Method for rapidly judging quality of calcium sulfate whisker product

Abstract

The invention provides a method for rapidly judging the quality of a calcium sulfate whisker product, and relates to the technical field of inorganic material quality detection, and the method comprises the following steps: S1, carrying out a filtration experiment on experimental calcium sulfate whisker slurry, and detecting the length-diameter ratio of calcium sulfate whiskers in the experimental calcium sulfate whisker slurry by using an electron microscope, establishing a'filtering time-quality grade 'dynamic database; s2, pouring the calcium sulfate whisker slurry to be detected into a standard filtering device, carrying out a filtering experiment, and recording the filtering time; s3, judging the quality grade of the calcium sulfate whiskers in the slurry based on a'filtering time-quality grade 'dynamic database; wherein the experimental calcium sulfate whisker slurry and the to-be-detected calcium sulfate whisker slurry are taken from the same production line; the amount of the experimental calcium sulfate whisker slurry is the same as that of the to-be-detected calcium sulfate whisker slurry. The method provided by the invention is simple to operate, the detection efficiency is improved, and the time consumption of single-time detection is less than 300s, which is increased by more than 10 times compared with the traditional method.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic material quality detection, in particular to a method for quickly judging the quality of a calcium sulfate whisker product. Background Art

[0002] Traditional calcium sulfate whisker quality testing relies on laboratory methods such as SEM electron microscopy to measure aspect ratios. These methods are primarily suitable for testing small laboratory samples and fail to reflect the real-world conditions of industrial-scale production. The limited sample volume, high frequency, and long testing times (≥60 minutes) significantly slow production efficiency. Furthermore, these methods are subject to expensive testing equipment, complex operation, inability to monitor in real time, and slow feedback. Consequently, rapid sorting of inferior batches of calcium sulfate whiskers is currently difficult to achieve in actual production.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The invention aims to solve the problems that laboratory sample testing is cumbersome, costly and cannot meet testing requirements during large-scale production of calcium sulfate whiskers, and provides a method for quickly judging the quality of calcium sulfate whisker products.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for quickly judging the quality of a calcium sulfate whisker product, comprising the following steps:

[0007] S1: Pour the experimental calcium sulfate whisker slurry into a standard filtration device to perform a filtration experiment, and use an electron microscope to detect the aspect ratio of the calcium sulfate whiskers in the experimental calcium sulfate whisker slurry to establish a "filtration time-quality grade" dynamic database;

[0008] S2: Pour the calcium sulfate whisker slurry to be tested into a standard filtration device, perform a filtration experiment, and record the filtration time;

[0009] S3: determining the quality grade of the calcium sulfate whiskers in the calcium sulfate whisker slurry to be tested based on the "filtration time-quality grade" dynamic database;

[0010] Wherein, the experimental calcium sulfate whisker slurry and the calcium sulfate whisker slurry to be tested are both taken from the same production line;

[0011] The amount of the experimental calcium sulfate whisker slurry is the same as the amount of the calcium sulfate whisker slurry to be tested.

[0012] Furthermore, based on the above technical solution, the "filtering time-quality level" dynamic database includes:

[0013] The filtration time of calcium sulfate whiskers with superior quality is less than 100s;

[0014] The filtration time of qualified calcium sulfate whiskers is 100s-270s;

[0015] Waste calcium sulfate whiskers and / or calcium sulfate crystal particles have a filtration time of >270s.

[0016] Furthermore, based on the above technical solution, the aspect ratio of the superior calcium sulfate whiskers is >60;

[0017] The aspect ratio of qualified calcium sulfate whiskers is 30-60;

[0018] The aspect ratio of the calcium sulfate short whiskers or calcium sulfate crystal particles is less than 30.

[0019] Furthermore, based on the above technical solution, the filtration time is started when the filtrate reaches 0.5 L and stops when the moisture content on the filter cake surface is ≤45%.

[0020] Furthermore, based on the above technical solution, the calcium sulfate whisker slurry to be tested is obtained from a reactor in a production line;

[0021] Alternatively, the calcium sulfate whisker slurry to be tested is prepared by mixing a product from a production line with water;

[0022] Alternatively, the calcium sulfate whisker slurry to be tested is prepared by mixing gypsum raw material with a whisker growth solution;

[0023] The products of the production line include one of the finished calcium sulfate whiskers prepared from metallurgical desulfurization gypsum, the finished calcium sulfate whiskers prepared from power plant gypsum, and the finished calcium sulfate whiskers prepared from rare earth white mud gypsum;

[0024] The gypsum raw material includes one of metallurgical desulfurization gypsum, power plant gypsum, and rare earth white mud gypsum;

[0025] The experimental calcium sulfate whisker slurry is obtained from a reactor of the same production line as the calcium sulfate whisker slurry to be tested.

