Method for comprehensively recovering tantalum and niobium ore by optimizing and grading magnetic separation of iron-lithium mica

Abstract

The application discloses a method for comprehensively recovering tantalum and niobium ore by optimizing and grading magnetic separation of iron lepidolite, and belongs to the technical field of comprehensive recovery and utilization of lithium ore resources, and comprises the following steps: crushing, coarse-grained strong magnetic rough separation, grading, fine-grained strong magnetic scavenging, grinding, fine-grained strong magnetic rough separation, fine-grained strong magnetic scavenging, fine-grained concentration, gravity separation and solid-liquid separation. The method adopts a physical beneficiation mode, selects a reasonable crushing, coarse-grained strong magnetic rough separation, grading, fine-grained strong magnetic scavenging, grinding, fine-grained strong magnetic rough separation, fine-grained strong magnetic scavenging, fine-grained concentration, gravity separation and solid-liquid separation combined beneficiation process, produces high-quality iron lepidolite concentrate, selects tantalum and niobium rough concentrate, coarse-grained building material sand, feldspar concentrate and other industrial products, the comprehensive utilization rate of the raw ore reaches 100%, tail water and tailings are zero discharged, a flotation process is not needed, each operation section is green and environmentally friendly, has high adaptability, and is suitable for large-scale production and application.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive recovery and utilization of lithium ore resources, and in particular to a method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica. Background Art

[0002] my country has rich reserves of lithium mineral resources. The main lithium-containing minerals are spodumene and lepidolite. Ferro-lepidolite is a type of lepidolite, generally found in granite pegmatite, and is often accompanied by muscovite, biotite, feldspar, quartz, tantalite, niobite, hematite, cassiterite and other minerals. Lepidolite is processed and purified to produce industrial products such as lithium carbonate, lithium iron phosphate, metallic lithium and lithium chemicals, which are widely used in lithium batteries, glass, metallurgy, chemical industry, medicine, military industry and other fields.

[0003] At present, lepidolite manufacturers mainly use processes such as "grinding + desliming + flotation", "grinding + strong magnetic separation + flotation", and "grinding + gravity separation + flotation" for recovery. These conventional mineral processing processes all have technical difficulties such as low metal recovery rate, heavy reagent pollution, long process flow, low mineral processing efficiency, high production cost, large equipment investment, small processing capacity, and low comprehensive utilization.

[0004] Valuable minerals such as lepidolite, tantalite, and niobium iron ore all have weak magnetism. The scaly structure of lepidolite generates surface adsorption tension when it comes into contact with water. Tantalite and niobium iron ore have the characteristics of large specific gravity and are both suitable for strong magnetic separation and gravity separation processes. The non-magnetic materials obtained through the strong magnetic separation process are high-quality feldspar materials for ceramics and glass. With the development of strong magnetic separation equipment and technologies such as high-gradient vertical ring magnetic separators, electromagnetic slurry magnetic separation, and low-temperature superconducting magnetic separators, as well as the increase in environmental protection awareness and supervision, and the pressure on tailings storage capacity, more and more lepidolite manufacturers are in urgent need of green and environmentally friendly strong magnetic separation processes to replace traditional flotation processes in order to improve the economic benefits and healthy development of mineral processing plants.

[0005] Therefore, it is an urgent problem to be solved at this stage to develop a method that can greatly improve the production processing capacity and product recovery rate, can separate high-quality industrial products such as coarse-grained building sand, feldspar concentrate, iron lithium mica concentrate, tantalum iron coarse concentrate, etc., achieve double zero discharge of tailings and tail water, and is suitable for large-scale production of iron lithium mica optimized graded magnetic separation and comprehensive recovery of tantalum and niobium ore. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a method for comprehensive recovery of tantalum-niobium ore through optimized graded magnetic separation of lithophile mica. The method adopts physical beneficiation and selects reasonable combined beneficiation process flow of crushing, coarse-grained strong magnetic roughing, classification, fine-grained strong magnetic scavenging, grinding, fine-grained strong magnetic roughing, fine-grained strong magnetic scavenging, fine-grained concentration, gravity separation, solid-liquid separation, etc. While producing high-quality lithophile mica concentrate, industrial products such as tantalum-niobium coarse concentrate, coarse-grained building material sand, and feldspar concentrate are also selected. The comprehensive utilization rate of the original ore reaches 100%, and zero discharge of tailings is achieved. No flotation process is required. All operation sections are green and environmentally friendly, with strong adaptability and suitable for large-scale production applications.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a method for comprehensively recovering tantalum-niobium ore by optimizing the graded magnetic separation of ferrolithium mica, comprising the following steps:

