A new energy-saving mineral processing technology for processing fine-grained magnetite concentrate

Abstract

The present invention discloses a new energy-saving beneficiation process for processing fine-grained magnetite concentrate. The fine-grained magnetite concentrate is fed into a double-overflow, three-product hydrocyclone for classification, yielding an inner overflow product, an outer overflow product, and an underflow product. The underflow product is then screened on a high-frequency fine screen. The underflow product is combined with the inner overflow product and fed into a second-stage weak magnetic separation process. The outer overflow product is then fed into a third-stage weak magnetic separation process. The overflow product is combined with the middlings and fed into fine grinding and a second-stage weak magnetic separation process. The result is an iron concentrate with an iron grade exceeding 65.0% and an iron recovery rate of nearly 90.0%. This new energy-saving beneficiation process, through a multi-product hydrocyclone and fine screen combined classification process, fully achieves narrow-size selection. It also enables early pre-grinding concentrate, significantly reducing the amount of subsequent ore fed to the grinding mill. The final tailings can be used as an iron calibrant for cement production. The present invention offers advantages such as energy conservation and high economic efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetite beneficiation, and in particular relates to a new process for fine classification and efficient separation of micro-grained magnetite coarse concentrate, which can obtain iron concentrate in advance without grinding. Background Art

[0002] Fine-grained magnetite refers to ore with minutely finely embedded minerals that requires fine grinding to separate them. This typically refers to ore ground to less than 43 μm, achieving a degree of separation of the target minerals above 90%. Currently, there are two main types of large-scale iron ore concentrators in China: those primarily processing magnetite and those primarily processing hematite (including minor amounts of limonite, specularite, and siderite). Magnetite concentrate accounts for approximately three-quarters of my country's total iron ore production, and most iron ore mines, both domestically and internationally, are primarily targeting these two types of ores for their mineral processing technology innovations. Furthermore, the majority of overseas iron ore resources controlled by Chinese mining companies have poor ore properties and selectivity, primarily characterized by a generally fine embedded ore size, high impurity content, and a predominance of low-grade, fine-grained magnetite. The resource reserves for which mining rights have been granted exceed 20 billion tons.

[0003] The main challenges in fine-grained magnetite beneficiation are: ① The finely distributed particle size of the useful minerals generally requires two to three stages of grinding, which consumes considerable energy to break down into individual pieces. The accompanying over-grinding not only wastes energy but also degrades subsequent separation performance, making the classification of the ground product particularly important. ② For magnetite ores with finely distributed particle sizes, a process consisting of staged grinding, low-intensity magnetic separation, and reverse flotation is typically used. However, the addition of various chemical agents during flotation can cause significant environmental pollution. Therefore, it is crucial to find a process that can replace reverse flotation and produce a qualified concentrate without further grinding. ③ When processing fine-grained materials, the classification efficiency of commonly used classification equipment, such as gravity sedimentation classification equipment (spiral classifiers) and fine screens, is relatively low. While cyclones, which rely on centrifugal sedimentation, offer certain advantages, conventional cyclones suffer from a wide range of graded product sizes, coarse overflow, and fine underflow. Therefore, improvements in cyclone structure and classification parameters are needed to improve classification efficiency and quality.

[0004] The traditional fine-grained and ultra-fine-grained magnetite beneficiation process requires fine grinding to obtain iron concentrate. Since it is impossible to obtain iron concentrate in the case of coarse particles, the energy consumption is extremely high. In order to solve the technical problems of long magnetite separation process and high energy consumption of fine-grained and micro-fine magnetite, Chinese patent application 201711107180.3 discloses an energy-saving beneficiation method for processing micro-grained magnetite. The beneficiation method sequentially subjects the iron ore to the first-stage grinding and classification, the first-stage weak magnetic separation, the second-stage grinding and classification, the second-stage weak magnetic separation, the first-stage washing magnetic separation, the third-stage grinding and classification, the third-stage weak magnetic separation, and the second-stage washing magnetic separation. The first-stage washing magnetic separation concentrate and the second-stage washing magnetic separation concentrate obtained are combined into a total concentrate, and all the weak magnetic separation tailings are combined into a total tailing. This method adopts the washing magnetic separation technology to carry out early collection of magnetite minerals that have been basically dissociated into monomers under coarser grinding fineness conditions, and the yield of the early-collected iron concentrate reaches 15% to 45%, which greatly reduces the amount of ore that needs to be finely ground subsequently and saves grinding energy consumption. However, this method still requires secondary grinding to obtain iron concentrate, and the energy consumption is still relatively high. Moreover, this method uses washing magnetic separation, which has a small processing capacity and low sorting accuracy. It is already a backward and obsolete mineral processing technology and is basically not used in industrial production.

