Method for measuring material extrusion work index

Abstract

The application discloses a kind of material extrusion work index determination methods, comprising the following steps: taking the material to be measured, screen analysis obtains the percentage e0 of fine powder content therein, and the corresponding mesh size when 80w.% material to be measured passes;Fine powder particle size is not more than Pi;Take the material to be measured and crush, obtain cake;After cake is scattered, screen analysis is carried out, and fine powder and coarse powder are obtained, and the fine powder increment after extrusion is calculated;The fine powder obtained in step S2 is reserved for future use, and the same measured material as the mass of fine powder is supplemented in coarse powder;Repeat steps S2-S3 at least three times until the system reaches balanced stable conditions;Take the fine powder in the material of the system after balance and stabilization, mix and screen, and obtain the corresponding mesh size when 80w.% fine powder passes;Extrusion work index is calculated according to the above data.The application solves the problems of difficult production capacity prediction of roll press and other material bed crushing equipment, lack of prediction means in production process, etc., and has important theoretical significance and practical value for the basic research of material bed crushing technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material bed crushing, and particularly to a method for measuring material extrusion work index. BACKGROUND

[0002] In the field of material processing, the crushing technology has always been a key link, especially the material bed crushing technology, which is increasingly important with the development of modern industry. Since the 1980s, high-pressure material bed crushing technology has emerged, and roller presses, vertical mills and other grinding equipment have been widely used. It has the advantages of high fine particle content, more micro-cracks and low unit crushing energy consumption, which meets the development trend of "more crushing and less grinding", and becomes the core technology to improve the crushing efficiency.

[0003] However, in the research and application process of material bed crushing technology, the evaluation of material fragility and the prediction of related production parameters have always been a difficult problem to be solved. The traditional laboratory-scale inter-particle bed crushing test method has many defects. The semi-industrial or small roller press crushing test is complex to operate, consumes a large amount of material and is time-consuming and labor-intensive. Moreover, the test results need to be corrected significantly before they can be applied to industrial design, which greatly limits their promotion in experimental research. The grindability and laboratory Bond work test are based on ball mills, which are single-particle crushing equipment and differ greatly from the working principle of roller presses and other material bed crushing equipment. For materials that are easy to grind and difficult to crush, the error is large. In the basic research of material bed crushing and the prediction of industrial capacity and power consumption of production lines using material bed crushing equipment, the results often deviate greatly from actual production. For example, in the cement industry, when using the Bond work index test to guide production, due to the difference in crushing principle between the Bond work index test and the actual production of roller presses and vertical mills, the reference value for equipment selection and process design is greatly discounted.

[0004] The particle bed piston pressure test can simulate the material layer crushing process and make some predictions on the working parameters of roller presses and other equipment, but it has obvious shortcomings. On the one hand, the applicability of its model and calculation empirical formula needs a lot of demonstration; on the other hand, the traditional piston pressure test only completes the crushing with one loading, which is quite different from the continuous crushing process of high-pressure roller mills. Moreover, most studies only focus on the prediction of crushing energy consumption or product particle size, and involve little in other key parameters for equipment selection and process design, failing to form a comprehensive, intuitive and feasible material bed crushing research test method. The POLYCOM grinding index (PGI) test of Germany's Thyssen Krupp Polysius Company can determine whether the material is suitable for high-pressure roller mill crushing, but it requires too much ore, has a complex test process, is time-consuming and labor-intensive, and is expensive, which brings many inconveniences to practical application.

[0005] In summary, the defects of the prior art in the evaluation of the crushability of the material in the material bed and the prediction of the production parameters, there is an urgent need for a new determination method and device which can be adapted to the mechanism of the material bed crushing equipment, is simple to operate, consumes less material and can accurately evaluate the crushing difficulty of the material, and then effectively predict the working parameters of the roller press and other equipment, and provide strong support for the development of material bed crushing technology. SUMMARY

[0006] The purpose of the present application is to provide a determination method of material extrusion work index, which solves the problems of difficulty in predicting the production capacity of roller press and other material bed crushing equipment, lack of prediction means in the production process, and has important theoretical significance and practical value for the basic research of material bed crushing technology.

