A continuous ball adding method for wet fine grinding

Abstract

The present invention relates to a continuous ball-adding method for wet fine grinding, and belongs to the field of ore dressing technology and control technology. The continuous ball-adding method for wet fine grinding uses a semi-theoretical formula of ball diameter to calculate the precise ball diameter required for each group of ore particles to be ground, and combines crushing statistical mechanics to complete the initial ball ratio, which is represented by a vector #imgabs0#; collects the mill running time t, the steel ball mass m corresponding to the size of the steel ball added to the mill, the total mass M of the initial steel ball, and the amount of ore entering the grinding mill Q i On-site operation parameters; calculate the required additional steel ball size and quantity through the steel ball wear mathematical model and the steel ball unit consumption mathematical model respectively; comprehensively analyze the calculation results of the steel ball wear mathematical model and the steel ball unit consumption mathematical model to select the optimal additional steel ball size and quantity; DCS controls the optimal additional steel ball size and quantity to be added to the mill. This method solves the problem of uneven product particle size distribution caused by intermittent ball addition at this stage.

Description

Technical Field

[0001] The invention relates to a continuous ball supplementing method for wet fine grinding, belonging to the field of ore dressing technology and control technology. Background Art

[0002] Grinding operation is the main link in mineral crushing. It not only consumes high energy and materials, but also the particle size of the grinding product has an important impact on subsequent separation. Therefore, research on improving grinding accuracy and grinding efficiency has always been a hot topic.

[0003] Grinding operation is the core unit for achieving efficient and selective separation of minerals, and maintaining the optimal grinding media ratio is an important factor affecting the energy consumption of the mill and the particle size characteristics of the grinding products.

[0004] At present, most small and medium-sized mills use the manual method of adding steel balls, which requires a lot of manual labor, and the timely and reliable addition of steel balls cannot be guaranteed, resulting in waste of raw materials and energy, low production efficiency, and is not conducive to the improvement of enterprise production indicators. In addition, there are major safety risks such as falling objects from high altitude and mechanical injuries in the process of adding steel balls, which is not conducive to the management and control of enterprise safety production.

[0005] The applicant has found that the ball adding systems currently in widespread use are intermittent ball adding systems with a long ball adding cycle, and they all have the same timeliness and reliability issues as manual ball adding. Moreover, the size and proportion of the additional steel balls are fixed values ​​preset in advance, lacking real-time and accuracy. In some concentrators, sound is used as a monitoring variable to determine whether additional steel balls need to be added, which mostly relies on experience and lacks theoretical basis. Summary of the invention

[0006] In view of the problems and shortcomings of the above-mentioned prior art, the present invention provides a method for continuously adding balls for wet fine grinding. The method solves the problem of uneven product particle size distribution caused by intermittent ball addition at the current stage, can provide stable feed for subsequent sorting, improve product recovery rate, and thus achieve the purpose of reducing costs and increasing efficiency. The present invention is implemented by the following technical solutions.

[0007] A continuous ball adding method for wet fine grinding, the specific steps are as follows:

[0008] Step 1. Determine the diameter and ratio of the steel balls

[0009] The ball diameter semi-theoretical formula is used to calculate the precise ball diameter required for each group of ore particles to be ground, and the initial ball ratio is completed in combination with crushing statistical mechanics. express;

[0010] Step 2: Collect on-site operating parameters

[0011] Collect the mill running time t, the steel ball mass m corresponding to the size of the steel ball added to the mill, the total mass of the initial steel balls M, and the amount of ore entering the mill Q i On-site operating parameters;

[0012] Step 3, calculate the required additional steel ball size and quantity through the steel ball wear mathematical model and the steel ball unit consumption mathematical model respectively;

[0013] (1) Mathematical model of steel ball wear

[0014] Combined with the wear law of steel balls, the mathematical model of adding steel balls is obtained:

[0015] Cycle sampling time t s The mass of the steel ball that needs to be added to the ball diameter corresponding to k is:

[0016]

[0017] Where: M is the total mass of the initial steel balls collected in Step 2;

[0018] S kj (t) is the steel ball wear characteristic parameter matrix, j = 1, 2, ..., n;

[0019] is the vector representation of the initial ball loading ratio in Step 1;

[0020] m={m1,m2,…,m j ,…m n}, m is the size of the steel ball added to the mill corresponding to the mass of the steel ball;

[0021] u is the correction factor for steel ball wear;

[0022] (2) Mathematical model of steel ball consumption

[0023] According to the relationship between the output of grinding products and the wear of steel balls, the empirical coefficient of steel ball unit consumption is determined as x; the mathematical model of steel ball unit consumption is:

[0024] Cycle sampling time t s The mass of the steel ball that needs to be added to the ball diameter corresponding to k is:

[0025]

[0026] Where: Q i The grinding amount in Step 2;

[0027] t is the mill running time collected in Step 2;

[0028] Step 4. Comprehensively analyze the calculation results of the steel ball wear mathematical model and the steel ball unit consumption mathematical model to select the optimal size and quantity of additional steel balls;

[0029] Step 5: DCS controls the optimal size and quantity of additional steel balls obtained in Step 4 to be added to the mill.

