Preparation method of quality control sample for coke particle size screening test

Abstract

The application discloses a preparation method of a quality control sample for coke particle size screening test, and belongs to the technical field of particle size test. The application comprises a double-layer screening machine composed of a 30mm layer and a 25mm layer; 15-30mm silica particle raw materials are screened into 25-30mm particle materials, and the part smaller than 25mm is discarded; the 25-30mm particle materials are repeatedly screened for 2-5 times to obtain mixed material A; 8-25mm silica particle raw materials are repeatedly screened for 4-8 times to obtain mixed material B; the mixed materials A and B are respectively packed and numbered according to 25.0kg / barrel, then combined into a unit (100.0kg) according to the mass ratio of A:B=1:1 and packed with iron barrels; after uniformity and stability evaluation, the quality control sample with a correction value of 50.0%+ / -1.0% and repeatability r=3s can be obtained, and can be used for unifying vibration parameters of different screening machines, monitoring mechanical parameter changes and quality control of coke particle size determination results.

Description

Technical Field

[0001] This invention relates to the field of particle size testing technology, specifically to the field of coke particle size screening testing, and particularly to a method for preparing quality control samples for coke particle size screening testing. Background Technology

[0002] Coke fines content is one of the key indicators for measuring coke quality, directly related to the safety and stability of blast furnace smelting, and is also the most controversial indicator in metallurgical coke trade. In the domestic metallurgical industry, coke particle size sieving has long used GB / T 2005-94, "Determination of Coke Fines Content and Sieving Composition of Metallurgical Coke." This method is applicable to the determination of coke fines content and sieving composition for large coke particles larger than 40 mm, medium-sized coke particles larger than 25 mm, and medium-sized coke particles between 25 and 40 mm. The method summary is as follows: Metallurgical coke samples are sieved using a mechanical sieve, and the percentage of each particle size to the total sample mass is calculated; this is the sieving composition. The percentage of coke particles smaller than 25 mm to the total sample mass is the coke fines content.

[0003] In production practice, the factors affecting the results of coke particle size screening mainly fall into two categories: first, differences in sampling and testing personnel operations; and second, the measurement method itself and the confirmation mechanism of the measurement results. It is generally believed that the efficiency of mechanical screening is closely related to the sieve surface structure, vibration parameters, the precision of mechanical installation, the quality of mechanical parts, and their degree of aging and fatigue. Even slight fluctuations in these factors can cause deviations in the measurement results. Furthermore, coke inevitably pulverizes during the screening process due to mutual friction and collision, leading to a gradual increase in coke dust. Therefore, repeatedly screening the same coke sample cannot be used to evaluate the consistency of the measurement results. In the field of particle size analysis, reference materials such as standard sand are known for equipment evaluation and calibration. However, currently, in the field of coke particle size screening, there is a lack of particle size screening quality control samples that can cover the entire particle size range of this screening test and possess sufficient abrasion resistance and particle size stability.

[0004] In summary, the current field of coke particle size screening and testing mainly faces three problems: First, there is a lack of reference standards for verifying and confirming the accuracy of coke fines testing results; second, there is a lack of a unified comparison platform for the mechanical installation and vibration parameters of screening machines used by different production units; and third, there is a lack of means to continuously monitor the changes in vibration parameters caused by fatigue and aging of mechanical parts of screening machines. Therefore, there is an urgent need to propose a new solution that can simultaneously address these three problems. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the results of coke fines determination in existing coke particle size screening tests cannot be confirmed, the vibration parameters of different screening machines cannot be unified, and the parameter changes caused by fatigue and aging of mechanical parts cannot be monitored. This invention provides a method for preparing quality control samples for coke particle size screening tests.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a quality control sample for coke particle size sieving inspection, comprising the following steps: S1: Preparation of the double-layer screening machine: The double-layer screening machine includes a base, a vibrating machine base, double-layer square hole screen plates and a receiving tray. The double-layer square hole screen plates are arranged from top to bottom as follows: the upper layer is a 30 mm square hole screen plate and the lower layer is a 25 mm square hole screen plate. S2: Preparation of coarse-grained homogenized material A: Silica particles with a particle size of 15-30 mm are continuously, slowly, and uniformly added to the double-layer screening machine obtained in step S1 for screening. Particles with a particle size between 25 and 30 mm that remain on the 25 mm square hole screen are recovered and added back to the screening machine for the next screening. This screening is repeated 2-5 times to obtain silica homogenized material A with a particle size of 25-30 mm. S3: Preparation of fine-grained homogenized material B: Silica particles with a particle size of 8~25 mm are continuously, slowly and uniformly added to the double-layer screening machine obtained in step S1 for repeated screening. After repeated screening 4~8 times, a final screening is performed using a single-layer 8 mm square hole standard sieve that is independent of the double-layer screening machine described in step S1. Materials smaller than 8 mm are discarded to obtain silica homogenized material B with a particle size of 8~25 mm. S4: Packaging: Using a weighing scale with a sensitivity of 0.1 kg, the silica mixture A and the silica mixture B are respectively packed into plastic buckets, each with a net weight of 25.0 kg. The buckets are numbered according to the packing order to obtain bucket-packaged mixtures A1~An and bucket-packaged mixtures B1~Bn respectively. S5: Combination Packaging: Each quality control sample unit is composed of two barrels of the barrel-packaged homogenized material A and two barrel-packaged homogenized material B. The total mass of each quality control sample unit is 100.0 kg. The mass ratio of the silica homogenized material A to the silica homogenized material B is 1:1. The sample is packaged in an iron drum to obtain the quality control sample for coke particle size screening.

