Preselection, enrichment and waste discarding method for low-grade fine-grain vanadium ore

Abstract

The invention discloses a method for pre-selecting, enriching and discarding low-grade fine-grain vanadium ore, and belongs to the technical field of mineral processing engineering. The method comprises the following steps: processing, crushing and screening a low-grade fine-grained vanadium ore raw material, carrying out microwave heating pretreatment, and carrying out a gradient high-intensity magnetic separation process of one-time roughing and two-time scavenging on the ball-milled fine-grained vanadium ore to obtain vanadium rough concentrate I; the tailings subjected to magnetic separation scavenging II are subjected to ball milling again and then subjected to size mixing activation, then primary flotation roughing, secondary flotation scavenging and tertiary flotation concentration are conducted, and vanadium rough concentrate II is obtained after flotation concentration is completed; the underflow of the flotation scavenging II enters the suspended vibration conical surface concentrator to be subjected to gravity concentration roughing and gravity concentration concentration, concentrate obtained after gravity concentration and concentration is returned to flotation scavenging I, middlings are returned to flotation scavenging II, the vanadium rough concentrate I and the vanadium rough concentrate II are combined to obtain total vanadium rough concentrate, and tailings obtained after gravity concentration roughing and gravity concentration concentration are combined into final tailings to be discarded. According to the method, through a multiple combined process combining pretreatment with vanadium ore enrichment, high-grade prevention and control can be achieved, the amount of vanadium ore entering wet leaching can be reduced, a large amount of tailings are removed, and acid consumption and production cost are reduced.

Description

Technical Field

[0001] The invention relates to the field of mineral processing engineering, and in particular to a method for preselection, enrichment and discarding of low-grade fine-grained vanadium ore. Background Art

[0002] Metallic vanadium is widely used in the steel industry, aerospace, chemical industry and new energy field due to its excellent performance. With the vigorous development of my country's manufacturing industry in recent years, the demand for vanadium metal has shown a growing trend. Vanadium ore is the main source of vanadium extraction. There are relatively rich low-grade stone coal vanadium ore resources in Hunan, Hubei and Guizhou in my country. This type of vanadium ore is characterized by low average grade, large output, fine embedded particle size, high carbon content, high content of gangue minerals, and greater difficulty in mineral processing; currently, most companies use roasting and then leaching or direct leaching to extract vanadium. This method consumes a lot of acid, is costly, and causes serious environmental pollution; therefore, the comprehensive recovery of a large number of such low-grade vanadium ores and the efficient utilization of such resources are urgent issues to be solved. Summary of the invention

[0003] In view of the above technical problems, the purpose of the present invention is to provide a method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore. On the basis of the process mineralogical property analysis of the low-grade fine-grained vanadium ore, different treatment methods are adopted according to the different properties of the vanadium ore particles, and a microwave pretreatment-magnetic-flotation-gravity combined process is proposed. First, high-gradient strong magnetic separation is adopted for magnetic vanadium mica to select iron-containing magnetic mica; then, a one-roughing, two-sweeping and three-fine flotation process is adopted for conventional vanadium mica to select another part of vanadium-containing mica; finally, for the fine-grained muddy vanadium mica after flotation, a suspended vibration cone concentrator one-roughing and one-fine gravity separation process is adopted to carry out partial tailings disposal; this process can pre-discard part of the tailings, reduce the acid consumption of wet vanadium extraction, and reduce the cost of the enterprise.

