalt content of less than 10%, with high power consumption, high requirements for zinc vapor recovery equipment, and large zinc volatilization pollution. The saltpeter smelting method has a long industrial process, uses expensive raw and auxiliary materials, has high production costs, and the exhaust gas pollutes the environment. The roasting-alkali leaching method is to convert tungsten waste into tungsten oxide through oxidation roasting, and the tungsten oxide is alkali-leached to generate sodium tungstate to achieve the purpose of recovering tungsten; however, in the production process of this method, the roasting equipment is severely blocked, the slag contains a high amount of tungsten, the metal recovery rate is low, and the secondary slag treatment cost is high; and the subsequent production of APT through traditional metallurgical processes generates a lot of wastewater and a large loss of raw and auxiliary materials. The electrochemical dissolution method has the disadvantages of low current efficiency, high production cost and unsuitability for treating powdered tungsten waste.

[0004] Tungsten acid is the raw material for producing a variety of chemical products such as metallic tungsten and tungsten-containing catalysts. At present, the main method for preparing tungsten acid from cemented carbide waste tungsten grinding materials is to first roast the cemented carbide waste to produce tungsten trioxide, and then perform alkaline leaching to obtain sodium tungstate solution or ammonium tungstate solution. However, the tungsten trioxide content in the alkaline leaching residue is usually around 40%, and secondary roasting-alkaline leaching is required; then, the sodium tungstate solution or ammonium tungstate solution is subjected to the production process of acid addition reaction to obtain tungsten acid products; the process is complicated, the tungsten loss is large, the treatment cost is high, and there is a lot of production wastewater.

[0005] The purpose of the present invention is to provide a method for preparing tungstic acid using cemented carbide waste tungsten grinding material with a short process, low cost and wide applicability, in view of the problems of long process, high production cost and low tungsten recovery rate in the existing cemented carbide waste tungsten grinding material recycling technology.

[0006] In summary, the present application now proposes a method for preparing tungstic acid from cemented carbide waste tungsten grinding material to solve the above-mentioned problems. Summary of the invention

[0007] The present invention aims to solve the problems raised in the background technology. This specification proposes a method for preparing tungstic acid from cemented carbide waste tungsten grinding material to solve the problems of complicated process flow, large tungsten loss and high processing cost in various cemented carbide waste tungsten grinding material regeneration processing technologies in the prior art.

[0008] Based on the above purpose, one or more embodiments of this specification provide a method for preparing tungsten acid from cemented carbide waste tungsten grinding material, the method comprising the following steps: S1: pre-treating the waste tungsten grinding material by roasting to obtain a roasted material; S2: mixing the roasted material obtained in S1 with the acidic solution, and stirring to obtain a solid-liquid mixture; S3: placing the solid-liquid mixture obtained in S2 in an autoclave; S3-1: introducing an oxidizing gas into the autoclave to perform a stirring leaching reaction; S3-2: After the reaction is complete, liquid-solid separation is performed; S3-3: After liquid-solid separation, wash the leaching residue with hot water for 3 to 5 times. The obtained leaching residue is tungstic acid solid phase, and the leaching liquid is cobalt salt solution.

[0009] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material provided in an embodiment of the present invention, the waste tungsten grinding material in step S1 comes from powdered waste tungsten grinding material generated in the cemented carbide production process; the waste tungsten grinding material includes: Tungsten oxide, 30%~95%; Cobalt mass, 2%~20%; Iron mass, 0.5% to 5%; Copper mass, 0.2% to 4%; Other impurity elements.

[0010] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the roasting pretreatment described in step S1 above adopts aerobic roasting, which is roasting in the air or with oxygen.

[0011] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the roasting pretreatment described in step S1 has a roasting temperature of 100-1000° C. and a roasting time of 1-6 hours.

[0012] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the acidic solution in step S2 is one or a mixture of sulfuric acid, hydrochloric acid, nitric acid or perchloric acid, and the mass concentration of the acidic solution is 20-300 g / L.

[0013] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the amount of the acidic solution added in step S2 is added according to the liquid-to-solid ratio of the roasting material, that is, the ratio of liquid volume to solid mass is 3~20:1mL / g.