[0007] To achieve the above purpose, the present application provides the following technical scheme:

[0008] In a first aspect, the present application discloses a determination method of material extrusion work index, comprising the following steps:

[0009] S1, taking the material to be measured, screening to obtain the percentage of fine powder content e0 in the material to be measured, and the corresponding sieve size when 80w.% of the material to be measured passes through; wherein the particle size of the fine powder is not greater than Pi;

[0010] S2, crushing the material to be measured by extrusion to obtain a cake; screening the cake after breaking up to obtain fine powder and coarse powder, and calculating the fine powder increment after extrusion;

[0011] S3, reserving the fine powder obtained in step S2 for later use, and adding the same amount of the measured material into the coarse powder;

[0012] S4, repeating steps S2-S3 at least three times until the system reaches a balanced and stable condition;

[0013] S5, reserving the fine powder in the material after the system reaches a balanced and stable condition, mixing and screening to obtain the corresponding sieve size when 80w.% of the fine powder passes through;

[0014] S6, calculating the extrusion work index according to the following formula:

[0015]

[0016] In the formula, E i is the extrusion work index, unit: kWh / t; e is the mass percentage of the fine powder increment after extrusion in the total amount of fine powder; G e is the average value of the fine powder increment of the last three times before the system reaches a balanced and stable condition, unit: g; F 80 is the corresponding sieve size when 80w.% of the material to be measured passes through, unit: µm; P 80The screen aperture corresponding to 80 w.% passing time after the system is balanced and stable, in units of pm.

[0017] Further scheme: further comprising step S7:

[0018] The predicted table yield is calculated according to the following formula:

[0019] T2 = T1 * Ei1 / Ei2

[0020] In the formula, T1 is the table yield of the material to be tested, in units of t / h; Ei1 is the extrusion work index of the material to be tested, in units of kWh / t; T2 is the table yield after material replacement, in units of t / h; Ei2 is the extrusion work index of the replaced material, in units of kWh / t.

[0021] Further scheme: in step S2, the fine powder increment after extrusion is calculated according to the following formula:

[0022] G ej = m j - m j-1 * e0,

[0023] In the formula, G ej is the fine powder increment in the material after the jth extrusion, m j is the fine powder amount after the jth extrusion, m j-1 is the fine powder amount after the (j-1)th extrusion, e0 is the fine powder content percentage obtained by screening the material, and j is a natural number greater than 1.

[0024] Further scheme: in step S4, the system reaches the balanced and stable condition when:

[0025] When the difference between the maximum value and the minimum value of the fine powder amount obtained for three consecutive times is less than or equal to 1% of the average value of the fine powder amount for the three times, the system reaches a stable state.

[0026] Further scheme: the value of Pi is 45-200 pm.

[0027] Preferably, the value of Pi is 80 pm.

[0028] Further scheme: the F 80 and P 80 are obtained by interpolation method.

[0029] Further scheme: in step S2, the extrusion pressure is 800-1200 kN.

[0030] In a second aspect, the present application discloses a computer readable storage medium, wherein a plurality of acquisition classification programs are stored on the computer readable storage medium, and the plurality of acquisition classification programs are used to be called by a processor and execute the determination method of the material extrusion work index.

[0031] Compared with the prior art, the present application has the following advantages:

[0032] In terms of operation and material consumption, compared with the traditional high-pressure roller mill semi-industrial type or small roller mill crushing test, the present application greatly reduces the material consumption, simplifies the operation process, greatly reduces the test cost and time cost, effectively solves the problems of complex traditional method, high material consumption and long time consumption, and is more conducive to the wide application in the test research.

[0033] From the aspects of crushing mechanism and production simulation, the extrusion work index test is highly consistent with the crushing mechanism of the material bed crushing equipment such as the roller mill and the vertical mill, and can accurately simulate the closed-circuit process in production and the material layer crushing process of the material. Through the actual extrusion crushing and subsequent detailed screening of the material, the test data obtained can truly reflect the characteristic changes of the material in the material bed crushing environment.

