Pre-sorting method for comprehensive utilization of high-intensity magnetic separation tailings

Abstract

A pre-sorting method for comprehensive utilization of high-intensity magnetic separation tailings. By using the characteristics of fine particle size and low iron mineral content of high-intensity magnetic separation tailings, silicon dioxide pre-sorted concentrates having a purity of more than 98% are obtained by means of first-stage high-intensity magnetic separation, ore grinding, second-stage high-intensity magnetic separation, centrifugal machine desliming, and flotation separation.

Description

A pre-separation method for comprehensive utilization of strong magnetic tailings Technical Field

[0001] The invention relates to the technical field of mineral processing, in particular to a pre-separation method for comprehensive utilization of strong magnetic tailings. Background Art

[0002] Currently, the comprehensive utilization of tailings resources is a national strategic development industry. On the one hand, comprehensive tailings utilization can recover valuable components from tailings, realizing resource utilization. On the other hand, comprehensive tailings utilization can reduce tailings emissions and achieve high-value utilization of tailings, resulting in significant economic and social benefits. Existing iron tailings utilization technologies primarily include: iron recovery from iron tailings; silicon recovery from iron tailings; use of iron tailings as building materials; and use of iron tailings as soil conditioners. In my country's conventional "stage grinding, coarse and fine separation-gravity magnetic flotation combined process" for iron ore sorting, the combined tailings consist of coarser-gravity magnetic tailings and finer-grained strong magnetic tailings and flotation tailings. Existing iron tailings comprehensive utilization technologies, with the exception of "iron recovery from iron tailings" that utilizes flotation tailings, all others utilize combined tailings for recovery. Furthermore, these technologies often focus solely on recovering valuable components (silicon or iron) or on a single utilization method, rarely considering a comprehensive approach to various utilization options. Since there are great differences in the particle size and content of each component element of the medium magnetic tailings, strong magnetic tailings and flotation tailings, different comprehensive utilization directions and comprehensive utilization technology studies are carried out on them respectively. At the same time, comprehensive consideration of the recovery of valuable components and other comprehensive utilization methods can make the comprehensive utilization of tailings more economical and reasonable, which is conducive to obtaining higher economic benefits, realizing large-scale disposal of tailings and reducing tailings emissions.

[0003] Summary of the Invention

[0004] In view of the fact that most of the existing iron tailings comprehensive utilization technologies use comprehensive tailings for recycling, and various technical studies only consider the recovery of valuable components (silicon or iron) or only consider one utilization direction, and rarely consider various utilization directions comprehensively, the present invention provides a pre-separation method for comprehensive utilization of strong magnetic tailings. By utilizing the characteristics of strong magnetic tailings with fine particle size and low iron mineral content, a silicon dioxide pre-separation concentrate with a purity of more than 98% is obtained through a low-cost traditional mineral processing process, providing a low-cost raw material for further obtaining high-purity silicon dioxide with a purity of 99%-99.99% through existing mature technologies (such as acid leaching technology, etc.), and at the same time obtaining silicon extraction residue with a particle size of -0.045mm accounting for more than 95%. Due to its fine particle size, it does not require grinding and can be directly used as a raw material for preparing other building materials (such as cement).

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A pre-separation method for comprehensive utilization of strong magnetic tailings comprises the following steps:

[0007] 1) One-stage strong magnetic separation: The strong magnetic tailings produced in the on-site production process are separated by a one-stage strong magnetic machine to obtain a one-stage strong magnetic concentrate and a one-stage strong magnetic tailings. The one-stage strong magnetic concentrate contains TFe 5% to 7% and SiO2 80% to 85% by weight;

[0008] 2) Grinding: Most of the iron minerals in the first-stage strong magnetic concentrate exist in the form of conjoined bodies. The first-stage strong magnetic concentrate is ground into a particle size of ≤0.045mm, accounting for more than 95%;

[0009] 3) The ground product of step 2) is then separated by a second-stage strong magnetic machine to obtain a second-stage strong magnetic concentrate and a second-stage strong magnetic tailings. The second-stage strong magnetic concentrate contains TFe 2.5% to 4% and SiO2 85% to 90% by weight;

