A method for evaluating grinding costs in magnetic separation-fine screening regrinding process

Abstract

The present invention relates to a method for evaluating the grinding cost in a magnetic separation - fine screening and re - grinding process, which is characterized by the following steps: 1) First, under the condition of obtaining the m - th concentrate grade product in the technological process, calculate the utilization coefficient q of each stage of the mill by measuring the feed particle size and product particle size of each stage of grinding n ; 2) Calculate the feed production rate γ of each stage of grinding operation by measuring the original ore grade, concentrate grade and tailing grade of each separation operation n ; 3) Through q n and γ n , calculate the comprehensive utilization coefficient q of the mill when obtaining the concentrate grade product under this condition 综m ; 4) Taking q 综1 when m = 1 as the benchmark, compare it with q 综m of different schemes to judge the level of grinding cost. The advantages of the present invention are: predicting the grinding cost by calculating q 综m can be used to guide on - site production and concentrator design, reasonably determine the grinding particle size of each stage of the mill, reasonably determine the concentrate grade, reduce production costs and improve economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of ore dressing technology, and in particular relates to an evaluation method for ore grinding cost in a magnetic separation-fine screening regrinding process. Background Art

[0002] At present, the ore dressing plants that mainly process lean magnetite mostly adopt the process flow of stage grinding, single magnetic separation, fine screening and regrinding. The grinding operation of the ore dressing plant is very important. The grinding capacity determines the production capacity of the ore dressing plant. The quality of the grinding effect, that is, the degree of dissociation of useful mineral monomers in the grinding product, determines the technical indicators of the iron concentrate of the ore dressing plant. Moreover, the energy consumption of the grinding operation accounts for 50-60% of the energy consumption of the ore dressing plant, or even more. It is the operation with the highest production cost in the single magnetic separation fine screening and regrinding process. Therefore, the grinding cost is directly related to the grade of the iron concentrate and the production capacity and production cost of the ore dressing plant. For a long time, the ore dressing plant has been pursuing high-grade concentrate alone, without organically combining the concentrate grade with the ore dressing cost. Whether in the production stage or in the ore dressing test stage, the lowest grinding cost has not been comprehensively considered, which is also an important reason for the high cost of iron concentrate. Therefore, the use of a reasonable method to predict the grinding cost of the single magnetic separation process is helpful to reduce the production cost of the enterprise and improve the economic benefits and competitiveness of the enterprise. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for evaluating the grinding cost in the magnetic separation-fine screening regrinding process. By adopting the method of calculating the comprehensive utilization coefficient of the mill, the grinding cost of the magnetic separation-fine screening process is predicted, thereby achieving the purpose of reasonably determining the grinding particle size of each stage and reducing production costs.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] The method for evaluating the grinding cost in the magnetic separation-fine screening regrinding process of the present invention is characterized by comprising the following steps:

[0006] Step 1: First, under the condition that the mth concentrate grade product is obtained in the process flow, the utilization coefficient q of each stage of the mill is calculated by measuring the feed particle size and product particle size of each stage of grinding and classification operation. n ,q n is the newly generated -200 mesh per unit time and unit mill volume, n is the number of grinding stages, n = 1, 2, 3, m is a natural number ≥ 1;

[0007] The q n The calculation formula is as follows:

[0008]

[0009] Where: qn is the utilization coefficient of the nth mill (T / m 3 h),

[0010] β 排n is the discharge particle size of the nth stage mill (-200 mesh content%),

[0011] β 给n is the feed particle size of the nth mill (-200 mesh content%),

[0012] Qn is the machine time of the nth stage mill (T / h),

[0013] Vn is the effective volume of the nth mill (m 3 );

[0014] Step 2: Calculate the yield of each operation by measuring the grade of the ore, the grade of the concentrate and the grade of the tailings in each separation operation, including the calculation of the yield rate of each grinding and classification operation γ n , and then we get the yield rate of the first-stage grinding and classification operation γ1, the yield rate of the second-stage grinding and classification operation γ2, and the yield rate of the third-stage grinding and classification operation γ3;

[0015] Step 3: Utilize the mill utilization coefficient q n And the ore yield rate of each grinding and classification operation γ n , calculate the comprehensive utilization coefficient q of the mill when the concentrate grade product is obtained under this condition 综m , T / m 3 ·h;

[0016] The comprehensive utilization coefficient of the mill when the concentrate grade product is obtained under this condition is q 综m The calculation formula is as follows:

[0017]

[0018] Step 4: The comprehensive utilization coefficient of the mill q when the concentrate grade product is obtained when m=1 综1 As the benchmark, the q of different schemes 综m Make a comparison to determine the grinding cost.