[0005] Research on refined classification technology is crucial for reducing over-crushing of fine-grained materials and lowering grinding energy consumption. By selecting narrow-size particles, beneficiation efficiency and separation accuracy can be effectively improved, enabling the early production of qualified concentrates and tailings disposal, in line with the principle of "early collection when possible, early disposal when possible." Of particular importance, the development of efficient, low-cost, and environmentally friendly fine-grained magnetite classification and sorting technologies, specifically tailored to the specific characteristics of my country's overseas iron ore resources, is directly linked to the speed of Chinese companies' overseas resource development. Therefore, developing a refined classification and efficient sorting process for fine-grained magnetite coarse concentrates is crucial. Summary of the Invention

[0006] The purpose of the present invention is to address the problems of high energy consumption and poor efficiency in the existing direct grinding process of fine-grained magnetite coarse concentrate, and to provide a new energy-saving mineral processing process for processing fine-grained magnetite coarse concentrate, which can obtain high yield, high recovery rate and high-grade iron concentrate without grinding. The fine classification and sorting method obtains iron concentrate through pre-grinding classification and sorting, thereby greatly reducing the subsequent grinding amount and significantly reducing the grinding energy consumption.

[0007] To achieve the above-mentioned object of the present invention, the present invention provides a new energy-saving mineral processing process for processing fine-grained magnetite coarse concentrate, which adopts the following processes and steps for separation:

[0008] (1) Fine-grained magnetite concentrate with an iron grade of 49.0% to 55.0% and a particle size of -0.076 mm accounting for 68.0% to 78.0% was fed into a double-overflow three-product hydrocyclone for classification, and three products with significantly different particle size composition and dissociation characteristics were obtained, namely: inner overflow product, outer overflow product and underflow product.

[0009] The cylinder of the double-overflow three-product hydrocyclone is cylindrical with an inner diameter of 50mm to 70mm and a cylinder height of 100mm to 150mm. The overflow pipe has a double overflow pipe structure with different diameters. The diameters of the inner and outer overflow pipes are 12mm to 15mm and 20mm to 30mm respectively. The product discharged from the inner overflow pipe is the inner overflow, and the product discharged from the outer overflow pipe is the outer overflow.

[0010] The feed concentration of the double overflow three-product hydrocyclone is preferably between 20% and 40%, preferably between 25% and 30%; the feed pressure of the double overflow three-product hydrocyclone is generally between 0.08MPa and 0.15MPa, preferably between 0.11MPa and 0.13MPa.

[0011] The particle size of the double overflow three-product hydrocyclone in the new energy-saving mineral processing technology of the present invention is d 内溢流 <d 外溢流 <d 底流 .

[0012] (2) The underflow product obtained in step (1) is fed into a high-frequency fine screen for screening to obtain an oversize product and an undersize product.

[0013] The mesh size of the high-frequency fine screen is 0.07mm to 0.1mm.

[0014] (3) The undersize product obtained in step (2) and the internal overflow product obtained in step (1) are combined and fed into a two-stage weak magnetic separation operation. The process of the two-stage weak magnetic separation operation is a first weak magnetic roughing selection II and a first weak magnetic concentration II. The concentrate of the first weak magnetic concentration II is an iron concentrate. The tailings of the first weak magnetic roughing selection II and the tailings of the first weak magnetic concentration II are combined into the final tailings.