[0014] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the oxidizing gas in step S3 is selected from oxygen or air or a mixture of the two, and the partial pressure of the oxidizing gas is 0.1-2.0 MPa.

[0015] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the solid-liquid mixture described in the above step S3 is stirred and leached, and the leaching reaction is carried out under the conditions of a reaction temperature of 100-200° C. and a holding time of 1-8 hours.

[0016] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the solid-liquid mixture described in step S3 is stirred and leached at a stirring rate of 100 to 600 rpm.

[0017] According to the method for preparing tungstic acid from cemented carbide waste tungsten grinding materials proposed in an embodiment of the present invention, the cobalt salt solution described in the above step S3 can be purified and impurities removed by chemical precipitation method, and then cobalt oxalate can be precipitated with ammonium oxalate to prepare a cobalt oxalate product, or the cobalt oxalate can be calcined to produce a cobalt oxide powder product.

[0018] According to the method for preparing tungsten acid from cemented carbide waste tungsten grinding material proposed in an embodiment of the present invention, the tungsten acid solid phase described in the above step S3 can be calcined to directly prepare a tungsten oxide product; the tungsten acid solid phase or tungsten oxide can also be dissolved into an ammonium tungstate solution by ammonia water, and the ammonium paratungstate product can be prepared after evaporation and crystallization; the tungsten acid solid phase or tungsten oxide can also be dissolved into a sodium tungstate solution by alkali leaching, and then the ammonium tungstate solution can be obtained by ion exchange process or extraction process, and the ammonium tungstate solution can be evaporated and crystallized to obtain the ammonium paratungstate product; the tungsten acid solid phase can also be complexed and dissolved by organic acid to form a tungsten acid complex solution, and the complex solution can be thermally decomposed to prepare high-purity tungstic acid.

[0019] According to the above, the present invention has the following beneficial effects: Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention utilizes the combined treatment technology of roasting pretreatment and oxygen pressure acid leaching to realize direct conversion of tungsten-containing phases such as tungsten carbide, tungstate, tungsten oxide, etc. in the roasted material of waste tungsten grinding material into tungsten acid solid phase in an aqueous solution system, while non-tungsten components such as cobalt and iron have strong solubility in the oxygen pressure acid leaching system and are transferred into the liquid phase, thus realizing a short process and efficient separation of tungsten from impurities such as cobalt and iron, greatly reducing energy consumption and production costs.

[0020] 2. The present invention includes a roasting pretreatment process, which can remove oil, moisture, low-temperature volatiles, etc. from the waste tungsten grinding material; and can achieve preliminary oxidation conversion and high-temperature activation treatment of tungsten, cobalt, iron and other components in the waste tungsten grinding material, which is beneficial to the subsequent oxygen pressure acid leaching process.

[0021] 3. The gas oxidant (oxygen or air) used in the present invention is widely available, cheap and easy to obtain, and avoids the defects of other technical methods such as low oxidation efficiency, large consumption of solid or liquid oxidants, and many impurities brought into the oxidant.

[0022] 4. Through the combined treatment technology of roasting pretreatment and oxygen pressure acid leaching, the waste tungsten grinding material can be used to prepare tungstic acid products in a short process, which solves many problems in the existing technical methods for preparing tungstic acid from cemented carbide waste tungsten grinding materials, such as long process flow, high cost, and low tungsten recovery efficiency. The method provided by the present invention can make the tungsten recovery rate in waste tungsten grinding materials as high as 95% or more.

[0023] 5. The present invention utilizes oxygen pressure acid leaching technology to directly convert tungsten-containing phases such as tungstates and tungsten oxides in the waste tungsten grinding material roasting material into tungsten acid solid phases in an aqueous solution system; and can also convert the colloidal tungstic acid in the leached slurry into crystalline tungstic acid precipitation, thereby promoting the separation and recovery of tungsten and other soluble components, and greatly improving the filtration performance of the leached slurry and the recovery rate of tungsten. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate one or more embodiments of the present specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only one or more embodiments of the present specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Attached Figure 1 It is a process flow diagram of the method of the present invention; Attached Figure 2 1 is an XRD analysis result diagram of the leached residue obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments.