[0030] The steel ball wear characteristic parameter matrix S in Step 2 kj (t) Through S kj =(D k 3 -D k+1 3 ) / D j 3 , D k is the ball diameter value corresponding to the kth position, D k+1 is the ball diameter value corresponding to the k+1th position, D j is the ball diameter value corresponding to the jth position (k=1,2,…,n; j=1,2,…,n).

[0031] The beneficial effects of the present invention are:

[0032] (1) The present invention can realize continuous ball replenishment, provide stable feed for subsequent separation, and improve product recovery rate.

[0033] (2) The present invention introduces multi-parameter analysis, comprehensively compares the calculation results of the two mathematical models, determines the final size and quantity of the additional balls, and ensures the scientificity and accuracy of the data.

[0034] (3) The present invention uses a distributed control system for calculation and control, so that the process of adding balls is fast and stable.

[0035] (4) The DCS system controls the automatic ball adding device to directly add steel balls to the mill, eliminating manual intervention and operation, eliminating safety risks such as falling objects and mechanical injuries during the steel ball adding process, and ensuring safe production of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the process of the present invention;

[0037] Figure 2 This is a ball supplementation curve diagram of a copper mine in Yunnan Province according to Example 1 of the present invention;

[0038] Figure 3 This is a ball supplement curve diagram of a mining enterprise in Panzhihua, Sichuan Province, in Example 2 of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0040] Example 1

[0041] like Figure 1 As shown, taking a copper mine in Yunnan as an example, the continuous ball adding method for wet fine grinding has the following specific steps:

[0042] Step 1. Determine the diameter and ratio of the steel balls

[0043] The ball diameter semi-theoretical formula is used to calculate the precise ball diameter required for each group of ore particles to be ground, and the initial ball ratio is completed in combination with crushing statistical mechanics. Indicated by; the initial assembly ratio of the steel balls in this example is Φ70:Φ50:Φ40:Φ30=15:25:35:25, using vector Expressed as {15%, 25%, 35%, 25%} T ; Based on the initial ball ratio, the supplementary ball ratio is determined by drawing a graph; first, the cumulative curve of the initial ball ratio is drawn. Its wear curve will move to the lower left. To maintain the original initial ball curve, the supplementary curve can be obtained by moving the initial ball curve to the upper right in parallel. Figure 2 It was concluded that the ratio of the additional balls was Φ70:Φ50:Φ40=27.5:47.5:25.

[0044] Step 2: Collect on-site operating parameters

[0045] Collect the mill running time t, the steel ball mass m corresponding to the size of the steel ball added to the mill, the total mass of the initial steel balls M, and the amount of ore entering the mill Q i On-site operating parameters;

[0046] Step 3, calculate the required additional steel ball size and quantity through the steel ball wear mathematical model and the steel ball unit consumption mathematical model respectively;

[0047] (1) Mathematical model of steel ball wear

[0048] Combined with the wear law of steel balls, the mathematical model of adding steel balls is obtained:

[0049] Steel ball wear characteristic parameter matrix S kj (t) Through S kj =(D k 3 -D k+1 3 ) / D j 3 , D k is the ball diameter value corresponding to the kth position, D k+1 is the ball diameter value corresponding to the k+1th position, D j is the ball diameter value corresponding to the jth position (k=1,2,…,n; j=1,2,…,n);

[0050] The calculated steel ball wear characteristic parameter matrix is:

[0051]

[0052] Cycle sampling time t s = Within 300s, the total mass of the initially installed steel balls is M = 150t, and the mass of the additional steel balls corresponding to the ball diameter k is:

[0053]

[0054] Where: M is the total mass of the initial steel balls collected in Step 2;

[0055] S kj (t) is the steel ball wear characteristic parameter matrix, j = 1, 2, ..., n;

[0056] is the vector representation of the initial ball loading ratio in Step 1;