[0004] In order to achieve the purpose of the present invention, the specific scheme of the present invention is as follows:

[0005] (1) First, the low-grade vanadium ore is crushed and screened to obtain the crushed vanadium ore;

[0006] (2) pre-treating the crushed vanadium ore obtained in step (1) under microwave conditions, and grinding the pre-treated vanadium ore;

[0007] (3) the product obtained in step (2) is treated by a high gradient strong magnetic separation process with one roughing and two scavenging, the concentrates from the one roughing and two scavenging are combined to obtain a vanadium rough concentrate I, and the tailings from the magnetic scavenging II are ground again;

[0008] (4) slurrying the product obtained in step (3), adding HCl to the slurry to adjust the pH to 3.5-4, adding an activator, and adding a collector;

[0009] (5) Float the pulp after sizing and activation. The flotation includes one-stage rougher flotation, two-stage scavenger flotation, and three-stage cleaner flotation. Among them, no collector is added during the rougher flotation and cleaner flotation processes. Hydrochloric acid is added during the scavenger flotation to adjust the pH and a collector is added. Sodium silicate is added during the first-stage cleaner flotation. The foam from the rougher flotation and the first-stage cleaner flotation is combined and enters the first-stage cleaner flotation. The foam from the second-stage scavenger flotation returns to the rougher flotation. The underflow from the cleaner flotation process sequentially returns to the previous operation. The foam product obtained after three-stage cleaner flotation is the crude vanadium concentrate II.

[0010] (6) The underflow from the second-stage scavenger flotation enters a suspension vibration cone surface ore separator for gravity separation. The gravity separation includes gravity separation rougher and gravity separation cleaner. The concentrate selected by the suspension vibration cone surface ore separator returns to the first-stage scavenger flotation, the middlings return to the second-stage scavenger flotation, and the tailings from the gravity separation rougher and gravity separation cleaner are combined as the final tailings for waste disposal.

[0011] Preferably, the particle size of the vanadium ore in step (1) is -2 mm.

[0012] Preferably, the microwave conditions in step (2) are: microwave power 300 - 400 W, microwave time 25 - 35 min, and microwave temperature 80 - 100 °C.

[0013] Preferably, in step (2), the pretreated vanadium ore is ground to -0.074 mm accounting for 80 - 85 wt%.

[0014] Preferably, in step (3), the magnetic field intensity for the first-stage rougher separation is 1.1 - 1.3 T, and the magnetic field intensities for the two-stage scavenger separations are 1.3 - 1.5 T and 1.5 - 1.7 T respectively.

[0015] Preferably, in step (3), the tailings are ground again to -0.074 mm accounting for 95 - 98 wt%.

[0016] Preferably, in step (4), the pulp concentration is 25 - 30 wt%, the activator is CaCl2 with an addition amount of 750 - 900 g / t, the collector is obtained by mixing dodecylamine, sodium oleate, and hydrochloric acid, where the mass ratio of dodecylamine, sodium oleate, and hydrochloric acid is 3 - 4:1 - 2:3 - 4, and the addition amount of the collector is 100 - 200 g / t.

[0017] Preferably, in step (5): the pulp concentration is 25 - 30 wt%, the pH is 3.5 - 4, where the pH is adjusted by adding HCl;

[0018] No collector is added during the rougher flotation and cleaner flotation processes. HCl is added during both the scavenger flotation and cleaner flotation to adjust the pH to 3.5 - 4;

[0019] 50 - 100 g / t of collector is added in the scavenging flotation I; 125 - 150 g / t of activator CaCl₂ and 25 - 50 g / t of collector are added in the scavenging flotation II; 140 - 160 g / t of water glass is added in the cleaning flotation I.

[0020] The collector is obtained by mixing dodecylamine, sodium oleate and hydrochloric acid, and the mass ratio of dodecylamine, sodium oleate and hydrochloric acid is 3 - 4:1 - 2:3 - 4.

[0021] Preferably, in step (6), the working conditions of the suspension vibrating conical surface separator are: the rotation speed of the suspension vibrating conical surface is 20 - 25 r / min, and the vibration frequency is 15 - 20 Hz; the conditions for the rough gravity separation and the cleaning gravity separation are: the pulp concentration for the rough gravity separation is 20 - 25%, and the pulp concentration for the cleaning gravity separation is 15 - 20%.