[0019] The calculation formula for judging the grinding cost is as follows:

[0020] q 综m / q 综1 -1 (3)

[0021] A positive result indicates that the grinding cost is saved, and the larger the value, the greater the grinding cost savings; a negative result indicates that the grinding cost is increased, and the larger the value, the greater the grinding cost increase.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] The production capacity of the ore dressing plant is determined by the grinding capacity, the quality of the grinding effect determines the technical indicators of the iron concentrate products of the ore dressing plant, the grinding cost directly determines the production cost of the ore dressing plant, and the grinding cost is directly related to the grade of the iron concentrate and the production capacity and production cost of the ore dressing plant. The present invention predicts the grinding cost of the magnetic separation-fine screening regrinding process by calculating the comprehensive utilization coefficient of the mill, which can be used to reasonably determine the grinding particle size of each stage when designing the ore dressing plant, and can also be used to guide on-site production and reasonably determine the concentrate grade. It is helpful to reduce the production cost of the enterprise and improve the economic benefits and competitiveness of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of the principle of the magnetic separation-fine screening and regrinding process of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0026] Example

[0027] like Figure 1 As shown, this embodiment uses the magnetic separation-fine screening and regrinding process as the principle process to compare different concentrate grade product solutions to determine the advantages and disadvantages of each solution and guide on-site production.

[0028] Scheme 1 (Baseline Scheme m = 1)

[0029] like Figure 1 As shown, the principle process of a magnetic separation-fine screening regrinding process of the present invention is: the raw ore is fed into a first-stage grinding operation, the particle size of the first-stage grinding operation product is -200 mesh and the content is 63%, the product of the first-stage grinding operation is fed into a first-stage magnetic separation operation, the first-stage magnetic separation concentrate is fed into a second-stage grinding operation, the particle size of the second-stage grinding operation product is -200 mesh and the content is 93%, the product of the second-stage grinding is fed into the second and third-stage magnetic separation operations for selection, the third-stage magnetic separation concentrate is fed into a fine screen, and the fine screen is fed into a third-stage grinding, the particle size of the third-stage grinding operation product is -200 mesh and the content is 95%, the product of the third-stage grinding is fed into a fourth-stage magnetic separation operation for selection, and the product under the screen is selected in a fifth-stage magnetic separation operation. The fourth-stage magnetic separation concentrate and the fifth-stage magnetic separation concentrate together constitute the final concentrate, and the final concentrate grade is 67.89% and the yield is 32.05%, and the tailings of each stage of magnetic separation are combined into the final tailings.

[0030] Step 1: Determine the feed size and product size of each grinding and classification operation, and calculate the utilization coefficient q of each grinding mill by formula (1): n (-200 mesh content newly generated per unit time and per unit mill volume), we get q1 = 0.382T / m 3h, q2 = 0.131 T / m 3 h, q3 = 0.127 T / m 3 ·h;

[0031] Step 2, by measuring the ore grade and the concentrate grade and tailings grade of each beneficiation operation, the conventional beneficiation process investigation method is used to calculate the yield of each operation, and the first-stage mill feed yield γ1 = 100%, the second-stage mill feed yield γ2 = 47.56%, and the third-stage mill feed yield γ3 = 7.15% are determined according to the yield of each operation;

[0032] Step 3: Use the mill utilization coefficient q of each section n and the mill yield γ n , calculate the comprehensive utilization coefficient q of the mill through formula (2) 综1 =0.1468T / m 3 ·h.

