Method for improving the leaching rate of cemented carbide grinding stock after oxidation

Abstract

The application discloses a method for improving the leaching rate of oxidized hard alloy grinding material, and comprises the following steps: S1, detecting the impurity content of the broken oxidized hard alloy grinding material, adding an activator and removing iron to obtain pretreated material; S2, gradient temperature roasting the pretreated material, and then water quenching and grinding to obtain a roasting product; S3, adding a leaching agent to the roasting product and adjusting the pH value, and then gradient aeration, microwave and ultrasonic synergistic leaching treatment, and solid-liquid separation to obtain a leaching liquid; through the activation agent, the leaching agent and the multi-field coupling synergy, the tungsten leaching rate is improved to more than 99.5%, and the impurity removal rate is more than 98%, so that the tungsten leaching problem of high-impurity grinding material is solved, and the difficulty of subsequent tungsten purification is reduced.

Description

Technical Field

[0001] This invention relates to the field of high-value recycling technology for cemented carbide waste, and in particular to a method for improving the leaching rate of oxidized cemented carbide grinding materials. Background Technology

[0002] As an important secondary source of tungsten resources, cemented carbide scrap has significant recycling value.

[0003] However, existing tungsten leaching processes suffer from multiple technical bottlenecks. In traditional alkaline leaching, Fe and Mn readily co-precipitate with tungsten hydroxides when dealing with high-impurity abrasive materials, resulting in a tungsten leaching rate of only 88%-92%. Although leaching can be enhanced by adding phosphates, the introduction of phosphorus leads to the formation of tungsten phosphate precipitate during subsequent tungsten purification, increasing separation costs. Furthermore, the oxidation-roasting combined with water leaching process requires high-temperature pretreatment above 700℃, resulting in high energy consumption and costs. Moreover, the leaching process largely relies on a single temperature field, leading to long reaction cycles, low production efficiency, high actual costs, and wastewater containing high concentrations of impurity ions after leaching.

[0004] Therefore, there is a need to provide a technical solution that is cost-effective and efficient, and has a high leaching rate of oxidized cemented carbide abrasive. Summary of the Invention

[0005] In view of this, this application provides a method for improving the leaching rate of oxidized cemented carbide abrasive, which solves the problem of how to improve the leaching rate of oxidized cemented carbide abrasive.

[0006] To achieve the above technical objectives, this application adopts the following technical solution: In a first aspect, this application provides a method for improving the leaching rate of oxidized cemented carbide abrasive, comprising the following steps: S1. Detect the impurity content of the crushed and oxidized cemented carbide grinding material, add an activator and remove iron to obtain pretreated material; S2. The pretreated material is subjected to gradient heating and calcination, followed by water quenching and grinding to obtain the calcined product; S3. Add a leaching agent to the calcined product and adjust the pH value. After gradient aeration, perform microwave and ultrasonic synergistic leaching treatment. After solid-liquid separation, obtain the leachate.

[0007] Preferably, in step S1, based on 100wt% of oxidized cemented carbide grinding material; when the impurity Fe2O3+MnO2 < 3wt%, the activator is 5wt%-8wt% sodium carbonate; when 3wt% ≤ impurity Fe2O3+MnO2 ≤ 6wt%, the activator is 5wt%-10wt% sodium carbonate and 2wt%-3wt% calcium oxide; when the impurity Fe2O3+MnO2 > 6wt%, the activator is 8wt%-15wt% sodium carbonate, 3wt%-5wt% calcium oxide and 1wt%-2wt% sodium fluoride.

[0008] Preferably, in step S2, the gradient heating calcination process is as follows: heating to 300°C at 5°C / min, and then heating to 400-600°C at 3°C / min.

[0009] Preferably, in step S2, when the impurity WO3 > 65 wt%, the temperature is increased to 400-450 ℃ at 3 ℃ / min; when the impurity WO3 ≤ 65 wt%, the temperature is increased to 500-600 ℃ at 3 ℃ / min.

[0010] Preferably, in step S3, the leaching agent includes 0.5-2 mol / L sodium hydroxide, 0.1-0.3 mol / L sodium persulfate, 0.05-0.2 mol / L sodium citrate, and a targeted additive; the targeted additive is sodium aluminate or sodium sulfate.

