Method for reducing tungsten trioxide content in ammonium paratungstate

Abstract

The invention relates to a method for reducing the content of tungsten trioxide in ammonium paratungstate, and belongs to the technical field of tungsten smelting, the method comprises the following steps: washing WO3 impurity-containing APT (ammonium paratungstate) with pure liquid, WO3 being insoluble in the pure liquid, APT being slightly soluble in the pure liquid, the pH value of the pure liquid being 6.5-7.5, the washing temperature being 40-50 DEG C, the washing time being 20-30 min, the liquid-solid ratio being 3: 1-5: 1, and the washing frequency being 1-3 times. According to the method, the content of tungsten trioxide in ammonium paratungstate is reduced by washing APT containing WO3 impurities, pure liquid such as pure water is adopted for washing, additional chemical reagents are not introduced, impurity ion pollution is avoided, it is guaranteed that the purity of the APT product meets the requirement, and the method is suitable for industrial production. Precise parameter values of washing parameters such as the pure liquid pH value, the washing temperature, the washing time, the liquid-solid ratio and the washing frequency are obtained through a single factor + orthogonal optimization experiment, precise control over the washing process is achieved, multi-factor cooperative regulation and control are achieved, the WO3 elution rate and the tungsten loss rate are balanced, and the process reliability is high.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of tungsten smelting, in particular to a method for reducing the content of tungsten trioxide in ammonium paratungstate. BACKGROUND

[0002] Ammonium paratungstate (APT) is a core product in the tungsten industry, and its quality and output directly affect the market competitiveness and profit level of enterprises. In the current industry, the WO3 content of APT products of some enterprises is higher than the average level of the industry, which meets the requirement of the national standard "not less than 88.5%", but the excessively high WO3 content will lead to a decrease in the physical quantity of the product and cause a loss of profit. At the same time, the fluctuation of the WO3 content is easy to cause an increase in the frequency of production adjustment and reduce the process stability of the production line.

[0003] The preparation of ammonium paratungstate from sodium tungstate solution in the tungsten metallurgy process mainly experiences two steps, i.e., the preparation of pure ammonium tungstate solution and the crystallization of ammonium paratungstate. The existing methods for reducing the WO3 content in APT mostly rely on the adjustment of crystallization parameters, which is easy to introduce impurity ions and affect the purity of the product, and only optimizes a single factor, so it is difficult to achieve the balance between "efficient reduction of WO3" and "low loss of tungsten". In addition, the process connection is complex, the modification is difficult, and the method cannot be applied to the existing production line efficiently, which leads to insufficient process economy and practicability. SUMMARY

[0004] In order to solve the problems existing in the current method for reducing the WO3 content in APT, the application provides a method for reducing the content of tungsten trioxide in ammonium paratungstate.

[0005] In one aspect of the present disclosure, a method for reducing the content of tungsten trioxide in ammonium paratungstate is provided, which comprises: washing APT containing WO3 impurities with a pure liquid, wherein WO3 is insoluble in the pure liquid, APT is slightly soluble in the pure liquid, the pH value of the pure liquid is 6.5-7.5, the washing temperature is 40-50 DEG C, the washing time is 20-30 min, the liquid-solid ratio is 3:1-5:1, and the washing frequency is 1-3 times.

[0006] Preferably, the pH value of the pure liquid is 7.0, the washing temperature is 45 DEG C, the liquid-solid ratio is 4:1, the washing time is 25 min, and the washing frequency is 2 times.

[0007] Preferably, the pH value of the pure liquid is 7.1, the washing temperature is 46 DEG C, the liquid-solid ratio is 4.1:1, the washing time is 24 min, and the washing frequency is 2 times.

[0008] Preferably, the pH value, the washing temperature, the liquid-solid ratio, the washing time and the washing frequency of the pure liquid are obtained by the following method: The APT containing WO3 impurities is washed by the pure liquid in a single-factor experiment, and the WO3 elution rate and tungsten loss rate of each group of experiments are detected after the washing is completed, and the experimental parameters include the pH value of the pure liquid, the washing temperature, the liquid-solid ratio, the washing time and the washing frequency; Based on the detection results, the experimental parameters are optimized under the conditions of WO3 elution rate ≥80% and tungsten loss rate ≤1%, and the optimized experimental parameter range is obtained; The optimal experimental parameters are obtained from the optimized experimental parameter range.

[0009] Preferably, the optimal experimental parameters obtained from the optimized experimental parameter range include: Based on the optimized experimental parameter range, the APT containing WO3 impurities is washed by the pure liquid in an orthogonal experiment, and the WO3 elution rate and tungsten loss rate of each group of experiments are detected after the washing is completed; Based on the detection results, the optimal experimental parameters are obtained.

