Method for controlling particle size and morphology of potassium fluoride

Abstract

The application discloses a kind of potassium fluoride particle size and morphology control method, belong to potassium fluoride production technical field, including preparation potassium fluoride raw material solution, control solution concentration and viscosity to set interval, keep uniform stable state by continuous stirring;Using single factor test combined with orthogonal test mode, control four process parameters of feed flow, spray disc rotating speed, drying tower import temperature, drying tower export temperature of spray drying process, establish the quantitative corresponding model of process parameter and potassium fluoride particle size, morphology;According to the particle size and morphology specification of target product, the corresponding process parameter combination is matched to carry out potassium fluoride product production;The particle size and morphology of the potassium fluoride product prepared are detected, and the batch consistency of continuous production is verified.The application controls the particle size and morphology of potassium fluoride production by the corresponding relationship of four process parameters and potassium fluoride particle size, morphology, so that the potassium fluoride product adapts to the use demand of particle size and morphology.

Description

Technical Field

[0001] This invention belongs to the field of potassium fluoride production technology and relates to a method for controlling the particle size and morphology of potassium fluoride. Background Technology

[0002] Potassium fluoride (KF) is a core inorganic fluoride raw material for the synthesis of pharmaceutical and pesticide intermediates. It can also be used as a flux for various metals or alloys, in glass engraving, food preservation, and in industries such as pharmaceuticals, pesticides, dyes, and electroplating. KF also has wide applications in chemical synthesis, such as as a fluorinating agent or catalyst in organic synthesis. The particle size and morphology of potassium fluoride directly affect the efficiency, yield, and process stability of downstream reactions. Currently, domestic potassium fluoride production mainly relies on traditional spray drying processes. Existing publicly available potassium fluoride preparation methods mostly focus on component purification and process optimization, with the core objective of improving product purity. However, they lack control over product characteristics, exhibiting wide particle size distributions and random morphologies, making customized production impossible and difficult to adapt to the personalized needs of different reaction systems in high-end pharmaceutical and pesticide intermediates. Summary of the Invention

[0003] To address the above problems, this invention proposes a method for controlling the particle size and morphology of potassium fluoride, which effectively solves the problems in the prior art.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for controlling the particle size and morphology of potassium fluoride includes:

[0006] S1. Prepare a potassium fluoride raw material solution, adjust the solution concentration and viscosity to the set range, and continuously stir to keep the solution in a uniform and stable state.

[0007] S2. Using a combination of single-factor experiments and orthogonal experiments, four process parameters of the spray drying process—feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature—were controlled. Based on the experimental data, a quantitative correspondence model between the process parameters and the particle size and morphology of potassium fluoride was established, and a comparison table of process parameters for different product specifications was created.

[0008] S3. Based on the particle size and morphology specifications of the target product, match the corresponding combination of process parameters to produce potassium fluoride products;

[0009] S4. The particle size and morphology of the prepared potassium fluoride product are tested to verify the batch consistency of continuous production.

[0010] Optionally, S2 includes:

[0011] S21. Determine the baseline intermediate values ​​of the four parameters: feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature. Following the principle of single variable, fix the other three parameters as the baseline values ​​each time and set multiple uniform gradient values ​​for the variable parameters for the experiment.

[0012] S22. Perform three parallel trials for each gradient level and take the arithmetic mean of the test results.

[0013] S23. Use a laser particle size analyzer to detect the particle size and particle size distribution of the product, and use a scanning electron microscope to observe typical morphology and perform quantitative evaluation.

[0014] S24. Clarify the influence of each parameter on particle size and morphology, and select three characteristic levels (low, medium, and high) for each parameter that have a wide adjustable range of particle size and good morphology stability, and arrange orthogonal experiments.

[0015] S25. Perform range analysis and variance analysis on the orthogonal experiment results, establish a particle size quantification regression model and a morphology quantification mapping model, and control the model prediction error to ≤5%;

[0016] S26. Match the optimal process parameters corresponding to the target product through a quantitative model, and establish a process parameter comparison table for different product specifications.

[0017] Optionally, the batch consistency of continuous production is ≥98% between batches produced over a continuous 72-hour period.

[0018] Optionally, it also includes S27, when the particle size and morphology of potassium fluoride deviate from the target specifications during the production process, at least one process parameter is adjusted according to the changing trend in the particle size quantification regression model and the morphology quantification mapping model.