[0009] S1: Crushing: Crushing the raw ore to obtain coarse-grained products;

[0010] S2: Coarse-grain strong magnetic roughing: The coarse-grain product is mixed with slurry and subjected to magnetic separation under a first magnetic field strength to obtain a first magnetic material and a first non-magnetic material;

[0011] S3: Classification: Screening the first non-magnetic material to obtain coarse particles on the sieve and fine particles under the sieve, wherein the coarse particles on the sieve are discharged into a coarse tailings sedimentation tank;

[0012] S4: Fine particle strong magnetic sweeping: The fine particles under the screen are subjected to magnetic separation under a second magnetic field strength to obtain a second magnetic material and a second non-magnetic material, and the second non-magnetic material is discharged into a fine tailings sedimentation tank;

[0013] S5: Grinding: Grinding the first magnetic material and the second magnetic material to obtain a fine-grained product;

[0014] S6: Fine particle strong magnetic roughing: the fine particle product is mixed with slurry and then subjected to magnetic separation under a third magnetic field strength to obtain a third magnetic material and a third non-magnetic material;

[0015] S7: Fine-grained strong magnetic sweeping and separation: the third non-magnetic material is subjected to magnetic separation under a fourth magnetic field strength to obtain a fourth magnetic material and a fourth non-magnetic material, and the fourth non-magnetic material is discharged into the fine-grained tailings sedimentation tank;

[0016] S8: Fine particle selection: mixing the third magnetic material and the fourth magnetic material and performing magnetic separation under a fifth magnetic field strength to obtain a fifth magnetic material and a fifth non-magnetic material, and mixing the fifth non-magnetic material into the fine particle product;

[0017] S9: Gravity separation: gravity separation is performed on the fifth magnetic material to obtain light minerals and heavy minerals, wherein the light minerals are discharged into a first concentrate sedimentation tank, and the heavy minerals are discharged into a second concentrate sedimentation tank;

[0018] S10: solid-liquid separation: the products in the coarse-grained tailings sedimentation tank, the fine-grained tailings sedimentation tank, the first concentrate sedimentation tank, and the second concentrate sedimentation tank are subjected to solid-liquid separation operations respectively, and the separated solids are coarse-grained building material sand, feldspar concentrate, iron lithium mica concentrate and tantalum niobium coarse concentrate respectively, and the separated liquid is recycled after clarification.

[0019] As a preferred technical solution, in step S1, the raw ore first enters a jaw crusher for coarse crushing and medium crushing, and then enters a high pressure roller mill for fine crushing.

[0020] As a preferred technical solution, in step S2, the first magnetic field strength is set to 1.4-1.6 Tesla, a vertical ring high gradient magnetic separator is used for magnetic separation, and the magnetic separation medium used is set to a high magnetic permeability stainless steel rod with a diameter of 5 mm.

[0021] As a preferred technical solution, in step S3, the first non-magnetic material enters a vibrating screen for classification;

[0022] And / or, in step S5, the mixture of the first magnetic material and the second magnetic material enters a ball mill for grinding;

[0023] And / or, in step S9, the fifth magnetic material enters the spiral chute for gravity separation.

[0024] As a preferred technical solution, in step S4, the second magnetic field strength is set to 1.6-1.8 Tesla, and a vertical ring high gradient magnetic separator is used for magnetic separation. The magnetic separation medium used is set to a high magnetic permeability stainless steel plate mesh with specifications of 5×10mm and 6×12mm and a ratio of 1:1.

[0025] As a preferred technical solution, in step S6, the third magnetic field strength is set to 1.3-1.5 Tesla, a vertical ring high gradient magnetic separator is used for magnetic separation, and the magnetic separation medium used is set to a high magnetic permeability stainless steel rod with a diameter of 2 mm.

