CN103056020A - Maximum optional size grading process for beneficiation and grinding - Google Patents

Abstract

The invention relates to a process for classifying the maximum optional particle size in ore dressing, which belongs to the process of beneficiation, grinding and classifying. The largest optional particle size classification process in ore dressing and grinding is characterized in that it includes the following steps: the belt feeds the ore into the ball mill, and the minerals flowing out of the grid plate of the ball mill enter the cyclone for classification from the discharge of the ball mill; The returned sand after classification by the cyclone returns to the grinding machine, and the overflow product after classification by the cyclone enters the high-frequency vibrating screen for two-stage classification. together into the grit chamber, and then sent to the cyclone by the sand pump to complete the closed-circuit classification cycle operation, and the under-screen product of the high-frequency vibrating screen enters the flotation feed. This process improves classification efficiency.

Description

The Largest Optional Particle Size Classification Process in Mineral Concentration and Grinding

technical field

The invention relates to a process for classifying the maximum optional particle size in ore dressing, which belongs to the process of beneficiation, grinding and classifying.

Background technique

The flow chart of the existing primary grinding and grading process is shown in Figure 2. The disadvantage is that the grading efficiency of the existing process is low.

We think that the flotation feed mineral materials after different grinding and classification processes are composed of different particle sizes, and this different particle size composition has a significant impact on the recovery rate of flotation operations. For example, in the flotation process of Dexing Copper Mine, the flotation recovery rate of +120 mesh particle size in the selected material is much lower than the flotation recovery rate of -200 mesh ~+400 mesh particle size of the intermediate particle size. In order to study the relationship between ore particle size composition and sorting index, we invented the maximum optional particle size classification process to improve ore particle size composition and sorting index.

Contents of the invention

The object of the present invention is to provide a maximum optional particle size classification process in ore dressing and grinding, which can improve the classification efficiency.

In order to achieve the above object, the technical solution adopted by the present invention is: the largest optional particle size classification process in ore dressing and grinding, which is characterized in that it includes the following steps: the belt feeds the ore into the ball mill, and the minerals flowing out from the grid plate of the ball mill From the discharge of the ball mill, it enters the cyclone classification (that is, the first-stage classification); the returned sand after the cyclone classification returns to the mill, and the overflow product after the cyclone classification enters the high-frequency vibrating screen for the second-stage classification; The returned sand of the high-frequency vibrating screen larger than the maximum optional particle size Dxmax enters the grit chamber together with the ball mill discharge, and then is lifted into the cyclone by the sand pump to complete the closed-circuit classification cycle operation. The under-screen product of the high-frequency vibrating screen Enter the flotation to ore (the next process).

The maximum optional screen aperture of the high-frequency vibrating screen is the same as the particle size of the maximum optional particle size Dxmax, and the maximum optional particle size Dxmax particle size ranges from 0.2mm to 0.3mm (60 mesh to 80 mesh).

Controlling the maximum optional particle size Dxmax is to determine the maximum optional particle size Dxmax for flotation on the basis of fully studying the intercalation particle size characteristics of useful metal minerals according to experiments and field experience. This concept of controlling the maximum optional particle size Dxmax can form the maximum optional particle size classification process, that is, the overflow product of a stage of classification (such as the first stage of Dexing hydrocyclone) is classified by high-frequency fine sieve, and the product under the screen enters In flotation, the products on the sieve will all be returned to the grinding.