[0019] Optionally, S27 further includes setting an allowable deviation threshold for potassium fluoride particle size and morphology and establishing a priority for process parameter adjustment.

[0020] Optionally, the concentration of the potassium fluoride solution is 30-40 wt%, and the viscosity is 15-30 mPa·s.

[0021] Optionally, the inlet temperature range of the drying tower is 530-570℃, and the outlet temperature range of the drying tower is 150-180℃.

[0022] Optionally, the potassium fluoride product includes small-particle-size potassium fluoride with D90≤20μm, large-particle-size potassium fluoride with 20μm<D90≤35μm, and spherical potassium fluoride with sphericity ≥90%.

[0023] Optionally, when preparing small particle size products with D90≤20μm, a centrifugal spray disc with shear toothed rings is used; when preparing large particle size products with 20μm<D90≤35μm, a smooth disc surface centrifugal spray disc is used.

[0024] Optionally, a dispersant is added to the potassium fluoride raw material solution.

[0025] Compared with the prior art, the present invention has the following beneficial effects: by controlling the particle size and morphology of potassium fluoride production through the correspondence between four process parameters, namely feed flow rate, spray disc rotation speed, drying tower inlet temperature, and drying tower outlet temperature, and potassium fluoride particle size and morphology, the potassium fluoride product can be adapted to the application requirements of particle size and morphology. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention discloses a method for controlling the particle size and morphology of potassium fluoride, comprising:

[0028] S1. Prepare a potassium fluoride raw material solution, adjust the solution concentration and viscosity to the set range, and continuously stir to keep the solution in a uniform and stable state.

[0029] S2. Using a combination of single-factor experiments and orthogonal experiments, four process parameters of the spray drying process—feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature—were controlled. Based on the experimental data, a quantitative correspondence model between the process parameters and the particle size and morphology of potassium fluoride was established, and a comparison table of process parameters for different product specifications was created.

[0030] S3. Based on the particle size and morphology specifications of the target product, match the corresponding combination of process parameters to produce potassium fluoride products;

[0031] S4. The particle size and morphology of the prepared potassium fluoride product are tested to verify the batch consistency of continuous production.

[0032] Specifically, the concentration and viscosity of the potassium fluoride raw material solution are adjusted, and the solution is kept uniform and stable by stirring to ensure consistent particle size and morphology during production. The correlation between four process parameters—feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature—and potassium fluoride particle size and morphology is established through single-factor experiments combined with orthogonal experiments. Based on the particle size and morphology required for the target product, the corresponding process parameters are adjusted to control the particle size and morphology of potassium fluoride.

[0033] In this way, by controlling the particle size and morphology of potassium fluoride through the correspondence between four process parameters—feed flow rate, spray disc rotation speed, drying tower inlet temperature, and drying tower outlet temperature—and potassium fluoride particle size and morphology, the particle size and morphology of potassium fluoride production can be adapted to the application requirements of potassium fluoride products with suitable particle size and morphology.

[0034] In some feasible methods, the concentration of potassium fluoride raw material solution is 30-40 wt%, the viscosity is 15-30 mPa·s, and the particle size and morphology of potassium fluoride include small-particle potassium fluoride with D90≤20μm, large-particle potassium fluoride with 20μm<D90≤35μm, spherical potassium fluoride with sphericity ≥90%, and irregular-shaped potassium fluoride customized according to customer needs. Parameters such as feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature are set according to the specifications of the production equipment. In this embodiment, the drying tower inlet temperature is limited to 530-570℃, and the drying tower outlet temperature is limited to 150-180℃ to reduce the range of variable variation and reduce the difficulty of implementing single-factor experiments and orthogonal experiments.

[0035] In this process, the particle size and morphology of potassium fluoride products are measured using a laser particle size analyzer and a scanning electron microscope, respectively. In routine production testing, morphology can also be measured using more convenient and lower-cost optical equipment such as magnifying glasses or microscopes. D90 represents the particle diameter corresponding to 90% of the cumulative particle size distribution as measured by the laser particle size analyzer.

[0036] As a specific embodiment of the method for controlling the particle size and morphology of potassium fluoride provided in the application, S2 includes:

[0037] S21. Determine the baseline intermediate values ​​of the four parameters: feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature. Following the principle of single variable, fix the other three parameters as the baseline values ​​each time and set multiple uniform gradient values ​​for the variable parameters for the experiment.

[0038] S22. Perform three parallel trials for each gradient level and take the arithmetic mean of the test results.