[0010] Preferably, the experimental parameters involved in the orthogonal experiment are the pH value of the pure liquid, the washing temperature and the liquid-solid ratio.

[0011] Preferably, the optimal experimental parameters obtained from the optimized experimental parameter range further include: Based on the obtained optimal experimental parameters, the APT containing WO3 impurities is washed by the pure liquid for multiple times, and the WO3 elution rate and tungsten loss rate of each time are detected after the washing is completed.

[0012] Preferably, the WO3 elution rate is 88.8%-89.0%, and the tungsten loss rate is ≤0.8%.

[0013] Preferably, it further includes drying the washed APT.

[0014] Preferably, the pure liquid is pure water.

[0015] Beneficial technical effects: 1. The application reduces the content of tungsten trioxide in ammonium paratungstate by washing the APT containing WO3 impurities, which uses a pure liquid such as pure water and does not introduce additional chemical reagents, thereby avoiding impurity ion pollution and ensuring that the purity of the APT product meets the requirements; 2. The WO3 content of the washed APT product is stably reduced to 88.8%-89.0%, and according to the calculation of 20,000 tons of APT production per year, the annual sales revenue is more than 1.08 million yuan, the single-ton processing cost is reduced by 5-8 yuan, the annual cost is saved by 10-16 million yuan, and the efficiency and cost optimization are obvious: 3. The washing process is simple to operate, can be directly connected to the existing production line, has simple process connection, is easy to modify the production line, reduces the production adjustment frequency, is easy to adapt to the existing production line, has strong adaptability, and has good process economy and practicability: 4. The washing parameters such as pH value of pure liquid, washing temperature, washing time, liquid-solid ratio, and washing frequency are obtained through "single factor + orthogonal optimization" experiments to achieve precise control of the washing process and multi-factor synergistic regulation, balancing WO3 elution rate and tungsten loss rate, resulting in high process reliability. Detailed Implementation

[0016] In one aspect of this disclosure, a method for reducing the tungsten trioxide content in ammonium paratungstate (APT) is provided, comprising: washing APT containing WO3 impurities with a pure liquid, wherein WO3 is insoluble in the pure liquid, APT is slightly soluble in the pure liquid, the pH value of the pure liquid is 6.5-7.5, the washing temperature is 40-50°C, the washing time is 20-30 min, the liquid-solid ratio is 3:1-5:1, and the washing frequency is 1-3 times.

[0017] APT containing WO3 impurities is washed with pure liquid without introducing additional chemical reagents, avoiding contamination by impurity ions, and ensuring that the purity of the APT product meets the requirements.

[0018] Preferably, the pure liquid is pure water, which is low in cost.

[0019] The design of WO3 being insoluble in pure liquid and APT being slightly soluble in pure liquid allows WO3 impurities on the surface of APT to be washed away by rinsing it with pure liquid. In addition, APT is heavier than WO3, so APT sinks directly to the bottom when it enters pure liquid, while WO3 remains suspended. Thus, by gently stirring the pure liquid containing APT, the WO3 that was not washed away can be separated from APT, improving the washing effect.

[0020] In addition, the slight solubility of APT in pure liquids allows a small amount of dissolved APT to form a "lubricating film" on the surface of undissolved APT. This film helps to remove WO3 particles. Moreover, during the washing process, some defective and fragile small APT crystals are dissolved and then recrystallized on the large APT crystals, making the surface of the large APT crystals smoother and stronger, which reduces the chance of WO3 being trapped and further improves the washing effect.

[0021] The specific values ​​and ranges of washing parameters such as pH value of pure liquid, washing temperature, washing time, liquid-solid ratio, and washing frequency are all obtained through precise parameter values ​​obtained by "single factor + orthogonal optimization" experiments. This enables precise control of the washing process, effectively achieving multi-factor synergistic regulation, balancing WO3 elution rate and tungsten loss rate, and ensuring high process reliability.

[0022] Moreover, the washing process is simple to operate, can be directly connected to existing production lines, has simple process integration, is easy to modify production lines, reduces the frequency of production adjustments, is easy to adapt to existing production lines, has strong adaptability, and has good process economy and practicality.

[0023] The WO3 content of the washed APT product also stabilized at 88.8%-89.0%, resolving the issue that fluctuations in content could lead to increased production adjustments and reduced process stability on the production line. Furthermore, based on an annual production capacity of 20,000 tons of APT, this would increase annual sales revenue by over 1.08 million yuan, reduce the processing cost per ton by 5-8 yuan, and save 100,000-160,000 yuan annually, demonstrating significant efficiency and cost optimization.

[0024] Preferably, the pure liquid has a pH of 7.0, the washing temperature is 45℃, the liquid-to-solid ratio is 4:1, the washing time is 25 minutes, and the washing frequency is 2 times. Alternatively, the pure liquid has a pH of 7.1, the washing temperature is 46℃, the liquid-to-solid ratio is 4.1:1, the washing time is 24 minutes, and the washing frequency is 2 times.

