Method for beneficiating, smelting and recycling volcanic rock type ultra-fine particle niobium-tantalum ore

Abstract

The invention belongs to the technical field of mineral processing engineering, and relates to a beneficiation, smelting and recovery process for volcanic rock type extremely-fine particle niobium-tantalum ore. The process comprises the steps of raw ore grinding, agglomeration magnetic separation, selective leaching, strong magnetic concentration and the like, is mainly used for strongly-weathered extremely-micro-fine-particle niobium-tantalum ores such as volcanic rock type tuffaceous silk phyllite and coarse tuffaceous, and is also particularly suitable for recycling of other weathered and micro-fine-particle niobium-tantalum ores. The process is advanced, reliable, simple and reasonable in technology, high in pertinence, low in operation cost and high in niobium-tantalum concentrate enrichment ratio, niobium and tantalum in the resources can be effectively recycled, and good industrialization prospects are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing engineering, and in particular to a method for beneficiating and smelting volcanic rock type ultra-fine-grained niobium-tantalum ore. Background Art

[0002] The mineral processing process mainly separates useful minerals from gangue minerals, which is a key link in obtaining qualified mineral raw material products. As a strategic key metal mineral in my country, the development and utilization of niobium-tantalum ore is related to the effective supply of raw materials in many fields of the national economy, including the electronics industry, aerospace, chemical equipment, and medical treatment. However, my country's external dependence on niobium-tantalum resources is very high, reaching more than 90%. Accelerating the efficient development and supply of domestic niobium-tantalum resources is particularly important to ensure the security of my country's strategic niobium-tantalum resources.

[0003] The current development and utilization of niobium and tantalum resources are mainly recovered from multi-metal co-existing resources such as lithium, niobium and tantalum, using flotation, magnetic separation, gravity separation and other process technologies. Generally, the co-existing niobium and tantalum in pegmatite-type spodumene ore is recovered by flotation co-enrichment process, and then lithium is separated by magnetic separation, gravity separation and other processes to obtain the final niobium and tantalum concentrate.

[0004] The present invention mainly targets highly weathered extremely fine-grained niobium-tantalum ores such as volcanic rock-type tuffaceous sericite phyllite and trachyte tuff in Shiyan, Hubei and Ankang, Shaanxi. The raw ore is mainly composed of sericite, albite, quartz, potassium feldspar, hematite, pyrrhotite, niobium iron ore, zircon and other minerals. The distribution rate of niobium and tantalum in niobium-tantalum iron ore is 70-85%. This type of resource usually has the characteristics of large resource reserves, high niobium content, associated tantalum, extremely fine mineral embedding (the embedding particle size of niobium-tantalum minerals is 0.1-50 nanometers, of which the content of 0.1-10 nanometers is ≥50%, and the content of -5 nanometers is about 80%), high weathering degree, easy to grind and break, and great difficulty in fine-grained ore dressing and enrichment.

[0005] It is difficult to effectively enrich this type of ultra-fine-grained niobium-tantalum ore to obtain a high-grade niobium-tantalum concentrate using conventional flotation, gravity separation and other process technologies. Although strong magnetic separation can enrich and improve the niobium-tantalum grade to a certain extent, the recovery rate is extremely low due to the extremely fine embedding of the target mineral (niobium-tantalum mineral), resulting in serious waste of niobium-tantalum resources. In addition, since the volcanic rock-type ultra-fine-grained niobium-tantalum ore targeted by the present invention contains hematite, the similar specific magnetic susceptibility makes it difficult to separate niobium-tantalum ore and hematite by magnetic separation, and the conventional direct magnetic separation process is difficult to further improve the niobium-tantalum grade, so that a qualified grade of niobium-tantalum concentrate product cannot be obtained.

[0006] Patent CN103418488A discloses a comprehensive recovery process for lithium polymetallic ore associated with fine-grained niobium and tantalum, and discloses a method for recovering niobium and tantalum by coarse grinding, sedimentation and desludging, flotation, agglomeration magnetic separation, gravity separation and other steps. The fine-grained niobium and tantalum resources associated with lithium ore resources are flotated to obtain lithium concentrate rich in niobium and tantalum, and then niobium and tantalum concentrate is separated from the lithium concentrate by magnetic separation, gravity separation and other processes. In this process, niobium and tantalum are co-associated recovered minerals, and their fineness is -0.045 mm, accounting for 78-85%. The agglomeration magnetic separation mentioned in the process mainly adopts sulfuric acid defoaming and encrypted magnetic medium magnetic separation process. Obviously, no flocculant is added before magnetic separation in this method, and the particle size of the niobium and tantalum minerals targeted is significantly coarser than the particle size of the niobium and tantalum minerals targeted by the present invention, while the niobium and tantalum of the present invention are mainly recovered minerals, and the fineness of niobium and tantalum is significantly finer.