[0022] The present invention proposes a combined process of "microwave pretreatment - magnetic separation of magnetic vanadium mica - flotation of ordinary vanadium mica - gravity separation of fine - sized vanadium mica"; first, the vanadium ore crushed to - 2 mm is subjected to microwave pretreatment to generate cracks on its surface; then the pretreated vanadium ore is ground, and after grinding, it enters a high - gradient magnetic separator for gradient magnetic separation. The magnetic separation concentrate is used as vanadium rough concentrate I, and the magnetic separation tailings enter the grinding process again. After grinding, they enter a stirring tank for activation and pulp conditioning. The conditioned pulp is subjected to one - stage rough flotation and two - stage scavenging flotation using a flotation column. The three - stage cleaning flotation is carried out using a flotation machine for cleaning flotation. The product of the cleaning flotation foam is used as vanadium rough concentrate II, and the underflow of the scavenging flotation enters a suspension vibrating conical surface separator for a one - rough and one - clean gravity separation process, and the obtained one - rough and one - clean gravity separation concentrate is used as the final waste - discarding product.

[0023] Compared with the prior art, what are the advantages of the present invention:

[0024] (1) For low - grade fine - sized vanadium ore, the present invention has developed a unique combined process of microwave pretreatment - magnetic separation - flotation - gravity separation; first, innovatively, microwave pretreatment is used for heating pyrolysis and structural modification, which can improve the grinding efficiency and flotation efficiency of vanadium ore; second, according to the characteristics of iron - containing vanadium mica in vanadium ore, high - gradient separation process is adopted for targeted enrichment and recovery; third, the magnetic separation tailings are further subjected to flotation recovery using a unique reagent system; fourth, for the fine - sized vanadium ore that cannot be effectively recovered by both magnetic separation and flotation processes, a new type of gravity separation equipment, the suspension vibrating conical surface separator, is used for enrichment, and the overall vanadium recovery effect is remarkable.

[0025] (2) The unique process for vanadium ore separation developed in the present invention, which combines microwave pretreatment, high-intensity magnetic separation, flotation, and gravity separation. When the fine-grained low-grade vanadium ore contains 0.95 - 1.53% V2O5, the grade of V2O5 in the total vanadium rougher concentrate is 2.12 - 4.11%, and the recovery rate of V2O5 is 81.14 - 85.07%; the grade of V2O5 in the tailings is 0.34 - 0.39%, and the waste rejection rate of the tailings is 66.21 - 69.09%.

[0026] (3) The unique process of pretreatment combined with ore dressing enrichment adopted in the present invention can discard a large amount of tailings, obtain high-grade vanadium ore, greatly reduce the amount of vanadium ore entering the subsequent wet leaching process, reduce acid consumption, save costs for enterprises, and be beneficial to environmental protection. Description of the Drawings

[0027] Figure 1 is the process flow chart of the present invention. Detailed Embodiments

[0028] The present invention will be further described in detail below with reference to the drawings and specific embodiments, but the protection scope of the present invention is not limited to the content described.

[0029] Example 1

[0030] In this example, the No. 1 low-grade fine-grained vanadium ore is used as the raw material. The ore sample contains 1.53% V2O5, in which V2O5 is mainly hosted in mica. The ore sample contains a small amount of potassium feldspar and a very small amount of siderite, and the main gangue mineral is quartz.

[0031] A method for pre-separation enrichment and waste rejection of low-grade fine-grained vanadium ore specifically includes the following steps:

[0032] (1) The low-grade vanadium ore raw ore is crushed and screened by a coarse crusher, a medium crusher, a fine crusher, and a roll crusher to a final particle size of -2 mm.

[0033] (2) The crushed vanadium ore obtained in step (1) is heated and pretreated under microwave conditions at 80 °C and a power of 300 W for 25 min, and the pretreated vanadium ore is ground by a ball mill to -0.074 mm accounting for 85 wt%.