Adjust the content of coarse-grained and fine-grained ore-discharging products of the ball mill to increase the content of intermediate grains, and then optimize the grain-graded composition of the flotation feed mineral material. The returned sand after the first-stage cyclone classification returns to the grinding machine, and the overflow product after the cyclone classification enters the high-frequency vibrating screen for the second-stage classification; the returned sand of the high-frequency vibrating screen is larger than the maximum optional particle size Dxmax and The ore discharged by the ball mill enters the grit chamber together, and then is sent to the cyclone by the sand pump to complete the closed-circuit classification cycle operation, and the under-screen product of the high-frequency vibrating screen enters the flotation feed (the next process). The control of the maximum optional particle size Dxmax is based on the full study of the intercalation particle size characteristics of useful metal minerals, and the initial determination of the maximum optional particle size Dxmax for flotation based on experiments and field experience. For the particle size greater than Dxmax, use high-efficiency grading equipment (such as high-frequency vibrating screen) to classify according to particle size, so that all of them can be returned to regrind, forming a closed circuit with the grinding machine. Change the Dxmax value of the high-frequency vibrating screen, the parameters of the ball mill and other factors to conduct multi-factor orthogonal experiments, and determine the relatively optimal combination of grinding conditions based on the particle size composition in the overflow, that is, reduce the content of coarse and fine particles, Increase the intermediate fraction content. According to the embedded particle size of different ores, several different flotation maximum optional particle sizes Dxmax are preliminarily determined, and then according to the test results to determine which size to choose for Dxmax.

In actual flotation, the optimal grading particle size composition is related to many factors such as the density of the ore, the physical and chemical properties of the surface, the collection capacity of the flotation agent on the ore particles, and the chemical properties (viscosity, concentration) of the pulp solution. Therefore, we It is considered that an evaluation system can be established by combining the flotation raw ore, concentrate, tailings screening data and quantity and quality indicators. For example, the relationship between each particle size and its recovery rate can be obtained by linear fitting or least square method, and the actual flotation rate can be obtained by calculation. Select the maximum optional granularity Dxmax.

The calculation method is: according to the flotation raw ore, concentrate and tailings screening results, the arithmetic average particle size d is _used to replace the particle size range, and the recovery rate ε _d of each particle size distribution in the concentrate is calculated. This index can It fully shows the recovery of each particle size in the raw ore, which can be used to determine the maximum optional particle size Dxmax, which is the particle size with zero recovery rate in the concentrate. The ε _d -d _arithmetic relationship curve can be used to optimize the particle size composition of flotation, thus providing a theoretical basis for the quality classification and Dxmax classification process.

The calculation formula of ε _d is:

In the formula: ε _d —the recovery rate of each particle size distribution in the concentrate;

_εfine —the recovery rate of flotation concentrate;

_εtailing —the recovery rate of flotation tailings.

And through the method of linear fitting, the maximum optional particle size Dxmax of the obtained data is obtained, and then the determined Dxmax is used to guide the grinding-one stage classification-high-frequency fine sieve classification process.

Determine the maximum optional particle size Dxmax of flotation according to the test and field experience: change the maximum optional particle size Dxmax of the high-frequency vibrating screen, ball mill parameters and other factors to conduct multi-factor orthogonal experiments, and determine based on the particle size composition in the overflow Relative to the best combination of grinding conditions, according to the particle size of different ores, several different maximum optional particle sizes Dxmax for flotation are preliminarily determined, and then according to the test results to determine which size to choose for the maximum optional particle size Dxmax.

An evaluation system can be established by combining the flotation raw ore, concentrate, tailings screening data and quantity and quality indicators. For example, the relationship between each particle size and its recovery rate can be obtained by linear fitting or least square method, and the actual flotation rate can be obtained through calculation. The maximum optional granularity Dxmax.

The maximum optional particle size classification process is shown in Figure 1. After the ball mill discharge material is classified by the cyclone, the high-frequency fine screen is used to carry out the Dxmax classification process to improve the classification efficiency and improve the particle size composition of the final flotation feed.

The beneficial effect of the invention is that the process can improve the classification efficiency.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Fig. 2 is a flow chart of the existing primary grinding and grading process.

Detailed ways

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

Embodiment 1 (the second grinding section of Sizhou Concentrator):

As shown in Figure 1, the maximum optional particle size classification process in ore dressing and grinding includes the following steps: the belt feeds the ore into the ball mill, and the minerals flowing out of the grid plate of the ball mill enter the cyclone from the discharge of the ball mill ( That is, the existing cyclone, because it is a stage of classification, it can be called a stage of cyclone, or a one-stage cyclone) classification (that is, a stage of classification); the returned sand after the cyclone classification is returned to the grinding machine, The overflow product after hydrocyclone classification enters the high-frequency vibrating screen (existing equipment) for second-stage classification; the returned sand of the high-frequency vibrating screen is larger than the maximum optional particle size Dxmax and enters the sand settling together with the ball mill discharge Then the sand pump will send it into the cyclone to complete the closed-circuit classification cycle operation, and the under-screen product of the high-frequency vibrating screen will enter the flotation feed (the next process).

