Method for comprehensively recovering tantalum, niobium and tin from lepidolite flotation tailings

Abstract

The invention provides a comprehensive recovery method for tantalum, niobium and tin in lepidolite flotation tailings, and relates to the technical field of comprehensive utilization of resources. The method comprises the following steps: firstly, grading the lepidolite tailings, and carrying out flotation on the lepidolite tailings of which the particle size is less than 0.038 mm to obtain low-grade tantalum-niobium-tin concentrate; carrying out gravity separation, centrifugal separation and shaking table separation on the fraction of + 0.038-0.15 mm to obtain high-grade tantalum-niobium-tin concentrate; and after the particle size larger than 0.15 mm is subjected to reselection, ore grinding is conducted again, and ore grinding products are returned to the initial grading operation. The method is environment-friendly in process, the lepidolite flotation tailings can be effectively utilized, and the problem that the recovery rate of tantalum, niobium and tin is low is solved.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive resource utilization, in particular to a method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings. Background Art

[0002] With the development of mineral processing, the accumulation of tailings is becoming more and more common, and the tailings contain rich metal and non-metallic mineral resources, which have not been effectively utilized. The accumulated tailings not only cause a waste of resources, but also have great harm to the natural environment.

[0003] Lepidolite flotation tailings contain a large amount of valuable metal elements. Currently, most of the lepidolite flotation tailings are directly piled up. Some studies also extract high-value elements from the lepidolite flotation tailings, and then use the waste residue as building materials, and finally carry out green backfilling. However, none of the existing studies involve the recovery of tantalum, niobium and tin in the tailings. With the rapid development of modern industry and high-tech, the demand for tantalum, niobium, tin and their products is increasing. Tantalum, niobium and tin are rare metals with relatively scarce mineral sources. Especially in recent years, the demand for tantalum, niobium and tin has been strong, while the resources of tantalum, niobium and tin are very scarce. Lepidolite concentrate is rich in high-quality tantalum, niobium, tin and other rare metals. According to the test report, the average tantalum grade of lepidolite ore is only 0.014%. Generally, the beneficiation relies on grinding and then re-selection to simply recover the dissociated coarse particles of tantalum, niobium and tin through spiral chutes and shaking tables. However, due to the flaky structure and soft texture of lepidolite, which is extremely difficult to grind, a large amount of tantalum, niobium and tin that are closely associated with mica cannot be recovered due to insufficient dissociation, resulting in a tantalum, niobium and tin beneficiation recovery rate of less than 25%, and extremely low beneficiation efficiency.

[0004] Therefore, in order to solve the problem of accumulation of lepidolite flotation tailings and effectively recover tantalum, niobium and tin, the present invention studies a new and convenient method for recovering tantalum, niobium and tin from lepidolite flotation tailings. Summary of the invention

[0005] In order to solve the above technical problems existing in the prior art, the embodiment of the present invention provides a method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings. The technical solution is as follows:

[0006] A method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings, the method comprising:

[0007] S1, classifying the lithium mica flotation tailings to obtain three particle sizes of -0.038mm, -0.15+0.038mm and +0.15mm;

[0008] S2, flotation separation of the -0.038 mm particle size obtained in step S1 to obtain a low-grade tantalum, niobium and tin concentrate;

[0009] S3, re-selecting the -0.15+0.038 mm particle size obtained in step S1 to obtain a re-selected concentrate;

[0010] S4, centrifugally separating the gravity separation concentrate obtained in step S3, and separating the concentrate after centrifugal separation on a shaking table to obtain a high-grade tantalum, niobium and tin concentrate;

[0011] S5. The +0.15 mm particle size obtained in step S1 is re-selected, and the re-selected concentrate is ground again and returned to step S1 for classification.

[0012] In the lithium mica flotation tailings in step S1, the Ta2O5 grade is 0.003-0.01%, the Nb2O5 grade is 0.003-0.01%, the SnO2 grade is 0.03-0.3%, and the particle size of -0.074 mm accounts for more than 40%.