[0057] m={m1,m2,…,m j ,…m n}, m is the size of the steel ball added to the mill corresponding to the mass of the steel ball;

[0058] u is the correction factor for steel ball wear;

[0059] Assume that at a certain time after the mill runs for t, the mass of steel balls added is m = {22.5, 37.5, 52.5, 37.5}, and the correction coefficient of steel ball wear is u = 1;

[0060] Calculated by the above model, within one sampling period, 0.47 kg of 70 mm steel balls need to be added, 0.88 kg of 50 mm steel balls need to be added, and 0.78 kg of 40 mm steel balls need to be added; if the mass of the steel balls to be added is less than the mass of one steel ball, the accumulated value will be used for the next period.

[0061] (2) Mathematical model of steel ball consumption

[0062] According to the relationship between the output of grinding products and the wear of steel balls, the empirical coefficient of steel ball unit consumption is determined as x; the mathematical model of steel ball unit consumption is:

[0063] Cycle sampling time t s The mass of the steel ball that needs to be added to the ball diameter corresponding to k is:

[0064]

[0065] Where: Q i The grinding amount in Step 2;

[0066] t is the mill running time collected in Step 2;

[0067] Assume that the empirical coefficient x of steel ball consumption of this mill is 0.18, the mill runs for 24 hours, and the amount of ore processed is Q i It is 3360 tons.

[0068] According to calculations, at this moment, within one sampling period, 0.58kg of 70mm steel balls need to be added, 0.99kg of 50mm steel balls need to be added, and 0.53kg of 40mm steel balls need to be added.

[0069] Step 4. Comprehensively analyze the calculation results of the steel ball wear mathematical model and the steel ball unit consumption mathematical model to select the optimal size and quantity of additional steel balls;

[0070] By comparing the deviations of the two model results and using the N-1 method (N>2) for optimization, the mathematical model calculation results of the steel ball wear show that the optimal size and quantity of additional steel balls are Φ70:Φ50:Φ40=0.47kg:0.88kg:0.78kg;

[0071] Step 5: DCS controls the optimal size and quantity of additional steel balls obtained in Step 4 to be added to the mill.

[0072] Example 2

[0073] like Figure 1 As shown, taking a ball mill of a mining enterprise in Panzhihua, Sichuan as an example, the continuous ball adding method for wet fine grinding has the following specific steps:

[0074] Step 1. Determine the diameter and ratio of the steel balls

[0075] The ball diameter semi-theoretical formula is used to calculate the precise ball diameter required for each group of ore particles to be ground, and the initial ball ratio is completed in combination with crushing statistical mechanics. Indicated by; the initial assembly ratio of the steel balls in this example is Φ40:Φ30:Φ25=45:30:25, using vector Expressed as {45%, 30%, 25%} T ; Based on the initial ball ratio, the supplementary ball ratio is determined by drawing a graph; first, the cumulative curve of the initial ball ratio is drawn. Its wear curve will move to the lower left. To maintain the original initial ball curve, the supplementary curve can be obtained by moving the initial ball curve to the upper right in parallel. Figure 3 It is concluded that the ratio of the additional balls is Φ40:Φ30=60:40;

[0076] Step 2: Collect on-site operating parameters

[0077] Collect the mill running time t, the steel ball mass m corresponding to the size of the steel ball added to the mill, the total mass of the initial steel balls M, and the amount of ore entering the mill Q iOn-site operating parameters;

[0078] Step 3, calculate the required additional steel ball size and quantity through the steel ball wear mathematical model and the steel ball unit consumption mathematical model respectively;

[0079] (1) Mathematical model of steel ball wear

[0080] Combined with the wear law of steel balls, the mathematical model of adding steel balls is obtained:

[0081] Steel ball wear characteristic parameter matrix S kj (t) Through S kj =(D k 3 -D k+1 3 ) / D j 3 , D k is the ball diameter value corresponding to the kth position, D k+1 is the ball diameter value corresponding to the k+1th position, D j is the ball diameter value corresponding to the jth position (k=1,2,…,n; j=1,2,…,n);

[0082] The calculated steel ball wear characteristic parameter matrix is:

[0083]

[0084] Cycle sampling time t s = Within 300s, the total mass of the initially installed steel balls is M = 120t, and the mass of the additional steel balls corresponding to the ball diameter k is:

[0085]

[0086] Where: M is the total mass of the initial steel balls collected in Step 2;

[0087] S kj (t) is the steel ball wear characteristic parameter matrix, j = 1, 2, ..., n;