The maximum optional sieve aperture of the high-frequency vibrating screen is the same as the maximum optional particle size Dxmax particle size. The particle size range of the maximum optional particle size Dxmax is (0.2mm~0.3mm), that is, (60 mesh~80 mesh).

In practice, the optimal grading particle size composition in actual flotation is related to many factors such as the density of the ore, the physical and chemical properties of the surface, the collection ability of the flotation agent on the ore particles, and the chemical properties (viscosity, concentration) of the pulp solution. In the field industrial test, the flotation feed +0.2mm (ie +80mm) is not an optional particle size. Therefore, the particle size of the maximum optional particle size Dxmax is selected as 80 mesh, that is, the screen size of the high-frequency vibrating screen is set at about 0.2mm.

After the industrial test, the grading index obtained by the maximum optional grading process is compared with the original grading process index, and the results are as follows:

For each test sample in the maximum optional particle size classification process (classification process of the present invention), the concentration and fineness of each sample after screening and analysis are shown in Table 1-1.

Table 1-1 Concentration and fineness results of each product in the maximum optional particle size classification process

According to Table 1-1, we can calculate the classification efficiency of the first-stage hydrocyclone and the second-stage high-frequency vibrating fine screen according to the newly generated -200 mesh particle size. The calculation results of grinding and grading are shown in Table 1-2.

Table 1-2: Maximum optional particle size classification process (classification process of the present invention) classification efficiency

project name unit/% 10# ball Total Grading Efficiency % 62.97 one-stage graded efficiency % 70.82 Two stage classification efficiency % 88.92

The concentration and fineness distribution of each sample in the original grinding and grading process after screening and analysis is shown in Table 1-3.

Table 1-3 Concentration and fineness distribution of each product in the original grinding and classification process

According to Table 1-3, we can calculate the classification efficiency of the first-stage hydrocyclone and the second-stage high-frequency vibrating fine screen according to the newly generated -200 mesh particle size. The classification efficiency calculation results are shown in Table 1-4.

Table 1-4: Classification efficiency of primary grinding and classification process

project name unit/% 8 ^# ball Total Grading Efficiency % 50.01 one-stage graded efficiency % 64.44 Two stage classification efficiency % 77.60

In summary, the total classification efficiency of the maximum optional particle size classification process is 62.97%, the first-stage classification efficiency is 70.82%, and the second-stage classification efficiency is 88.92%; the total classification efficiency of the original grinding classification is 50.01%, the first-stage classification efficiency is 64.44%, and the second-stage classification efficiency is 77.60% %. It can be seen that the maximum optional particle size classification process (classification process of the present invention) is compared with the original grinding and classification process, the total classification efficiency has improved by 25.92%, the first-stage classification efficiency has improved by 9.90%, and the second-stage classification efficiency has improved by 14.58% .

Claims (2)

1. The maximum optional particle size classification process in ore dressing and grinding is characterized in that it includes the following steps: the belt feeds the ore into the ball mill, and the minerals flowing out of the grid plate of the ball mill enter the cyclone for classification from the discharge of the ball mill; The returned sand after cyclone classification returns to the grinding machine, and the overflow product after cyclone classification enters the high-frequency vibrating screen for second-stage classification; the returned sand of the high-frequency vibrating screen is larger than the maximum optional particle size Dxmax and ball milling The discharged ore enters the grit chamber together, and then is sent to the cyclone by the sand pump to complete the closed-circuit classification cycle operation, and the under-screen product of the high-frequency vibrating screen enters the flotation feed. 2. The maximum optional particle size classification process in ore dressing and grinding according to claim 1 is characterized in that: the maximum optional screen aperture of the high-frequency vibrating screen is the same as the particle diameter of the maximum optional particle size Dxmax particle size, and the maximum The optional particle size Dxmax ranges from 0.2mm to 0.3mm.

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