[0034] (3) The product obtained in step (2) is processed by a high-gradient high-intensity magnetic separation process with one roughing and two scavenging. The magnetic field intensity for one roughing is 1.1 T, and the magnetic field intensities for the two scavengings are 1.3 T and 1.5 T respectively. The concentrates from one roughing and two scavengings are combined to obtain vanadium rougher concentrate I, and the tailings from magnetic separation scavenging II are ground again by a ball mill to -0.074 mm accounting for 95 wt%.

[0035] (4) The product obtained in step (3) is put into a stirring tank, water is added to adjust the concentration of the pulp to 25 wt%, HCl is added to adjust the pH of the pulp to 3.5 - 4, the addition amount of the activator CaCl2 is 750 g / t, and the addition amount of the collector is 100 g / t. The collector is prepared from dodecylamine, sodium oleate and hydrochloric acid in a mass ratio of 3:1:3.

[0036] (5) The pulp after conditioning and activation is subjected to a flotation process of one roughing, two scavengings and three cleanings using a flotation column. No collector is added during the roughing process of flotation, and the foam from the roughing of flotation enters the first cleaning of flotation; During the scavenging process of flotation, HCl is added to adjust the pH to 3.5 - 4. Among them, 50 g / t of collector is added in the first scavenging of flotation. The collector is prepared from dodecylamine, sodium oleate and hydrochloric acid in a mass ratio of 3:1:3. The foam from the first scavenging of flotation enters the first cleaning of flotation; 125 g / t of the activator CaCl2 and 25 g / t of the collector are added in the second scavenging of flotation. The collector is prepared from dodecylamine, sodium oleate and hydrochloric acid in a mass ratio of 3:1:3. The foam from the second scavenging of flotation is returned to the roughing of flotation; No collector is added during the cleaning process of flotation, and HCl is added to adjust the pH to 3.5 - 4. 140 g / t of water glass is added in the first cleaning of flotation. The underflow from the cleaning process of flotation is sequentially returned to the previous operation in order. The foam product obtained after three cleanings of flotation is the vanadium rough concentrate II.

[0037] (6) The bottom liquid from the second scavenging of flotation enters a shaking conical surface ore separator for gravity separation. The gravity separation includes gravity separation roughing and gravity separation cleaning. Among them, the rotational speed of the shaking conical surface ore separator is 20 r / min, the vibration frequency is 15 Hz. The pulp concentration of the gravity separation roughing is adjusted to 20%, and the pulp concentration of the gravity separation cleaning is adjusted to 15%. The concentrate from the gravity separation cleaning of the shaking conical surface ore separator is returned to the first scavenging of flotation, and the middlings are returned to the second scavenging of flotation. The tailings from the gravity separation roughing and gravity separation cleaning are combined as the final tailings for waste disposal.

[0038] Example 2

[0039] In this example, the No. 2 low - grade fine - grained vanadium ore is used as the raw material. The ore sample contains 1.18% of V2O5, in which V2O5 is mainly hosted in mica. The ore sample contains a small amount of potassium feldspar and a very small amount of siderite, and the main gangue mineral is quartz.

[0040] A method for pre - enrichment and waste disposal of low - grade fine - grained vanadium ore specifically includes the following steps:

[0041] (1) The raw ore of low - grade vanadium ore is crushed and screened to a final particle size of - 2 mm using coarse, medium and fine crushers and roll crushers.

[0042] (2) The crushed vanadium ore obtained in step (1) is subjected to heat pretreatment for 30 min under microwave conditions at 90 °C and a power of 350 W. The pretreated vanadium ore is ground in a ball mill to a particle size where -0.074 mm accounts for 82 wt%.