[0007] Furthermore, the silica has a density greater than or equal to 2.60 g / cm³, a SiO₂ content greater than or equal to 99 wt%, a crystal phase composition of α-quartz, and an average grain size of 5~10 μm.

[0008] Furthermore, the maximum particle size of the quality control sample is 28-35 mm, and the minimum particle size is 5-10 mm.

[0009] Furthermore, the external dimensions of the square-hole mechanical sieve in step S1 are 2100 mm long × 1340 mm wide × 1310 mm high, and the total weight of the sieve is 500 kg; each layer of the square-hole mechanical sieve is a perforated sieve with a sieve size of 1630 mm × 700 mm and square holes, and all the holes of each layer of sieve are completely included within an effective area of ​​1630 mm × 690 mm.

[0010] Furthermore, the amount of 15-30 mm silica particle raw material fed in step S2 is 11-12 tons; the amount of 8-25 mm silica particle raw material fed in step S3 is 4-6 tons.

[0011] Furthermore, the plastic bucket mentioned in step S4 has a wall thickness of 2 mm and a volume of 25 L.

[0012] Furthermore, in step S4, the quantity of barrelled homogenized material A is 400 barrels, and the quantity of barrelled homogenized material B is 400 barrels; in step S5, the quantity of quality control samples is 200 sample units.

[0013] Furthermore, the method also includes step S6, uniformity evaluation: 15 units, numbered H1 to H15, are randomly selected from the quality control sample units obtained in step S5. For each unit, the following operation is performed: 100.0 kg of material from the unit is continuously, slowly, and uniformly added to the square-hole mechanical sieve for sieving, ensuring that the sample does not overlap on the sieve surface. After sieving, the mass of each particle size is weighed using a 0.1 kg sensitivity balance, and the mass mH of the material with a particle size less than 25 mm is recorded. i After the measurement is completed, the materials of each particle size fraction are remixed and the total mass of the materials (MH) is weighed. i As the starting material for the next measurement; each unit was measured 3 times to obtain mH ij and MH ij Where i = 1~15, j = 1~3, calculate the percentage of <25 mm mass JM in each measurement according to formula (I). ij : JM ij % = mH ij / MH ij × 100% (I) One-way ANOVA was used to assess the repeatability between and within units.

[0014] Furthermore, the method also includes step S7, stability evaluation: Three units, numbered W1 to W3, are randomly selected from the quality control sample units obtained in step S5. For each unit, the mass percentage (mW) of material with a particle size less than 25 mm is continuously and repeatedly measured 50 times according to the sieving operation described in step S6. iji = 1~3, j = 1~50; plot the number of repeated measurements j as the x-axis and mW as the y-axis. ij Using the vertical axis, a functional relationship is established for the change of the <25 mm mass percentage with the number of repeated measurements. The linear segment is fitted with least squares linearly, and the slope of the obtained linear segment is the increment of the <25 mm mass percentage corresponding to each additional use of the quality control sample unit.

[0015] Furthermore, the quality control sample has two characteristic parameters: correction value and repeatability. The correction value is 50.0% ± 1.0%, which refers to the range that the mass percentage of <25 mm material measured for the first time according to the sieving operation described in step S6 should fall within when the sieving equipment meets the technical parameters specified in step S1 and is under normal qualified conditions. The repeatability of the method is r = 3s, where s is the standard deviation of the mass percentage of <25 mm material obtained by continuously measuring 3 times according to the sieving operation described in step S6 for a quality control sample unit.

