Method for improving separation efficiency of high-gradient magnetic separator

Abstract

The invention relates to a method for improving the separation efficiency of a high-gradient magnetic separator, and belongs to the technical field of high-gradient magnetic separation. The method comprises the following steps: firstly, screening or grading to-be-separated materials of a high-gradient magnetic separator, and dividing the to-be-separated materials into a plurality of particle grades from fine to coarse; sorting operation is carried out in a single high-gradient magnetic separator, materials with the finest fraction are firstly added, and then materials with the thicker fraction are sequentially added until feeding is finished. According to the high-gradient magnetic separator, the strong magnetic area around the magnetic medium is fully utilized for separating fine particles, the weak magnetic area around the magnetic medium is fully utilized for separating coarse particles, the capturing probability of fine particle materials is improved, the separation precision of coarse particle materials is improved, and therefore the separation efficiency of the high-gradient magnetic separator is effectively improved.

Description

Technical Field

[0001] The invention relates to a method for improving the separation efficiency of a high gradient magnetic separator, and belongs to the technical field of high gradient magnetic separation. Background Art

[0002] High gradient magnetic separation is an important method for separating weakly magnetic materials. In the field of mineral processing, high gradient magnetic separation is widely used for the separation of weakly magnetic minerals and non-metallic minerals. The particle size of the ore particles has a significant effect on the magnetism of the ore particles. Conventionally, the minerals are generally classified into coarse and fine particles, and the coarse and fine particles are separated by different magnetic separators or other separate treatments.

[0003] The magnetic medium is the core component of the high gradient magnetic separator. In a uniform background magnetic field, the magnetic field force distribution in the magnetic attraction zone around the round rod magnetic medium shows the characteristics of being strong inside and weak outside, that is, the closer to the surface of the magnetic medium, the greater the magnetic field force. The area close to the surface of the magnetic medium with a larger magnetic field force is called a strong magnetic area, and the area slightly away from the surface of the magnetic medium with a relatively small magnetic field force is called a weak magnetic area. The strong magnetic area can capture both fine particles and coarse particles at the same time, while the weak magnetic area can only capture coarse particles. In other words, only the strong magnetic area can capture fine particles. If the area is occupied by coarse particles, then fine particles are difficult to capture. This is one of the important reasons why fine particles of useful minerals are easily lost in production practice.

[0004] After years of research, the inventors have found that if the materials are graded, and then the coarse and fine particle grades are sent to different magnetic separators for separation, the magnetic competition for capture between coarse particles and fine particles can be effectively avoided, which is beneficial to the recovery and separation of fine particle materials. However, for magnetic separators for separating fine particles, the weak magnetic area around the magnetic medium can be used to capture coarse particles, but it is idle and wasted; for magnetic separators for separating coarse particles, since the magnetic force provided by the strong magnetic area of ​​the magnetic medium is very large, low-grade coarse particles will be captured, thereby reducing the separation accuracy. In addition, the grading-coarse / fine branch magnetic separation requires an increase in the number of high-gradient magnetic separators and complicates the production process. If the strong and weak magnetic areas around the magnetic medium can be fully utilized to complete the separation of fine and coarse particles on a single magnetic separator, the separation efficiency of the high-gradient magnetic separator can be maximized. Summary of the invention

[0005] In order to maximize the separation efficiency of a high gradient magnetic separator, the present invention provides a method for improving the separation performance of a high gradient magnetic separator, which is achieved through the following technical solutions.

[0006] A method for improving the separation efficiency of a high gradient magnetic separator, wherein the material to be separated by the high gradient magnetic separator is pre-screened or graded to separate it into several particle sizes from fine to coarse; the separation operation is performed in a single high gradient magnetic separator, the material of the finest particle size is added first, and then the materials of the coarser particle sizes are added in sequence until the feeding is completed.

[0007] The materials to be selected by the high gradient magnetic separator are first screened or graded, from fine to coarse, into P1, P2, ..., P n-1 , P n Particle size, n≥2.