[0013] The flotation process in step S2 is as follows: the flotation pulp concentration is 10-20%, and a low-grade tantalum, niobium and tin concentrate is obtained through one roughing selection, three scavenging selections and three concentrating selections;

[0014] Among them, the primary roughing reagent system is: water glass dosage 500~1000g / t, sodium carbonate dosage 500~1000g / t, collector is o-aminobenzoic acid cinnamyl ester and bis (1,3-propylenediamine) copper chloride mixed in a mass ratio of 1:1, dosage is 100~500g / t;

[0015] The dosage of the first sweeping agent is 1 / 3 of that of the first roughing agent, and the dosage of the second and third sweeping agents is 1 / 4 of that of the first roughing agent.

[0016] The reagent system for selecting is: only water glass is added for selection, the amount of water glass used for the first selection is 100~200g / t, and the amount of water glass used for the second and third selections is 50~100g / t.

[0017] During flotation, the stirring speed of the flotation machine is 2000-3000rpm, the stirring time of water glass and sodium carbonate reagent is 30-60min, and the stirring time of the collector is 10-20min.

[0018] In the low-grade tantalum, niobium and tin concentrate obtained in step S2, the Ta2O5 grade is 3-6%, the recovery rate is 20-30%, the Nb2O5 grade is 3-6%, the recovery rate is 20-30%, and the SnO2 grade is 5-10%, and the recovery rate is 25-35%.

[0019] In the step S3 and step S5, the gravity separation adopts one of a spiral chute or a spreading chute, and the feed concentration is 15-25%.

[0020] In step S4, the centrifugal separation adopts a continuous vertical centrifugal separator, the feed concentration is 10-20%, the centrifuge speed is 200-300 rpm, the backwash water pressure is 0.2-0.3 MPa, and the feed rate is 25-30 t / h.

[0021] In the high-grade tantalum, niobium and tin concentrate obtained in step S4, the Ta2O5 grade is 10-20%, the recovery rate is 50-60%, the Nb2O5 grade is 10-20%, the recovery rate is 50-60%, and the SnO2 grade is 5-10%, and the recovery rate is 40-60%.

[0022] In step S5, the grinding concentration is 25-35%, and the grinding fineness is -0.15 mm, accounting for 100%.

[0023] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0024] In the above scheme, the process of first grading and then sorting is adopted to achieve the recovery of tantalum, niobium and tin in a narrow particle size, avoid the problem of high loss of valuable metals due to different particle sizes, and improve the recovery rate of tantalum, niobium and tin; moreover, the new collector cinnamyl o-aminobenzoate and bis(1,3-propylenediamine)copper chloride are used to float tantalum, niobium and tin minerals, which can achieve efficient flotation of fine tantalum, niobium and tin, and improve the enrichment ratio and recovery rate of fine tantalum, niobium and tin; in addition, a continuous centrifugal concentrator is used to sort the gravity concentration concentrate. The continuous centrifuge has a large processing capacity and a high enrichment ratio. Compared with the traditional gravity concentration concentrate that directly enters the shaking table for concentration, this process has a large processing capacity and can greatly reduce the number of shaking tables for concentration, thereby reducing the production area.

[0025] The above-mentioned lithium mica sorting tailings adopt the classification-flotation recovery of fine-grained tantalum and niobium-staged gravity recovery of intermediate-grade tantalum and niobium-coarse-grained regrinding and re-sorting process, which can achieve efficient recovery of low-grade tantalum, niobium and tin in lithium mica flotation tailings. The comprehensive recovery rate of Ta2O5 reaches 60~80%, the comprehensive recovery rate of Nb2O5 reaches 60~80%, and the comprehensive recovery rate of SnO2 reaches 70~90%, which solves the problem of low recovery rate of tantalum, niobium and tin. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 The present invention provides a flow chart of a method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0029] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0030] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0031] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0032] The embodiment of the present invention provides a method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings. Figure 1 The method flow chart of comprehensive recovery of tantalum, niobium and tin from lithium mica flotation tailings is shown, and the method may include the following steps:

[0033] S1, classifying the lithium mica flotation tailings to obtain three particle sizes of -0.038mm, -0.15+0.038mm and +0.15mm;