[0015] The magnetic induction intensity of the primary weak magnetic roughing II is 0.2T to 0.3T, and the magnetic induction intensity of the primary weak magnetic concentrating II is 0.1T to 0.2T.

[0016] (4) The overflow product obtained in step (1) is fed into a three-stage weak magnetic separation operation, wherein the three-stage weak magnetic separation operation comprises a primary weak magnetic roughing I, a primary weak magnetic concentration I, and a magnetic column concentration. The concentrate obtained by the magnetic column concentration is an iron concentrate, and the iron concentrate is combined with the iron concentrate obtained in step (3) to form a total concentrate with an iron grade of ≥65.0%; the tailings obtained by the magnetic column concentration are middlings; and the tailings obtained by the primary weak magnetic roughing I and the tailings obtained by the primary weak magnetic concentration I are combined to form the final tailings.

[0017] (5) The oversize product obtained in step (2) and the middlings obtained in step (4) are combined and fed into subsequent grinding and selection operations.

[0018] (6) The finely ground product obtained in step (5) is fed into a two-stage weak magnetic separation operation. The process of the two-stage weak magnetic separation operation is a primary weak magnetic roughing selection III and a primary weak magnetic concentration III. The concentrate of the primary weak magnetic concentration III is an iron concentrate. The tailings of the primary weak magnetic roughing selection III and the tailings of the primary weak magnetic concentration III are combined into the final tailings.

[0019] According to test detection and analysis, the final tailings discharged from step (3), step (4) and step (6) generally have an iron content between 19.0% and 20.0%, and can be sold as an iron corrector for cement production at a price of approximately RMB 60 to 80 per ton.

[0020] Furthermore, in step (4), the magnetic induction intensity of the primary weak magnetic roughing selection I is 0.2T to 0.3T, and the magnetic induction intensity of the primary weak magnetic fine selection I is 0.1T to 0.2T; the magnetic induction intensity of the magnetic column selection is 0.02T to 0.03T, the separation magnetic field period of the magnetic column selection is 2s to 3s, and the rising water volume is 200ml / s to 300ml / s.

[0021] The results of research and testing show that the dissociation degree of the five products obtained by steps (1) and (2) is dd 底流筛下 ≈dd 内溢流 >dd 外溢流 >dd 底流 >dd 底流筛上。

[0022] Compared with the existing technology, the new energy-saving mineral processing technology for processing fine-grained magnetite coarse concentrate of the present invention has the following innovations and beneficial effects:

[0023] (1) The new energy-saving mineral processing technology of the present invention adopts a double overflow three-product hydrocyclone and a high-frequency fine screen combined classification process to obtain five classified products with different particle sizes and different dissociation degrees, creating conditions for fine sorting.

[0024] (2) The new energy-saving mineral processing technology of the present invention can obtain iron concentrate with a yield of more than 60% and an iron grade of more than 65.0% in advance through fine sorting without grinding. On the one hand, it can achieve early fineness before grinding, and on the other hand, it greatly reduces the subsequent amount of ore fed into the grinding mill, which has significant advantages such as energy saving, consumption reduction, and good economic benefits.

[0025] (3) The new energy-saving mineral processing technology of the present invention realizes fine classification by precisely controlling the feed pressure, feed concentration and cyclone structural parameters of the double overflow three-product hydrocyclone, thereby obtaining three products with significantly different selectivity.

[0026] (4) Narrow particle size separation is one of the main means to improve the efficiency and accuracy of mineral processing. The present invention fully achieves the purpose of narrow particle size separation through a multi-product hydrocyclone and fine screen combined classification process.