[0039] S23. Use a laser particle size analyzer to detect the particle size and particle size distribution of the product, and use a scanning electron microscope to observe typical morphology and perform quantitative evaluation.

[0040] S24. Clarify the influence of each parameter on particle size and morphology, and select three characteristic levels (low, medium, and high) for each parameter that have a wide adjustable range of particle size and good morphology stability, and arrange orthogonal experiments.

[0041] S25. Perform range analysis and variance analysis on the orthogonal experiment results, establish a particle size quantification regression model and a morphology quantification mapping model, and control the model prediction error to ≤5%;

[0042] S26. Match the optimal process parameters corresponding to the target product through a quantitative model, and establish a process parameter comparison table for different product specifications.

[0043] It should be understood that by setting up single-factor experiments combined with orthogonal experiments to establish particle size quantification regression models and morphology quantification mapping models, and by selecting optimal process parameters for different product specifications and establishing a process parameter comparison table, it is convenient to adjust process parameters in actual production.

[0044] Specifically, in the single-factor experiment, based on actual production equipment and experience, the feed flow rate, spray disc rotation speed, drying tower inlet temperature, and drying tower outlet temperature were selected as four factors. Each parameter is selected from its adjustable range, and the midpoint of the range is selected as the base. A uniform gradient value is set. For example, if the inlet temperature of the drying tower is 530-570℃, 550℃ is selected as the base, and 530℃, 540℃, 550℃, 560℃, and 570℃ are set as gradient values. The other three parameter values ​​are fixed to the midpoint of the parameter. Tests are conducted one by one according to the gradient value of the inlet temperature of the drying tower.

[0045] Particle size and morphology were measured using a laser particle size analyzer and scanning electron microscope, and the data were recorded and analyzed. The core particle size indicator was: This refers to the upper limit of the particle size of 90% of the volume particles. The morphology quantification index can be obtained by weighted scoring. Specifically, multiple standards are set for morphology evaluation, such as sphericity, density, and dispersibility. The weights are set according to the shape required. In this embodiment, a 10-point system is used, with sphericity accounting for 5 points, density for 3 points, and dispersibility for 2 points, to score the test results.

[0046] Based on the results of single-factor experiments, the range of particle size with wide adjustable range and controllable morphology stability was selected as the range for orthogonal experiments within the four process parameter intervals. Within this range, three characteristic levels (low, medium, and high) were selected. Forming four factors and three levels An orthogonal array is used to conduct 9 sets of experiments. To ensure accuracy, each set can be repeated 9 times or more in parallel. The terms "low," "medium," and "high" refer to the magnitude of the parameter values. For example, if the feed flow rate range is 60-90 L / h, the low, medium, and high values ​​can be set to 60, 75, and 90, respectively.

[0047] Nine groups were obtained after orthogonal experiment. The mean and the mean of the morphology score were compared, and a range analysis was performed:

[0048] Range analyze:

[0049] ;

[0050] in, for Factors in The mean value at a horizontal level, such as when the feed flow rate is at a low level, i.e., 60 L / h, is obtained in three sets. Mean or average morphological score Three groups The average of the mean or the mean of the appearance score. The larger the particle size, the stronger its influence on particle size or morphology. Based on Mean-range analysis selects the optimal combination for small particle size and the optimal combination for large particle size, i.e., taking the optimal combination for each factor. The process parameters corresponding to the minimum and maximum values ​​are combined. The optimal combination for high sphericity is selected based on the mean and range analysis of the morphology scores.

[0051] Analysis of variance (ANOVA) is performed on the data to quantitatively determine significance. In ANOVA, the total sum of squares characterizes the overall volatility of all experimental data. This is broken down into individual factor sums of squares and error sums of squares. The individual factor sums of squares correspond to systematic index fluctuations caused by changes in factor levels, while the error sums of squares correspond to random fluctuations caused by accidental factors such as random operations and equipment drift. The total degrees of freedom, individual factor degrees of freedom, and error degrees of freedom are then used to represent the independent information contained in the total fluctuation, factor fluctuation, and error fluctuation, respectively, eliminating incomparability caused by differences in data dimensionality and number of levels. Dividing each sum of squares by its corresponding degrees of freedom yields standardized factor mean squares and error mean squares, making fluctuations from different sources comparable at the same scale. Finally, the F-test statistic combined with the F-distribution critical value is used to quantitatively determine whether the influence of the corresponding factor on the experimental index is statistically significant. Specifically, this includes:

[0052] Total Sum of Squares :

[0053] ;

[0054] in, , which is the sum of all test indicators. For the first Group 1 trial Second parallel measured value In this embodiment, the total number of orthogonal experiments is [number]. It is 9. In this embodiment, the number of parallel repetitions for each group of experiments is [number]. The test indicators are 3 in total, comprising 27 test indicators.