[0016] In another aspect, this invention provides a quality control sample for coke particle size sieving inspection. The quality control sample is a quality control sample unit prepared according to the above method. Each unit is composed of silica blend A and silica blend B in a 1:1 mass ratio, and the total mass of the unit is 100.0 kg. When the mechanical sieving operation procedure specified in GB / T 2005-94 is performed, the mass percentage of material passing through the 25 mm square hole sieve obtained in the first measurement should fall within the range of 50.0% ± 1.0%, and the standard deviation s of the mass percentage of material passing through the 25 mm square hole sieve obtained in three consecutive measurements should be less than or equal to 0.04%.

[0017] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: (1) The present invention selects silica with high SiO2 content and α-quartz crystal phase as quality control sample matrix. Silica has high wear resistance and mechanical strength. During repeated screening, the particle size is stable and the amount of pulverization is small. It can provide a basically constant <25 mm mass percentage for a long time and stably, so as to serve as a common reference standard for unifying the mechanical installation and vibration parameters of different screening machines.

[0018] (2) The present invention utilizes the high toughness and high strength of silica to ensure the particle size stability of the quality control sample. Thus, when the mechanical parts of the screening machine are fatigued, aged, or the installation accuracy changes, the measurement results of the same quality control sample on the screening machine will deviate from the correction value. Therefore, it can be used to detect changes in the screening parameters of the screening machine in a timely manner and ensure the stability of the measurement results.

[0019] (3) This invention removes particles in the raw materials whose particle size falls near the boundary and is easy to migrate during sieving in advance, and releases the stress of the raw materials by repeated sieving and aging, so that the particle size composition of the resulting mixed materials A and B is stable and converged; by combining the two particle size mixed materials in a 1:1 mass ratio and packaging them into 100.0 kg quality control sample units, the uniformity between units and the stability of single / multiple uses are systematically evaluated by variance analysis and linear regression methods, respectively, to ensure that the prepared quality control samples have stable and reliable characteristic parameters.

[0020] (4) The quality control sample obtained by this invention has a clear correction value (50.0%±1.0%) and repeatability index (r=3s), which can be directly used for the evaluation of coke particle size screening test method, comparison of different screening machines and quality control of test results, providing an objective and traceable basis for the handling of disputes over coke content determination results in metallurgical coke trade.

[0021] (5) The three elements of the present invention—silica matrix selection, double-layer screening machine modification, and 1:1 combination of two particle sizes—are mutually synergistic and indispensable. As shown in Comparative Example 1, if only silica matrix is ​​used without double-layer modification of the screening machine, the inter-unit variance F=4.270>F critical value 2.037 of the obtained quality control sample is not up to standard. As shown in Comparative Example 2, if only screening machine modification and double particle size combination are performed but coke is still used as matrix, the stability slope of the obtained quality control sample is ≥2.0% / time, and it deviates from the correction value within 10 times. Only when all three elements are present can a stable quality control sample with the correction value of 50.0%±1.0%, repeatability r≤0.12%, and stability slope <0.01% / time described in the present invention be obtained. The combination of the three elements produces a non-obvious synergistic technical effect. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the process flow for the preparation method of quality control samples for coke particle size screening and testing as described in Example 1 of the present invention; Figure 2 This is a schematic diagram of the internal assembly structure of the quality control sample unit obtained in Embodiment 1 of the present invention, wherein 1 is a silica mixture A with a particle size of 25~30 mm, 2 is a silica mixture B with a particle size of 8~25 mm, and 3 is an iron drum packaging. Figure 3 This is a schematic diagram of the stacked structure of the modified double-layer screening machine in Embodiment 1 of the present invention, wherein 4 is the receiving tray, 5 is the original fourth layer 25 mm screen plate, 6 is the 30 mm square hole screen plate, and 7 is the screening machine base and vibrating machine base. Figure 4 This is a stability evaluation curve showing the change in the mass percentage of <25mm material as a function of the number of measurements obtained from 50 consecutive repeated measurements of 3 quality control sample units (W1, W2, W3) in Example 1 of the present invention. Figure 5 This is a uniformity evaluation chart of the mean and standard deviation of the mass percentage of materials <25 mm obtained from three repeated measurements of each of the 15 quality control sample units (H1~H15) in Example 1 of the present invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely examples and do not constitute a limitation on the scope of protection of the present invention.

[0024] To avoid repetition, the materials, equipment, and testing methods involved in the following embodiments are described uniformly below, and will not be repeated in each embodiment: (1) Raw materials: silica ore (crushed and granulated), density 2.62~2.65 g / cm³, SiO2 content ≥99 wt%, crystal phase composition confirmed by X-ray diffraction (XRD) analysis as α-quartz, average grain size 5~10 μm; among which silica particles with a particle size of 15~30 mm and silica particles with a particle size of 8~25 mm were obtained from the same batch of ore according to particle size classification.