[0027] (5) The energy-saving mineral processing technology of the present invention combines the undersize product and the internal overflow product into a two-stage weak magnetic separation process consisting of "primary weak magnetic roughing II and primary weak magnetic concentration II" according to the particle size and dissociation degree of the different graded screening products, and feeds the external overflow product into a three-stage weak magnetic separation process consisting of "primary weak magnetic roughing I, primary weak magnetic concentration I, and magnetic separation column concentration", thereby achieving narrow particle size fine separation, and finally obtaining mineral processing technical indicators of iron recovery rate greater than 75.0% and iron concentrate grade greater than 65.0 before grinding. Research and calculation results show that compared with the mineral processing process of fine grinding and then separation, the energy consumption of the energy-saving mineral processing technology of the present invention is reduced by more than 45.0%, and the total iron recovery rate is increased by more than 5%. Taking the annual processing of 3 million tons of fine-grained magnetite rough concentrate as an example, more than 100,000 tons of iron concentrate with TFe greater than 65.0% can be recovered each year, and the annual sales volume can be increased by more than 90 million yuan, achieving unexpected technical effects.

[0028] (6) The iron content in the final tailings discharged by the new energy-saving mineral processing process of the present invention is generally between 19.0% and 20.0%. After being combined, it can be used as an iron corrector for cement production, with a price of about 60 to 80 yuan per ton. Taking the annual processing of 3 million tons of fine-grained magnetite coarse concentrate as an example, 800,000 tons of iron corrector for cement production can be obtained each year, with a selling price of 48 to 64 million yuan. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a principle flow chart before grinding of a new energy-saving mineral processing process for processing fine-grained magnetite concentrate of the present invention;

[0030] Figure 2 This is a process flow chart of ore regrinding and re-selection in a new energy-saving mineral processing technology for processing fine-grained magnetite coarse concentrate of the present invention.

[0031] Figure 3The present invention is a new energy-saving mineral processing technology for processing fine-grained magnetite coarse concentrate. DETAILED DESCRIPTION

[0032] To further describe the present invention, a new energy-saving mineral processing process for processing fine-grained magnetite coarse concentrate of the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0033] Depend on Figure 3 The present invention is a new energy-saving mineral processing process for processing fine-grained magnetite coarse concentrate. Figure 1 、 Figure 2 It can be seen that the energy-saving new mineral processing process for treating fine-grained magnetite coarse concentrate of the present invention is implemented by the following steps:

[0034] The fine-grained magnetite concentrate sample used in the embodiment of the new energy-saving mineral processing process for processing fine-grained magnetite concentrate of the present invention was taken from the weak magnetic separation concentrate of the dressing plant of Shandong Hualian Mining Co., Ltd. The iron grade of the sample was 52.96%, and the content of the -0.076 mm particle size in the sample accounted for 74.78%. The particle size composition and metal content distribution of the sample are shown in Table 1.

[0035] Table 1 Sample particle size composition and metal content distribution

[0036]

[0037] (1) The fine-grained magnetite concentrate was subjected to double overflow three-product hydrocyclone classification to obtain three products with significantly different particle size composition and dissociation characteristics, namely, inner overflow product, outer overflow product, and underflow product; the particle size composition and metal content distribution of the three products are shown in Table 2, Table 3, and Table 4;

[0038] Table 2 Overflow particle size composition and metal content distribution

[0039]

[0040] Table 3 Overflow particle size composition and metal content distribution

[0041]

[0042] Table 4 Underflow particle size composition and metal content distribution

[0043]

[0044] The cylinder of the three-product hydrocyclone with double overflow is cylindrical, with a diameter of 50mm, a cylinder height of 110mm, and a bottom flow port diameter of 8mmmm. The overflow pipe has a double overflow pipe structure with different diameters. The diameters of the inner and outer overflow pipes are 12mm and 20mm respectively. The product discharged from the inner overflow pipe is the inner overflow, and the product discharged from the outer overflow pipe is the outer overflow.