[0010] 4) Centrifuge desliming: The centrifuge can effectively remove the fine mud in the second-stage strong magnetic concentrate. The obtained centrifuge concentrate contains TFe 2% to 3.5% and SiO2 85% to 95% by weight, providing a product of suitable particle size for flotation;

[0011] 5) Flotation separation: The centrifuge concentrate is separated by direct flotation, reverse flotation or mixed direct and reverse flotation to obtain flotation concentrate and flotation tailings. The flotation concentrate contains TFe 0.5% to 2.0% and SiO2 93% to 99% by weight. The flotation concentrate can be used as a pre-separation concentrate and can be further processed by existing mature technologies (such as acid leaching technology) to obtain high-purity silicon dioxide with a purity of 99% to 99.99%.

[0012] The particle size of the processed strong magnetic tailings is ≤0.045mm, accounting for 65% to 85%. The main element chemical composition contains TFe 8% to 11% and SiO2 70% to 80% by weight.

[0013] The silicon extraction residue composed of the first stage strong magnetic tailings, the second stage strong magnetic tailings, the centrifuge tailings and the flotation tailings contains TFe 10% to 13.5% by weight, and the particle size ≤ 0.045 mm accounts for more than 85%.

[0014] The magnetic induction intensity of a strong magnetic machine is greater than 1.2T.

[0015] The magnetic induction intensity of the second-stage strong magnetic machine is greater than 1.2T.

[0016] Flotation operations can adjust the reagent system according to the different impurity contents in the centrifuge concentrate, remove iron and other impurities in a targeted manner, further increase the silica content, and reduce the reagent usage and cost of subsequent leaching operations, which are relatively expensive.

[0017] Strong magnetic separation, centrifuge desludging and flotation separation operations not only effectively reduce the iron mineral content in the tailings and increase the silica content, but also effectively remove some impurities such as calcium oxide and magnesium oxide.

[0018] The silicon extraction residue composed of the first stage strong magnetic tailings, the second stage strong magnetic tailings, the centrifuge tailings and the flotation tailings contains TFe 10% to 13.5% by weight, and the particle size of -0.045mm accounts for more than 85%. The silicon extraction residue does not need to be ground and can be directly used as a high-quality raw material for preparing other building materials (such as cement).

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention proposes a method of using different comprehensive utilization technologies to treat tailings according to the particle size and element content of each tailing that constitutes the comprehensive tailings. In view of the characteristics of strong magnetic tailings with fine particle size, low iron mineral content, and most of the iron minerals distributed below -0.025mm, which are difficult to economically recover, a technology is proposed to obtain silicon dioxide pre-selected concentrate through a low-cost traditional mineral processing process, and the silicon residue obtained at the same time can be directly used as a raw material for preparing other building materials (such as cement). Taking into account the recovery of valuable components and other comprehensive utilization methods, the comprehensive utilization of tailings can be made more economical and reasonable, which is conducive to obtaining higher economic benefits, realizing large-scale disposal of tailings, and reducing tailings emissions. The specific effects are as follows:

[0021] 1. The strong magnetic tailings produced in the on-site production process are separated by a strong magnetic machine under the condition of magnetic induction intensity greater than 1.2T, and a strong magnetic concentrate with low iron content and high silicon content can be obtained;

[0022] 2. Most of the iron minerals in the first stage strong magnetic concentrate exist in the form of conjoined bodies. Grinding them can improve the degree of dissociation and obtain more monomeric gangue. Then, through strong magnetic separation, the second stage strong magnetic concentrate with higher silicon content can be obtained.

[0023] 3. The two-stage strong magnetic operation not only effectively reduces the iron mineral content in the tailings, but also effectively removes some impurities such as calcium oxide and magnesium oxide.

[0024] 4. The second-stage strong magnetic concentrate has a fine particle size and is in a suspended state. The separation efficiency of other traditional mineral processing equipment is not good enough. The centrifuge can effectively remove the fine mud in the second-stage strong magnetic concentrate, which not only provides a suitable product for flotation, but also reduces the content of impurities such as calcium oxide and magnesium oxide in the centrifuge concentrate, reduces the amount of reagents used in subsequent operations, and greatly reduces costs.