[0043] (3) The product obtained in step (2) is processed by a high-gradient high-intensity magnetic separation process with one rough selection and two scavenging selections. The magnetic field intensity for the first rough selection is 1.2 T, and the magnetic field intensities for the two scavenging selections are 1.4 T and 1.6 T respectively. The concentrates from the first rough selection and the two scavenging selections are combined to obtain vanadium rough concentrate I. The tailings from the second magnetic scavenging are ground again in a ball mill to a particle size where -0.074 mm accounts for 97 wt%.

[0044] (4) The product obtained in step (3) is put into a stirring tank, and water is added to adjust the pulp concentration to 27 wt%. HCl is added to adjust the pH of the pulp to 3.5 - 4. The addition amount of the activator CaCl2 is 825 g / t, and the addition amount of the collector is 150 g / t. The collector is prepared from dodecylamine, sodium oleate, and hydrochloric acid in a mass ratio of 3.5:1.5:3.5.

[0045] (5) The pulp after conditioning and activation is subjected to a flotation process with one rough selection, two scavenging selections, and three cleaning selections in a flotation column. No collector is added during the rough flotation process, and the foam from the rough flotation enters the first cleaning flotation; during the scavenging flotation process, HCl is added to adjust the pH to 3.5 - 4. Among them, 75 g / t of collector is added in the first scavenging flotation. The collector is prepared from dodecylamine, sodium oleate, and hydrochloric acid in a mass ratio of 3.5:1.5:3.5, and the foam from the first scavenging flotation enters the first cleaning flotation; 140 g / t of activator CaCl2 and 35 g / t of collector are added in the second scavenging flotation. The collector is prepared from dodecylamine, sodium oleate, and hydrochloric acid in a mass ratio of 3.5:1.5:3.5, and the foam from the second scavenging flotation is returned to the rough flotation; no collector is added during the cleaning flotation process, and HCl is added to adjust the pH to 3.5 - 4. 150 g / t of water glass is added in the first cleaning flotation. The underflow from the cleaning flotation process is sequentially returned to the previous operation. The foam product obtained after three cleaning flotation processes is vanadium rough concentrate II.

[0046] (6) The bottom liquid from the second scavenging flotation enters a shaking conical surface separator for gravity separation, which includes gravity rough separation and gravity cleaning separation. Among them, the rotational speed of the shaking conical surface separator is 23 r / min, and the vibration frequency is 18 Hz. The pulp concentration for the gravity rough separation is adjusted to 20%, and the pulp concentration for the gravity cleaning separation is adjusted to 20%. The concentrate from the gravity cleaning separation of the shaking conical surface separator is returned to the first scavenging flotation, and the middlings are returned to the second scavenging flotation. The tailings from the gravity rough separation and the gravity cleaning separation are combined as the final tailings for waste disposal.

[0047] Example 3

[0048] In this embodiment, the raw material is No. 3 low-grade fine-grained vanadium ore. The ore sample contains 0.95% V2O5, and V2O5 is mainly hosted in mica. The ore sample contains a small amount of potassium feldspar and a very small amount of siderite, and the main gangue mineral is quartz.

[0049] A pre-selection enrichment and waste rejection method for low-grade fine-grained vanadium ore specifically includes the following steps:

[0050] (1) The raw low-grade vanadium ore is crushed and screened by a coarse crusher, a medium crusher, a fine crusher and a roll crusher to a final particle size of -2 mm.

[0051] (2) The crushed vanadium ore obtained in step (1) is heated and pre-treated under microwave conditions at 100 °C and a power of 400 W for 35 min, and the pre-treated vanadium ore is ground by a ball mill to -0.074 mm accounting for 85 wt%.

[0052] (3) The product obtained in step (2) is treated by a high-gradient high-intensity magnetic separation process with one rough selection and two scavenging selections. The magnetic field intensity for one rough selection is 1.3 T, and the magnetic field intensities for the two scavenging selections are 1.5 T and 1.7 T respectively. The concentrates from one rough selection and two scavenging selections are combined to obtain vanadium rough concentrate I, and the tailings from magnetic separation scavenging II are ground again by a ball mill to -0.074 mm accounting for 98 wt%.