[0055] Single-factor sum of squares :

[0056] ;

[0057] in, As factors of The sum of the mean values ​​of all parallel experiments at the same level. In this embodiment, the number of test groups for each level of a single factor is [number]. It is 3;

[0058] Total degrees of freedom:

[0059] ;

[0060] Single-factor degrees of freedom:

[0061] ;

[0062] in, In this embodiment, the number of feature levels is... It is 3. , , , The corresponding factors represent four elements;

[0063] Sum of squared errors The sum of squared errors reflects the fluctuation of the indicator caused by random factors such as random operation and equipment fluctuations.

[0064] ;

[0065] in, For the first The mean of the parallel trials,

[0066] Error degrees of freedom:

[0067] ;

[0068] factor Mean square:

[0069] ;

[0070] Mean square error:

[0071] ;

[0072] F-test statistic:

[0073] ;

[0074] Based on the F-value and the critical value of the F-distribution The comparison is used to determine significance, among which The critical value of the F-distribution is obtained from the F-distribution table, taking a value of 0.05 or 0.01.

[0075] like If so, then the effect of this factor is highly significant;

[0076] like If so, then the effect of this factor is significant;

[0077] like If the effect of this factor is not significant, then the effect of this factor is not significant.

[0078] Based on orthogonal experimental data, a particle size quantification regression model was established using the least squares method, including:

[0079] ;

[0080] ;

[0081] ;

[0082] in, for The predicted value, For the regression constant term, for , , , The regression coefficients of the four factors , , , There are four factors, namely the values ​​of four process parameters. The coefficient of determination measures how well the model fits the experimental data. These are measured values. The arithmetic mean of all experimentally measured values. For the first Model predictions for the group of experiments. This represents the model prediction error, used to verify the model's prediction accuracy. The measured values ​​are used for independent verification experiments. In this embodiment, the model prediction error is ≤5%.

[0083] Based on orthogonal experimental data, a morphology quantification mapping model is established:

[0084] ;

[0085] in, To predict morphological quantitative scores, For the regression constant term, for , , , The regression coefficients of the four factors , , , There are four factors, namely the values ​​of four process parameters.

[0086] Based on the aforementioned prediction model, process parameters are adjusted to obtain the corresponding process parameters for each product specification. After actual verification, a process parameter comparison table is generated, and parameters are adjusted during production based on this table. During production, the batch consistency of continuous production is ≥98% between batches over a continuous 72-hour production period.

[0087] Furthermore, it also includes S27, where, during the production process, when the particle size and morphology of potassium fluoride deviate from the target specifications, at least one process parameter is adjusted based on the changing trends in the particle size quantification regression model and the morphology quantification mapping model. To facilitate adjustment, allowable deviation thresholds for potassium fluoride particle size and morphology are set, and a priority for process parameter adjustment is established.

[0088] It should be understood that in actual production, changes in the production environment and other conditions may cause changes in the particle size and morphology of the product. When the deviation exceeds the threshold, adjustments are made by adjusting the priority of the set process parameters in an attempt to make the particle size and morphology conform to the standard.

[0089] Specifically, this can be based on the range mentioned above. analyze, The larger the particle size, the stronger its influence on particle size or morphology, according to the range. Prioritize adjustments from largest to smallest, focusing on process parameters that strongly influence particle size or morphology. Alternatively, adjustments can be based on the speed of response to parameter changes; for example, if the spray disc speed responds fastest to changes, prioritize adjusting the spray disc speed to reduce the defect rate. The allowable deviation threshold can be set according to actual production requirements; in this embodiment, it can be set to [value missing]. A deviation of ±3% from the target value results in a decrease in morphology score exceeding 1 point. Taking particle size adjustment as an example, parameter adjustments include:

[0090] ;

[0091] in, For the expected adjustment amount, This represents the deviation value of the actual particle size target product. The regression coefficients corresponding to the factors to be adjusted. If there is still a deviation after adjusting one factor to its maximum or minimum value, the remaining part is adjusted through the next lower priority factor.