[0025] Using the above-mentioned optimized washing parameters achieves optimal synergistic control of multiple factors, resulting in the best balance between WO3 elution rate and tungsten loss rate.

[0026] In this embodiment of the disclosure, the pH value, washing temperature, liquid-to-solid ratio, washing time, and washing frequency of the pure liquid are obtained by the following methods: S1. Wash APT containing WO3 impurities with pure liquid in a single-factor experiment. After washing, the WO3 elution rate and tungsten loss rate of each group of experiments are detected. The experimental parameters include the pH value of the pure liquid, washing temperature, liquid-solid ratio, washing time and washing frequency. S2. Based on the detection results, the experimental parameters were optimized under the conditions of WO3 elution rate ≥80% and tungsten loss rate ≤1%, and the optimized experimental parameter range was obtained. S3. Obtain the optimal experimental parameters from the optimized range of experimental parameters.

[0027] Specifically, in S1, a single-factor experiment means that there is only one variable in each group of experiments. For example, if 5 groups of experiments are set up, each group of experiments corresponds to a changing experimental parameter. In this way, it is possible to know which experimental parameters have a greater impact on the washing effect.

[0028] Then S2 determines the optimal range of experimental parameter combinations by optimizing experimental parameters, such as through orthogonal optimization.

[0029] Finally, further experiments were conducted to obtain the optimal experimental parameters. This allows for precise control of the washing process, effectively achieving synergistic regulation of multiple factors, balancing the WO3 elution rate and tungsten loss rate, and ensuring high process reliability.

[0030] In this embodiment of the disclosure, S3, obtaining the optimal experimental parameters from the optimized range of experimental parameters, includes: S31. Based on the optimized experimental parameter range, APT containing WO3 impurities was washed with pure liquid in an orthogonal experimental manner, and the WO3 elution rate and tungsten loss rate of each group of experiments were detected after washing. S32. Based on the detection results, obtain the optimal experimental parameters.

[0031] Preferably, the experimental parameters that are changed in the orthogonal experiment are the pH value of the pure liquid, the washing temperature, and the liquid-to-solid ratio. This design can reduce the amount of experimentation and quickly identify the experimental parameters that affect the washing effect.

[0032] Furthermore, S3, the step of obtaining the optimal experimental parameters from the optimized range of experimental parameters, also includes: S33. Based on the obtained optimal experimental parameters, APT containing WO3 impurities was washed multiple times with pure liquid, and the WO3 elution rate and tungsten loss rate were measured after each washing. This design, through multiple batches of repeated experiments, monitors the stability of WO3 content and the fluctuation of tungsten loss rate, forming an operating procedure that can be directly applied to workshop production. Under this operating procedure, the WO3 elution rate is 88.8%-89.0%, and the tungsten loss rate is ≤0.8%.

[0033] In addition, after obtaining the optimal experimental parameters based on the test results, S32 needs to simultaneously adjust the connection details between the washing process and the existing APT crystallization process.

[0034] In this embodiment, the APT containing WO3 impurities is washed with pure liquid and then dried.

[0035] The method for reducing the tungsten trioxide content in ammonium paratungstate in this embodiment achieves a stable reduction in WO3 content and tungsten loss while ensuring the purity of APT by washing away APT containing WO3 impurities. This method is compatible with existing production lines and, compared with traditional methods, can reduce modification and operating costs and improve process economy and stability.

[0036] The following two specific embodiments will be used to describe in detail a method for reducing the tungsten trioxide content in ammonium paratungstate according to this application. Example 1

[0037] A method for reducing the tungsten trioxide content in ammonium paratungstate, comprising the following steps: 1. Preparation for single-factor experiments: APT samples with WO3 content of 89.2% from the crystallization workshop were selected and divided into 5 groups, each with 100g. The pH value of the washing water (6.5, 7.0, 7.5), washing temperature (40℃, 45℃, 50℃), washing time (20min, 25min, 30min), liquid-solid ratio (3:1, 4:1, 5:1), and washing frequency (1 time, 2 times, 3 times) were controlled as single variables, and the other parameters were fixed as intermediate values. 2. Single-factor data collection: After each group of experiments, the WO3 content and tungsten loss rate in APT were measured, the data were recorded, and the parameter ranges with WO3 elution rate ≥80% and tungsten loss rate ≤1% were selected. The ranges were: pH 6.8-7.2, temperature 42-48℃, liquid-solid ratio 3.5:1-4.5:1, time 22-28min, and frequency 2 times. 3. Orthogonal optimization experiment: With pH, ​​temperature, and liquid-to-solid ratio as the core factors, three levels were set for each (pH: 6.8, 7.0, 7.2; temperature: 42℃, 45℃, 48℃; liquid-to-solid ratio: 3.5:1, 4:1, 4.5:1). An L9(3³) orthogonal experiment was conducted to determine the optimal combination as pH 7.0, temperature 45℃, liquid-to-solid ratio 4:1, time 25min, and frequency 2. 4. Process verification and integration: Ten batches of repeated experiments were conducted with optimal parameters to monitor the WO3 content to be stable at 88.8%-89.0% and the tungsten loss rate ≤0.8%; the integration of the washing process and the crystallization process was adjusted, and the conveying speed and drying temperature parameters of APT after washing were clarified to form an operating procedure. Example 2