[0026] As a preferred technical solution, in step S7, the fourth magnetic field strength is set to 1.4-1.6 Tesla, and a vertical ring high gradient magnetic separator is used for magnetic separation. The magnetic separation medium used is set to a high magnetic permeability stainless steel plate mesh with specifications of 4×8mm and 6×12mm and a ratio of 2:1.

[0027] As a preferred technical solution, in step S8, the fifth magnetic field strength is set to 1.2-1.4 Tesla, and a vertical ring high gradient magnetic separator is used for magnetic separation. The magnetic separation medium used is set to a high magnetic permeability stainless steel plate mesh with specifications of 4×8mm and 5×10mm and a ratio of 1:1.

[0028] As a preferred technical solution, in step S10, the product in the coarse-grained tailings sedimentation tank enters the vibrating screen for dehydration, and the separated solid matter is the coarse-grained building material sand; the product in the fine-grained tailings sedimentation tank enters the ceramic filter for solid-liquid separation after precipitation and concentration, and the separated solid matter is the feldspar concentrate; the product in the first concentrate sedimentation tank enters the plate and frame filter press for solid-liquid separation after precipitation and concentration, and the separated solid matter is the iron lithium mica concentrate; the product in the second concentrate sedimentation tank enters the disc filter for solid-liquid separation after concentration in the sedimentation tank, and the separated solid matter is the tantalum niobium coarse concentrate.

[0029] As a preferred technical solution, in step S10, the whiteness of the feldspar concentrate is 61.00-63.00%, the Fe2O3 content is 0.16-0.18%, and the K2O+Na2O content is 8.50-9.50%; the Li2O content in the iron lithium mica concentrate is 2.35-2.45%; and the Ta2O5+Nb2O5 content in the tantalum-niobium crude concentrate is 18.00-20.00%.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. The present invention adopts a physical beneficiation method and selects reasonable combined beneficiation process flow of crushing, coarse-grained strong magnetic roughing, classification, fine-grained strong magnetic scavenging, grinding, fine-grained strong magnetic roughing, fine-grained strong magnetic scavenging, fine-grained concentration, gravity separation, solid-liquid separation, etc., to produce high-quality iron lithium mica concentrate while selecting tantalum niobium coarse concentrate, coarse-grained building material sand, feldspar concentrate and other industrial products. The comprehensive utilization rate of the original ore reaches 100%, and zero discharge of tailings is achieved. There is no need to use flotation process. Each operation section is green and environmentally friendly, with strong adaptability and suitable for large-scale production application.

[0032] 2. The present invention addresses the differences in physical and chemical properties such as mineral composition, specific magnetic susceptibility, particle size distribution, particle size structure, dissociation degree, and density among different minerals such as lepidolite, tantalite, niobium iron ore, and feldspar. Under coarse-grained crushing conditions, the present invention performs a high-field strength roughing operation, and then performs a high-field strength sweeping operation after classification. While ensuring the recovery rate, most of the gangue minerals can be discarded, effectively reducing the production cost of subsequent grinding operations and significantly increasing the production throughput. Under fine-grained grinding conditions, the present invention sequentially performs a high-field strength roughing operation, a high-field strength sweeping operation, and a high-field strength concentration operation, thereby further improving the product quality of metal minerals that have achieved monomer dissociation. The fifth non-magnetic material obtained in the concentration operation is returned to the roughing operation section, which can further improve the product recovery rate. Gravity separation can effectively separate the tantalum-niobium ore with a larger specific gravity from the lepidolite with a smaller specific gravity, thereby increasing the added value of the product.

[0033] 3. The present invention uses a vertical ring high gradient magnetic separator for strong magnetic separation of coarse and fine particles, which can greatly improve the production processing capacity and recovery rate; uses conventional equipment such as a jaw crusher, a high-pressure roller mill, a vibrating screen, a vertical ring high gradient magnetic separator, a ball mill, a spiral chute, and selects appropriate process conditions such as magnetic field strength, magnetic separation medium, pulsation frequency, classification particle size, grinding fineness, roughing, scavenging, cleaning, and gravity separation for different operating sections, and can increase the production processing capacity by 40-50% and the product recovery rate by 10-15% compared with the conventional lepidolite beneficiation process.