[0045] The feed concentration of the double overflow three-product hydrocyclone is 30% and the feed pressure is 0.12 MPa;

[0046] (2) The underflow product obtained in step (1) is fed into a high-frequency fine screen for screening to obtain an oversize product and an undersize product; the mineral dissociation degrees of the internal overflow, external overflow, and undersize products are shown in Table 5;

[0047] Table 5 Analysis of mineral dissociation degree of internal overflow, external overflow and underflow screen products

[0048]

[0049] The mesh size of the high-frequency fine sieve is 0.076 mm;

[0050] (3) combining the undersize product obtained in step (2) and the internal overflow product obtained in step (1) and feeding them into a two-stage weak magnetic separation operation, wherein the process of the two-stage weak magnetic separation operation is a primary weak magnetic roughing II and a primary weak magnetic concentration II, the concentrate obtained from the primary weak magnetic concentration II is an iron concentrate, and the tailings from the primary weak magnetic roughing II and the tailings from the primary weak magnetic concentration II are combined into the final tailings;

[0051] The magnetic induction intensity of the primary weak magnetic roughing II is 0.2T, and the magnetic induction intensity of the primary weak magnetic concentrating II is 0.12T;

[0052] (4) The overflow product obtained in step (1) is fed into a three-stage weak magnetic separation operation, wherein the three-stage weak magnetic separation operation comprises a primary weak magnetic roughing I, a primary weak magnetic concentration I, and a magnetic column concentration. The concentrate obtained by the magnetic column concentration is an iron concentrate, and the iron concentrate and the iron concentrate obtained in step (3) are combined to form a total concentrate with an iron grade of 65.83%; the tailings obtained by the magnetic column concentration are middlings; the tailings obtained by the primary weak magnetic roughing I and the tailings obtained by the primary weak magnetic concentration I are combined to form the final tailings;

[0053] The magnetic induction intensity of the weak magnetic roughing I is 0.2T, and the magnetic induction intensity of the weak magnetic concentrating I is 0.12T; the separation magnetic field cycle of the magnetic column concentrating is 2 seconds, the magnetic induction intensity is 0.02T, and the rising water volume is 220ml / s;

[0054] (5) combining the oversize product obtained in step (2) and the middlings obtained in step (4) and feeding them into subsequent grinding and selection operations;

[0055] Through the above process, iron concentrate with a yield of 61.20%, an iron grade of 65.83% and an iron recovery rate of 76.42% can be obtained in advance.

[0056] (6) The finely ground product obtained in step (5) is fed into a two-stage weak magnetic separation process. The process of the two-stage weak magnetic separation process is a weak magnetic roughing III and a weak magnetic fine separation III. The magnetic induction intensity of the weak magnetic roughing III is 0.2T, and the magnetic induction intensity of the weak magnetic fine separation III is 0.12T.

[0057] The concentrate obtained from the primary weak magnetic concentration III is an iron concentrate with an iron grade of 63.74%. It is combined with the previously obtained concentrate with a yield of 61.20% and an iron grade of 65.83% to obtain a final concentrate with an iron grade of 65.52% and an iron recovery rate of 89.66%.

[0058] The tailings of the primary weak magnetic roughing II and the primary weak magnetic concentration II discharged in step (3), the tailings of the primary weak magnetic roughing I and the primary weak magnetic concentration I discharged in step (4), and the tailings of the primary weak magnetic roughing III and the primary weak magnetic concentration III discharged in step (6) are combined and sold as iron correctors for cement production, thereby achieving full resource utilization without solid waste discharge.