[0025] (2) Screening equipment: Based on the square-hole mechanical sieve conforming to Chapter 4 of GB / T 2005-94, the equipment is modified. The overall technical parameters of the square-hole mechanical sieve are as follows: external dimensions are 2100 mm long × 1340 mm wide × 1310 mm high; the number of sieve layers is 4 (from top to bottom, the first layer is an 80 mm square-hole sieve, the second layer is a 60 mm square-hole sieve, the third layer is a 40 mm square-hole sieve, and the fourth layer is a 25 mm square-hole sieve); the total weight of the sieve is about 500 kg; the sieve inclination angle is 11.5°; the sieve amplitude is 3~6 mm; the motor power is 2.2 kW, the speed is 450 r / min; and the speed ratio is 1:1. Each layer of sieve is a perforated sieve with a sieve size of 1630 mm × 700 mm, and all perforations are contained within an effective area of ​​1630 mm × 690 mm. The punching parameters for each layer of the original sieve plates are as follows: First layer, 80 mm sieve plate: a=32.5 mm, b=25 mm, c=72.5 mm, d=15 mm, steel plate thickness 2.0 mm, alternating 16 longitudinal holes and 7 or 6 transverse holes; Second layer, 60 mm sieve plate: a=20 mm, b=20 mm, c=57.5 mm, d=15 mm, steel plate thickness 2.0 mm, alternating 21 longitudinal holes and 9 or 8 transverse holes; Third layer, 40 mm sieve plate: a=30 mm, b=30 mm, c=55.0 mm, d=10 mm, steel plate thickness 1.5 mm, alternating 31 longitudinal holes and 13 or 12 transverse holes; Fourth layer, 25 mm sieve plate: a=25.5 mm, b=24 mm, c=40.0 mm, d=8 mm, steel plate thickness 1.5 mm. mm, with 47 holes in the longitudinal direction and 20 or 19 holes in the lateral direction arranged alternately.

[0026] (3) Test method: The mass percentage of <25 mm material in the quality control sample was determined according to the mechanical sieving operation procedure specified in GB / T 2005-94. That is, 100.0 kg of material in each quality control sample unit was continuously, slowly and uniformly added to a square-hole mechanical sieve for sieving, and the sample was kept from overlapping on the sieve surface. After sieving, the mass of each particle size was weighed using a weighing scale with a sensitivity of 0.1 kg. The mass percentage of material with a particle size less than 25 mm was calculated according to the following formula (I): S i % = m i / m × 100% (II) In the formula: S i The percentage by mass for particles <25 mm is expressed in %; m iThe mass of material with particle size <25 mm is expressed in kg; m is the total mass of the sample, also expressed in kg. After each measurement, the two particle size fractions are remixed and the total mass is weighed to serve as the starting material for the next measurement. The weighing scale has a sensitivity of 0.1 kg and should be zeroed before each use.

[0027] Example 1

[0028] This embodiment provides a method for preparing quality control samples for coke particle size sieving inspection. See [link to relevant documentation]. Figure 1 This includes the following steps: S1: Preparation of the double-layer screening machine. Based on the square-hole mechanical sieve conforming to Chapter 4 of GB / T 2005-94, the machine is modified as follows: the original first layer (80 mm square-hole sieve plate) and the original second layer (60 mm square-hole sieve plate) are completely removed; the original third layer (40 mm square-hole sieve plate) is replaced with a square-hole sieve plate with a sieve aperture size of 30 mm × 30 mm. After replacement, the center-to-center spacing of the sieve apertures and the total number of apertures (i.e., alternating arrangement of 31 apertures in the longitudinal direction and 13 or 12 apertures in the lateral direction) are completely consistent with the original third layer sieve plate. After modification, the double-layer screening machine is composed of 30 mm square-hole sieve plates and 25 mm square-hole sieve plates arranged sequentially from top to bottom, while retaining the base, vibrating machine base, receiving tray, and other components. See [link to relevant documentation] for the layered structure of the modified screening machine. Figure 3 .

[0029] S2: Preparation of coarse-grained homogenized material A. Take 11.5 tons of silica granules with a particle size of 15~30 mm and add them continuously, slowly and evenly to the double-layer sieve obtained in step S1 for sieving. Control the amplitude of the sieve to 4 mm and ensure that the sample does not overlap on the sieve surface. Each sieving lasts for about 5 minutes. After sieving, discard the fine particles and powder with a particle size <25 mm that fall into the receiving tray. Collect the coarse particles (>30 mm) that remain on the 30 mm sieve and store them separately. Add the particles that remain on the 25 mm sieve, i.e., the particle size between 25 and 30 mm, back into the sieve for the next sieving. Repeat this sieving process 3 times to obtain about 10.0 tons of silica homogenized material A with a particle size range that is stably converged to 25~30 mm.