[0034] S2, flotation separation of the -0.038 mm particle size obtained in step S1 to obtain a low-grade tantalum, niobium and tin concentrate;

[0035] S3, re-selecting the -0.15+0.038 mm particle size obtained in step S1 to obtain a re-selected concentrate;

[0036] S4, centrifugally separating the re-selected concentrate obtained in step S3, and separating the concentrate on a shaking table to obtain a high-grade tantalum, niobium and tin concentrate;

[0037] S5. The +0.15 mm particle size obtained in step S1 is re-selected, and the re-selected concentrate is ground again and returned to step S1 for classification.

[0038] This will be described below with reference to specific embodiments.

[0039] Example 1

[0040] The lithium mica flotation tailings selected in this embodiment have a Ta2O5 grade of about 0.006%, a Nb2O5 grade of about 0.008%, a SnO2 grade of about 0.15%, and a particle size of -0.074 mm accounting for more than 40%.

[0041] like Figure 1 First, the lithium mica flotation tailings are graded to obtain three particle sizes: -0.038 mm, -0.15+0.038 mm and +0.15 mm.

[0042] Then, the -0.038 mm particle size is subjected to flotation, and a flotation operation of one roughing, three fines and three sweeps is adopted to obtain a flotation concentrate (i.e., a low-grade TaNbSn concentrate) and tailings. In the first roughing, the amount of water glass used is 800 g / t, the amount of sodium carbonate used is 800 g / t, and the collector is a mixture of cinnamyl anthranilate and bis(1,3-propylenediamine)copper chloride in a mass ratio of 1:1, and the amount used is 300 g / t;

[0043] The amount of water glass, sodium carbonate and collector used in the first sweep is 1 / 3 of that in the first rough sweep, and the amount of water glass, sodium carbonate and collector used in the second and third sweeps is 1 / 4 of that in the first rough sweep;

[0044] Only water glass is added in the first concentration, the amount of water glass used in the first concentration is 100g / t, and the amount of water glass used in the second and third concentrations is 50g / t.

[0045] In the low-grade TaNbSn concentrate obtained by flotation, the Ta2O5 grade is 4.2%, the recovery rate is 25.8%, the Nb2O5 grade is 4.3%, the recovery rate is 25.4%, and the SnO2 grade is 7.1%, and the recovery rate is 30.1%.

[0046] The -0.15+0.038mm particle size is re-selected using a spiral chute, and the re-selection feed concentration is 18%.

[0047] The gravity-separated concentrate is further centrifuged and then subjected to shaking table gravity separation to obtain high-grade TaNbSn concentrate. Among the high-grade TaNbSn concentrate, the Ta2O5 grade is 16.8% and the recovery rate is 56.6%, the Nb2O5 grade is 16.7% and the recovery rate is 55.2%, and the SnO2 grade is 6.4% and the recovery rate is 55.4%.

[0048] Among them, the LX-60 vortex centrifuge test machine is used for centrifugal separation. In the centrifugal separation, the feed concentration is about 16%, the centrifuge speed is 240rpm, the backwash water pressure is 0.25MPa, and the feed volume is about 26t / h. And tap water is used as much as possible, and the water cannot contain obvious suspended matter, sediment and particles, because poor water quality may block the backwash water hole and affect the normal operation of the flow meter.

[0049] The +0.15mm particle size is re-selected using a cloth chute, and the re-selected concentrate is ground again and returned to the initial classification operation. Among them, the grinding concentration is about 27%, and the grinding fineness of -0.15mm accounts for 100%.

[0050] In the above process, the tailings obtained are combined and then uniformly processed, and the two TaNbSn concentrates obtained are combined as the final TaNbSn concentrate.

[0051] Example 2

[0052] The lithium mica flotation tailings selected in this embodiment have a Ta2O5 grade of about 0.004%, a Nb2O5 grade of 0.003%, a SnO2 grade of about 0.05%, and a particle size of -0.074 mm accounting for more than 40%.