[0027] Please see attached Figure 1 , the method comprises the following steps: S1: pre-treating the waste tungsten grinding material by roasting to obtain a roasted material.

[0028] Furthermore, the method provided in the embodiment of the present invention is applicable to any tungsten-containing grinding material. In order to improve production efficiency and the recovery rate of tungsten, the raw material waste tungsten grinding material is optimized. The preferred chemical composition of the waste tungsten grinding material is: tungsten oxide mass content of 30% to 95%, cobalt mass content of 2% to 20%, iron mass content of 0.5% to 5%, copper mass content of 0.2% to 4%, and also contains a small amount of other impurity elements such as Ni, C, Cr, SiO2, V, etc.; the particle size of the waste tungsten grinding material generally ranges from 60 to 1200 mesh. It should be noted that the above-mentioned substances and element contents are only to meet the need for full disclosure, and do not constitute a limitation on the scheme itself. The method provided by the present invention is applicable to waste tungsten grinding materials obtained by commercial and existing processing methods. In addition, the present invention does not specifically limit the source of the waste tungsten grinding material, which can be obtained through commercial purchase, or it can be tungsten-containing waste generated in the existing cemented carbide production process. The inventors have found that the finer the particle size of the waste tungsten grinding material, the larger the contact area with the acidic solution, and the easier it is to participate in the oxygen pressure acid leaching conversion reaction.

[0029] Furthermore, in an embodiment of the present invention, the calcination pretreatment adopts aerobic calcination, which is calcination by exposing to air or introducing oxygen.

[0030] Furthermore, in the embodiment of the present invention, the roasting pretreatment, the roasting temperature is 100-1000°C, the roasting time is 1-6h; after high-temperature roasting, the impurities such as oil, moisture, low-temperature volatiles, etc. of the waste tungsten grinding material can be removed, and the reaction activity of the waste tungsten grinding material can be improved, and the tungsten, cobalt, iron, copper and other components in the waste tungsten grinding material and tungsten carbide can be oxidized and converted into tungstates, metal oxides and other phases, which is beneficial to the subsequent oxygen pressure acid leaching technology treatment, so that the subsequent leaching rate and leaching rate are doubled. The inventors have found that the above roasting temperature and roasting time can ensure the complete conversion of the waste tungsten grinding material.

[0031] S2: Mix the roasted material obtained in S1 with the acid solution, and stir to obtain a solid-liquid mixture.

[0032] Furthermore, in an embodiment of the present invention, the acidic solution is selected from at least one of sulfuric acid, hydrochloric acid, nitric acid, and perchloric acid. In order to reduce the pollution of the exhaust gas to the environment, sulfuric acid is preferably selected; the mass concentration of the acidic solution is 20-300 g / L; the higher the concentration of the acidic solution, the faster the reaction rate of the subsequent oxygen pressure acid leaching.

[0033] Furthermore, in an embodiment of the present invention, the amount of the acidic solution added is 3-20:1 mL / g according to the liquid-solid ratio (ratio of liquid volume to solid mass) of the roasting material; further, the liquid-solid ratio is preferably 6-12:1; the larger the liquid-solid ratio, the better the leaching and separation effect, which can significantly improve the leaching rate of non-tungsten components such as cobalt and the yield of tungstic acid.

[0034] S3: The solid-liquid mixture obtained in S2 is placed in an autoclave, and an oxidizing gas is introduced into the autoclave. The leaching reaction is stirred at a certain temperature for a period of time. After the reaction is complete, liquid-solid separation is performed. After liquid-solid separation, the leached residue is washed with hot water for 3 to 5 times. The leached residue obtained is a tungstate solid phase, and the leaching liquid is a cobalt salt solution.