[0034] In terms of device parameter prediction and production control, the present application has the following advantages: based on the determined extrusion work index, the particle size of the finished product after the extrusion crushing of the roller mill can be accurately estimated, which provides a key reference for product quality control; the mill output of the roller mill can be effectively predicted, which helps enterprises to reasonably plan the production scale and progress; at the same time, the prediction of power consumption and power consumption helps to optimize the energy allocation in the production process, realizes energy saving and emission reduction and cost control. In the design and selection process of the roller mill, the present application provides a reliable theoretical basis, so that the equipment selection is more suitable for the actual production demand, improves the overall efficiency and stability of the production system, and comprehensively promotes the application and development of the material bed crushing technology in industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The determination method flowchart of the present application;

[0036] Figure 2 The material screen size F 80 Interpolation calculation schematic diagram;

[0037] Figure 3 The material screen size P 80 Interpolation calculation schematic diagram; DETAILED DESCRIPTION

[0038] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0039] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0040] Please refer to Figure 1 A method for measuring the extrusion work value of a material, which is performed according to the following steps:

[0041] S1) Screen 500g of the material to be measured (with a maximum particle size of 5mm) using a nested screen to obtain the particle size distribution thereof, as shown in Table 1; according to Table 1, the percentage of the content of fine powder ≤Pi in the material to be measured e0=14.91%, and the screen size F 80 obtained according to the interpolation method (see step S5); wherein, Pi is 80μm;

[0042] Table 1 Particle size distribution of the material to be measured

[0043]

[0044] S2) Another 500g of the material to be measured is placed into a pressure testing machine, laid flat in the device, and the material is laid flat, the final loading force is set to 900kN, and the material is extruded and crushed, when the loading force reaches the set value, the force is unloaded and the car is returned to complete the extrusion test;

[0045] S3) The extruded material (cake) is taken out of the pressure testing machine, scattered, and screened using a nested screen to obtain the amount of fine powder m1 and the amount of coarse powder (particle size >80μm) M1=500-m1 in the extruded material, wherein the fine powder increment G e1 =m1-m0*e;

[0046] S4) The fine powder is reserved for use, and the weight of the material to be measured equivalent to the weight of the removed fine powder is supplemented in the coarse powder, i.e. the weight of the raw material m1 of the measured material is supplemented in the coarse powder after the first extrusion, the total weight of the extruded material m=500g is kept unchanged, and the steps of S2-S3 are repeated until the fine powder increment (Gen-2 , G en-1 , G en ) the difference between the maximum and minimum values ΔG e , G e ≤ 1%; the amount of fine powder before and after each extrusion is shown in Table 2; the fine powder grading after the system reached equilibrium is shown in Table 3; from Table 2, it can be seen that the system reached equilibrium after the 7th extrusion test;

[0047] Table 2 Fine powder amount ≤80um before and after extrusion test

[0048]

[0049] Table 3 Average grading of fine powder ≤80um in material after three consecutive equilibrium extrusions

[0050]

[0051] S5) After mixing the fine powder ≤Pi in the material after equilibrium extrusion, sieve analysis is performed using a nested sieve, and the screen size corresponding to 80% passing of the fine powder is obtained by interpolation method, i.e. P 80 ; as shown in Figure 2 and Figure 3 , F 80 and P 80 are calculated by interpolation method:

[0052] F 80 = 5000 - (99.60% - 20%) * (5000 - 2500) / (99.60% - 65.83%) = 3549.01 μm;

[0053] P 80 = 63 - (90.08% - 80%) * (63 - 54) / (90.08% - 76.90%) = 56.1 μm;

[0054] G e = (89.18 + 88.92 + 88.80) / 3 = 88.97 g;

[0055] △G e = (89.12 - 88.80) / 88.5 = 0.43%, which meets the equilibrium condition;

[0056] e = (89.18 + 88.92 + 88.80) / (104.61 + 104.52 + 104.38) = 85.13%;

[0057] The above data is brought into the formula to calculate the extrusion work index E i1 of the material to be tested:

[0058] = 4.09 kWh / t.

[0059] wherein E i1 is the extrusion work index, kWh / t; e is the percentage of the increase of the fine powder ≤ Pi after the material balance of the press to the total amount of the fine powder ≤ Pi, e = (G en-2 + G en-1 + G en ) / (m n-2 + m n-1 + m n ); G e is the average value of the increase of the fine powder ≤ Pi after the last three continuous extrusions, g; F 80 and P 80 are the 80% passing aperture diameters of the initial material and the product, respectively, µm.

[0060] S6) According to the production, the production T1 of the material to be tested (i.e. material one) is 261 t / h, and after replacing the material two, the production is reduced to 243 t / h. The extrusion work index of the material two is determined by the test, and the raw material gradation control is the same as that of the material one. The process data of the press bed crushing test of the material two is shown in Table 4; the average gradation of the fine powder ≤ 80 µm in the material after the system balance and stabilization of the material two is shown in Table 5.