[0053] like Figure 1 First, the lithium mica flotation tailings are graded to obtain three particle sizes: -0.038 mm, -0.15+0.038 mm and +0.15 mm.

[0054] Then, the -0.038 mm particle size is subjected to flotation, and a flotation operation of one roughing, three fines and three sweeps is adopted to obtain a flotation concentrate (i.e., a low-grade TaNbSn concentrate) and tailings. In the first roughing, the amount of water glass used is 1000 g / t, the amount of sodium carbonate used is 900 g / t, and the collector is a mixture of o-aminobenzoic acid cinnamyl ester and bis(1,3-propylenediamine) copper chloride in a mass ratio of 1:1, and the amount used is 500 g / t;

[0055] The amount of water glass, sodium carbonate and collector used in the first sweep is 1 / 3 of that in the first rough sweep, and the amount of water glass, sodium carbonate and collector used in the second and third sweeps is 1 / 4 of that in the first rough sweep;

[0056] Only water glass is added in the selection. The amount of water glass used in the first selection is 200g / t, and the amount of water glass used in the second and third selections is 100g / t.

[0057] In the low-grade TaNbSn concentrate obtained by flotation, the Ta2O5 grade is 3.9%, the recovery rate is 26.9%, the Nb2O5 grade is 4.9%, the recovery rate is 27.3%, and the SnO2 grade is 8.2%, and the recovery rate is 28.7%.

[0058] The -0.15+0.038mm particle size is re-selected using a spiral chute, and the re-selection feed concentration is 19%.

[0059] The gravity-separated concentrate is further centrifugally separated, and after centrifugal separation, the concentrate is subjected to shaking table gravity separation to obtain high-grade TaNbSn concentrate. Among the high-grade TaNbSn concentrate obtained, the Ta2O5 grade is 17.2%, the recovery rate is 57.6%, the Nb2O5 grade is 17.1%, the recovery rate is 56.4%, and the SnO2 grade is 7.1%, and the recovery rate is 56.3%.

[0060] Among them, the centrifugal separation uses the LX-60 vortex centrifuge test machine. In the centrifugal separation, the feed concentration is about 16%, the centrifuge speed is 280rpm, the backwash water pressure is 0.28MPa, and the feed volume is about 28t / h. And tap water is used as much as possible, and the water cannot contain obvious suspended matter, sediment and particles, because poor water quality may block the backwash water hole and affect the normal operation of the flow meter.

[0061] The +0.15mm particle size is re-selected using a spreading chute, and the re-selected concentrate is ground again and returned to the initial classification operation. Among them, the grinding concentration is about 30%, and the grinding fineness of -0.15mm accounts for 100%.

[0062] In the above process, the tailings obtained are combined and then uniformly processed, and the two TaNbSn concentrates obtained are combined as the final TaNbSn concentrate.

[0063] Example 3

[0064] The lithium mica flotation tailings selected in this embodiment have a Ta2O5 grade of about 0.007%, a Nb2O5 grade of about 0.005%, a SnO2 grade of about 0.1%, and a particle size of -0.074 mm accounting for more than 40%.

[0065] like Figure 1 First, the lithium mica flotation tailings are graded to obtain three particle sizes: -0.038 mm, -0.15+0.038 mm and +0.15 mm.

[0066] Then, the -0.038 mm particle size is subjected to flotation, and a flotation operation of one roughing, three fines and three sweeps is adopted to obtain a flotation concentrate (i.e., a low-grade TaNbSn concentrate) and tailings. In the first roughing, the amount of water glass used is 700 g / t, the amount of sodium carbonate used is 850 g / t, and the collector is a mixture of cinnamyl anthranilate and bis(1,3-propylenediamine)copper chloride in a mass ratio of 1:1, and the amount used is 250 g / t;

[0067] The amount of water glass, sodium carbonate and collector used in the first sweep is 1 / 3 of that in the first rough sweep, and the amount of water glass, sodium carbonate and collector used in the second and third sweeps is 1 / 4 of that in the first rough sweep;

[0068] Only water glass is added in the first concentration, the amount of water glass used in the first concentration is 120g / t, and the amount of water glass used in the second and third concentrations is 60g / t.