[0088] is the vector representation of the initial ball loading ratio in Step 1;

[0089] m={m1,m2,…,m j ,…m n}, m is the size of the steel ball added to the mill corresponding to the mass of the steel ball;

[0090] u is the correction factor for steel ball wear;

[0091] Assume that at a certain time after the mill runs for t, the mass of steel balls added is m = {54.0, 36.0, 30.0}, and the correction coefficient of steel ball wear is u = 1;

[0092] Calculated by the above model, within one sampling period, 1.32 kg of 40 mm steel balls need to be added, and 0.65 kg of 30 mm steel balls need to be added; if the mass of the steel balls to be added is less than the mass of one steel ball, the accumulated value will be used for the next period.

[0093] (2) Mathematical model of steel ball consumption

[0094] According to the relationship between the output of grinding products and the wear of steel balls, the empirical coefficient of steel ball unit consumption is determined as x; the mathematical model of steel ball unit consumption is:

[0095] Cycle sampling time t s The mass of the steel ball that needs to be added to the ball diameter corresponding to k is:

[0096]

[0097] Where: Q i The grinding amount in Step 2;

[0098] t is the mill running time collected in Step 2;

[0099] Assume that the empirical coefficient x of steel ball consumption of this mill is 0.21, the mill runs for 24 hours, and the amount of ore processed is Q i It is 2640 tons.

[0100] According to calculations, 1.16 kg of 40 mm steel balls and 0.77 kg of 50 mm steel balls need to be added during one sampling period at this moment.

[0101] Step 4. Comprehensively analyze the calculation results of the steel ball wear mathematical model and the steel ball unit consumption mathematical model to select the optimal size and quantity of additional steel balls;

[0102] By comparing the deviations of the two model results and using the N-by-N method (N≤2) for optimization, it is concluded that the steel ball wear mathematical model calculation result is the optimal size and quantity of additional steel balls, that is, Φ40:Φ30=1.32kg:0.65kg;

[0103] Step 5: DCS controls the optimal size and quantity of additional steel balls obtained in Step 4 to be added to the mill.

[0104] The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A continuous ball adding method for wet fine grinding, characterized in that The specific steps are as follows: Step 1. Determine the diameter and ratio of the steel balls The ball diameter semi-theoretical formula is used to calculate the precise ball diameter required for each group of ore particles to be ground, and the initial ball ratio is completed in combination with crushing statistical mechanics. express; Step 2: Collect on-site operating parameters Collect the mill running time t, the steel ball mass m corresponding to the size of the steel ball added to the mill, the total mass of the initial steel ball M, and the amount of ore entering the mill Q i On-site operating parameters; Step 3, calculate the required additional steel ball size and quantity through the steel ball wear mathematical model and the steel ball unit consumption mathematical model respectively; (1) Mathematical model of steel ball wear Combined with the wear law of steel balls, the mathematical model of adding steel balls is obtained: Cycle sampling time t s The mass of the steel ball that needs to be added to the ball diameter corresponding to k is: Where: M is the total mass of the initial steel balls collected in Step 2; S kj (t) is the steel ball wear characteristic parameter matrix, j = 1, 2, ..., n; is the vector representation of the initial ball loading ratio in Step 1; m={m1,m2,…,m j ,…m n }, m is the size of the steel ball added to the mill corresponding to the mass of the steel ball; u is the correction factor for steel ball wear; (2) Mathematical model of steel ball consumption According to the relationship between the output of grinding products and the wear of steel balls, the empirical coefficient of steel ball unit consumption is determined as x; the mathematical model of steel ball unit consumption is: Cycle sampling time t s The mass of the steel ball that needs to be added to the ball diameter corresponding to k is: Where: Q i The grinding amount in Step 2; t is the mill running time collected in Step 2; Step 4. Comprehensively analyze the calculation results of the steel ball wear mathematical model and the steel ball unit consumption mathematical model to select the optimal size and quantity of additional steel balls; Step 5: DCS controls the optimal size and quantity of additional steel balls obtained in Step 4 to be added to the mill.

2. The continuous ball adding method for wet fine grinding according to claim 1, characterized in that: The steel ball wear characteristic parameter matrix S in Step 2 kj (t) Through S kj =(D k 3 -D k+1 3 ) / D j 3 Calculated, D k is the ball diameter value corresponding to the kth position, D k+1 is the ball diameter value corresponding to the k+1th position, D j is the ball diameter value corresponding to the jth position (k=1,2,…,n; j=1,2,…,n).

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