[0035] Furthermore, in an embodiment of the present invention, the oxidizing gas introduced into the autoclave is selected from at least one of oxygen and air, and the partial pressure of the oxidizing gas is controlled to be 0.1-2.0 MPa. The inventors have found that the greater the partial pressure of the oxidizing gas, the stronger the oxidizing ability, which can significantly improve the reaction effect of various tungsten-containing phases in the roasting material being converted into tungstic acid; if the amount of the oxidizing gas is less, the time for oxygen pressure acid leaching of the roasting material needs to be extended.

[0036] Furthermore, in an embodiment of the present invention, the solid-liquid mixture is stirred for leaching, and the leaching reaction is carried out under the conditions of a reaction temperature of 100-200°C and a holding time of 1-8 hours. The inventors have found that increasing the reaction temperature can not only promote the oxygen pressure acid leaching reaction, but also promote the conversion of colloidal tungstic acid into crystalline tungstic acid precipitation and greatly improve the filtration performance of the leached slurry. However, a higher reaction temperature places more stringent requirements on the equipment operation of the autoclave.

[0037] Furthermore, in an embodiment of the present invention, the solid-liquid mixture is stirred for leaching at a stirring rate of 100 to 600 rpm. The inventors have found that the above stirring rate can accelerate the leaching reaction effect of the roasted material.

[0038] Furthermore, in the embodiment of the present invention, the technical principle of oxygen pressure acid leaching of waste tungsten grinding material roasting material is: on the one hand, the oxidizing gas with a certain pressure in the autoclave has a higher solubility in the acidic solution and exhibits a stronger oxidizing property, and the tungsten-containing phases such as tungsten carbide and low-valent tungsten oxide in the roasting material are oxidized and acid-leached to be converted into tungstic acid solid phase; on the other hand, the high temperature (greater than 100°C) and superior hydrothermal conditions maintained in the autoclave not only promote the acid dissolution reaction of various tungstates in the roasting material, but also can hydrothermally convert the colloidal tungstic acid in the leached slurry into crystalline tungstic acid precipitation; both promote the separation and recovery of tungsten and soluble components such as cobalt, iron, and copper, and effectively improve the filtration performance of the leached slurry and the yield of tungstic acid.

[0039] Furthermore, the traditional single acid leaching process and atmospheric pressure oxidation acid leaching process are not enough to oxidize tungsten carbide and / or tungsten in the waste tungsten grinding material, and can only achieve the effect of leaching components such as cobalt and iron. However, the method of the present invention can prepare tungstic acid in a short process by subjecting the activated calcined material to oxygen pressure acid leaching treatment on the basis of calcination pretreatment, and realize the separation and recovery of tungsten and soluble components such as cobalt, iron, and copper.

[0040] Furthermore, in the embodiments of the present invention, the liquid-solid separation method is any technology in the prior art that can achieve liquid-solid separation, such as plate and frame filter pressing, filtration, etc., which will not be described in detail here.

[0041] Furthermore, in the embodiments of the present invention, the leaching residue is washed with hot water for 3 to 5 times in order to allow the soluble cobalt salt entrained in the tungstate solid phase to enter the liquid phase through multiple washings, thereby improving the purity of the tungstate solid phase and the recovery rate of tungsten.

[0042] Furthermore, in the embodiments of the present invention, the cobalt salt solution, after being purified and impurities removed by chemical precipitation, can be used to prepare a cobalt oxalate product by precipitating cobalt with ammonium oxalate or the cobalt oxalate can be calcined to produce a cobalt oxide powder product.

[0043] Furthermore, the tungstic acid solid phase described in the above step S3 can be calcined to directly prepare a tungsten oxide product; the tungstic acid solid phase or tungsten oxide can also be dissolved into an ammonium tungstate solution by ammonia water, and then the ammonium paratungstate product can be prepared after evaporation and crystallization; the tungstic acid solid phase or tungsten oxide can also be dissolved into a sodium tungstate solution by alkali leaching, and then the ammonium tungstate solution can be obtained by ion exchange process or extraction process, and the ammonium tungstate solution can be evaporated and crystallized to obtain the ammonium paratungstate product; the tungstic acid solid phase can also be complexed and dissolved by an organic acid to form a tungstic acid complex solution, and the complex solution can be thermally decomposed to prepare high-purity tungstic acid.