[0026] Furthermore, based on the above technical solution, the volume of the calcium sulfate whisker slurry to be tested is in an integer ratio to the total discharge volume of the reactor, which is 1:500-1000;

[0027] Alternatively, the mass volume ratio of the product of the production line to water is 1000 g:10-20 L;

[0028] Alternatively, the mass volume ratio of the gypsum raw material to the whisker growth solution is 1000 g:10-20 L;

[0029] The amount of the experimental calcium sulfate whisker slurry and the amount of the calcium sulfate whisker slurry to be tested are both 5-15 L.

[0030] Furthermore, based on the above technical solution, the standard filtration device includes a Buchner funnel, a filter membrane, a conical suction flask and a vacuum filter;

[0031] The filter membrane is laid in the Buchner funnel;

[0032] A rubber sealing ring is provided between the Buchner funnel and the mouth of the conical suction filtration flask;

[0033] A hose is connected between the suction nozzle of the conical suction filtration bottle and the vacuum filter.

[0034] Furthermore, based on the above technical solution, the conical filtration bottle is provided with a 0.5L capacity mark on the bottle body;

[0035] And / or, the capacity of the conical filtration flask is greater than the capacity of the Büchner funnel;

[0036] And / or, the filtration pressure of the vacuum filter is -0.1 to -0.04 MPa.

[0037] Furthermore, based on the above technical solution, the pore size of the filter membrane is 30 μm-60 μm.

[0038] Furthermore, based on the above technical solution, the method for quickly judging the quality of calcium sulfate whiskers products further comprises: performing SEM or XRD detection on the judgment result.

[0039] The present invention provides a method for quickly judging the quality of calcium sulfate whisker products, which has the following beneficial effects:

[0040] 1. Simple operation and improved detection efficiency: a single test takes less than 300 seconds, which is more than 10 times faster than traditional methods;

[0041] 2. Cost advantage: No large-scale instruments are required, and the testing cost is greatly reduced. If the filtrate from the calcium sulfate whisker preparation process is used (the whisker growth agent in the filtrate is somewhat polluting), this method does not cause any new pollution and the filtrate can be returned to the production line for reuse. If the finished whiskers are added with water, the filtered water is pollution-free.

[0042] 3. Process optimization value: Real-time feedback can guide the adjustment of process parameters such as reaction temperature and pH value. A single test can cover the entire production line capacity, reducing the testing frequency to once per batch.

[0043] 4. Anti-interference design: The timing starts when the filtrate reaches 0.5L, avoiding the influence of unstable flow state in the initial filter cake formation stage.

[0044] 5. The present invention has the characteristics of short process, simple operation, low equipment requirements, etc. It is used to detect the quality of calcium sulfate whiskers prepared from industrial by-product gypsum produced in various industries such as steel and thermal power generation. The method has a wide range of uses and can effectively solve the problem that calcium sulfate whisker detection can only rely on expensive instruments such as SEM. The entire detection process is simple, convenient and easy to implement, with good feasibility, and has broad application prospects in the industrial production of calcium sulfate whiskers.

[0045] 6. This invention enables rapid detection based on filtration time, with a single test time of ≤5 minutes. Compared to traditional methods that rely on laboratory methods such as SEM / XRD, which take ≥60 minutes per test, this method is 12 times more efficient. It also requires no complex equipment and can be operated by only one ordinary production line employee, reducing equipment and labor costs and improving production efficiency. The filtrate obtained from filtration can be reused, and the zero-emission design complies with the requirements of the "General Principles for Green Factory Evaluation" (GB / T 36132-2018). This method fills the gap in industrial-grade real-time quality monitoring technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 This is an SEM image of a high-quality calcium sulfate whisker provided in Example 1 of the present invention;

[0048] Figure 2 The SEM images of the waste calcium sulfate short whiskers and calcium sulfate crystal particles provided by the present invention;

[0049] Figure 3 An SEM image of calcium sulfate whiskers in a slurry of calcium sulfate whiskers to be tested in a reactor for preparing calcium sulfate whiskers from power plant gypsum provided in Example 3 of the present invention;

[0050] Figure 4 An SEM image of the calcium sulfate whiskers in the calcium sulfate whisker slurry to be tested in the reaction kettle for preparing calcium sulfate whiskers from rare earth white mud gypsum provided in Example 4 of the present invention;

[0051] Figure 5 This is an SEM image of calcium sulfate whiskers prepared using metallurgical desulfurization gypsum as a raw material and a whisker growth solution at a mass volume ratio of 1000g:20L provided in Example 5 of the present invention;

[0052] Figure 6SEM image of calcium sulfate whiskers prepared using metallurgical desulfurization gypsum as raw material and whisker growth solution at a mass volume ratio of 1000g:10L provided in Example 6 of the present invention;

[0053] Figure 7 A schematic structural diagram of a standard device provided by the present invention;

[0054] Figure 8 The "filtration time-quality level" dynamic database curve provided by the present invention;

[0055] icon:

[0056] 1. Buchner funnel; 2. Filter membrane; 3. Conical filter flask; 4. Vacuum filter; 5. Rubber sealing ring; 6. Vacuum nozzle of conical filter flask; 7. Hose. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The process parameters for which specific conditions are not specified in the following examples are generally in accordance with conventional conditions.