[0061] Table 4 Process data of the press bed crushing test of the material two

[0062]

[0063] Table 5 Average gradation of the fine powder ≤ 80 µm in the material after the last three continuous extrusions of the material two

[0064]

[0065] The extrusion work index Ei2 of the material two is calculated as follows:

[0066] P80 = 63 - (92.46% - 80%) * (63 - 54) / (92.46% - 77.25%) = 55.63 µm;

[0067] ΔG e = (82.53 + 83.28 + 82.70) / 3 = 82.84 g;

[0068] e = (82.53 + 83.28 + 82.70) / (97.53 + 97.82 + 97.28) = 84.92%;

[0069] = 4.08 kWh / t.

[0070] Comparing the extrusion work indexes Ei1 and Ei2 of the two materials, the predicted table output T2 of the production material two can be obtained, T2 = T1 * Ei1 / Ei2 = 244.03 t / h, which is basically consistent with the actual production situation.

[0071] Although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the specification is described in this way only for clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

[0072] Therefore, the above only describes the preferred embodiments of the present application, and is not intended to limit the scope of the present application; that is, various equivalent transformations made within the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A method for measuring a material extrusion work index, characterized by, The method comprises the following steps: S1, taking the material to be measured, screening to obtain the content percentage e0 of fine powder therein, and the corresponding sieve size when 80w.% of the material to be measured passes through; wherein the particle size of the fine powder is not greater than Pi; S2, taking the material to be measured to perform extrusion crushing to obtain a cake; screening the cake after being broken up to obtain fine powder and coarse powder, and calculating the fine powder increment after extrusion; S3, reserving the fine powder obtained in step S2 for later use, and adding the same mass of the material to be measured into the coarse powder; S4, repeating steps S2-S3 at least three times until the system reaches a balanced stable condition; S5, reserving the fine powder in the material after the system reaches the balanced stable condition, mixing and screening to obtain the corresponding sieve size when 80w.% of the fine powder passes through; S6, calculating the extrusion work index according to the following formula: In the formula, E i is the extrusion work index, with units of kWh / t; e is the mass percentage of the fine powder increment after extrusion balance in the total amount of fine powder; G e is the average value of the last three fine powder increments before system balance, with units of g; F 80 is the corresponding sieve size when 80 w.% passes through in the material to be tested, with units of µm; P 80 is the corresponding sieve size when 80 w.% passes through in the fine powder after the system balances and stabilizes, with units of µm.

2. The method for measuring the material extrusion work index according to claim 1, characterized by, The method further comprises step S7: According to the following formula, the predicted table yield is calculated: T2=T1* Ei1 / Ei2 In the formula, T1 is the table yield of the material to be measured, in units of t / h; Ei1 is the extrusion work index of the material to be measured, in units of kWh / t; T2 is the table yield of the replaced material, in units of t / h; and Ei2 is the extrusion work index of the replaced material, in units of kWh / t.

3. The method for determining the material extrusion work index according to claim 1, characterized in that, In step S2, the fine powder increment after extrusion is calculated according to the following formula: G ej = m j -m j-1 *e0, wherein G ej is the fine powder increment of the material after the jth extrusion, m j is the fine powder amount of the material after the jth extrusion, m j-1 is the fine powder amount of the material after the j-1th extrusion, e0 is the fine powder content percentage obtained by sieve analysis of the material, and j is a natural number greater than 1.

4. The method for determining the material extrusion work index according to claim 1, characterized in that, In step S4, the balanced stable condition of the system is: When the difference between the maximum value and the minimum value of the fine powder amount obtained for three times is less than or equal to 1% of the average value of the fine powder amount of the three times, the system reaches a stable state.

5. The method for determining the material extrusion work index according to claim 1, characterized in that, The value of Pi is 45-200µm.

6. The method for determining the material extrusion work index according to claim 3, characterized in that, The value of Pi is 80µm.

7. The method for determining the material extrusion work index according to claim 1, characterized in that, The F 80 and P 80 are calculated by interpolation.

8. The method for determining the material extrusion work index according to claim 1, characterized in that, In step S2, the extrusion force is 800-1200kN.

9. A computer readable storage medium, characterized in that, The computer readable storage medium stores a plurality of acquisition classification programs, and the plurality of acquisition classification programs are used to be called and executed by the processor to perform the method for measuring the extrusion work index of the material according to any one of claims 1-8.

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