[0044] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0045] Example 1 A method for preparing tungstic acid from cemented carbide and cemented carbide waste tungsten grinding material, the steps are as follows: 500g of cemented carbide waste tungsten grinding material containing WO3 85.32wt%, Co 11.02wt%, Fe 1.78wt% and Cu 0.89wt% was weighed and put into a muffle furnace for oxidation roasting at 500℃ for 2h to obtain a roasted material; a sulfuric acid solution with a mass concentration of 120g / L was added to the roasted material and the liquid-solid ratio was controlled to be 10:1, and the solid-liquid mixture was obtained by stirring; the oxygen pressure leaching conditions of the solid-liquid mixture were: oxygen partial pressure 0.8MPa, reaction temperature 150℃, insulation time 3h, stirring rate 400rpm; after leaching, the liquid and solid were separated, and the leached residue was washed with hot water 5 times.

[0046] After analysis and testing: as attached Figure 2 As shown in the figure, the XRD analysis results confirmed that the obtained leaching residue was a spectrum of tungstic acid; the tungsten recovery rate in the waste tungsten grinding material was as high as 96.7%, and the leaching rates of cobalt, iron and copper were 99.2%, 99.9% and 99.8% respectively.

[0047] Example 2 A method for preparing tungstic acid from cemented carbide and cemented carbide waste tungsten grinding material, the steps are as follows: 500g of cemented carbide waste tungsten grinding material containing WO3 91.06wt%, Co 5.32wt%, Fe 2.12wt% and Cu 1.07wt% was weighed and put into a muffle furnace for oxidation roasting at 800℃ for 2h to obtain a roasted material; a sulfuric acid solution with a mass concentration of 160g / L was added to the roasted material and the liquid-solid ratio was controlled to be 8:1, and the solid-liquid mixture was obtained by stirring; the oxygen pressure leaching conditions of the solid-liquid mixture were: air partial pressure 1.2MPa, reaction temperature 170℃, insulation time 2h, stirring rate 500rpm; after leaching, the liquid and solid were separated, and the leached residue was washed 4 times with hot water.

[0048] After analysis and detection: XRD analysis results confirmed that the obtained leaching residue was a spectrum of tungstic acid; the tungsten recovery rate in the waste tungsten grinding material was as high as 97.3%, and the leaching rates of cobalt, iron and copper were 99.5%, 99.9% and 99.8% respectively.

[0049] Example 3 A method for preparing tungstic acid from cemented carbide and cemented carbide waste tungsten grinding material, the steps are as follows: 500g of cemented carbide waste tungsten grinding material containing WO3 74.57wt%, Co 12.35wt%, Fe 4.36wt% and Cu 2.66wt% was weighed and put into a muffle furnace for oxidative roasting at 300℃ for 2h to obtain a roasted material; a sulfuric acid solution with a mass concentration of 180g / L was added to the roasted material and the liquid-solid ratio was controlled to be 5:1, and the solid-liquid mixture was obtained by stirring; the oxygen pressure leaching conditions of the solid-liquid mixture were: oxygen partial pressure 2.0MPa, reaction temperature 200℃, insulation time 1h, stirring rate 400rpm; after leaching, the liquid and solid were separated, and the leached residue was washed 3 times with hot water.

[0050] After analysis and detection: XRD analysis results confirmed that the obtained leaching residue was a spectrum of tungstic acid; the tungsten recovery rate in the waste tungsten grinding material was as high as 98.2%, and the leaching rates of cobalt, iron and copper were 99.3%, 99.8% and 99.7% respectively.

[0051] Example 4 A method for preparing tungstic acid from cemented carbide and cemented carbide waste tungsten grinding material, the steps are as follows: 500g of cemented carbide waste tungsten grinding material containing WO3 85.32wt%, Co 11.02wt%, Fe 1.78wt% and Cu 0.89wt% was weighed and put into a muffle furnace for oxidation roasting at 1000℃ for 1h to obtain a roasted material; a hydrochloric acid solution with a mass concentration of 50g / L was added to the roasted material and the liquid-solid ratio was controlled to be 20:1, and the solid-liquid mixture was obtained by stirring; the oxygen pressure leaching conditions of the solid-liquid mixture were: oxygen partial pressure 0.3MPa, reaction temperature 110℃, insulation time 1h, stirring rate 400rpm; after leaching, the liquid and solid were separated, and the leached residue was washed with hot water 3 times.