[0008] When the high gradient magnetic separator is a continuous high gradient magnetic separator, the magnetic medium box is provided with feed ports A1, A2, ..., A3, A4, A5, A6, A7, A8, A9, A10, A20, A31, A42, A53, A64, A75, A76, A8, A9, A10, A110, A120, A130, A140, A150, A160, A17 n-1 , Feed port A n , feed port A1, feed port A2, ..., feed port A n-1 , Feed port A n The corresponding particle sizes of the materials to be selected are P1, P2, ..., P n-1 , P n Particle size, n≥2.

[0009] The high gradient magnetic separator is a wet high gradient magnetic separator or a dry high gradient magnetic separator.

[0010] The principle of the present invention is as follows Figure 1 As shown:

[0011] like Figure 1 As shown in A, under the action of the uniform background magnetic field B0, the magnetic medium will be magnetized, and magnetic attraction areas will be induced on the upper and lower sides parallel to B0. The closer to the surface of the magnetic medium, the greater the magnetic field force. For the convenience of description, the magnetic attraction area around the magnetic medium is divided into a strong magnetic area and a weak magnetic area. The weak magnetic area can only capture coarse particles, and the strong magnetic area can capture fine particles and coarse particles at the same time. When directly feeding-magnetic separation, the strong magnetic area will be occupied by some coarse particles, and fine particles are easily lost into the tailings due to the lack of sufficient capture sites. In addition, low-grade lean intergrowths can be captured in the strong magnetic area, such as Figure 1 As shown in B.

[0012] If the strong magnetic area and weak magnetic area around the magnetic medium can be fully utilized to separate fine particles and coarse particles respectively, the fine particles will have more capture sites, and low-grade coarse particles will not easily enter the magnetic separation concentrate. To achieve this effect, the present invention proposes a material classification method - first fine and then coarse feeding for magnetic separation, such as Figure 1 C. In this way, the strong magnetic area of ​​the magnetic medium will give priority to sorting fine-grained materials, greatly increasing the probability of capturing fine-grained materials, which is beneficial to improving the recovery rate; then the weak magnetic area is used to sort coarse-grained materials, avoiding the capture of low-grade coarse particles in the strong magnetic area, which is beneficial to improving the concentrate grade.

[0013] The beneficial effects of the present invention are:

[0014] The present invention makes full use of the strong magnetic field around the magnetic medium to separate fine particles and the weak magnetic field to separate coarse particles, which is beneficial to improving the capture probability of fine particle materials and the separation accuracy of coarse particle materials, thereby effectively improving the separation efficiency of the high gradient magnetic separator. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the principle of the present invention; wherein A is the magnetic field area distribution around the magnetic medium; B is a schematic diagram of the particle capture distribution around the magnetic medium when direct feeding-magnetic separation is adopted; C is a schematic diagram of the particle capture distribution around the magnetic medium when the classification-fine-then-coarse magnetic separation proposed by the present invention is adopted.

[0016] Figure 2 This is a diagram of the implementation of the present invention on a continuous high gradient magnetic separator. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0018] Example 1

[0019] A comparative test was conducted in a periodic pulsating high gradient magnetic separator using ilmenite tailings with a particle size of -500 mesh accounting for 70.71% and a TiO2 grade of 4.30% as raw materials. The first group directly separated the raw materials by magnetic separation; the second group first used a 500-mesh standard sieve to screen the raw materials into coarse and fine particles. During the test, the fine particles were first fed, and then the coarse particles were fed. Under the same background magnetic field (0.8T), feed flow rate (3cm / s), pulsating stroke (14mm), and pulsating stroke (300rpm), the comparative indicators of the two groups of tests are shown in Table 1.

[0020] As can be seen from Table 1, by adopting the classification-fine-first-coarse magnetic separation scheme described in the present invention, the TiO2 grade of the concentrate can be increased from 13.66% to 14.94%, the TiO2 recovery rate can be increased from 58.27% to 64.81%, and the mineral processing efficiency can be significantly improved.