[0011] Preferably, when the SiO2 content in the calcined product is greater than 2 wt%, the targeted additive is 0.03-0.08 mol / L sodium aluminate; when the impurity ... 2+ When the concentration is >1wt%, the targeted additive is sodium sulfate at a concentration of 0.02-0.05 mol / L.

[0012] Preferably, in step S3, the pH value is 12-14.

[0013] Preferably, the gradient aeration step is as follows: first, air is introduced at a rate of 1-3 L / min, and then pure oxygen is introduced at a rate of 0.5-1 L / min.

[0014] Preferably, ultrasound is applied during the microwave radiation interval.

[0015] Preferably, the microwave parameters are as follows: when the tungsten concentration in the system is <50g / L, 2450MHz microwave radiation is applied for 6 minutes every 25 minutes, with a power of 700-800W; when the tungsten concentration in the system is ≤50g / L and ≤80g / L, 2450MHz microwave radiation is applied for 5 minutes every 30 minutes, with a power of 600-700W; when the tungsten concentration in the system is >80g / L, 2450MHz microwave radiation is applied for 4 minutes every 35 minutes, with a power of 500-600W; the ultrasonic parameters are as follows: frequency 20-30kHz, power 300-500W.

[0016] The beneficial effects of this application are as follows: This application improves the tungsten leaching rate to over 99.5% and the impurity removal rate to over 98% through the synergistic effect of activator, leaching agent and multi-field coupling, solving the problem of tungsten leaching of high impurity grinding materials and reducing the difficulty of subsequent tungsten purification; This application uses sodium persulfate, which, combined with additives, can be recycled, thus reducing costs. The leaching system of this application contains no strong acids or highly toxic reagents, the pH value of the wastewater is stable at 10-11, and the impurity concentration is low. It can meet the discharge standards after simple neutralization, and the amount of solid waste generated is reduced by 60%. This application allows for dynamic adjustment of process parameters based on the impurity content of the grinding material, adapting to different types of oxidized cemented carbide grinding materials with Fe, Mn, and Si contents, without requiring equipment replacement and exhibiting strong process adaptability. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] This application provides a method for improving the leaching rate of oxidized cemented carbide abrasives, comprising the following steps: S1. Detect the impurity content of the crushed and oxidized cemented carbide grinding material, add an activator and remove iron to obtain pretreated material; S2. The pretreated material is subjected to gradient heating and calcination, followed by water quenching and grinding to obtain the calcined product; S3. Add a leaching agent to the calcined product and adjust the pH value. After gradient aeration, perform microwave and ultrasonic synergistic leaching treatment. After solid-liquid separation, obtain the leachate.

[0019] This application improves the tungsten leaching rate to over 99.5% and the impurity removal rate to over 98% through the synergistic effect of activators, leaching agents and multi-field coupling, solving the problem of tungsten leaching from high-impurity grinding materials and reducing the difficulty of subsequent tungsten purification.

[0020] In some embodiments, in step S1, based on 100wt% of oxidized cemented carbide grinding material; when the impurity Fe2O3+MnO2 < 3wt%, the activator is 5wt%-8wt% sodium carbonate; when 3wt% ≤ impurity Fe2O3+MnO2 ≤ 6wt%, the activator is 5wt%-10wt% sodium carbonate and 2wt%-3wt% calcium oxide; when the impurity Fe2O3+MnO2 > 6wt%, the activator is 8wt%-15wt% sodium carbonate, 3wt%-5wt% calcium oxide and 1wt%-2wt% sodium fluoride.

[0021] In this embodiment, a jaw crusher is used to crush the oxidized cemented carbide grinding material to 10-50 mm. The contents of WO3, Fe2O3, MnO2, and SiO2 in the material are quickly detected by X-ray fluorescence spectrometry (XRF). The activator ratio is dynamically adjusted according to the impurity content. Among them, calcium oxide can fix Si to form calcium silicate precipitate, and sodium fluoride promotes the conversion of Fe and Mn into soluble fluorides. After crushing, the material is subjected to magnetic separation to remove iron (magnetic field strength 12000 Gs) to remove free iron impurities and avoid the formation of iron-tungsten compounds in subsequent roasting.