[0069] In the low-grade TaNbSn concentrate obtained by flotation, the Ta2O5 grade is 4.3%, the recovery rate is 26.8%, the Nb2O5 grade is 4.6%, the recovery rate is 24.4%, and the SnO2 grade is 6.8%, and the recovery rate is 31.1%.

[0070] The -0.15+0.038mm particle size is re-selected using a spiral chute, and the feed concentration is 18%.

[0071] The gravity-separated concentrate is further centrifuged and then subjected to shaking table gravity separation to obtain high-grade TaNbSn concentrate. Among the high-grade TaNbSn concentrate, the Ta2O5 grade is 18.0% and the recovery rate is 54.6%, the Nb2O5 grade is 15.7% and the recovery rate is 56.2%, and the SnO2 grade is 6.8% and the recovery rate is 55.3%.

[0072] Among them, the LX-60 vortex centrifuge test machine is used for centrifugal separation. In the centrifugal separation, the feed concentration is about 16%, the centrifuge speed is 220rpm, the backwash water pressure is 0.23MPa, and the feed volume is about 27t / h. And tap water is used as much as possible, and the water cannot contain obvious suspended matter, sediment and particles, because poor water quality may block the backwash water hole and affect the normal operation of the flow meter.

[0073] The +0.15mm particle size is re-selected using a cloth chute, and the re-selected concentrate is ground again and returned to the initial classification operation. Among them, the grinding concentration is about 27%, and the grinding fineness of -0.15mm accounts for 100%.

[0074] In the above process, the tailings obtained are combined and then uniformly processed, and the two TaNbSn concentrates obtained are combined as the final TaNbSn concentrate.

[0075] Example 4

[0076] The lithium mica flotation tailings selected in this embodiment have a Ta2O5 grade of about 0.01%, a Nb2O5 grade of about 0.009%, a SnO2 grade of about 0.25%, and a particle size of -0.074 mm accounting for more than 40%.

[0077] like Figure 1 First, the lithium mica flotation tailings are graded to obtain three particle sizes: -0.038 mm, -0.15+0.038 mm and +0.15 mm.

[0078] Then, the -0.038 mm particle size is subjected to flotation, and a flotation operation of one roughing, three fines and three sweeps is adopted to obtain a flotation concentrate (i.e., a low-grade TaNbSn concentrate) and tailings. In the first roughing, the amount of water glass used is 680 g / t, the amount of sodium carbonate used is 680 g / t, and the collector is a mixture of cinnamyl anthranilate and bis(1,3-propylenediamine) copper chloride in a mass ratio of 1:1, and the amount used is 350 g / t;

[0079] The amount of water glass, sodium carbonate and collector used in the first sweep is 1 / 3 of that in the first rough sweep, and the amount of water glass, sodium carbonate and collector used in the second and third sweeps is 1 / 4 of that in the first rough sweep;

[0080] Only water glass is added in the selection, the amount of water glass used in the first selection is 160g / t, and the amount of water glass used in the second and third selections is 80g / t.

[0081] In the low-grade TaNbSn concentrate obtained by flotation, the Ta2O5 grade is 4.4%, the recovery rate is 26.8%, the Nb2O5 grade is 4.6%, the recovery rate is 27.4%, and the SnO2 grade is 9.1%, and the recovery rate is 31.1%.

[0082] The -0.15+0.038mm particle size is re-selected using a spiral chute, and the feed concentration is 18%.

[0083] The gravity-separated concentrate is further centrifuged and then subjected to shaking table gravity separation to obtain high-grade TaNbSn concentrate. Among the high-grade TaNbSn concentrate, the Ta2O5 grade is 16.6% and the recovery rate is 55.6%, the Nb2O5 grade is 15.7% and the recovery rate is 56.2%, and the SnO2 grade is 8.4% and the recovery rate is 52.4%.