[0030] S3: Preparation of fine-grained homogenized material B. Take 4.5 tons of silica particles with a particle size of 8~25 mm and add them continuously, slowly and uniformly to the double-layer sieve obtained in step S1 for repeated sieving. Control the amplitude of the sieve to 4 mm and ensure that the sample does not overlap on the sieve surface. Repeat the sieving 6 times to fully release the potential pulverization and abrasion in the raw material. Finally, perform a final sieve with a single-layer 8 mm square hole standard sieve to discard the fine powder smaller than 8 mm, and obtain about 3.0 tons of silica homogenized material B with a particle size range stably converged to 8~25 mm.

[0031] S4: Packaging. Using a weighing scale with a sensitivity of 0.1 kg, pack the silica mixture A into plastic drums with a wall thickness of 2 mm and a volume of 25 L. Each drum has a net weight of 25.0 kg. Number the drums A1 to A400 according to the packing sequence, for a total of 400 drums. Pack the silica mixture B into plastic drums of the same size in the same way. Each drum has a net weight of 25.0 kg. Number the drums B1 to B400 according to the packing sequence, for a total of 400 drums. Discard any small amount of scrap material generated during the packing process.

[0032] S5: Combined Packaging. Each quality control sample unit consists of two drums of mixed material A and two drums of mixed material B, with a total unit mass of 100.0 kg. Mixed material A accounts for 50.0 kg of the mass, and mixed material B accounts for 50.0 kg of the mass, i.e., a mass ratio of 1:1. These four drums of materials are then packaged together in iron drums and numbered C1 to C200 according to the combination sequence, resulting in 200 quality control sample units, i.e., 200 drums of quality control samples. The internal combination structure of the obtained quality control sample units is described in [reference needed]. Figure 2 .

[0033] Measurements showed that the maximum particle size of the quality control sample obtained in this embodiment was 30 mm, and the minimum particle size was 8 mm.

[0034] Example 2

[0035] The only difference between this embodiment and embodiment 1 is that the number of repeated screenings in step S2 is adjusted from 3 times to 2 times, the number of repeated screenings in step S3 is adjusted from 6 times to 4 times, and the screening amplitude in steps S2 and S3 is adjusted from 4 mm to 3 mm; the other raw materials, parameters and steps are the same as in embodiment 1.

[0036] Example 3

[0037] The only difference between this embodiment and embodiment 1 is that the number of repeated screenings in step S2 is adjusted from 3 to 5, the number of repeated screenings in step S3 is adjusted from 6 to 8, and the screening amplitude in steps S2 and S3 is adjusted from 4 mm to 6 mm; the other raw materials, parameters and steps are the same as in embodiment 1.

[0038] Comparative Example 1

[0039] The difference between this comparative example and Example 1 is that: no modification was made to the square hole mechanical sieve; instead, the original four-layer sieve, which includes four layers of square hole sieves of 80 mm, 60 mm, 40 mm, and 25 mm as specified in GB / T 2005-94, was used for sieving; in step S2, the silica particles with a particle size of 25-30 mm were sieved only once; in step S3, the silica particles with a particle size of 8-25 mm were sieved only twice before being directly packaged; the remaining steps are the same as in Example 1.

[0040] Comparative Example 2

[0041] The difference between this comparative example and Example 1 is that metallurgical coke with a particle size of 25-30 mm is used instead of silica with a particle size of 25-30 mm as the coarse-grained raw material, and metallurgical coke with a particle size of 8-25 mm is used instead of silica with a particle size of 8-25 mm as the fine-grained raw material; the other raw materials, parameters and steps are the same as in Example 1.

[0042] To systematically evaluate the homogeneity, stability, and key characteristic parameters of the quality control samples prepared in this invention, the 200 quality control sample units (C1~C200) obtained in Example 1 were evaluated for homogeneity, stability, and correction values ​​and repeatability using the following methods.