[0022] In some embodiments, in step S2, the gradient heating calcination process is as follows: heating to 300°C at 5°C / min, and then heating to 400-600°C at 3°C / min.

[0023] In this embodiment, the temperature is increased to 300℃ at 5℃ / min and held for 1 hour to remove adsorbed water and organic impurities from the material; then the temperature is increased to 400-600℃ at 3℃ / min and held for 1-3 hours, with the final temperature depending on the WO3 content.

[0024] In some embodiments, in step S2, when the impurity WO3 > 65 wt%, the temperature is increased to 400-450 ℃ at 3 ℃ / min; when the impurity WO3 ≤ 65 wt%, the temperature is increased to 500-600 ℃ at 3 ℃ / min.

[0025] In this embodiment, the conversion of tungsten into soluble sodium tungstate (Na2WO4) is precisely controlled by programmed temperature rise, while the excessive oxidation of impurity ions is suppressed.

[0026] After calcination, the material is quenched in stages: first, the calcined material is pre-cooled in hot water at 80-90℃ for 30 seconds, and then transferred to a room temperature water quenching tank to avoid excessive temperature difference that could cause the material to clump; after water quenching, it is ground to 200-300 mesh using a planetary ball mill. During the grinding process, 0.5% polyethylene glycol (PEG-4000) is added to prevent fine powder from agglomerating.

[0027] In some embodiments, in step S3, the leaching agent includes 0.5-2 mol / L sodium hydroxide, 0.1-0.3 mol / L sodium persulfate, 0.05-0.2 mol / L sodium citrate, and a targeted additive; the targeted additive is sodium aluminate or sodium sulfate.

[0028] In this embodiment, after analyzing the composition of the roasted product, the composition of the leaching agent is dynamically adjusted using an automatic solution preparation system; the main solution includes 0.5-2 mol / L sodium hydroxide and 0.1-0.3 mol / L sodium persulfate, wherein the concentration of sodium persulfate is determined according to the Fe... 2+ Content adjustment (Fe) 2+ For every 1% increase, the sodium persulfate concentration increases by 0.05 mol / L; sodium citrate is used as a basic additive to complex Fe and Mn ions.

[0029] In some embodiments, when the SiO2 content in the calcined product is greater than 2 wt%, the targeted additive is 0.03-0.08 mol / L sodium aluminate; when the impurity content in the calcined product is greater than 2 wt%, the targeted additive is 0.03-0.08 mol / L sodium aluminate; 2+ When the concentration is >1wt%, the targeted additive is sodium sulfate at a concentration of 0.02-0.05 mol / L.

[0030] In this embodiment, sodium aluminate is used to generate sodium aluminosilicate precipitate to avoid co-precipitation of silicon and tungsten; sodium sulfate is used to generate calcium sulfate precipitate.

[0031] In some embodiments, the pH value in step S3 is 12-14.

[0032] In this embodiment, sodium hydroxide is automatically added through an online pH monitoring system to stabilize the pH of the leaching system at 12-14, with a fluctuation range of ≤±0.2.

[0033] In some embodiments, the gradient aeration step is as follows: first, air is introduced at a rate of 1-3 L / min, and then pure oxygen is introduced at a rate of 0.5-1 L / min.

[0034] In this embodiment, air is introduced 3 hours before the reaction at a flow rate of 1-3 L / min. During the air introduction process, according to Fe... 2+ Adjust flow rate based on content, Fe 2+ High content results in high flow rate, making Fe 2+ Oxidized to Fe 3+ In the later stage, pure oxygen is introduced at a flow rate of 0.5-1 L / min, and the dissolved oxygen concentration is controlled to be ≥8 mg / L using an online dissolved oxygen monitor (DO) to promote the decomposition of sodium persulfate and generate sulfate free radicals. SO4 - ), to enhance tungsten dissolution.

[0035] In some embodiments, ultrasound is applied during the microwave radiation interval.