[0052] After analysis and detection: XRD analysis results confirmed that the obtained filter residue was the spectrum of tungsten acid; the tungsten recovery rate in the waste tungsten grinding material was as high as 97.3%, and the leaching rates of cobalt, iron and copper were 98.4%, 99.2% and 98.3% respectively.

[0053] Example 5 A method for preparing tungstic acid from cemented carbide and cemented carbide waste tungsten grinding material, the steps are as follows: 500g of cemented carbide waste tungsten grinding material containing WO3 91.06wt%, Co 5.32wt%, Fe 2.12wt% and Cu 1.07wt% was weighed and put into a muffle furnace for oxidative roasting at 100℃ for 6h to obtain a roasted material; a nitric acid solution with a mass concentration of 300g / L was added to the roasted material and the liquid-solid ratio was controlled to be 6:1, and the solid-liquid mixture was obtained by stirring; the oxygen pressure leaching conditions of the solid-liquid mixture were: oxygen partial pressure 0.1MPa, reaction temperature 100℃, insulation time 8h, stirring rate 400rpm; after leaching, the liquid and solid were separated, and the leached residue was washed 4 times with hot water.

[0054] After analysis and detection: XRD analysis results confirmed that the obtained leaching residue was a spectrum of tungstic acid; the tungsten recovery rate in the waste tungsten grinding material was as high as 95.5%, and the leaching rates of cobalt, iron and copper were 99.2%, 99.9% and 99.8% respectively.

[0055] Example 6 A method for preparing tungstic acid from cemented carbide and cemented carbide waste tungsten grinding material, the steps are as follows: 500g of cemented carbide waste tungsten grinding material containing WO3 74.57wt%, Co 12.35wt%, Fe 4.36wt% and Cu 2.66wt% was weighed and put into a muffle furnace for oxidative roasting at 500℃ for 2h to obtain a roasted material; a perchloric acid solution with a mass concentration of 180g / L was added to the roasted material and the liquid-solid ratio was controlled to be 3:1, and the solid-liquid mixture was obtained by stirring; the oxygen pressure leaching conditions of the solid-liquid mixture were: air partial pressure 0.7MPa, reaction temperature 160℃, insulation time 2h, stirring rate 600rpm; after leaching, the liquid and solid were separated, and the leached residue was washed 3 times with hot water.

[0056] After analysis and detection: XRD analysis results confirmed that the obtained filter residue was the spectrum of tungstic acid; the tungsten recovery rate in the waste tungsten grinding material was as high as 98.7%, and the leaching rates of cobalt, iron and copper were 99.3%, 99.9% and 99.7% respectively.

[0057] Comparative Example 1 Other conditions were the same as those in Example 1, except that no oxygen was introduced during the oxygen pressure leaching step of the solid-liquid mixture.

[0058] After analysis and detection, the XRD analysis results show that there are a large number of WC phases and low-valent tungsten oxide phases in the leaching residue, and no tungsten acid phase is present; the leaching rates of cobalt, iron, and copper are 46.5%, 67.1%, and 52.1%, respectively; that is, during the oxygen pressure acid leaching process, if no oxidizing gas is introduced, it is difficult to achieve the oxidative acid leaching conversion effect of tungsten carbide, low-valent tungsten oxide and other tungsten-containing phases, and it is difficult to separate impurities such as cobalt, iron, and copper by deep acid leaching.

[0059] Comparative Example 2 Other conditions are the same as those in Example 2, except that the waste tungsten grinding material is not subjected to calcination pretreatment.