[0034] 4. The equipment and processes used in the present invention for valuable minerals with weak magnetism, such as lithobite, tantalite, and niobite, do not generate any pollution. The filter press water produced by the green and environmentally friendly process can be recycled after clarification, achieving zero tail water discharge. Moreover, the process conditions of each operation section of the present invention can be adjusted in a timely manner according to the different mineral content and types, and the adaptability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a process flow chart of an embodiment of a method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to the present invention. DETAILED DESCRIPTION

[0036] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0037] A lithium mica beneficiation plant in Hunan Province previously used a "crushing-grinding-desliming-flotation" process. The fine mud removed before flotation resulted in a loss of approximately 15-20% of lithium metal, and the total recovery rate of lithium concentrate from flotation was 65-70%. The flotation agent production cost was high and caused pollution, leading to technical challenges such as low mineral processing recovery rates, small production throughput, low comprehensive utilization rates, high pressure on environmental protection and storage capacity, a long process flow, and difficult equipment management.

[0038] Research has found that the Li2O content in the fine mud removed before flotation at the production site is 0.30-0.35%, similar to the 0.37% grade of the original ore. This fine mud covers and contaminates the surface of the lepidolite, making it difficult for collectors to adhere and consuming large amounts of reagents through adsorption, deteriorating the flotation process. Premature removal of some fine mud before flotation results in a loss of metal content in the fine lepidolite flakes, and this fine mud tailings occupy a large amount of land resources. The various reagents added during the flotation process, such as slurry conditioners, dispersants, and collectors, are expensive, and some drug ions in the tailings easily seep into the ground, causing water pollution. Fine grinding of the original ore destroys the flake structure of some lepidolite, making some of the fine lepidolite flakes difficult to recover. The original ore is directly fed into the crushing and grinding process, increasing the electricity cost of the grinding process. After desliming, the fine-grained ore, which accounts for 80% of the yield, enters the flotation operation, where nearly 60% of the non-magnetic gangue minerals directly affect production throughput and increase production costs.

[0039] Regarding the technical and process problems in the above production, please refer to Figure 1 Table 1 is a specific implementation case of the copper-molybdenum ore dressing plant using a method for gravity classification optimization magnetic separation of copper-molybdenum concentrate provided by the present invention, comprising the following steps:

[0040] S1: Broken:

[0041] The raw ore with a particle size of -200mm is crushed coarsely and medium to -20mm by a jaw crusher, and then enters a high-pressure roller mill for fine crushing to obtain a coarse-grained product with a particle size of -3mm.

[0042] S2: Coarse-grain strong magnetic roughing:

[0043] The coarse-grained product with a particle size of -3mm is mixed into a 35% slurry concentration and enters a vertical ring high gradient magnetic separator for the first stage of strong magnetic roughing. The magnetic field strength of the vertical ring high gradient magnetic separator is 1.4-1.6 Tesla, the medium is a Ø5mm high magnetic permeability stainless steel rod, and the pulsation is 0HZ. Under these parameters, the flake, medium flake and conjoined iron lithium mica that has been dissociated into monomers and the tantalite and niobium iron ore that are in a conjoined state or have been dissociated can be pre-selected; the coarse concentrate product (the first magnetic material) with a Li2O content of 1.20-1.40% and a Ta2O5+Nb2O5 content of 0.50-0.54% and the non-magnetic tailings (the first non-magnetic material) with a Li2O content of 0.14-0.16% are obtained.

[0044] S3: Grading:

[0045] The first non-magnetic material is put into a vibrating screen for classification to obtain coarse particles with a particle size of +0.5 mm and fine particles with a particle size of -0.5 mm. The coarse particles with a particle size of +0.5 mm have a Li2O content of 0.07-0.08% and a Ta2O5+Nb2O5 content of 0.006-0.008%, and are discharged into a coarse-grained tailings sedimentation pond.