[0036] In some embodiments, the parameters of the microwave are as follows: when the tungsten concentration in the system is <50g / L, 2450MHz microwave radiation is applied for 6 minutes every 25 minutes, with a power of 700-800W; when the tungsten concentration in the system is ≤50g / L and ≤80g / L, 2450MHz microwave radiation is applied for 5 minutes every 30 minutes, with a power of 600-700W; when the tungsten concentration in the system is >80g / L, 2450MHz microwave radiation is applied for 4 minutes every 35 minutes, with a power of 500-600W; the parameters of the ultrasonic are as follows: frequency 20-30kHz, power 300-500W.

[0037] In this embodiment, a variable frequency microwave generator is used to adjust the microwave parameters in real time according to the tungsten concentration in the leachate, so as to avoid excessive microwave radiation that could lead to excessively high local temperatures; while the ultrasonic waves destroy the passivation film on the material surface through the cavitation effect, thereby accelerating the penetration of the leachate.

[0038] In this embodiment, the basic reaction parameters for microwave and ultrasonic synergistic leaching treatment are as follows: solid-liquid ratio 1:5-10 g / mL, adjusted according to the particle size of the material; when the particle size is 200 mesh, the solid-liquid ratio is 1:5-1:7, and when the particle size is 300 mesh, the solid-liquid ratio is 1:8-1:10; the leaching temperature is controlled by a jacketed water bath to maintain a leaching temperature of 80-100℃ with a temperature difference ≤±1℃, and the pressure is atmospheric pressure; the stirring speed is 300-500 r / min, using an anchor-type stirring paddle, and the stirring speed is dynamically adjusted according to the solid-liquid ratio; when the solid-liquid ratio is 1:5, the stirring speed is 500 r / min, and when it is 1:10, the stirring speed is 300 r / min.

[0039] In this embodiment, the leaching process also includes in-situ impurity control: In the initial stage of the reaction (0-2h): sodium citrate preferentially reacts with Fe. 3+ Mn 2+ A stable complex is formed with a stability constant logK > 20 to suppress the formation of hydroxide precipitates; Mid-reaction (2-4h): If the system becomes slightly turbid (turbidity > 50 NTU) by monitoring with an online turbidity meter, 0.02-0.05 mol / L of disodium EDTA will be automatically added to further complex residual impurity ions. Later stage of the reaction (4 hours to completion): Add 0.01-0.03 mol / L sodium bicarbonate to adjust the pH of the system to 12.5-13.5, so that excess Ca... 2+ Mg 2+ Carbonate precipitate is generated and removed in real time by a dynamic filtration device with a filter membrane pore size of 0.22μm, thus preventing the adsorption of tungsten ions.

[0040] After leaching, the slurry is pumped to a belt filter at a high temperature of 70-80℃. During the filtration process, the filter cloth is heated by hot air at a temperature of 85-90℃ to prevent sodium tungstate crystals from clogging the filter pores. The filter residue is washed in stages: first, it is washed twice with a 0.1 mol / L dilute sodium hydroxide solution at 80-85℃, and then washed once with hot water at 80℃. The washing liquid and filtrate are combined, and the filter residue is discharged after testing and the tungsten content is <0.5%.

[0041] The following specific embodiments further illustrate this solution.