Claims

1. A new energy-saving mineral processing process for processing fine-grained magnetite concentrate, characterized by Use the following steps: (1) A fine-grained magnetite concentrate with an iron grade of 49.0% to 55.0% and a particle size of -0.076 mm, with a content of 68.0% to 78.0%, is fed into a double overflow three-product hydrocyclone for classification, and an inner overflow product, an outer overflow product and an underflow product are obtained respectively; the cylinder of the double overflow three-product hydrocyclone is cylindrical, with an inner diameter of 50mm to 70mm and a cylinder height of 100mm to 150mm, and the overflow pipe is a double overflow pipe structure with different diameters, and the diameters of the inner and outer overflow pipes of the overflow pipe are 12mm to 15mm and 20mm to 30mm respectively. The product discharged from the inner overflow pipe is the inner overflow, and the product discharged from the outer overflow pipe is the outer overflow; the particle size of each product after classification by the double overflow three-product hydrocyclone is d 内溢流 <d 外溢流 <d 底流 ; (2) feeding the underflow product obtained in step (1) into a high-frequency fine screen for screening to obtain an oversize product and an undersize product; (3) combining the undersize product obtained in step (2) and the internal overflow product obtained in step (1) and feeding them into a two-stage weak magnetic separation operation, wherein the process of the two-stage weak magnetic separation operation is a primary weak magnetic roughing II and a primary weak magnetic concentration II, the concentrate obtained from the primary weak magnetic concentration II is an iron concentrate, and the tailings from the primary weak magnetic roughing II and the tailings from the primary weak magnetic concentration II are combined into the final tailings; (4) The overflow product obtained in step (1) is fed into three-stage weak magnetic separation operations, wherein the three-stage weak magnetic separation operations are a weak magnetic roughing I, a weak magnetic concentration I, and a magnetic column selection. The concentrate selected by the magnetic column is an iron concentrate, and the iron concentrate is combined with the iron concentrate obtained in step (3) to form a total concentrate with an iron grade of ≥65.0%; the tailings selected by the magnetic column are middlings; the tailings obtained by the weak magnetic roughing I and the tailings obtained by the weak magnetic concentration I are combined to form the final tailings; the magnetic induction intensity of the weak magnetic roughing I is 0.2T~0.3T, and the magnetic induction intensity of the weak magnetic concentration I is 0.1T~0.2T; the magnetic induction intensity of the magnetic column selection is 0.02T~0.03T, the separation magnetic field period of the magnetic column selection is 2s~3s, and the rising water volume is 200ml / s~300ml / s; (5) combining the oversize product obtained in step (2) and the middlings obtained in step (4) and feeding them into a fine-grain grinding operation; (6) The finely ground product obtained in step (5) is fed into a two-stage weak magnetic separation process. The process of the two-stage weak magnetic separation process is a primary weak magnetic roughing III and a primary weak magnetic concentration III. The concentrate of the primary weak magnetic concentration III is an iron concentrate, and the tailings of the primary weak magnetic roughing III and the tailings of the primary weak magnetic concentration III are combined into the final tailings.

2. A new energy-saving mineral processing process for processing fine-grained magnetite concentrate, characterized by Use the following steps: (1) A fine-grained magnetite concentrate with an iron grade of 49.0% to 55.0% and a particle size of -0.076 mm, with a content of 68.0% to 78.0%, is fed into a double overflow three-product hydrocyclone for classification, and an inner overflow product, an outer overflow product and an underflow product are obtained respectively; the cylinder of the double overflow three-product hydrocyclone is cylindrical, with an inner diameter of 50mm to 70mm and a cylinder height of 100mm to 150mm, and the overflow pipe is a double overflow pipe structure with different diameters, and the diameters of the inner and outer overflow pipes of the overflow pipe are 12mm to 15mm and 20mm to 30mm respectively. The product discharged from the inner overflow pipe is the inner overflow, and the product discharged from the outer overflow pipe is the outer overflow; the particle size of each product after classification by the double overflow three-product hydrocyclone is d 内溢流 <d 外溢流 <d 底流 ; (2) feeding the underflow product obtained in step (1) into a high-frequency fine screen for screening to obtain an oversize product and an undersize product; (3) combining the undersize product obtained in step (2) and the internal overflow product obtained in step (1) and feeding them into a two-stage weak magnetic separation operation, wherein the process of the two-stage weak magnetic separation operation is a primary weak magnetic roughing II and a primary weak magnetic concentration II, the concentrate of the primary weak magnetic concentration II is an iron concentrate, and the tailings of the primary weak magnetic roughing II and the tailings of the primary weak magnetic concentration II are discharged respectively; (4) The overflow product obtained in step (1) is fed into three-stage weak magnetic separation operations, wherein the three-stage weak magnetic separation operations are a weak magnetic roughing I, a weak magnetic concentration I, and a magnetic column selection. The concentrate selected by the magnetic column is an iron concentrate, and the iron concentrate is combined with the iron concentrate obtained in step (3) to form a total concentrate with an iron grade of ≥65.0%; the tailings selected by the magnetic column are middlings; the tailings of the weak magnetic roughing I and the tailings of the weak magnetic concentration I are discharged respectively; the magnetic induction intensity of the weak magnetic roughing I is 0.2T~0.3T, and the magnetic induction intensity of the weak magnetic concentration I is 0.1T~0.2T; the magnetic induction intensity of the magnetic column selection is 0.02T~0.03T, the separation magnetic field period of the magnetic column selection is 2s~3s, and the rising water volume is 200ml / s~300ml / s; (5) combining the oversize product obtained in step (2) and the middlings obtained in step (4) and feeding them into a fine-grain grinding operation; (6) feeding the finely ground product obtained in step (5) into a two-stage weak magnetic separation process, wherein the process of the two-stage weak magnetic separation process is a primary weak magnetic roughing III and a primary weak magnetic concentration III, the concentrate of the primary weak magnetic concentration III is an iron concentrate, and the tailings of the primary weak magnetic roughing III and the tailings of the primary weak magnetic concentration III are discharged respectively; (7) The tailings of the primary weak magnetic roughing II and the primary weak magnetic concentration II discharged from step (3), the tailings of the primary weak magnetic roughing I and the primary weak magnetic concentration I discharged from step (4), and the tailings of the primary weak magnetic roughing III and the primary weak magnetic concentration III discharged from step (6) are combined and sold as an iron corrector for cement production.