[0043] 1. Uniformity evaluation. From C1 to C200, the first and last two elements (C1 and C200) and 13 randomly selected elements were chosen, for a total of 15 elements numbered H1 to H200. 15 The mechanical sieving operation was performed according to the procedures specified in GB / T 2005-94 (i.e., 100.0 kg of material from each unit was continuously, slowly, and uniformly added to a square-hole mechanical sieve for sieving, ensuring that the samples did not overlap, and weighing them with a weighing scale with a sensitivity of 0.1 kg after sieving). The mass mHi of the material with a particle size <25 mm in each unit was determined, and the total mass MHi of the mixed material was also determined (where MH0 = 100.0 kg is the initial total mass of the unit). Each unit was measured three times to obtain mHij and MH. ij (i=1~15, j=1~3), calculate the percentage of <25 mm mass JMij for each measurement according to formula (I): JM ij % = mH ij / MH ij × 100% (I) JM obtained in Example 1, with 15 units and 3 measurements per unit. ij The data are summarized in Table 1, and one-way ANOVA was used to assess repeatability between and within units. The results of the ANOVA are summarized in Table 2. The means and standard deviations of the 15 units are plotted on... Figure 5 .

[0044] Table 1. Uniformity test data of 15 quality control sample units in Example 1 (unit: %)

[0045] From Table 1 and Figure 5As can be seen, the mean of the <25 mm mass percentage of the 15 quality control sample units is between 50.033% and 50.090%, with a range of only 0.057%. The mean of all units falls within the specified range of the correction value of 50.0% ± 1.0%.

[0046] Table 2. Results of one-way ANOVA for the 15 quality control sample units in Example 1

[0047] As can be seen from the variance analysis results in Table 2, the F-value (1.494) of the variance between units is less than the critical F-value (2.037) corresponding to the significance level α=0.05, and the corresponding P-value (0.173) is greater than 0.05. Therefore, it can be determined that there is no statistically significant difference in the percentage of <25mm mass among the units of each quality control sample, that is, the uniformity between units of the prepared quality control sample meets the requirements.

[0048] 2. Stability Evaluation. Three quality control sample units, numbered W1, W2, and W3, were randomly selected from C1 to C200. Following the mechanical sieving procedure specified in GB / T2005-94, the mass percentage mWij (i=1~3, j=1~50) of the material <25 mm was repeatedly measured 50 times in each unit. After each measurement, the two particle sizes were mixed, and the total mass MWij was used as the starting material for the next measurement. After each measurement, the mixture was returned to the corresponding unit's container for further mixing and the next measurement was performed. 50 mWij values ​​were obtained from each unit, resulting in 150 data points from the three units. These were plotted as curves showing the change in the mass percentage of <25 mm material with the number of measurements. (See [reference needed]). Figure 4 The specific measurement data are summarized in Table 3.

[0049] Table 3. Percentage of <25 mm mass (unit: %) of the three quality control sample units in Example 1, measured repeatedly 50 times.

[0050] (a) Number of measurements j = 1~10

[0051] (b) Number of measurements j = 11~20

[0052] (c) Number of measurements j = 21~30

[0053] (d) Number of measurements j = 31~40

[0054] (e) Number of measurements j = 41~50

[0055] For the i-th unit, a function relationship was established between the <25 mm mass percentage and the number of repeated measurements (j) as the x-axis and mWij as the y-axis. Least-squares linear fitting was performed on the linear segment (j=1~30), and the slope of the resulting linear segment represents the increment of the <25 mm mass percentage for each additional use of the quality control sample unit. Testing showed that the average slope of the linear segment for units W1, W2, and W3 in the first 30 measurements was approximately 0.0050% / measure (i.e., the <25 mm mass percentage increased by approximately 0.005% with each additional use). After approximately 30 repeated measurements, the slope of the curves for all three units significantly increased to approximately 0.010~0.015% / measure, indicating that the sample had entered a significant powdering stage. Based on this, it was determined that the effective usage of the quality control sample obtained in this embodiment does not exceed 30 times, and the increment of the <25 mm mass percentage for each use is approximately 0.005%.

[0056] 3. Repeatability of Calibration Values ​​and Methods. The calibration value refers to the range within which the mass percentage of <25 mm material measured for the first time according to GB / T 2005-94 should fall, provided the sieving equipment meets the technical parameters of the square-hole mechanical sieve specified in Chapter 4 of GB / T 2005-94 (i.e., external dimensions 2100 mm × 1340 mm × 1310 mm, total sieve weight approximately 500 kg, sieve inclination angle 11.5°, amplitude 3~6 mm, motor power 2.2 kW, rotation speed 450 r / min, speed ratio 1:1). In this embodiment, the calibration value is specified as 50.0% ± 1.0%. Actual measurements showed that the initial values ​​for units W1, W2, and W3 were 50.01%, 50.02%, and 50.01%, respectively, all falling within the above calibration value range.