[0060] After analysis and detection, the XRD analysis results show that there are a large number of WC phases in the leached slag, and no tungsten acid phase or tungsten oxide phase is present; the leaching rates of cobalt, iron, and copper are 61.2%, 74.5%, and 68.9%, respectively; that is, the waste tungsten grinding material has not been pre-treated by roasting such as degreasing and high-temperature active modification, so it is difficult to achieve the oxidation conversion of tungsten carbide and the conversion of tungstates such as cobalt, iron, and copper.

[0061] The above embodiments are only used to illustrate and explain the present invention, and should not be interpreted as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope of protection intended by the present invention.

[0062] One or more embodiments of this specification are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of this disclosure.

Claims

1. A method for preparing tungstic acid from cemented carbide waste tungsten grinding material, characterized in that: The method comprises the following steps: S1: pre-treating the waste tungsten grinding material by roasting to obtain a roasted material; S2: mixing the roasted material obtained in S1 with the acidic solution, and stirring to obtain a solid-liquid mixture; S3: placing the solid-liquid mixture obtained in S2 in an autoclave; S3-1: introducing an oxidizing gas into the autoclave to perform a stirring leaching reaction; S3-2: After the reaction is complete, liquid-solid separation is performed; S3-3: After liquid-solid separation, wash the leaching residue with hot water for 3 to 5 times. The obtained leaching residue is tungstic acid solid phase, and the leaching liquid is cobalt salt solution.

2. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 1, characterized in that: The waste tungsten grinding material in step S1 comes from the powdered waste tungsten grinding material generated in the production process of cemented carbide; Waste tungsten grinding materials include: Tungsten oxide, 30%~95%; Cobalt mass, 2%~20%; Iron mass, 0.5% to 5%; Copper mass, 0.2% to 4%; Other impurity elements.

3. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 1, characterized in that: The roasting pretreatment described in the above step S1 adopts aerobic roasting, which is roasting by exposing to air or introducing oxygen.

4. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 1, characterized in that: In the calcination pretreatment described in step S1 above, the calcination temperature is 100-1000° C. and the calcination time is 1-6 hours.

5. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 4, characterized in that: The acidic solution in step S2 is one or a mixture of sulfuric acid, hydrochloric acid, nitric acid or perchloric acid, and the mass concentration of the acidic solution is 20-300 g / L.

6. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 5, characterized in that: The amount of the acidic solution added in step S2 is based on the liquid-to-solid ratio of the roasting material, that is, the ratio of liquid volume to solid mass is 3-20:1 mL / g.

7. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 6, characterized in that: The oxidizing gas in step S3 is selected from oxygen or air or a mixture of the two, and the partial pressure of the oxidizing gas is 0.1-2.0 MPa.

8. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 7, characterized in that: The solid-liquid mixture described in step S3 is stirred and leached, and the leaching reaction is carried out under the conditions of a reaction temperature of 100-200° C. and a heat preservation time of 1-8 hours.

9. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 8, characterized in that: The solid-liquid mixture described in step S3 is stirred for leaching at a stirring rate of 100 to 600 rpm.

10. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 9, characterized in that: The cobalt salt solution described in step S3 above, after being purified and impurities removed by chemical precipitation, can be used to precipitate cobalt with ammonium oxalate to prepare a cobalt oxalate product, or the cobalt oxalate can be calcined to produce a cobalt oxide powder product.

11. The method for preparing tungstic acid from cemented carbide waste tungsten grinding material according to claim 10, characterized in that: The tungstic acid solid phase described in the above step S3 can be calcined to directly prepare a tungsten oxide product; the tungstic acid solid phase or tungsten oxide can also be dissolved into an ammonium tungstate solution by ammonia water, and then the ammonium paratungstate product can be prepared after evaporation and crystallization; the tungstic acid solid phase or tungsten oxide can also be dissolved into a sodium tungstate solution by alkali leaching, and then the ammonium tungstate solution can be obtained by ion exchange process or extraction process, and the ammonium tungstate solution can be evaporated and crystallized to obtain the ammonium paratungstate product; Organic acid can also be used to dissolve tungstic acid in solid phase complex to form a tungstic acid complex solution, and the complex solution can be thermally decomposed to prepare high-purity tungstic acid.

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