[0084] Among them, the centrifugal separation uses the LX-60 vortex centrifuge test machine. In the centrifugal separation, the feed concentration is about 16%, the centrifuge speed is 270rpm, the backwash water pressure is 0.25MPa, and the feed volume is about 26t / h. And tap water is used as much as possible, and the water cannot contain obvious suspended matter, sediment and particles, because poor water quality may block the backwash water hole and affect the normal operation of the flow meter.

[0085] The +0.15mm particle size is re-selected using a cloth chute, and the re-selected concentrate is ground again and returned to the initial classification operation. Among them, the grinding concentration is about 27%, and the grinding fineness of -0.15mm accounts for 100%.

[0086] In the above process, the tailings obtained are combined and then uniformly processed, and the two TaNbSn concentrates obtained are combined as the final TaNbSn concentrate.

[0087] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings, characterized in that: The method comprises: S1, classifying the lithium mica flotation tailings to obtain three particle sizes of -0.038mm, -0.15+0.038mm and +0.15mm; S2, flotation separation of the -0.038 mm particle size obtained in step S1 to obtain a low-grade tantalum, niobium and tin concentrate; S3, re-selecting the -0.15+0.038 mm particle size obtained in step S1 to obtain a re-selected concentrate; S4, centrifugally separating the gravity separation concentrate obtained in step S3, and separating the concentrate after centrifugal separation on a shaking table to obtain a high-grade tantalum, niobium and tin concentrate; S5, re-select the +0.15 mm particle size obtained in step S1, and grind the re-selected concentrate again before returning to step S1 for classification.

2. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 1, characterized in that: In the lithium mica flotation tailings in step S1, the Ta2O5 grade is 0.003-0.01%, the Nb2O5 grade is 0.003-0.01%, the SnO2 grade is 0.03-0.3%, and the particle size of -0.074 mm accounts for more than 40%.

3. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 1, characterized in that: The flotation process in step S2 is: the flotation concentration is 10-20%, and a low-grade tantalum, niobium and tin concentrate is obtained through one roughing, three scavenging and three cleaning processes; Among them, the primary roughing reagent system is: water glass dosage 500~1000g / t, sodium carbonate dosage 500~1000g / t, collector is o-aminobenzoic acid cinnamyl ester and bis (1,3-propylenediamine) copper chloride mixed in a mass ratio of 1:1, dosage is 100~500g / t; The dosage of the first sweeping agent is 1 / 3 of that of the first roughing agent, and the dosage of the second and third sweeping agents is 1 / 4 of that of the first roughing agent. The reagent system for selecting is: only water glass is added for selection, the amount of water glass used for the first selection is 100~200g / t, and the amount of water glass used for the second and third selections is 50~100g / t.

4. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 3, characterized in that: During the flotation, the stirring speed of the flotation machine is 2000-3000rpm, the stirring time of water glass and sodium carbonate reagent is 30-60min, and the stirring time of the collector is 10-20min.

5. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 1, characterized in that: In the low-grade tantalum, niobium and tin concentrate obtained in step S2, the Ta2O5 grade is 3-6%, the recovery rate is 20-30%, the Nb2O5 grade is 3-6%, the recovery rate is 20-30%, and the SnO2 grade is 5-10%, and the recovery rate is 25-35%.

6. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 1, characterized in that: In the step S3 and step S5, the gravity separation adopts one of a spiral chute or a spreading chute, and the feed concentration is 15-25%.

7. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 1, characterized in that: In step S4, the centrifugal separation adopts a continuous vertical centrifugal separator, the feed concentration is 10-20%, the centrifuge speed is 200-300 rpm, the backwash water pressure is 0.2-0.3 MPa, and the feed rate is 25-30 t / h.

8. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 1, characterized in that: In the high-grade tantalum, niobium and tin concentrate obtained in step S4, the Ta2O5 grade is 10-20%, the recovery rate is 50-60%, the Nb2O5 grade is 10-20%, the recovery rate is 50-60%, and the SnO2 grade is 5-10%, and the recovery rate is 40-60%.

9. The method for comprehensive recovery of tantalum, niobium and tin from lepidolite flotation tailings according to claim 1, characterized in that: In step S5, the grinding concentration is 25-35%, and the grinding fineness is -0.15 mm, accounting for 100%.

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