[0007] The current research has not involved the extremely finely embedded niobium-tantalum ore (the embedded particle size of niobium-tantalum mineral is 0.1-50 nanometers, of which the content of 0.1-10 nanometers is ≥50%, and the content of -5 nanometers is about 80%) or niobium-tantalum ore of similar fineness. Obviously, the niobium-tantalum ore of fineness involved in the present invention is more difficult to beneficiate.

[0008] Based on the above analysis, in order to rationally develop and utilize this type of extremely fine-grained niobium-tantalum ore resources, the present invention provides a more feasible beneficiation and recovery method, which improves the niobium-tantalum recovery rate while obtaining high-grade niobium-tantalum concentrate, and provides a technical reference for the development and utilization of this type of resources. Summary of the invention

[0009] Aiming at the difficulty that volcanic rock-type niobium-tantalum ore is extremely finely embedded and difficult to be effectively enriched by conventional ore dressing methods, the present invention provides a beneficiation and recovery method of fine-grained agglomeration strong magnetism + selective leaching + strong magnetic selection, which can achieve efficient enrichment of niobium-tantalum minerals and obtain niobium-tantalum concentrate products.

[0010] The object of the present invention is achieved through the following technical scheme: A method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore, comprising the following steps:

[0011] S1. Grinding: Grinding the volcanic rock type ultra-fine-grained niobium-tantalum ore to a particle size of -0.045 mm, which accounts for ≥95% of the total ore mass ratio;

[0012] S2, first magnetic separation: adding a conditioning agent to the slurry obtained after grinding and stirring evenly, and performing the conditioned slurry for the first high gradient magnetic separation to obtain a magnetically separated coarse concentrate and tailings 1;

[0013] Among them, the adjuster includes an adjuster 1 and polyacrylamide in a mass ratio range of 20 to 50:1, the adjuster 1 is polyferric chloride and / or polyaluminium chloride, and the usage of the adjuster is 10 to 50 g / ton of ore; the magnetic field intensity of the first high gradient magnetic separation is 0.8 to 1.6 Tesla, preferably 1.2 to 1.4 Tesla.

[0014] Furthermore, the method further comprises the following steps:

[0015] S3, leaching: adding a selective leaching agent to the magnetically separated coarse concentrate slurry for leaching to obtain leaching residue and leaching liquid;

[0016] S4, second magnetic separation: directly add water to the leached residue to adjust the pulp to a pulp concentration of 15-30%, and perform a second high gradient magnetic separation to obtain a niobium-tantalum concentrate product and tailings 2;

[0017] The selective leaching agent is composed of concentrated hydrochloric acid and ferric chloride in a mass ratio of 0.5 to 1:1; the magnetic field strength of the second high gradient magnetic separation is 0.8 to 1.6 Tesla, preferably 1.2 to 1.4 Tesla;

[0018] S5. Adding sodium hydroxide solution into the leaching solution to precipitate and obtain a crude iron hydroxide product.

[0019] Furthermore, the niobium-tantalum mineral embedding particle size of the volcanic rock type ultra-fine-grained niobium-tantalum ore is 0.1 to 50 nanometers, wherein the content of 0.1 to 10 nanometer particle size is ≥50%.

[0020] Furthermore, in step S1, the degree of dissociation of useful mineral monomers after grinding is above 85%.

[0021] Furthermore, in step S2, the concentration of the ore pulp obtained after grinding is 20-35%.

[0022] Furthermore, in step S2, the first high gradient magnetic separation is a roughing separation or a combination of a roughing separation and a scavenging separation.

[0023] Furthermore, in step S3, the liquid-solid mass ratio of the leaching is 2 to 5:1, the reaction temperature is 50 to 80 degrees Celsius, the stirring speed is 50 to 150 rpm, and the reaction time is 0.5 to 3 hours.

[0024] Furthermore, in step S4, the second high gradient magnetic separation is a roughing separation or a combination of a roughing separation and a scavenging separation.

[0025] Furthermore, in step S4, the leached residue is slurried with water to obtain a slurry concentration of 15-30%.