[0025] 5. The flotation operation can adjust the reagent system according to the different impurity contents in the centrifuge concentrate, remove iron and other impurities in a targeted manner, further increase the silica content, reduce the reagent usage in the subsequent leaching operation with relatively high costs, and reduce costs.

[0026] 6. After flotation separation, a pre-sorted concentrate with a silicon dioxide content of 93-99% can be obtained, which provides low-cost raw materials for further obtaining high-purity silicon dioxide with a purity of 99% to 99.99% through existing mature technologies (such as acid leaching technology).

[0027] 7. The first stage strong magnetic tailings, second stage strong magnetic tailings, centrifuge tailings and flotation tailings are used as silicon extraction residues. Their components are still mainly silicon and iron, and the particle size is -0.045mm, accounting for more than 85%. No grinding is required, and they can be directly used as high-quality raw materials for the preparation of other building materials (such as cement). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a flow chart of a pre-separation method for comprehensive utilization of strong magnetic tailings according to the present invention. DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0030] Example 1:

[0031] As shown in Figure 1, this embodiment uses a certain stage of grinding, gravity-magnetic-flotation combined process to produce strong magnetic tailings, with a particle size of ≤0.045mm accounting for 77.27%, and the main element chemical composition by weight percentage contains TFe 8.51% and SiO2 78.16%. The following steps are followed for separation:

[0032] 1) The strong magnetic tailings produced in the on-site production process are separated by a first-stage strong magnetic machine under the condition of magnetic induction intensity of 1.4T to obtain a first-stage strong magnetic concentrate and a first-stage strong magnetic tailings. The first-stage strong magnetic concentrate contains 5.86% TFe and 82.27% SiO2 by weight;

[0033] 2) Most of the iron minerals in the first-stage strong magnetic concentrate exist in the form of conjoined bodies, which are ground into a particle size of ≤0.045mm (96.5%) using a tower mill;

[0034] 3) The ground products are then separated by a two-stage strong magnetic machine under the condition of magnetic induction intensity of 1.4T to obtain a two-stage strong magnetic concentrate and a two-stage strong magnetic tailings. The two-stage strong magnetic concentrate contains 3.71% TFe and 86.92% SiO2 by weight;

[0035] 4) The centrifuge can effectively remove the fine mud in the second-stage strong magnetic concentrate. The obtained centrifuge concentrate contains TFe 2.53% and SiO2 90.57% by weight, providing a product of suitable particle size for flotation.

[0036] 5) Using direct flotation, the centrifuge concentrate was separated under the following reagent conditions: pH = 9-10, 1800g / ton of starch, and 1000g / ton of collector, to obtain flotation concentrate and flotation tailings. The flotation concentrate contained TFe 1.00% and SiO2 95.03% by weight. The flotation concentrate was used as a pre-separated concentrate and subjected to high-temperature and high-pressure acid leaching at 180°C to obtain high-purity silica with a purity of 99.68%.

[0037] 6) The first stage strong magnetic tailings, second stage strong magnetic tailings, centrifuge tailings and flotation tailings are used as silicon extraction residues, and their composition is still mainly silicon and iron, with TFe 11.26%, SiO2 68.87%, and particle size ≤0.045mm accounting for 90.5%. This product does not require grinding and can be directly used as high-quality raw materials for the preparation of other building materials (such as cement).

[0038] Example 2:

[0039] As shown in Figure 1, this embodiment uses a certain stage of grinding, gravity-magnetic-flotation combined process to produce strong magnetic tailings, with a particle size of ≤0.045mm accounting for 77.27%, and the main element chemical composition by weight percentage contains TFe 8.51% and SiO2 78.16%. The following steps are followed for separation:

[0040] 1) The strong magnetic tailings produced in the on-site production process are separated by a first-stage strong magnetic machine under the condition of magnetic induction intensity of 1.4T to obtain a first-stage strong magnetic concentrate and a first-stage strong magnetic tailings. The first-stage strong magnetic concentrate contains 5.86% TFe and 82.27% SiO2 by weight;