[0042] Example 1 A method for improving the leaching rate of oxidized cemented carbide abrasives includes the following steps: S1. 1000g of oxidized cemented carbide grinding material was crushed to 20mm using a jaw crusher. The contents of WO3, Fe2O3, MnO2, and SiO2 in the material were quickly detected by X-ray fluorescence spectrometry (XRF). The results showed that the material contained 62% WO3, 4.5% Fe2O3, 1.2% MnO2, and 2.3% SiO2. 80g of sodium carbonate, 30g of calcium oxide, and 15g of sodium fluoride were added to the oxidized cemented carbide grinding material as activators. The material was then subjected to magnetic separation (magnetic field strength 12000Gs) to remove 0.8g of free iron impurities, resulting in a pretreated material. S2. The pretreated material is subjected to gradient heating and calcination. The temperature is increased to 300℃ at 5℃ / min and held for 1 hour, and then increased to 550℃ at 3℃ / min and held for 2 hours. After calcination, the calcined material is pre-cooled in 80℃ hot water for 30 seconds, and then transferred to a room temperature water quenching tank. After water quenching, it is ground to 200 mesh by a planetary ball mill. During the grinding process, 0.5% polyethylene glycol is added to obtain the calcined product. S3. A leaching agent is added to the calcined product. The leaching agent comprises a mixed aqueous solution of 1.8 mol / L NaOH, 0.25 mol / L sodium persulfate, 0.15 mol / L sodium citrate, and 0.05 mol / L sodium aluminate. Sodium hydroxide is automatically added via an online pH monitoring system to stabilize the pH of the leaching system at 13.8. The system is subjected to gradient aeration under the following conditions: a solid-liquid ratio of 1:8 g / mL (leaching agent 10 L), a leaching temperature of 95℃, a pressure of atmospheric pressure, and a stirring speed of 450 r / min. Microwave and ultrasonic synergistic leaching treatment is then performed. The gradient aeration steps are as follows: air is introduced 3 hours before the leaching reaction at a flow rate of 2.5 L / min, followed by air introduction for the next 2 hours. Pure oxygen was introduced at a flow rate of 0.9 L / min, and the dissolved oxygen concentration was controlled to be ≥8 mg / L using an online dissolved oxygen (DO) monitor. During the microwave radiation intervals, ultrasound was applied. When the tungsten concentration in the leaching system was <50 g / L, microwaves were applied at a power of 750 W for 25 min / session, with each treatment lasting 6 min. The ultrasonic frequency was 25 kHz and the ultrasonic power was 300 W. When the tungsten concentration in the leaching system was 50-80 g / L, microwaves were applied at a power of 650 W for 30 min / session, with each treatment lasting 5 min. The ultrasonic frequency was 25 kHz and the ultrasonic power was 400 W. After obtaining the preliminary leachate, it was filtered at 75°C, and the filter residue was washed three times. The filtrates were combined to obtain the final leachate. In this embodiment, the tungsten leaching rate was 99.7%, the WO3 concentration in the filtrate was 85.6 g / L, and the concentrations of Fe, Mn, and Si impurities were 0.08 g / L, 0.03 g / L, and 0.05 g / L, respectively.

[0043] Example 2 A method for improving the leaching rate of oxidized cemented carbide abrasives includes the following steps: S1. 1000g of oxidized cemented carbide grinding material was crushed to 20mm using a jaw crusher. The contents of WO3, Fe2O3, MnO2, and SiO2 in the material were quickly detected by X-ray fluorescence spectrometry (XRF). The results showed that the material contained 68% WO3, 1.2% Fe2O3, 0.5% MnO2, and 0.8% SiO2. 60g of sodium carbonate was added to the oxidized cemented carbide grinding material as an activator. The material was then subjected to magnetic separation (magnetic field strength 12000Gs) to remove 0.3g of free iron impurities, resulting in a pretreated material. S2. The pretreated material is subjected to gradient heating and calcination. The temperature is increased to 300℃ at 5℃ / min and held for 1 hour, and then increased to 450℃ at 3℃ / min and held for 1.5 hours. After calcination, the calcined material is pre-cooled in 80℃ hot water for 30 seconds, and then transferred to a room temperature water quenching tank. After water quenching, it is ground to 200 mesh by a planetary ball mill. During the grinding process, 0.5% polyethylene glycol is added to obtain the calcined product. S3. A leaching agent is added to the calcined product. The leaching agent comprises a mixed aqueous solution of 1.2 mol / L NaOH, 0.15 mol / L sodium persulfate, and 0.08 mol / L sodium citrate. Sodium hydroxide is automatically added via an online pH monitoring system to stabilize the pH of the leaching system at 13.2. The system is subjected to gradient aeration under the following conditions: a solid-liquid ratio of 1:7 g / mL (leaching agent 10 L), a leaching temperature of 90℃, a pressure of atmospheric pressure, and a stirring speed of 400 r / min. Microwave and ultrasonic synergistic leaching treatment is then performed. The gradient aeration steps are as follows: air is introduced 3 hours before the leaching reaction at a flow rate of 1.8 L / min, followed by pure oxygen for the next 1.5 hours. The flow rate was 0.7 L / min, and the dissolved oxygen concentration was controlled to be ≥8 mg / L using an online dissolved oxygen monitor (DO). During the microwave radiation intervals, ultrasound was applied. When the tungsten concentration in the leaching system was <50 g / L, microwave was applied at 700 W for 25 min / session, with each treatment lasting 6 min. When the tungsten concentration in the leaching system was 50-80 g / L, microwave was applied at 600 W for 30 min / session, with each treatment lasting 5 min. When the tungsten concentration in the leaching system was >80 g / L, microwave was applied at 550 W for 35 min / session, with each treatment lasting 4 min. After obtaining the preliminary leachate, it was filtered at 72°C, and the filter residue was washed twice. The filtrates were combined to obtain the final leachate. In this embodiment, the tungsten leaching rate was 99.9%, the WO3 concentration in the filtrate was 92.3 g / L, and the concentrations of Fe, Mn, and Si impurities were 0.02 g / L, 0.01 g / L, and 0.03 g / L, respectively.