[0038] A method for reducing the tungsten trioxide content in ammonium paratungstate, comprising the following steps: 1. Preparation for single-factor experiments: APT samples with WO3 content of 89.3% were selected, 150g per group, and divided into 5 groups to control single variables: pH value of washing water (6.5, 7.0, 7.5), temperature (40℃, 45℃, 50℃), time (20min, 25min, 30min), liquid-solid ratio (3:1, 4:1, 5:1), and frequency (1 time, 2 times, 3 times). 2. Single-factor data collection: After detection, the parameter ranges with WO3 elution rate ≥80% and tungsten loss rate ≤1% were selected, and the ranges were: pH 6.9-7.3, temperature 43-47℃, liquid-solid ratio 3.8:1-4.2:1, time 23-27min, and frequency 2 times; 3. Orthogonal optimization experiment: With pH, ​​temperature and liquid-solid ratio as the core factors, three levels were set up. The optimal combination was determined by L9(3³) orthogonal experiment as pH 7.1, temperature 46℃, liquid-solid ratio 4.1:1, time 24min, and frequency 2 times. 4. Process verification and integration: 15 batches of repeated experiments showed that the WO3 content was stable at 88.9%-89.0% and the tungsten loss rate was ≤0.9%; the connection rhythm between washing and crystallization processes was optimized, key points for equipment operation and maintenance were formulated, and operating procedures applicable to the workshop were formed.

[0039] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for reducing the tungsten trioxide content in ammonium paratungstate, characterized in that, include: Wash APT containing WO3 impurities with a pure liquid, wherein WO3 is insoluble in the pure liquid and APT is slightly soluble in the pure liquid, the pH value of the pure liquid is 6.5-7.5, the washing temperature is 40-50℃, the washing time is 20-30 min, the liquid-solid ratio is 3:1-5:1, and the washing frequency is 1-3 times.

2. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 1, characterized in that: The pure liquid has a pH of 7.0, the washing temperature is 45℃, the liquid-to-solid ratio is 4:1, the washing time is 25 minutes, and the washing frequency is 2 times.

3. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 1, characterized in that: The pure liquid has a pH of 7.1, the washing temperature is 46℃, the liquid-to-solid ratio is 4.1:1, the washing time is 24 minutes, and the washing frequency is 2 times.

4. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 2 or 3, characterized in that: The pH value, washing temperature, liquid-to-solid ratio, washing time, and washing frequency of the pure liquid were obtained using the following methods: APT containing WO3 impurities was washed with pure liquid in a single-factor experiment. After washing, the WO3 elution rate and tungsten loss rate of each group of experiments were measured. The experimental parameters included the pH value of the pure liquid, washing temperature, liquid-solid ratio, washing time and washing frequency. Based on the test results, the experimental parameters were optimized under the conditions of WO3 elution rate ≥80% and tungsten loss rate ≤1%, and the optimized experimental parameter range was obtained. Obtain the optimal experimental parameters from the optimized range of experimental parameters.

5. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 4, characterized in that: Obtaining the optimal experimental parameters from the optimized range of experimental parameters includes: Based on the optimized range of experimental parameters, APT containing WO3 impurities was washed with pure liquid in an orthogonal experimental manner, and the WO3 elution rate and tungsten loss rate of each group of experiments were detected after washing. Based on the test results, the optimal experimental parameters are obtained.

6. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 5, characterized in that: The experimental parameters that were changed in the orthogonal experiment were the pH value of the pure liquid, the washing temperature, and the liquid-to-solid ratio.

7. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 5, characterized in that: The process of obtaining the optimal experimental parameters from the optimized range of experimental parameters also includes: Based on the obtained optimal experimental parameters, APT containing WO3 impurities was washed multiple times with pure liquid, and the WO3 elution rate and tungsten loss rate were measured after each washing.

8. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 7, characterized in that: The WO3 elution rate was 88.8%-89.0%, and the tungsten loss rate was ≤0.8%.

9. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 1, characterized in that: This also includes APT after drying and washing.

10. The method for reducing the tungsten trioxide content in ammonium paratungstate according to claim 1, characterized in that: The pure liquid is pure water.