3. A new energy-saving mineral processing process for treating fine-grained magnetite concentrate according to claim 1 or 2, characterized in that: The feed concentration of the double overflow three-product hydrocyclone is 20% to 40%, and the feed pressure is 0.11 MPa to 0.13 MPa.

4. A new energy-saving mineral processing process for treating fine-grained magnetite concentrate according to claim 3, characterized in that: In step (2), the mesh size of the high-frequency fine sieve is 0.07 mm to 0.1 mm.

5. The new energy-saving mineral processing process for treating fine-grained magnetite concentrate according to claim 4 is characterized in that: In step (3), the magnetic induction intensity of the primary weak magnetic roughing II is 0.2T~0.3T, and the magnetic induction intensity of the primary weak magnetic concentrating II is 0.1T~0.2T.

6. A new energy-saving mineral processing process for treating fine-grained magnetite concentrate according to claim 5, characterized in that: In step (5), the grinding fineness of the fine-grained grinding operation is -0.043 mm and the particle size content is between 76% and 86%.

7. A new energy-saving mineral processing process for treating fine-grained magnetite concentrate according to claim 6, characterized in that: In step (6), the magnetic induction intensity of the primary weak magnetic roughing III is 0.2T~0.3T, and the magnetic induction intensity of the primary weak magnetic concentrating III is 0.1T~0.2T.

8. A new energy-saving mineral processing process for treating fine-grained magnetite concentrate according to claim 1 or 2, characterized in that: In step (1), the feed concentration of the double overflow three-product hydrocyclone is 20%~40%, and the feed pressure is 0.11MPa~0.13MPa; in step (2), the mesh size of the high-frequency fine screen is 0.07mm~0.1mm; in step (3), the magnetic induction intensity of the primary weak magnetic roughing II is 0.2T~0.3T, and the magnetic induction intensity of the primary weak magnetic concentrating II is 0.1T~0.2T; in step (4), the magnetic induction intensity of the primary weak magnetic roughing I is 0.2T~0.3T, the magnetic induction intensity of the primary weak magnetic concentrating I is 0.1T~0.2T, the magnetic induction intensity of the magnetic column selection is 0.02T~0.03T, and the separation magnetic field period of the magnetic column selection is 2s~3s. s, the rising water volume is 200ml / s~300ml / s; in step (5), the grinding fineness of the fine-grained grinding operation is -0.043mm and the particle size content is between 76% and 86%; in step (6), the primary weak magnetic roughing III is 0.2T~0.3T, and the magnetic induction intensity of the primary weak magnetic selection III is 0.1T~0.2T.

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