[0041] 2) The iron minerals in the first-stage strong magnetic concentrate are mostly in the form of conjoined bodies, which are ground to a particle size of ≤ 0.045 mm, accounting for 96.5%;

[0042] 3) The ground products are then separated by a two-stage strong magnetic machine under the condition of magnetic induction intensity of 1.4T to obtain a two-stage strong magnetic concentrate and a two-stage strong magnetic tailings. The two-stage strong magnetic concentrate contains 3.71% TFe and 86.92% SiO2 by weight;

[0043] 4) The centrifuge can effectively remove the fine mud in the second-stage strong magnetic concentrate. The obtained centrifuge concentrate contains TFe 2.53% and SiO2 90.57% by weight, providing a product of suitable particle size for flotation.

[0044] 5) The centrifuge concentrate was separated using forward and reverse flotation operations. The forward flotation reagent system was: pH = 9-10, 900g / ton starch, and 1000g / ton collector; the reverse flotation reagent system was: pH = 2, 50g / ton dodecylamine, and 2000g / ton sodium petroleum sulfonate. Flotation concentrate and flotation tailings were obtained. The flotation concentrate contained 0.65% TFe and 98.04% SiO2 by weight. The flotation concentrate was used as a pre-separated concentrate and subjected to pressure acid leaching at normal temperature and pressure to obtain high-purity silica with a purity of 99.89%.

[0045] 6) The first stage strong magnetic tailings, second stage strong magnetic tailings, centrifuge tailings and flotation tailings are used as silicon extraction residues, and their composition is still mainly silicon and iron, with TFe 11.59%, SiO2 68.02%, and particle size ≤0.045mm accounting for 90.5%. This product does not require grinding and can be directly used as high-quality raw materials for the preparation of other building materials (such as cement).

Claims

1. A pre-separation method for comprehensive utilization of strong magnetic tailings, characterized in that: The following steps are involved: 1) One-stage strong magnetic separation: The strong magnetic tailings are separated by a one-stage strong magnetic machine to obtain a one-stage strong magnetic concentrate and a one-stage strong magnetic tailings. The one-stage strong magnetic concentrate contains TFe 5% to 7% and SiO2 80% to 85% by weight. 2) Grinding: Grind the first stage of strong magnetic concentrate with a tower mill to a particle size of ≤0.045mm accounting for more than 95%; 3) The grinding product of step 2) is further separated by a two-stage strong magnetic machine to obtain a two-stage strong magnetic concentrate and a two-stage strong magnetic tailings. The two-stage strong magnetic concentrate contains TFe 2.5% to 4% and SiO2 85% to 90% by weight; 4) Centrifuge desludging: A centrifuge is used to remove the mud in the second-stage strong magnetic concentrate. The obtained centrifuge concentrate contains TFe 2% to 3.5% and SiO2 85% to 95% by weight; 5) Flotation separation: The centrifuge concentrate is separated by flotation operation to obtain flotation concentrate and flotation tailings. The flotation concentrate contains TFe 0.5% to 2.0% and SiO2 93% to 99% by weight.

2. A pre-separation method for comprehensive utilization of strong magnetic tailings according to claim 1, characterized in that: The particle size of the processed strong magnetic tailings is ≤0.045mm, accounting for 65% to 85%, and contains TFe 8% to 11% and SiO2 70% to 80% by weight.

3. A pre-separation method for comprehensive utilization of strong magnetic tailings according to claim 1, characterized in that: The silicon extraction residues consisting of the first stage strong magnetic tailings, the second stage strong magnetic tailings, the centrifuge tailings and the flotation tailings contain TFe 10% to 13.5% by weight, and the particle size ≤ 0.045 mm accounts for more than 85%.

4. A pre-separation method for comprehensive utilization of strong magnetic tailings according to claim 1, characterized in that: The magnetic induction intensity of a strong magnetic machine is greater than 1.2T.

5. A pre-separation method for comprehensive utilization of strong magnetic tailings according to claim 1, characterized in that: The magnetic induction intensity of the two-stage strong magnetic machine is greater than 1.2T.

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