[0058] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0059] According to a first aspect of the present invention, there is provided a method for quickly determining the quality of a calcium sulfate whisker product, comprising the following steps:

[0060] S1: Pour the experimental calcium sulfate whisker slurry into a standard filtration device to perform a filtration experiment, and use an electron microscope to detect the aspect ratio of the calcium sulfate whiskers in the experimental calcium sulfate whisker slurry to establish a "filtration time-quality grade" dynamic database;

[0061] Wherein, in specific calcium sulfate whisker production line, in the early stage, carry out the production experiment of multiple batches of calcium sulfate whiskers by adjusting processing parameter, from this production line reactor, get the calcium sulfate whisker slurries of different batches and carry out filtration experiment as the experiment calcium sulfate whisker slurries, record corresponding filtration time, and detect the aspect ratio of calcium sulfate whisker in the described experiment calcium sulfate whisker slurries with electron microscope, the filtration time of filtrate when obtaining different aspect ratios by experiment, to obtain multiple groups of valid data such as can be 20 groups or more than 20 groups, draw thus and stop experiment after having the obvious aspect ratio-filtration time curve of trend.Then carry out the monitoring of the follow-up calcium sulfate whisker production quality of this production line based on this curve.It should be noted that the aspect ratio-filtration time curve that the production line of different processes obtains cannot be used interchangeably and is that the filtration time-quality grade dynamic database that the production line of different processes obtains is different.The filtration time-quality grade dynamic database that such as hydrothermal process production line obtains with production lines such as acidification process high pressure method is different.

[0062] S2: Pour the calcium sulfate whisker slurry to be tested into a standard filtration device, perform a filtration experiment, and record the filtration time;

[0063] S3: Based on the "filtration time-quality grade" dynamic database, determine the quality grade of the calcium sulfate whiskers in the calcium sulfate whisker slurry to be tested,

[0064] Wherein, the experimental calcium sulfate whisker slurry and the calcium sulfate whisker slurry to be tested are both taken from the same production line;

[0065] The amount of the experimental calcium sulfate whisker slurry is the same as the amount of the calcium sulfate whisker slurry to be tested.

[0066] Specifically, the present invention abandons the traditional complex model that relies on microscopic morphology detection and constructs a rapid quality determination system based on macroscopic fluid dynamics for the first time. By comparing the filtration time of the calcium sulfate whisker slurry to be tested with the filtration time range (preset time threshold) corresponding to calcium sulfate whiskers of various quality grades in a dynamic database, the quality grading of calcium sulfate whiskers is achieved. This subverts the passive detection mode that relies on electron microscopy observation in traditional methods and realizes real-time, low-cost monitoring of calcium sulfate whisker quality in industrial scenarios.

[0067] The invention addresses the problem that there is no simple detection method in the industrial production of calcium sulfate whiskers. The filtration time of water in calcium sulfate whisker slurry is used to characterize the quality of the calcium sulfate whiskers. The detection method has a short process and uses simple equipment, thereby achieving the purpose of quickly and accurately detecting the quality of the calcium sulfate whiskers.

[0068] As an optional embodiment of the present invention, the "filtering time-quality level" dynamic database includes:

[0069] The filtration time of calcium sulfate whiskers of superior quality is less than 100s (such as 95s, 90s, 85s, etc.);

[0070] The filtration time of qualified calcium sulfate whiskers is 100s-270s (such as 110s, 150s, 180s, 200s, 250s, etc.);

[0071] The filtration time of waste calcium sulfate whiskers and / or calcium sulfate crystal particles is greater than 270s (such as 300s, 320s, 350s, etc.).

[0072] Specifically, if Figure 8 As shown in the figure, the present invention takes calcium sulfate whisker slurry from the production line for filtration experiment, records the filtration time, and uses an electron microscope to detect the aspect ratio of the calcium sulfate whiskers in the slurry to obtain a "filtration time-quality grade" dynamic database curve. It can be seen from the curve that when the filtration time is 100s and 270s, there are dynamic characteristic points with relatively obvious changes in the curve. Therefore, 100s and 270s are set as the time thresholds in the present invention. It should be noted that the time thresholds for different production lines should be different, and it is necessary to determine the filtration time-quality grade dynamic database suitable for the production line based on certain preliminary experiments.

[0073] Typically, but not limiting, the production line of the present invention has an annual output of 50,000 tons, the preparation process is a hydrothermal method, and the source of desulfurization gypsum includes any one of steel metallurgical desulfurization gypsum, power plant gypsum or rare earth white mud gypsum. The source of gypsum has no effect on the production process.