[0044] Comparative Example 1 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that the microwave power is 600W throughout the process; the leaching solution has a tungsten leaching rate of 97.2%, a WO3 concentration of 89.5g / L in the filtrate, and impurity concentrations of Fe, Mn, and Si of 0.08g / L, 0.04g / L, and 0.06g / L, respectively.

[0045] Comparative Example 2 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that the ultrasonic process is omitted; in the resulting leachate, the tungsten leaching rate is 96.5%, the WO3 concentration in the filtrate is 88.8 g / L, and the concentrations of Fe, Mn, and Si impurities are 0.10 g / L, 0.05 g / L, and 0.07 g / L, respectively.

[0046] Comparative Example 3 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that the final calcination temperature is 700°C; the leaching solution obtained has a tungsten leaching rate of 98.1%, a WO3 concentration of 90.2 g / L in the filtrate, and impurity concentrations of Fe, Mn, and Si of 0.06 g / L, 0.03 g / L, and 0.05 g / L, respectively.

[0047] Comparative Example 4 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that the pH value is 11; the leaching solution has a tungsten leaching rate of 95.8%, a WO3 concentration of 87.9 g / L in the filtrate, and impurity concentrations of Fe, Mn, and Si of 0.15 g / L, 0.08 g / L, and 0.09 g / L, respectively.

[0048] Comparative Example 5 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that only air with a flow rate of 1.8 L / min is introduced throughout the process, and pure oxygen is not introduced. In the resulting leachate, the tungsten leaching rate is 97.5%, the WO3 concentration in the filtrate is 89.8 g / L, and the concentrations of Fe, Mn, and Si impurities are 0.09 g / L, 0.04 g / L, and 0.06 g / L, respectively.

[0049] Comparative Example 6 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that the leaching agent does not contain sodium persulfate; in the resulting leaching solution, the tungsten leaching rate is 90.3%, the WO3 concentration in the filtrate is 83.1 g / L, and the concentrations of Fe, Mn, and Si impurities are 0.52 g / L, 0.31 g / L, and 0.04 g / L, respectively.

[0050] Comparative Example 7 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that the leaching agent does not contain sodium citrate, while the other components remain unchanged. In the resulting leaching solution, the tungsten leaching rate is 93.7%, the WO3 concentration in the filtrate is 86.4 g / L, and the concentrations of Fe, Mn, and Si impurities are 0.28 g / L, 0.16 g / L, and 0.05 g / L, respectively.

[0051] Comparative Example 8 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that 0.05 mol / L sodium aluminate is added to the leaching agent; in the resulting leaching solution, the tungsten leaching rate is 99.8%, the WO3 concentration in the filtrate is 92.1 g / L, and the concentrations of Fe, Mn, and Si impurities are 0.02 g / L, 0.01 g / L, and 0.03 g / L, respectively.

[0052] Comparative Example 9 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that the concentration of sodium hydroxide in the leaching agent is adjusted to 0.3 mol / L; in the resulting leaching solution, the tungsten leaching rate is 94.5%, the WO3 concentration in the filtrate is 87.2 g / L, and the concentrations of Fe, Mn, and Si impurities are 0.18 g / L, 0.09 g / L, and 0.08 g / L, respectively.