[0046] S4: Fine-grained strong magnetic sweeping:

[0047] The -0.5mm undersize fine particles are mixed into a 30% slurry concentration and enter the vertical ring high gradient magnetic separator for the second stage of strong magnetic scavenging operation. The magnetic field strength of the vertical ring high gradient magnetic separator is 1.6-1.8 Tesla, the medium specifications are 5×10mm+6×12mm, the ratio of high magnetic permeability stainless steel plate mesh is 1:1, and the pulsation is 5HZ. Under these parameters, iron lithium mica and tantalum niobium ore in the form of conjoined bodies, fine flakes or fine particles can be separated to obtain a scavenging concentrate product (second magnetic material) with a Li2O content of 0.80-0.90% and a Ta2O5+Nb2O5 content of 0.20-0.30%, as well as a non-magnetic tailings (second non-magnetic material) with a Li2O content of 0.08-0.09%. The second non-magnetic material is discharged into the fine tailings sedimentation pond.

[0048] S5: Grinding:

[0049] The second magnetic material is fed into a ball mill for wet grinding. The grinding concentration of the ball mill is 67%, which can separate the metal minerals and gangue minerals that are present in a conjoined state into monomers, and obtain a fine-grained product with a fineness of 60-65% of -200 mesh.

[0050] S6: Fine-grain strong magnetic roughing:

[0051] The fine-grained product is slurried into a 25% slurry concentration and enters the vertical ring high gradient magnetic separator for the third stage of strong magnetic roughing operation. The magnetic field strength of the vertical ring high gradient magnetic separator is 1.3-1.5 Tesla, the medium is a Ф2mm high magnetic permeability stainless steel rod, and the pulsation is 10HZ. Under these parameters, the monomer dissociation and the intergrowth of lithium mica and tantalum-niobium ore can be selected to obtain a coarse concentrate product (the third magnetic material) with a Li2O content of 1.80-1.90% and a Ta2O5+Nb2O5 content of 1.20-1.40%, as well as a non-magnetic material (the third non-magnetic material) with a Li2O content of 0.60-0.80%.

[0052] S7: Fine-grained strong magnetic sweeping:

[0053] The third non-magnetic material is mixed into a 20% slurry concentration and enters the vertical ring high gradient magnetic separator for the fourth stage of strong magnetic sweeping operation; the magnetic field strength of the vertical ring high gradient magnetic separator is 1.4-1.6 Tesla, the medium specifications are 4×8mm+6×12mm, the high magnetic permeability stainless steel plate mesh with a ratio of 2:1, and the pulsation is 5HZ. Under these parameters, some conjoined bodies and fine-grained metal minerals can be effectively recovered to obtain a sweeping concentrate product (fourth magnetic material) with a Li2O content of 1.20-1.30% and a Ta2O5+Nb2O5 content of 0.90-0.95%, as well as a non-magnetic material (fourth non-magnetic material) with a Li2O content of 0.07-0.09%. The fourth non-magnetic material is discharged into the fine tailings sedimentation pond.

[0054] S8: Fine Grain Selection:

[0055] The third magnetic material and the fourth magnetic material are mixed and prepared into a 15% slurry concentration before entering the vertical ring high gradient magnetic separator for the fifth stage of strong magnetic separation. The magnetic field strength of the vertical ring high gradient magnetic separator is 1.2-1.4 Tesla, the medium specifications are 4×8mm+5×10mm, the high magnetic permeability stainless steel plate mesh is 1:1, and the pulsation is 20HZ. By reducing the magnetic field strength, optimizing the medium structure, and increasing the pulsation, high-quality lepidolite concentrate products can be separated to obtain a concentrate product (the fifth magnetic material) with a Li2O content of 2.30-2.40% and a Ta2O5+Nb2O5 content of 4.5-5.0%, as well as a non-magnetic middling product (the fifth non-magnetic material) with a Li2O content of 0.40-0.60%. The fifth non-magnetic material is mixed into the fine particle product.

[0056] S9: Gravity sorting:

[0057] The fifth magnetic material enters a spiral chute for gravity separation. By utilizing the density and particle size differences between the minerals, the granular tantalum-niobium ore with a high specific gravity can be effectively separated from the lepidolite with a low specific gravity in the form of flakes, thereby obtaining lepidolite concentrate (light mineral) with a Li2O content of 2.35-2.45% and tantalum-niobium crude concentrate (heavy mineral) with a Ta2O5+Nb2O5 content of 18.00-20.00%. The light minerals are discharged into the first concentrate sedimentation tank, and the heavy minerals are discharged into the second concentrate sedimentation tank.