[0074] As an optional embodiment of the present invention, the aspect ratio of the calcium sulfate whiskers of high quality is greater than 60 (such as 64, 70, 80, 90, etc.);

[0075] The aspect ratio of qualified calcium sulfate whiskers is 30-60 (such as 40, 45, 50, 55, etc.);

[0076] The aspect ratio of the calcium sulfate short whiskers or calcium sulfate crystal particles is less than 30 (such as 10, 20, 25, etc.).

[0077] Specifically, when calcium sulfate whiskers are used as reinforcements in composite materials, their aspect ratio (the aspect ratio of calcium sulfate whiskers refers to the ratio of their length to their diameter (the width of the whisker cross section, typically 1 μm)) is a core parameter that determines mechanical properties. The interfacial bonding strength between the whiskers and the matrix material is positively correlated with their effective contact area. The inventors found that the higher the aspect ratio, the more obvious the reinforcing effect of the whiskers on the matrix material. In other words, the higher the aspect ratio of the calcium sulfate whiskers, the better the quality of the whiskers.

[0078] Furthermore, the inventors obtained a dynamic database of “filtration time-quality level” through filtering experiments, including:

[0079] When the aspect ratio is greater than 30, the whiskers can form a continuous load transfer path, significantly improving the tensile strength of the composite material; when the aspect ratio is greater than 60, the fibrous calcium sulfate whiskers are intertwined to form a dense three-dimensional porous network with a high porosity, thereby making the interfacial stress distribution more uniform and significantly reducing the fluid (water) resistance. The fluid (water) can pass quickly along the open channels between the whiskers, which is manifested as a short filtration time and can meet the needs of high-end application scenarios; however, when the aspect ratio is less than 30, short calcium sulfate whiskers or calcium sulfate crystal particles are easily accumulated to form a dense layered structure, and the porosity is significantly reduced, such as Figure 2 As shown in Figure 2, the resulting tortuous or even clogged fluid path significantly prolongs filtration time. Further experimental verification (such as comparing SEM observations with filtration time) revealed a negative correlation between filtration time and aspect ratio, making filtration time a direct indicator of whisker quality.

[0080] As an optional embodiment of the present invention, the filtration time refers to that the filtrate starts timing when it reaches 0.5L, until the moisture content on the filter cake surface is less than or equal to 45% (such as 44%, 43%, 40% etc.), at which point the filter cake surface presents relative dryness, is smooth or slightly has fine cracks, and timing is stopped. More preferably, when adopting the same aspect ratio-filtration time curve to determine the quality of different batches of whisker products to be measured, the determination of the filtration termination time point should be substantially identical with the moisture content on the filter cake surface when filtration is terminated when the curve is obtained, such as the moisture content on the filter cake surface when different batches of whisker slurries to be measured are terminated and the moisture content on the filter cake surface when filtration is terminated when the curve is obtained, all should be controlled within a small range, such as the difference between the maximum and minimum values is no more than 5%, and the smaller the difference, the more accurate the whisker quality obtained; more specifically, when obtaining the aspect ratio-filtration time curve, the termination filtration time point of each filtrate or the whisker product to be measured should be controlled within the range of 40-45% moisture content on the filter cake surface.

[0081] Specifically, starting the timing when the filtrate reaches 0.5 L avoids the influence of the unstable flow state in the initial filter cake formation stage.

[0082] Specifically, the present invention uses a portable microwave moisture tester of model TEWS ME 1100 (accuracy ±1%) to test the moisture content of the filter cake surface.

[0083] As an optional embodiment of the present invention, the calcium sulfate whisker slurry to be tested is obtained from a reactor in a production line; typically, but not limitedly, there are 10 reactors in the production line, and 10 portions of the calcium sulfate whisker slurry to be tested are taken from each reactor;

[0084] Alternatively, the calcium sulfate whisker slurry to be tested is prepared by mixing a product from a production line with water;

[0085] Alternatively, the calcium sulfate whisker slurry to be tested is prepared by mixing gypsum raw material with a whisker growth solution; typically, but not limiting, the whisker growth solution is a mixed solution of an existing conventional whisker growth solution and water in a volume ratio of 0.2:1;

[0086] The experimental calcium sulfate whisker slurry is obtained from a reactor of the same production line as the calcium sulfate whisker slurry to be tested.

[0087] As an optional embodiment of the present invention, the products of the production line include finished calcium sulfate whiskers prepared from metallurgical desulfurization gypsum, finished calcium sulfate whiskers prepared from power plant gypsum, or finished calcium sulfate whiskers prepared from rare earth white mud gypsum;

[0088] The gypsum raw materials include metallurgical desulfurization gypsum, power plant gypsum, rare earth white mud gypsum and the like.

[0089] Specifically, the present invention ensures that a single sampling can fully reflect the crystallization uniformity of the entire batch of products through the design of a standardized detection unit, completely solving the core pain point of the disconnection between small-sample laboratory testing and industrial-grade working conditions.