[0033] Scheme 2 (Comparison scheme m=2)

[0034] like Figure 1 As shown, the principle process of a magnetic separation-fine screening regrinding process of the present invention is: the raw ore is fed into a first-stage grinding operation, the particle size of the first-stage grinding operation product is -200 mesh and the content is 58%, the product of the first-stage grinding operation is fed into a first-stage magnetic separation operation, the first magnetic concentrate is fed into a second-stage grinding operation, the particle size of the second-stage grinding operation product is -200 mesh and the content is 87%, the second-stage grinding product is fed into the second and third-stage magnetic separation operations for selection, the third magnetic concentrate is fed into a fine screen, and the fine screen is fed into a third-stage grinding, the particle size of the third-stage grinding operation product is -200 mesh and the content is 90%, the third-stage grinding product is fed into a fourth-stage magnetic separation operation for selection, the underscreen product is selected in a fifth-stage magnetic separation operation, and the fourth and fifth magnetic concentrates together constitute the final concentrate, the final concentrate grade is 66.40%, the yield is 33.35%, and the tailings of each magnetic separation stage are combined into the final tailings.

[0035] Step 1: Determine the feed size and product size of each grinding and classification operation, and calculate the utilization coefficient q of each grinding mill by formula (1): n (-200 mesh content newly generated per unit time and per unit mill volume), we get q1 = 0.383 T / m 3 h, q2 = 0.162T / m 3 h, q3 = 0.147 T / m 3 ·h;

[0036] Step 2, by measuring the ore grade and the concentrate grade and tailings grade of each beneficiation operation, the conventional beneficiation process investigation method is used to calculate the yield of each operation, and the first-stage mill feed yield γ1=100%, the second-stage mill feed yield γ2=49.42%, and the third-stage mill feed yield γ3=8.38% are determined according to the yield of each operation;

[0037] Step 3: Use the mill utilization coefficient q of each section n and the mill yield γ n , calculate the comprehensive utilization coefficient q of the mill through formula (2) 综2 =0.1605T / m 3 ·h.

[0038] Comparison of the two solutions

[0039] With q 综1 As a benchmark, calculate q 综2 / q 综1 -1=9.33%, indicating that the grinding cost of Scheme 2 is saved by 9.33% compared with Scheme 1.

[0040] By analogy, we can also calculate the comprehensive utilization coefficient q of different mills such as m=3, m=4, etc. 综m , and q 综1 By making a comparison, the grinding cost of the magnetic separation-fine screening and regrinding process can be predicted, which can be used to guide on-site production and reasonably determine the concentrate grade, thereby reducing the production cost of the enterprise and improving the economic benefits and competitiveness of the enterprise.

Claims

1. A method for evaluating grinding costs in a magnetic separation-fine screening regrinding process, characterized in that The following steps are involved: Step 1: First, under the condition that the mth concentrate grade product is obtained in the process flow, the utilization coefficient q of each stage of the mill is calculated by measuring the feed particle size and product particle size of each stage of grinding and classification operation. n ,q n is the newly generated -200 mesh content per unit time and unit mill volume, n is the number of grinding stages, n = 1, 2, 3, m is a natural number ≥ 1; Step 2: Calculate the yield rate of each operation by measuring the ore grade, the concentrate grade and the tailings grade of each separation operation, including calculating the yield rate of each grinding and classification operation γ n , and then we get the yield rate of the first-stage grinding and classification operation γ1, the yield rate of the second-stage grinding and classification operation γ2, and the yield rate of the third-stage grinding and classification operation γ3; Step 3: Utilize the mill utilization coefficient q n And the ore yield rate of each grinding and classification operation γ n , calculate the comprehensive utilization coefficient q of the mill when the concentrate grade product is obtained under the mth condition 综m , T / m 3 h, calculated as follows: Step 4: The comprehensive utilization coefficient of the mill q when the concentrate grade product is obtained when m=1 综1 As the benchmark, with q 综2 The q of the scheme 综m Compare and judge the grinding cost. The calculation formula is as follows: q 综m / q 综1 -1 (3) A positive result indicates a cost savings; a negative result indicates a cost increase.

2. The method for evaluating grinding costs in a magnetic separation-fine screening regrinding process according to claim 1, characterized in that: In step 1, the q n The calculation formula is as follows: Where: q n is the utilization coefficient of the nth mill, T / m 3 h, β 排n is the discharge particle size of the nth mill, -200 mesh content%, β 给n is the feed particle size of the nth mill, -200 mesh content%, Qn is the operating time of the nth stage mill, T / h, Vn is the effective volume of the nth mill, m 3 .

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