[0058] S10: Solid-liquid separation:

[0059] The products in the coarse-grained tailings sedimentation tank (coarse particles with a particle size of +0.5mm on the sieve) are sent to the vibrating screen for dehydration to obtain qualified building sand raw materials with high hardness and uniform particles; the products in the fine-grained tailings sedimentation tank (the second non-magnetic material and the fourth non-magnetic material) are precipitated and concentrated and then sent to the ceramic filter for solid-liquid separation to obtain high-quality raw materials with a Fe2O3 content of 0.16-0.18%, a K2O+Na2O content of 8.50-9.50%, and a whiteness of 61.00-63.00%. The product (light minerals) in the first concentrate sedimentation tank is precipitated and concentrated, and then enters a disc filter for solid-liquid separation to obtain a high-quality lepidolite concentrate product with a Li2O content of 2.35-2.45%; the product (heavy minerals) in the second concentrate sedimentation tank is precipitated and concentrated, and then enters a plate and frame filter press for solid-liquid separation to obtain a tantalum-niobium crude concentrate product with a Ta2O5+Nb2O5 content of 18.00-20.00%, which can be used as an industrial product or further purified.

[0060] It should be noted that the crushing, grading, magnetic separation, gravity separation and other operations in the mineral processing process of the present invention all adopt green and environmentally friendly physical mineral processing technology. The tail water produced by the solid-liquid separation operation of each product can be returned to each operation process for recycling after clarification, and there is no need to use flotation technology. It is green and environmentally friendly and suitable for large-scale production applications.

[0061] Table 1 Test indexes of coarse and fine particles by strong magnetic separation and gravity separation (%)

[0062]

[0063] The present invention targets the differences in physical and chemical properties such as mineral composition, specific magnetic susceptibility, particle size distribution, particle size structure, dissociation degree, density, etc. of different minerals such as lepidolite, tantalite, niobium iron ore, and feldspar. Under coarse-grained crushing conditions, the present invention performs a high-field strength roughing operation, and then performs a high-field strength sweeping operation after classification. While ensuring the recovery rate, most of the gangue minerals can be discarded, effectively reducing the production cost of subsequent grinding operations and significantly increasing the production throughput. Under fine-grained grinding conditions, the present invention sequentially performs a high-field strength roughing operation, a high-field strength sweeping operation, and a high-field strength concentrating operation, so that the product quality of metal minerals that have achieved monomer dissociation can be further improved. The fifth non-magnetic material obtained in the concentrating operation is returned to the roughing operation section, which can further improve the product recovery rate. Gravity separation can effectively separate the tantalum-niobium ore with a larger specific gravity from the lepidolite with a smaller specific gravity, thereby increasing the added value of the product.

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica, characterized in that: The following steps are involved: S1: Crushing: Crushing the raw ore to obtain coarse-grained products; S2: Coarse-grain strong magnetic roughing: The coarse-grain product is mixed with slurry and subjected to magnetic separation under a first magnetic field strength to obtain a first magnetic material and a first non-magnetic material; S3: Classification: Screening the first non-magnetic material to obtain coarse particles on the sieve and fine particles under the sieve, wherein the coarse particles on the sieve are discharged into a coarse tailings sedimentation tank; S4: Fine particle strong magnetic sweeping: The fine particles under the screen are subjected to magnetic separation under a second magnetic field strength to obtain a second magnetic material and a second non-magnetic material, and the second non-magnetic material is discharged into a fine tailings sedimentation tank; S5: Grinding: Grinding the first magnetic material and the second magnetic material to obtain a fine-grained product; S6: Fine particle strong magnetic roughing: the fine particle product is mixed with slurry and then subjected to magnetic separation under a third magnetic field strength to obtain a third magnetic material and a third non-magnetic material; S7: Fine-grained strong magnetic sweeping and separation: the third non-magnetic material is subjected to magnetic separation under a fourth magnetic field strength to obtain a fourth magnetic material and a fourth non-magnetic material, and the fourth non-magnetic material is discharged into the fine-grained tailings sedimentation tank; S8: Fine particle selection: mixing the third magnetic material and the fourth magnetic material and performing magnetic separation under a fifth magnetic field strength to obtain a fifth magnetic material and a fifth non-magnetic material, and mixing the fifth non-magnetic material into the fine particle product; S9: Gravity separation: gravity separation is performed on the fifth magnetic material to obtain light minerals and heavy minerals, wherein the light minerals are discharged into a first concentrate sedimentation tank, and the heavy minerals are discharged into a second concentrate sedimentation tank; S10: solid-liquid separation: the products in the coarse-grained tailings sedimentation tank, the fine-grained tailings sedimentation tank, the first concentrate sedimentation tank, and the second concentrate sedimentation tank are subjected to solid-liquid separation operations respectively, and the separated solids are coarse-grained building material sand, feldspar concentrate, iron lithium mica concentrate and tantalum niobium coarse concentrate respectively, and the separated liquid is recycled after clarification.

2. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of iron lithium mica according to claim 1, characterized in that: In step S1, the raw ore first enters a jaw crusher for coarse crushing and medium crushing, and then enters a high pressure roller grinding mill for fine crushing.

3. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to claim 1, characterized in that: In step S2, the first magnetic field strength is set to 1.4-1.6 Tesla, a vertical ring high gradient magnetic separator is used for magnetic separation, and the magnetic separation medium used is a high magnetic permeability stainless steel rod with a diameter of 5 mm.

4. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to claim 1, characterized in that: In step S3, the first non-magnetic material enters the vibrating screen for classification; And / or, in step S5, the mixture of the first magnetic material and the second magnetic material enters a ball mill for grinding; And / or, in step S9, the fifth magnetic material enters the spiral chute for gravity separation.

5. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of iron lithium mica according to claim 3, characterized in that: In step S4, the second magnetic field strength is set to 1.6-1.8 Tesla, and a vertical ring high gradient magnetic separator is used for magnetic separation. The magnetic separation medium used is set to a high magnetic permeability stainless steel plate mesh with specifications of 5×10 mm and 6×12 mm and a ratio of 1:

1.

6. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to claim 5, characterized in that: In step S6, the third magnetic field strength is set to 1.3-1.5 Tesla, and a vertical ring high gradient magnetic separator is used for magnetic separation. The magnetic separation medium used is a high magnetic permeability stainless steel rod with a diameter of 2 mm.

7. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to claim 6, characterized in that: In step S7, the fourth magnetic field strength is set to 1.4-1.6 Tesla, and a vertical ring high gradient magnetic separator is used for magnetic separation. The magnetic separation medium used is set to a high magnetic permeability stainless steel plate mesh with specifications of 4×8 mm and 6×12 mm and a ratio of 2:

1.

8. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to claim 7, characterized in that: In step S8, the fifth magnetic field strength is set to 1.2-1.4 Tesla, and a vertical ring high gradient magnetic separator is used for magnetic separation. The magnetic separation medium used is set to a high magnetic permeability stainless steel plate mesh with specifications of 4×8 mm and 5×10 mm and a ratio of 1:

1.

9. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to claim 1, characterized in that: In step S10, the product in the coarse-grained tailings sedimentation tank enters the vibrating screen for dehydration, and the separated solid matter is the coarse-grained building material sand; the product in the fine-grained tailings sedimentation tank enters the ceramic filter for solid-liquid separation after precipitation and concentration, and the separated solid matter is the feldspar concentrate; the product in the first concentrate sedimentation tank enters the plate and frame filter press for solid-liquid separation after precipitation and concentration, and the separated solid matter is the iron lithium mica concentrate; the product in the second concentrate sedimentation tank enters the disc filter for solid-liquid separation after concentration in the sedimentation tank, and the separated solid matter is the tantalum niobium coarse concentrate.

10. The method for comprehensive recovery of tantalum-niobium ore by optimized graded magnetic separation of ferrolithium mica according to claim 1 or 9, characterized in that: The whiteness of the feldspar concentrate is 61.00-63.00%, the Fe2O3 content is 0.16-0.18%, and the K2O+Na2O content is 8.50-9.50%; the Li2O content in the iron lithium mica concentrate is 2.35-2.45%; and the Ta2O5+Nb2O5 content in the tantalum-niobium crude concentrate is 18.00-20.00%.

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