[0090] As an optional embodiment of the present invention, the volume of the calcium sulfate whisker slurry to be tested is in an integer ratio to the total discharge volume of the reactor, which is 1:500-1000 (e.g., 1:600, 1:700, 1:800, 1:900, etc.); typically, but not limitingly, if the total discharge volume of the reactor is 500 L, the volume of the calcium sulfate whisker slurry to be tested taken out is 1 L;

[0091] Typically, but not limited to, the production line has 10 reactors, 1L is sampled from each reactor, and the total amount of samples taken from the 10 reactors is 10L;

[0092] Alternatively, the whisker product and water have a mass-to-volume ratio of 1000 g:10-20 L (e.g., 1000 g:12 L, 1000 g:14 L, 1000 g:16 L, 1000 g:18 L, etc.); typically, but not limitingly, for the whisker product already obtained in the production line, the whisker product and water can be prepared into 10 L of slurry with a mass-to-volume ratio of 1000 g:10 L;

[0093] Alternatively, the mass volume ratio of the gypsum raw material to the whisker growth solution is 1000 g:10-20 L (e.g., 1000 g:12 L, 1000 g:14 L, 1000 g:16 L, 1000 g:18 L, etc.); typically, but not limiting, for the gypsum raw material, the gypsum raw material and the whisker growth solution can be prepared into 10 L of slurry with a mass volume ratio of 1000 g:10 L;

[0094] Specifically, different manufacturers need to determine the amount of calcium sulfate whisker slurry to be tested suitable for each production line based on the output of their own production lines. Different production line outputs or different shapes and capacities of Büchner funnels will result in different filtration times, and the time threshold of each production line will definitely be different. Those skilled in the art can design a unique "filtration time-quality grade" dynamic database suitable for their respective production lines based on the method for quickly judging the quality of calcium sulfate whisker products provided by the present invention.

[0095] The amount of the experimental calcium sulfate whisker slurry and the amount of the calcium sulfate whisker slurry to be tested are both 5-15 L (such as 6 L, 8 L, 10 L, 12 L, etc.);

[0096] Typically, but not limiting, if there are 8 reactors in the production line, the amount of the experimental calcium sulfate whisker slurry and the amount of the calcium sulfate whisker slurry to be tested can be 8 L. Similarly, 12 reactors can be used to take 12 L.

[0097] Specifically, the standard filtration device and the amount of calcium sulfate whisker slurry to be tested obtained in step S2 are completely consistent with the standard filtration device and the amount of experimental calcium sulfate whisker slurry used in the filtration experiment in step S1.

[0098] As an optional embodiment of the present invention, Figure 7 As shown, the standard filtration device includes a Buchner funnel 1, a filter membrane 2, a conical suction flask 3 and a vacuum filter 4;

[0099] The filter membrane 2 is laid in the Buchner funnel 1;

[0100] A rubber sealing ring 5 is provided between the Buchner funnel 1 and the mouth of the conical suction filtration flask 3;

[0101] A hose 7 is connected between the suction nozzle 6 of the conical suction flask and the vacuum filter 4 .

[0102] As an optional embodiment of the present invention, the conical filtration bottle is provided with a 0.5L capacity mark on the bottle body;

[0103] The capacity of the conical filtration flask is greater than that of the Buchner funnel;

[0104] The filtration pressure of the vacuum filter is -0.1 to -0.04 MPa.

[0105] The pore size of the filter membrane is 30 μm-60 μm (such as 40 μm, 45 μm, 50 μm, 55 μm, etc.).

[0106] Specifically, the minimum pore size is set at 30 μm because when the whiskers are waste products with an aspect ratio of less than 30, the filter cake is the primary barrier to water filtration, and the pore size of the filter paper no longer plays a significant role. Therefore, the shortest aspect ratio of qualified whiskers is set at 30 (the typical whisker width is 1 μm, so the length generally needs to be at least 30 μm), resulting in a meaningful minimum pore size of 30 μm for the filter membrane. The maximum pore size of the filter membrane is set at 60 μm to prevent excessive loss of calcium sulfate whiskers.

[0107] As an optional embodiment of the present invention, the method for quickly judging the quality of calcium sulfate whiskers further comprises: performing SEM or XRD detection on the judgment result.

[0108] The present invention will be further described in detail below with reference to specific examples and comparative examples.

[0109] The production lines described in the following embodiments of the present invention are all the same production line, all with an annual output of 50,000 tons, and the preparation process is a hydrothermal calcium sulfate whisker production line. The raw material desulfurization gypsum comes from any one of steel metallurgical desulfurization gypsum, power plant gypsum or rare earth white mud gypsum.

[0110] The specific experiment of the present invention to obtain the "filtration time-quality level" dynamic database is as follows:

[0111] The production line was used to produce 20 batches of products in the early stage. The production process of each batch was exactly the same. A total of 20 groups of experimental calcium sulfate whisker slurries (each group of slurry volume was 10 L) were selected from the production line. Figure 7 The filtration experiment was carried out using the standard filtration device shown in the figure. When the filtration was stopped, the moisture content of the filter cake was in the range of 40-45%. The aspect ratio of the calcium sulfate whiskers in the slurry was 30-120 μm when the electron microscope was used to detect the aspect ratio of the calcium sulfate whiskers in the slurry. Figure 8 The experiment was stopped after the aspect ratio-filtration time curve with an obvious trend was shown;

[0112] The obtained aspect ratio-filtration time curve can be used to judge the quality of the calcium sulfate whisker product to be measured obtained in each embodiment, that is, Figure 8 .