[0057] The repeatability r of the method is defined as r = 3s, where s is the standard deviation of the percentage of <25mm material mass obtained from three consecutive measurements of a quality control sample unit. As shown in Table 1, the standard deviations s of the three measurements for each of the 15 units are approximately between 0.006% and 0.040%. Therefore, the typical value of the repeatability r of this method does not exceed 0.12%, which can meet the accuracy requirements for coke particle size screening.

[0058] 4. Comparative tests of Examples 2, 3, Comparative Example 1, and Comparative Example 2. The quality control samples obtained from each example and comparative example were tested according to the above-described methods for homogeneity evaluation, stability evaluation, and correction value and repeatability assessment. The key performance indicators are summarized in Table 4.

[0059] Table 4. Comparison of key performance characteristics of the quality control samples obtained from each embodiment and the comparative example.

[0060] As shown in Table 4, all three examples yielded quality control samples with the percentage of <25 mm mass falling within the range of 50.0% ± 1.0% in the first test. The inter-unit variance analysis showed F values ​​all less than the critical F value of 2.037, P values ​​all greater than 0.05, and no significant differences between units. The slope of the stability linear segment did not exceed 0.01% / test. The three examples covered the lower limit, middle, and upper limit of the range for the number of sievings and amplitude specified in the claims. Comparative Example 1, due to the lack of modification to the sieving machine and the sieving number being lower than the lower limit of the scope of this invention, resulted in insufficient release of raw material stress and relatively active particle migration near the particle size boundary. Consequently, the inter-unit variance of the obtained quality control sample was significantly amplified (F = 4.270 > critical F value of 2.037), failing the uniformity test, and the first test value deviated from the correction value. Comparative Example 2 used metallurgical coke instead of silica as the matrix. Due to the low hardness, well-developed pores, and much lower abrasion resistance of coke compared to silica, the percentage of particles <25 mm increased from 52% to over 60% after only 3 repeated measurements, and the slope of the stability linear segment exceeded 2% / test. This completely failed to meet the particle size stability requirements of the quality control sample, further proving the necessity of using silica as the matrix for the quality control sample in this invention.

[0061] As can be seen from the comparison of the above embodiments and comparative examples, the method for preparing quality control samples for coke particle size sieving inspection provided by the present invention involves modifying the square-hole mechanical sieve specified in GB / T 2005-94 into a double layer, repeatedly sieving and aging the silica raw material, and forming a 100.0 kg quality control sample unit by combining two particle sizes in a 1:1 ratio. With the aid of system uniformity, stability and correction value evaluation, the obtained quality control sample has the advantages of stable particle size, uniformity between units and clear characteristic parameters. It can simultaneously realize the confirmation of coke particle size measurement results, the unification of vibration parameters of different sieving machines and the monitoring of parameter drift caused by mechanical fatigue aging.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a quality control sample for coke particle size sieving inspection, characterized in that, The method includes the following steps: S1: Preparation of the double-layer screening machine: The double-layer screening machine includes a base, a vibrating machine base, double-layer square hole screen plates and a receiving tray. The double-layer square hole screen plates are arranged from top to bottom as follows: the upper layer is a 30 mm square hole screen plate and the lower layer is a 25 mm square hole screen plate. S2: Preparation of coarse-grained homogenized material A: Silica particles with a particle size of 15-30 mm are continuously, slowly, and uniformly added to the double-layer screening machine obtained in step S1 for screening. Particles <25 mm are discarded. Particles with a particle size between 25 and 30 mm that remain on the 25 mm square hole screen are recovered and added back to the screening machine for the next screening. This screening is repeated 2-5 times to obtain silica homogenized material A with a particle size of 25-30 mm. S3: Preparation of fine-grained homogenized material B: Silica particles with a particle size of 8~25 mm are continuously, slowly and uniformly added to the double-layer screening machine obtained in step S1 for repeated screening. After repeated screening 4~8 times, a final screening is performed using a single-layer 8 mm square hole standard sieve that is independent of the double-layer screening machine described in step S1. Materials smaller than 8 mm are discarded to obtain silica homogenized material B with a particle size of 8~25 mm. S4: Packaging: Using a weighing scale with a sensitivity of 0.1 kg, the silica mixture A and the silica mixture B are respectively packed into plastic buckets, each with a net weight of 25.0 kg. The buckets are numbered according to the packing order to obtain bucket-packaged mixtures A1~An and bucket-packaged mixtures B1~Bn respectively. S5: Combination Packaging: Each quality control sample unit is composed of two barrels of the barrel-packaged homogenized material A and two barrel-packaged homogenized material B. The total mass of each quality control sample unit is 100.0 kg. The mass ratio of the silica homogenized material A to the silica homogenized material B is 1:

1. The sample is packaged in an iron drum to obtain the quality control sample for coke particle size screening.

2. The method for preparing quality control samples for coke particle size sieving inspection according to claim 1, characterized in that: The silica has a density greater than or equal to 2.60 g / cm³, a SiO₂ content greater than or equal to 99 wt%, a crystal phase composition of α-quartz, and an average grain size of 5~10 μm.