[0021] Table 1

[0022]

[0023] Example 2

[0024] A copper sulfide ore with a grinding fineness of -325 mesh accounting for 50.27% and a Cu grade of 0.532% was used as raw material, and a comparative test study was carried out in a periodic pulsating high-gradient magnetic separator. The first group directly magnetically separated the raw materials; the second group first used a 325-mesh standard sieve to screen the raw materials into coarse and fine particles. During the test, the fine particles were first fed, and then the coarse particles were fed. Under the same background magnetic field (1.5T), feed flow rate (3.5cm / s), pulsation stroke (5mm), and pulsation stroke (200rpm), the comparative indicators of the two groups of tests are shown in Table 2.

[0025] Table 2

[0026]

[0027] As shown in Table 2, by adopting the classification-fine-first-coarse magnetic separation scheme of the present invention, the Cu grade of the concentrate can be increased from 1.02% to 1.56%, the Cu recovery rate can be increased from 47.69% to 64.53%, and the ore dressing efficiency can be significantly improved.

[0028] Example 3

[0029] A comparative test was carried out on a continuous large-particle high-gradient magnetic separator using a specularite ore with a particle size of -3.0 mm and an Fe grade of 17.85%.

[0030] The first group directly magnetically separates the raw materials;

[0031] The second group used a double-layer linear vibrating screen to screen the raw materials into three particle sizes: -0.5mm (yield 45%, marked as P1), 0.5-1.5mm (yield 30%, marked as P2) and 1.5-3.0mm (yield 25%, marked as P3). During the test, the feed port of the continuous high-gradient magnetic separator was divided into three parts, which were marked as A1, A2 and A3 along the direction of movement of the magnetic medium box, among which A1 was the first feed port after the magnetic medium entered the separation area. A3 is the last feed port before the magnetic medium leaves the separation area. The screened or graded materials are fed into the corresponding feed port, wherein P1 grade materials are fed into A1 feed port, P2 grade materials are fed into A2 feed port, and P3 grade materials are fed into A3 feed port. When the high-gradient magnetic separation operation is carried out continuously, the magnetic medium will first contact and separate the materials fed into A1 feed port, and then contact and separate the materials fed into A2 and A3 feed ports in turn until the high-gradient magnetic separation operation is completed.

[0032] Under the same background magnetic field (0.6T), feed flow rate (3cm / s), pulsation stroke (5mm), and pulsation frequency (300rpm), the comparative indicators of the two groups of tests are shown in Table 3.

[0033] Table 3

[0034]

[0035] It can be seen from Table 3 that by adopting the classification-fine-first-coarse magnetic separation scheme described in the present invention, the Fe grade of the concentrate can be increased from 31.69% to 35.46%, the Fe recovery rate can be increased from 89.98% to 91.97%, and the mineral processing efficiency can be significantly improved.

[0036] 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 method for improving the separation efficiency of a high gradient magnetic separator, characterized in that: The materials to be selected in the high gradient magnetic separator are pre-screened or graded, and divided into several particle sizes from fine to coarse; the sorting operation is carried out in a single high gradient magnetic separator, the finest particle size material is added first, and then the coarser particle size materials are added in sequence until the feeding is completed.

2. The method for improving the separation efficiency of a high gradient magnetic separator according to claim 1, characterized in that: The materials to be selected by the high gradient magnetic separator are first screened or graded, from fine to coarse, into P1, P2, ..., P n-1 , P n Particle size, n≥2.

3. The method for improving the separation efficiency of a high gradient magnetic separator according to claim 2, characterized in that: When the high gradient magnetic separator is a continuous high gradient magnetic separator, the moving direction of the magnetic medium box in the high gradient magnetic separator is respectively provided with feed ports A1, A2, ..., A n-1 , Feed port A n , feed port A1, feed port A2, ..., feed port A n-1 , Feed port A n The corresponding particle sizes of the materials to be selected are P1, P2, ..., P n-1 , P n Particle size, n≥2.

4. The method for improving the separation efficiency of a high gradient magnetic separator according to claim 2, characterized in that: The high gradient magnetic separator is a wet high gradient magnetic separator or a dry high gradient magnetic separator.

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