[0113] The capacity of the Buchner funnel of the standard filtration device used in each embodiment is 10 L, the pore size of the filter membrane is 30 μm, and the diameter of the filter membrane is 30 cm.

[0114] Example 1

[0115] (1) The corresponding production line in this embodiment is: annual output of 50,000 tons, the preparation process is hydrothermal method, the desulfurization gypsum is sourced from steel metallurgy desulfurization gypsum, and calcium sulfate whiskers are produced;

[0116] (2) There are ten reactors producing calcium sulfate whiskers in the production line. 1 L of slurry is taken from each reactor, and a total of 10 L of calcium sulfate whisker slurry to be tested is obtained;

[0117] (3) Pour 10L of calcium sulfate whisker slurry to be tested into Figure 7 In the standard filtration apparatus shown (Buchner funnel capacity of 10 L), in which the Buchner funnel is equipped with a filter membrane with a pore size of 30 μm, a vacuum pump is turned on to maintain -0.1 MPa, and a filtration experiment is performed. When the filtrate reaches 0.5 L, the timing is started and the filtration time is recorded. The moisture content of the filter cake surface is tested using a portable microwave moisture meter model TEWS ME 1100 (accuracy ±1%). The measured moisture content of the filter cake surface is 43%, and the timing is stopped. The filtration time is 86 s.

[0118] (4) Based on the dynamic database of "filtration time-quality grade": the calcium sulfate whiskers with a quality grade of superior quality have a filtration time of <100s; it is determined that the quality grade of the calcium sulfate whiskers in the slurry is superior, and the aspect ratio of the calcium sulfate whiskers should be >60;

[0119] (5) SEM test of calcium sulfate whiskers in the filter cake, such as Figure 1 As shown, its aspect ratio is greater than 60, which proves that the determination result obtained in step (4) is accurate and reliable.

[0120] Example 2

[0121] (1) Prepare 10 L of calcium sulfate whisker slurry by mixing the finished calcium sulfate whisker prepared from metallurgical desulfurization gypsum with water at a mass volume ratio of 1000 g:10 L;

[0122] (2) Pour 10L of calcium sulfate whisker slurry to be tested into Figure 7 In the standard filtration apparatus shown (Buchner funnel capacity is 10 L), in which the Buchner funnel is equipped with a filter membrane with a pore size of 30 μm, a vacuum pump is turned on to maintain -0.1 MPa, and a filtration experiment is performed. When the filtrate reaches 0.5 L, the timing is started and the filtration time is recorded. The moisture content of the filter cake surface is tested using a portable microwave moisture meter model TEWS ME 1100 (accuracy ±1%). When the moisture content of the filter cake surface is measured to be 40%, the timing is stopped; the filtration time is 90 s;

[0123] (3) Based on the dynamic database of "filtration time-quality grade": the calcium sulfate whiskers with a quality grade of superior quality have a filtration time of <100s; to determine that the quality grade of the calcium sulfate whiskers in the slurry is superior, the aspect ratio of the calcium sulfate whiskers should be >60;

[0124] (4) The calcium sulfate whiskers in the filter cake were subjected to SEM detection, and their aspect ratio was greater than 60, confirming that the determination result obtained in step (3) was accurate and reliable.

[0125] Example 3

[0126] (1) The corresponding production line in this embodiment is: annual output of 50,000 tons, the preparation process is hydrothermal method, the desulfurization gypsum is sourced from power plant gypsum, and calcium sulfate whiskers are produced;

[0127] (2) There are 10 reactors producing calcium sulfate whiskers in the production line. 1 L of slurry is taken from each reactor, and a total of 10 L of calcium sulfate whisker slurry to be tested is obtained;

[0128] (3) Pour 10L of calcium sulfate whisker slurry to be tested into Figure 7 In the standard filtration apparatus shown (Buchner funnel capacity of 10 L), in which the Buchner funnel is equipped with a filter membrane with a pore size of 30 μm, a vacuum pump is turned on to maintain -0.1 MPa, and a filtration experiment is performed. When the filtrate reaches 0.5 L, the timing is started and the filtration time is recorded. The moisture content of the filter cake surface is tested using a portable microwave moisture meter model TEWS ME 1100 (accuracy ±1%). The measured moisture content of the filter cake surface is 43%, and the timing is stopped. The filtration time is 86 s.