3. The method for preparing quality control samples for coke particle size sieving inspection according to claim 1, characterized in that: The maximum particle size of the quality control sample is 30-35 mm, and the minimum particle size is 8-10 mm.

4. The method for preparing quality control samples for coke particle size sieving inspection according to claim 1, characterized in that: The external dimensions of the square hole mechanical sieve in step S1 are 2100 mm long × 1340 mm wide × 1310 mm high, and the total weight of the sieve is 500 kg. Each layer of the square hole mechanical sieve is a perforated sieve with a sieve size of 1630 mm × 700 mm and square holes. All the holes of each layer of sieve are completely included within the effective area of ​​1630 mm × 690 mm.

5. The method for preparing quality control samples for coke particle size sieving inspection according to claim 1, characterized in that: The amount of 15-30 mm silica particle raw material fed in step S2 is 11-12 tons; the amount of 8-25 mm silica particle raw material fed in step S3 is 4-6 tons.

6. The method for preparing quality control samples for coke particle size sieving inspection according to claim 1, characterized in that: In step S4, the quantity of barrelled homogenized material A is 400 barrels, and the quantity of barrelled homogenized material B is 400 barrels; in step S5, the quantity of quality control samples is 200 sample units.

7. The method for preparing quality control samples for coke particle size sieving inspection according to claim 1, characterized in that: The method further includes step S6, uniformity evaluation: 15 units, numbered H1 to H15, are randomly selected from the quality control sample units obtained in step S5. For each unit, the following procedure is performed: 100.0 kg of material from the unit is continuously, slowly, and uniformly added to the square-hole mechanical sieve for sieving, ensuring that the sample does not overlap on the sieve surface. After sieving, the mass of each particle size is weighed using a 0.1 kg sensitivity balance, and the mass (mH) of the material with a particle size less than 25 mm is recorded. i After the measurement is completed, the materials of each particle size fraction are remixed and the total mass of the materials (MH) is weighed. i As the starting material for the next measurement; each unit was measured 3 times to obtain mH ij and MH ij Where i = 1~15, j = 1~3, calculate the percentage of <25 mm mass JM in each measurement according to formula (I). ij : JM ij % = mH ij / MH ij × 100% (I) One-way ANOVA was used to assess the repeatability between and within units.

8. The method for preparing quality control samples for coke particle size sieving inspection according to claim 7, characterized in that: The method further includes step S7, stability evaluation: Three units, numbered W1 to W3, are randomly selected from the quality control sample units obtained in step S5. For each unit, the mass percentage (mW) of materials with a particle size less than 25 mm is continuously and repeatedly measured 50 times according to the sieving operation described in step S6. ij i = 1~3, j = 1~50; plot the number of repeated measurements j as the x-axis and mW as the y-axis. ij Using the vertical axis, a functional relationship is established for the change of the <25 mm mass percentage with the number of repeated measurements. The linear segment is fitted with least squares linearly, and the slope of the obtained linear segment is the increment of the <25 mm mass percentage corresponding to each additional use of the quality control sample unit.

9. The method for preparing quality control samples for coke particle size sieving inspection according to claim 7, characterized in that: The quality control sample has two characteristic parameters: correction value and repeatability. The correction value is 50.0% ± 1.0%, which refers to the range that the mass percentage of <25 mm material measured for the first time according to the sieving operation described in step S6 should fall into when the sieving equipment meets the technical parameters specified in step S1 and is under normal qualified conditions; the repeatability of the method is r = 3s, where s is the standard deviation of the mass percentage of <25 mm material obtained by continuously measuring 3 times according to the sieving operation described in step S6 for a quality control sample unit.

10. A quality control sample for coke particle size sieving inspection, characterized in that: The quality control sample is a quality control sample unit prepared according to the method of claim 1. Each unit is composed of silica mixture A and silica mixture B in a 1:1 mass ratio, and the total mass of the unit is 100.0 kg. When the mechanical sieving operation procedure specified in GB / T 2005-94 is used for testing, the mass percentage of material passing through the 25 mm square hole sieve obtained in the first measurement should fall within the range of 50.0% ± 1.0%, and the standard deviation s of the mass percentage of material passing through the 25 mm square hole sieve obtained in three consecutive measurements should be less than or equal to 0.04%.

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