[0092] As another specific embodiment of the method for controlling the particle size and morphology of potassium fluoride provided in the application, preparation For products with a particle size ≤20μm, a centrifugal spray disc with a shear toothed ring is used to prepare products with a particle size <20μm. For products with large particle sizes ≤35μm, a smooth-surface centrifugal spray disc is used. By changing the spray disc and adjusting the process parameters, it is easier to better control the particle size and morphology of potassium fluoride.

[0093] As another specific embodiment of the method for controlling the particle size and morphology of potassium fluoride provided in the application, a dispersant is added to the potassium fluoride raw material solution. The dispersant helps maintain a uniform and stable state during stirring.

[0094] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the particle size and morphology of potassium fluoride, characterized in that, include: S1. Prepare a potassium fluoride raw material solution, adjust the solution concentration and viscosity to the set range, and continuously stir to keep the solution in a uniform and stable state. S2. Using a combination of single-factor experiments and orthogonal experiments, four process parameters of the spray drying process—feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature—were controlled. Based on the experimental data, a quantitative correspondence model between the process parameters and the particle size and morphology of potassium fluoride was established, and a comparison table of process parameters for different product specifications was created. S3. Based on the particle size and morphology specifications of the target product, match the corresponding combination of process parameters to produce potassium fluoride products; S4. The particle size and morphology of the prepared potassium fluoride product are tested to verify the batch consistency of continuous production.

2. The method for controlling the particle size and morphology of potassium fluoride according to claim 1, characterized in that: S2 includes: S21. Determine the baseline intermediate values ​​of the four parameters: feed flow rate, spray disc speed, drying tower inlet temperature, and drying tower outlet temperature. Following the principle of single variable, fix the other three parameters as the baseline values ​​each time and set multiple uniform gradient values ​​for the variable parameters for the experiment. S22. Perform three parallel trials for each gradient level and take the arithmetic mean of the test results. S23. Use a laser particle size analyzer to detect the particle size and particle size distribution of the product, and use a scanning electron microscope to observe typical morphology and perform quantitative evaluation. S24. Clarify the influence of each parameter on particle size and morphology, and select three characteristic levels (low, medium, and high) for each parameter that have a wide adjustable range of particle size and good morphology stability, and arrange orthogonal experiments. S25. Perform range analysis and variance analysis on the orthogonal experiment results, establish a particle size quantification regression model and a morphology quantification mapping model, and control the model prediction error to ≤5%; S26. Match the optimal process parameters corresponding to the target product through a quantitative model, and establish a process parameter comparison table for different product specifications.

3. The method for controlling the particle size and morphology of potassium fluoride according to claim 2, characterized in that: The batch consistency of continuous production is defined as ≥98% consistency between batches produced over a continuous 72-hour period.

4. The method for controlling the particle size and morphology of potassium fluoride according to claim 3, characterized in that: It also includes S27, when the particle size and morphology of potassium fluoride deviate from the target specifications during the production process, at least one process parameter is adjusted according to the changing trend in the particle size quantification regression model and the morphology quantification mapping model.

5. The method for controlling the particle size and morphology of potassium fluoride according to claim 4, characterized in that: S27 further includes setting the allowable deviation threshold for potassium fluoride particle size and morphology and establishing the priority for process parameter adjustment.

6. A method for controlling the particle size and morphology of potassium fluoride according to any one of claims 1-5, characterized in that: The concentration of the potassium fluoride raw material solution is 30-40 wt%, and the viscosity is 15-30 mPa·s.

7. A method for controlling the particle size and morphology of potassium fluoride according to any one of claims 1-5, characterized in that: The inlet temperature range of the drying tower is 530-570℃, and the outlet temperature range is 150-180℃.

8. A method for controlling the particle size and morphology of potassium fluoride according to any one of claims 1-5, characterized in that: The potassium fluoride products include small-particle-size potassium fluoride with D90≤20μm, large-particle-size potassium fluoride with 20μm<D90≤35μm, and spherical potassium fluoride with sphericity ≥90%.

9. The method for controlling the particle size and morphology of potassium fluoride according to claim 8, characterized in that: When preparing small particle size products with D90≤20μm, a centrifugal spray disc with shear toothed rings is used; when preparing large particle size products with 20μm<D90≤35μm, a centrifugal spray disc with a smooth surface is used.

10. A method for controlling the particle size and morphology of potassium fluoride according to any one of claims 1-5, characterized in that: A dispersant is added to the potassium fluoride raw material solution.