[0129] (4) Based on the dynamic database of "filtration time-quality grade": the calcium sulfate whiskers with a quality grade of superior quality have a filtration time of <100s; it is determined that the quality grade of the calcium sulfate whiskers in the slurry is superior, and the aspect ratio of the calcium sulfate whiskers should be >60;

[0130] (5) SEM test of calcium sulfate whiskers in the filter cake, such as Figure 3 As shown, its aspect ratio is 120-180, which proves that the determination result obtained in step (4) is accurate and reliable.

[0131] Example 4

[0132] (1) The corresponding production line in this embodiment is: annual output of 50,000 tons, the preparation process is hydrothermal method, the source of desulfurized gypsum is rare earth white mud gypsum, and calcium sulfate whiskers are produced;

[0133] (2) There are 10 reactors producing calcium sulfate whiskers in the production line. 1 L of slurry is taken from each reactor, and a total of 10 L of calcium sulfate whisker slurry to be tested is obtained;

[0134] (3) Pour 10L of calcium sulfate whisker slurry to be tested into Figure 7In the standard filtration apparatus shown (Buchner funnel capacity is 10 L), in which the Buchner funnel is equipped with a filter membrane with a pore size of 30 μm, a vacuum pump is turned on to maintain -0.1 MPa, and a filtration experiment is performed. When the filtrate reaches 0.5 L, the timing is started and the filtration time is recorded. The moisture content of the filter cake surface is tested using a portable microwave moisture meter model TEWS ME 1100 (accuracy ±1%). When the moisture content of the filter cake surface is measured to be 40%, the timing is stopped; the filtration time is 165 s;

[0135] (4) Based on the dynamic database of "filtration time-quality grade": the filtration time of calcium sulfate whiskers with a quality grade of superior quality is within the range of 100s-270s; the quality grade of the calcium sulfate whiskers in the slurry is determined to be qualified, and the aspect ratio of the calcium sulfate whiskers should be within the range of 30-60;

[0136] (5) SEM test of calcium sulfate whiskers in the filter cake, such as Figure 4 As shown, its aspect ratio is 30 to 60, which proves that the determination result obtained in step (4) is accurate and reliable.

[0137] Example 5

[0138] (1) Metallurgical desulfurization gypsum raw material and whisker growth solution (the volume ratio of water to whisker growth solution is 0.2:1) are used to prepare a calcium sulfate whisker slurry to be tested at a mass volume ratio of 1000 g:20 L, totaling 10 L;

[0139] (2) Pour 10L of calcium sulfate whisker slurry to be tested into Figure 7 In the standard filtration apparatus shown (Buchner funnel capacity is 10 L), in which the Buchner funnel is equipped with a filter membrane with a pore size of 30 μm, a vacuum pump is turned on to maintain -0.1 MPa, and a filtration experiment is performed. When the filtrate reaches 0.5 L, the timing is started and the filtration time is recorded. The moisture content of the filter cake surface is tested using a portable microwave moisture meter model TEWS ME 1100 (accuracy ±1%). When the moisture content of the filter cake surface is measured to be 45%, the timing is stopped; the filtration time is 150 s;

[0140] (3) Based on the dynamic database of "filtration time-quality grade": the filtration time of calcium sulfate whiskers with a quality grade of superior quality is within the range of 100s-270s; the quality grade of the calcium sulfate whiskers in the slurry is determined to be qualified, and the aspect ratio of the calcium sulfate whiskers should be within the range of 30-60;

[0141] (4) SEM test of calcium sulfate whiskers in the filter cake, such as Figure 5 As shown, its aspect ratio is 30 to 60, which proves that the determination result obtained in step (3) is accurate and reliable.

[0142] Example 6

[0143] (1) Calcium sulfate whisker slurry to be tested was prepared by mixing metallurgical desulfurization gypsum raw material and whisker growth solution (the volume ratio of water to whisker growth solution was 0.2:1) at a mass volume ratio of 1000 g:10 L, a total of 10 L;

[0144] (2) Pour 10L of calcium sulfate whisker slurry to be tested into Figure 7 In the standard filtration apparatus shown (Buchner funnel capacity of 10 L), in which the Buchner funnel is equipped with a filter membrane with a pore size of 30 μm, a vacuum pump is turned on to maintain -0.1 MPa, and a filtration experiment is performed. When the filtrate reaches 0.5 L, the timing is started and the filtration time is recorded. The moisture content of the filter cake surface is tested using a portable microwave moisture meter model TEWS ME 1100 (accuracy ±1%). The measured moisture content of the filter cake surface is 42%, and the timing is stopped. The filtration time is 278 s.

[0145] (3) Based on the dynamic database of "filtration time-quality grade": the calcium sulfate whiskers with a quality grade of superior quality have a filtration time of >270s; the quality grade of the calcium sulfate whiskers in the slurry is determined to be waste, and the slurry contains calcium sulfate crystal particles or short calcium sulfate whiskers;

[0146] (4) SEM test of calcium sulfate whiskers in the filter cake, such as Figure 6 As shown, its aspect ratio is 15-20, and there are many microparticle crystals, which proves that the determination result obtained in step (3) is accurate and reliable.