[0053] (4) The product obtained in step (3) is put into a stirring tank, and water is added to adjust the concentration of the pulp to 30 wt%. HCl is added to adjust the pH of the pulp to 3.5 - 4. The addition amount of the activator CaCl2 is 900 g / t, and the addition amount of the collector is 200 g / t. The collector is prepared according to the mass ratio of dodecylamine, sodium oleate and hydrochloric acid of 4:2:4.

[0054] (5) The pulp after conditioning and activation is subjected to a flotation process of one rough selection, two scavenging selections and three cleaning selections by a flotation column. No collector is added during the rough flotation process, and the foam from the rough flotation enters the first cleaning flotation; HCl needs to be added during the scavenging flotation process to adjust the pH to 3.5 - 4. Among them, 100 g / t of collector is added in the first scavenging flotation. The collector is prepared according to the mass ratio of dodecylamine, sodium oleate and hydrochloric acid of 4:2:4, and the foam from the first scavenging flotation enters the first cleaning flotation; 150 g / t of activator CaCl2 and 50 g / t of collector are added in the second scavenging flotation. The collector is prepared according to the mass ratio of dodecylamine, sodium oleate and hydrochloric acid of 4:2:4, and the foam from the second scavenging flotation returns to the rough flotation; No collector is added during the cleaning flotation process, and HCl is added to adjust the pH to 3.5 - 4. 160 g / t of water glass is added in the first cleaning flotation. The underflow from the cleaning flotation process is sequentially returned to the previous operation. The foam product obtained after three cleaning flotation selections is vanadium rough concentrate II.

[0055] (6) The bottom liquid of the second scavenging flotation enters a suspended vibration conical surface ore separator for gravity separation, which includes gravity roughing and gravity cleaning. Among them, the rotation speed of the suspended vibration conical surface ore separator is 25 r / min, the vibration frequency is 20 Hz. The pulp concentration of the gravity roughing is adjusted to 25%, and the pulp concentration of the gravity cleaning is adjusted to 20%. The concentrate of the gravity cleaning of the suspended vibration conical surface ore separator is returned to the first scavenging flotation, and the middlings are returned to the second scavenging flotation. The tailings of the gravity roughing and gravity cleaning are combined as the final tailings for waste disposal.

[0056] The indexes and beneficial effects of obtaining vanadium concentrate in Examples 1 to 3 are shown in Table 1.

[0057] Table 1 shows the indexes and beneficial effects obtained in Examples 1 to 3 by using the method of the present invention.

[0058]

[0059]

[0060] According to Table 1, for the fine-grained low-grade vanadium ore in Examples 1 - 3, when the fine-grained low-grade contains 0.95 - 1.53% V2O5, the grade of V2O5 in the total vanadium rough concentrate is 2.12 - 4.11%, and the recovery rate of V2O5 is 81.14 - 85.07%; the grade of V2O5 in the tailings is 0.34 - 0.39%, and the waste disposal rate of the tailings is 66.21 - 69.09%. The present invention realizes the efficient enrichment of low-grade V2O5 in fine-grained low-grade vanadium ore, and at the same time, the tailings of low-grade V2O5 can be discarded.

[0061] After analysis, by using the combined process and reagent system of "microwave pretreatment - magnetic separation of magnetic vanadium mica - flotation of ordinary vanadium mica - gravity separation of fine-grained vanadium mica" of the present invention, different processes are used for vanadium mica with different properties, and the process has strong pertinence; secondly, the low-grade vanadium ore is discarded by a suspended vibration conical surface ore separator, providing higher-grade vanadium ore for hydrometallurgy, reducing the acid consumption of hydrometallurgy, reducing the cost of subsequent processes, and reducing environmental pollution.