[0053] Comparative Example 10 A method for improving the leaching rate of oxidized cemented carbide abrasive is the same as in Example 2, except that 0.15 mol / L phosphate is used to replace sodium persulfate in the leaching agent, while the other components remain unchanged. In the resulting leaching solution, the tungsten leaching rate is 92.8%, the WO3 concentration in the filtrate is 85.3 g / L, and the concentrations of Fe, Mn, and Si impurities are 0.22 g / L, 0.13 g / L, and 0.07 g / L, respectively.

[0054] This application improves the tungsten leaching rate to over 99.5% and the impurity removal rate to over 98% through the synergistic effect of activators, leaching agents and multi-field coupling, solving the problem of tungsten leaching from high-impurity grinding materials and reducing the difficulty of subsequent tungsten purification.

[0055] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving the leaching rate of oxidized cemented carbide abrasives, characterized in that, Includes the following steps: S1. Detect the impurity content of the crushed and oxidized cemented carbide grinding material, add an activator and remove iron to obtain pretreated material; S2. The pretreated material is subjected to gradient heating and calcination, followed by water quenching and grinding to obtain the calcined product; S3. Add a leaching agent to the calcined product and adjust the pH value. After gradient aeration, perform microwave and ultrasonic synergistic leaching treatment. After solid-liquid separation, obtain the leachate.

2. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 1, characterized in that, In step S1, based on 100wt% of oxidized cemented carbide grinding material; when the impurity Fe2O3+MnO2 < 3wt%, the activator is 5wt%-8wt% sodium carbonate; when 3wt% ≤ impurity Fe2O3+MnO2 ≤ 6wt%, the activator is 5wt%-10wt% sodium carbonate and 2wt%-3wt% calcium oxide; when the impurity Fe2O3+MnO2 > 6wt%, the activator is 8wt%-15wt% sodium carbonate, 3wt%-5wt% calcium oxide and 1wt%-2wt% sodium fluoride.

3. The method for improving the leaching rate of oxidized cemented carbide grinding materials according to claim 1, characterized in that, In step S2, the gradient heating calcination process is as follows: the temperature is increased to 300°C at a rate of 5°C / min, and then increased to 400-600°C at a rate of 3°C / min.

4. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 3, characterized in that, In step S2, when the impurity WO3 > 65 wt%, the temperature is increased to 400-450 ℃ at 3 ℃ / min; when the impurity WO3 ≤ 65 wt%, the temperature is increased to 500-600 ℃ at 3 ℃ / min.

5. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 1, characterized in that, In step S3, the leaching agent includes 0.5-2 mol / L sodium hydroxide, 0.1-0.3 mol / L sodium persulfate, 0.05-0.2 mol / L sodium citrate, and targeted additives; the targeted additives are sodium aluminate or sodium sulfate.

6. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 5, characterized in that, When the SiO2 content in the calcined product is greater than 2 wt%, the appropriate additive is 0.03-0.08 mol / L sodium aluminate; when the impurity content in the calcined product is higher than 2 wt%, the appropriate additive is 0.03-0.08 mol / L sodium aluminate. 2+ When the concentration is >1wt%, the targeted additive is sodium sulfate at a concentration of 0.02-0.05 mol / L.

7. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 1, characterized in that, In step S3, the pH value is 12-14.

8. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 1, characterized in that, The gradient aeration steps are as follows: first, air is introduced at a rate of 1-3 L / min, and then pure oxygen is introduced at a rate of 0.5-1 L / min.

9. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 1, characterized in that, Ultrasonic waves are applied during the microwave radiation intervals.

10. The method for improving the leaching rate of oxidized cemented carbide abrasives according to claim 1, characterized in that, The microwave parameters are as follows: when the tungsten concentration in the system is <50g / L, 2450MHz microwave radiation is applied for 6 minutes every 25 minutes, with a power of 700-800W; when the tungsten concentration in the system is ≤50g / L and ≤80g / L, 2450MHz microwave radiation is applied for 5 minutes every 30 minutes, with a power of 600-700W; when the tungsten concentration in the system is >80g / L, 2450MHz microwave radiation is applied for 4 minutes every 35 minutes, with a power of 500-600W. The ultrasonic parameters are as follows: frequency 20-30kHz, power 300-500W.