[0147] In summary, the present invention provides a method for quickly judging the quality of calcium sulfate whisker products. Through the synergistic effect of standardized sampling and production line adaptation design, the three-dimensional structure-fluid resistance correlation mechanism, and the filter membrane pore size optimization rules, the detection time is compressed from the traditional 60 minutes to within 5 minutes, the cost is reduced by more than 90%, and it can be directly embedded in the production line to realize closed-loop process control, filling the technical gap in the field of industrial quality monitoring of calcium sulfate whiskers.

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for quickly judging the quality of calcium sulfate whisker products, characterized in that, The steps include: S1: Pour the experimental calcium sulfate whisker slurry into a standard filtration device to perform a filtration experiment, and use an electron microscope to detect the aspect ratio of the calcium sulfate whiskers in the experimental calcium sulfate whisker slurry to establish a "filtration time-quality grade" dynamic database; S2: Pour the calcium sulfate whisker slurry to be tested into a standard filtration device, perform a filtration experiment, and record the filtration time; S3: determining the quality grade of the calcium sulfate whiskers in the calcium sulfate whisker slurry to be tested based on the "filtration time-quality grade" dynamic database; Wherein, the experimental calcium sulfate whisker slurry and the calcium sulfate whisker slurry to be tested are both taken from the same production line; The amount of the experimental calcium sulfate whisker slurry is the same as the amount of the calcium sulfate whisker slurry to be tested.

2. the method for quick judgment calcium sulfate whisker product quality according to claim 1, is characterized in that, The "filtering time-quality level" dynamic database includes: The filtration time of calcium sulfate whiskers with superior quality is less than 100s; The filtration time of qualified calcium sulfate whiskers is 100s-270s; Waste calcium sulfate whiskers and / or calcium sulfate crystal particles have a filtration time of >270s.

3. the method for quick judgment calcium sulfate whisker product quality according to claim 2, is characterized in that, The aspect ratio of high-quality calcium sulfate whiskers is >60; The aspect ratio of qualified calcium sulfate whiskers is 30-60; The aspect ratio of the calcium sulfate short whiskers or calcium sulfate crystal particles is less than 30.

4. the method for quick judgment calcium sulfate whisker product quality according to claim 1, is characterized in that, The filtration time is the time that starts when the filtrate reaches 0.5 L and stops when the moisture content on the filter cake surface is ≤45%.

5. the method for quick judgment calcium sulfate whisker product quality according to claim 1, is characterized in that, The calcium sulfate whisker slurry to be tested is obtained from a reactor in a production line; Alternatively, the calcium sulfate whisker slurry to be tested is prepared by mixing a product from a production line with water; Alternatively, the calcium sulfate whisker slurry to be tested is prepared by mixing gypsum raw material with a whisker growth solution; The products of the production line include one of the finished calcium sulfate whiskers prepared from metallurgical desulfurization gypsum, the finished calcium sulfate whiskers prepared from power plant gypsum, and the finished calcium sulfate whiskers prepared from rare earth white mud gypsum; The gypsum raw material includes one of metallurgical desulfurization gypsum, power plant gypsum, and rare earth white mud gypsum; The experimental calcium sulfate whisker slurry is obtained from a reactor on the same production line as the calcium sulfate whisker slurry to be tested.

6. the method for quick judgment calcium sulfate whisker product quality according to claim 5, is characterized in that, The volume of the calcium sulfate whisker slurry to be tested is in an integer ratio of 1:500 to 1000 to the total volume of the total discharge of the reactor; Alternatively, the mass volume ratio of the product of the production line to water is 1000 g:10-20 L; Alternatively, the mass volume ratio of the gypsum raw material to the whisker growth solution is 1000 g:10-20 L; The amount of the experimental calcium sulfate whisker slurry and the amount of the calcium sulfate whisker slurry to be tested are both 5-15 L.

7. the method for quick judgment calcium sulfate whisker product quality according to claim 1, is characterized in that, The standard filtration device includes a Buchner funnel, a filter membrane, a conical suction flask and a vacuum filter; The filter membrane is laid in the Buchner funnel; A rubber sealing ring is provided between the Buchner funnel and the mouth of the conical suction filtration flask; A hose is connected between the suction nozzle of the conical suction filtration bottle and the vacuum filter.

8. the method for quick judgment calcium sulfate whisker product quality according to claim 7, is characterized in that, The conical filtration bottle is provided with a 0.5L capacity mark on the bottle body; And / or, the capacity of the conical filtration flask is greater than the capacity of the Büchner funnel; And / or, the filtration pressure of the vacuum filter is -0.1 to -0.04 MPa.

9. the method for quick judgment calcium sulfate whisker product quality according to claim 8, is characterized in that, The pore size of the filter membrane is 30 μm-60 μm.

10. The method for quickly judging calcium sulfate whisker product quality according to claim 1, wherein The method for quickly judging the quality of calcium sulfate whisker products further comprises: performing SEM or XRD detection on the judgment result.

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