[0062] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments; it should be understood that the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; without conflict, the embodiments and features in the present application can be combined with each other; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

Claims

1. A method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore, characterized in that: The specific steps include: (1) First, the low-grade vanadium ore is crushed and screened to obtain the crushed vanadium ore; (2) pre-treating the crushed vanadium ore obtained in step (1) under microwave conditions, and grinding the pre-treated vanadium ore; (3) the product obtained in step (2) is treated by a high gradient strong magnetic separation process with one roughing and two scavenging, the concentrates from the one roughing and two scavenging are combined to obtain a vanadium rough concentrate I, and the tailings from the magnetic scavenging II are ground again; (4) slurrying the product obtained in step (3), adding HCl to the slurry to adjust the pH to 3.5-4, adding an activator, and adding a collector; (5) flotation is performed on the pulp after pulping and activation, and the flotation includes one flotation roughing, two flotation scavenging, and three flotation concentrating processes; wherein, no collector is added in the flotation roughing and concentrating processes, hydrochloric acid is added to adjust the pH and a collector is added in the flotation scavenging, and water glass is added in the flotation concentrating I; the foams of the flotation roughing and flotation scavenging I are combined and enter the flotation concentrating I; the foams of the flotation scavenging II are returned to the flotation roughing, and the underflow of the flotation concentrating process is returned to the previous operation in sequence, and the foam product obtained after the three flotation concentrating is the vanadium rough concentrate II; (6) The bottom flow of flotation scavenging II enters the suspended vibration cone concentrator for gravity separation, which includes gravity roughing and gravity concentrating. The concentrate from gravity concentrating by the suspended vibration cone concentrator is returned to flotation scavenging I, and the middlings are returned to flotation scavenging II. The tailings from gravity roughing and gravity concentrating are combined and discarded.

2. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: The particle size of the vanadium ore in step (1) is -2 mm.

3. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: The microwave conditions in step (2) are: microwave power 300-400 W, microwave time 25-35 min, microwave temperature 80-100° C.

4. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: In step (2), the pretreated vanadium ore is ground to -0.074 mm, accounting for 80-85 wt%.

5. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: In step (3), the magnetic field strength of the first rough selection is 1.1-1.3 T, and the magnetic field strengths of the two sweep selections are 1.3-1.5 T and 1.5-1.7 T respectively.

6. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: In step (3), the tailings are ground again to -0.074 mm, accounting for 95-98 wt%.

7. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: In step (4), the slurry concentration is 25-30wt%, the activator is CaCl2, the addition amount is 750-900g / t, the collector is a mixture of dodecylamine, sodium oleate and hydrochloric acid, wherein the mass ratio of dodecylamine, sodium oleate and hydrochloric acid is 3-4:1-2:3-4, and the addition amount of the collector is 100-200g / t.

8. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: In step (5), the slurry concentration is 25-30 wt % and the pH is 3.5-4, wherein the pH is adjusted by adding HCl; No collector was added in the flotation roughing and flotation cleaning processes, and HCl was added in the flotation sweeping and flotation cleaning processes to adjust the pH to 3.5-4; Add 50-100g / t of collector to flotation scavenging I; add 125-150g / t of activator CaCl2 and 25-50g / t of collector to flotation scavenging II; add 140-160g / t of water glass to flotation scavenging I; The collector is obtained by mixing dodecylamine, sodium oleate and hydrochloric acid, wherein the mass ratio of dodecylamine, sodium oleate and hydrochloric acid is 3-4:1-2:3-4.

9. The method for pre-selection, enrichment and disposal of low-grade fine-grained vanadium ore according to claim 1, characterized in that: The working conditions of the suspended vibration cone concentrator in step (6) are: the suspended vibration cone speed is 20-25r / min, and the vibration frequency is 15-20Hz; wherein the conditions for the roughing gravity separation and the fine gravity separation are: the pulp concentration of the roughing gravity separation is 20-25%, and the pulp concentration of the fine gravity separation is 15-20%.

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