[0026] Furthermore, in step S5, the concentration of the sodium hydroxide solution is 10-30%, and the mass volume ratio of sodium hydroxide to the leaching solution is 100-1000 g / L.

[0027] The basic principle of the present invention is: after grinding, the pulp containing niobium-tantalum minerals that have achieved basic monomer dissociation is added with an appropriate amount of adjusting agent to achieve extremely fine niobium-tantalum mineral agglomeration and flocculation, and after the first high-gradient strong magnetic separation operation, the niobium-tantalum crude concentrate product is effectively enriched. At this time, the niobium-tantalum crude concentrate product has a high content of hematite, and it is difficult to further purify it by magnetic separation to obtain a high-grade niobium-tantalum concentrate. The niobium-tantalum crude concentrate product is selectively leached, and the hematite enters the solution. Subsequently, sodium hydroxide is used to precipitate to obtain a crude iron hydroxide product, and the leached slag is further subjected to a second high-gradient strong magnetic separation to obtain a high-grade niobium-tantalum concentrate product. This process technology is used to achieve effective enrichment and recovery of volcanic rock-type extremely fine-grained niobium-tantalum ore.

[0028] The main innovative features of the present invention are explained as follows:

[0029] 1. A flocculant with an inorganic high molecular polymer as the main component is used to achieve agglomeration and flocculation of extremely fine niobium and tantalum minerals. The iron and aluminum particles contained in polyferric chloride and polyaluminium chloride are cleverly used to form adsorption with the iron, tantalum, niobium and other points with lattice missing formed by grinding and cleavage on the surface of niobium and tantalum minerals. Under the bridging effect of the high molecular polymer, selective agglomeration of niobium and tantalum minerals is easily formed, which effectively solves the problem of extremely low recovery rate due to the excessively fine particle size of niobium and tantalum minerals in traditional magnetic separation operations, and creates conditions for the first high-gradient strong magnetic separation of such extremely fine niobium and tantalum minerals to effectively recover niobium and tantalum.

[0030] 2. For the niobium-tantalum crude concentrate product obtained after the first high-gradient strong magnetic separation operation, due to the presence of a high content of limonite, it is more difficult to separate niobium-tantalum iron ore and limonite with similar magnetic susceptibility, which hinders the traditional beneficiation method from further purification to obtain high-grade niobium-tantalum concentrate products. The present invention innovatively adopts a leaching method to selectively dissolve limonite into the solution, while the niobium-tantalum iron ore does not dissolve into the slag, thus achieving separation. Its innovative selective leaching agent uses a combination of hydrochloric acid and ferric chloride heated to 50-80 degrees Celsius to destroy the lattice of limonite and has high solubility, while it is almost insoluble in niobium-tantalum iron ore, achieving highly selective dissolution of limonite at relatively low temperatures (50-80 degrees Celsius), creating conditions for the second high-gradient magnetic separation.

[0031] The beneficial effects of the present invention are as follows: the present invention adopts a beneficiation and recovery method of extremely fine-grained agglomeration, strong magnetism, selective leaching, and strong magnetic selection, which breaks through the technical difficulties that are difficult to solve with traditional beneficiation methods for this type of resources. High-grade niobium-tantalum concentrate is obtained, and the recovery rate of niobium-tantalum is improved, providing a new technical method for the intensive, economical and efficient development of niobium-tantalum strategic resources. The adoption of this technical method can significantly improve the grade and recovery rate of niobium-tantalum concentrate, and can be applied on a large scale to the development and utilization of this type of extremely fine niobium-tantalum resources and other similar niobium-tantalum mines at home and abroad. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Comparison of high gradient magnetic separation test procedures for slurry preparation with or without flocculation;

[0033] Figure 2 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0035] Example 1

[0036] A method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore, comprising the following steps:

[0037] Preparation of the first high gradient magnetic separation raw material: ultra-fine niobium-tantalum ore is ground to a particle size of -0.045 mm, accounting for 95% of the total ore mass ratio. At this time, the dissociation degree of niobium-tantalum mineral monomers is 90%. Polyferric chloride and polyaluminium chloride are added to the slurry after grinding (slurry concentration is 30%). The total mass of the two is 40 g / ton relative to the mass of the original ore, and the mass ratio between the two is 1:1. The slurry after adding polyferric chloride and polyaluminium chloride is then mixed with polyacrylamide, and the mass ratio of the total mass of polyferric chloride and polyaluminium chloride to polyacrylamide is 30:1.

[0038] The first high gradient magnetic separation: the prepared raw material with the adjusting agent added is fed into the high gradient magnetic separator for magnetic separation. The magnetic field strength is 1.4 Tesla. The high gradient magnetic separation operation is a combination of a roughing selection and a scavenging selection.

[0039] Comparative Example 1

[0040] The difference between the recovery method of Comparative Example 1 and Example 1 is that no polyferric chloride, polyaluminium chloride and polyacrylamide are added, that is, no adjusting agent is added, and other conditions are consistent with Example 1.

[0041] The first high gradient magnetic separation test was conducted using the niobium-tantalum ore dressing and recovery method provided in Example 1 of the present invention, and a comparative test was conducted with the non-flocculation direct high gradient magnetic separation process provided in Comparative Example 1. The raw ore used was a volcanic rock type ultra-fine-grained niobium-tantalum ore from Shiyan, Hubei Province, in which the niobium-tantalum iron ore had an embedded particle size of -5 microns and a content of 80%. The comparative magnetic separation test process is as follows: Figure 1 The comparative test results are shown in Table 1.

[0042] Table 1 Comparison of the first high gradient magnetic separation test results of an extremely fine-grained niobium-tantalum ore in Hubei

[0043]

[0044] The results show that the recovery rates of niobium and tantalum in the magnetically separated concentrate obtained by the slurry adjustment + first high gradient magnetic separation process provided in Example 1 of the present invention are 31.71% and 35.19%, respectively, which are significantly higher than those of direct magnetic separation without flocculation and slurry adjustment in Comparative Example 1. This shows that the adjusting agent in Example 1 plays an important role in the magnetic separation process.

[0045] Example 2

[0046] Process such as Figure 2 As shown, based on Example 1, the following steps are also included:

[0047] Selective leaching: A leaching agent is added to the magnetic concentrate obtained by the first high gradient magnetic separation in Example 1 of Table 1, and the leaching agent is mainly composed of concentrated hydrochloric acid and ferric chloride, and the mass ratio of the two is 0.5:1. The liquid-solid mass ratio of the leaching is 3:1, the temperature of the leaching reaction is controlled to be 60 degrees Celsius, the stirring speed is 100 rpm, and the leaching time is 2.5 hours.

[0048] Second high gradient magnetic separation: The leached residue obtained by selective leaching is slurried with water to a pulp concentration of 20%, and fed into the second high gradient magnetic separator for magnetic separation. The magnetic field strength is 1.2 Tesla, and the high gradient magnetic separation is a one-stage operation. The final niobium-tantalum concentrate (Nb2O5+Ta2O5) obtained has a grade of 32.0%, a Nb2O5 recovery rate of 24.85%, and a Ta2O5 recovery rate of 26.13%.

[0049] Recovery of ferric hydroxide: adding sodium hydroxide solution to the leachate obtained by selective leaching to precipitate a crude ferric hydroxide product with a TFe grade of 42%, the mass volume ratio of the added sodium hydroxide relative to the leachate is 200 g / L, and the concentration of the sodium hydroxide solution is 20%.

[0050] Comparative Example 2

[0051] The magnetic concentrate obtained by the direct high gradient magnetic separation process without flocculation and slurry adjustment in Comparative Example 1 in Table 1 was further subjected to magnetic separation and concentration (without selective leaching, and the magnetic separation conditions were the same as those in Example 2). The niobium tantalum concentrate (Nb2O5+Ta2O5) with a grade of 2.43% was finally obtained, which was equivalent to the grade of the first magnetic concentrate obtained by the direct high gradient magnetic separation process without flocculation and slurry adjustment in Table 1, indicating that it is difficult to further improve the niobium tantalum grade by magnetic separation and concentration without selective leaching.

[0052] Comparative Example 3

[0053] Comparative Example 3 uses the same raw ore, the same grinding particle size, the same flocculation adjusting agent and the first high gradient magnetic separation conditions as Examples 1 and 2, and then uses commonly used concentrated sulfuric acid for leaching, and the leaching conditions are the same as those of Example 2. It is found that after leaching in Comparative Example 3, both niobium-tantalum ore and hematite are leached into the solution, and the result that hematite is selectively leached into the solution and niobium-tantalum ore is leached into the leached residue is not achieved, resulting in the subsequent difficulty in separating the two. This shows that the conventional leaching agent has poor selectivity.

[0054] Comparative Example 4

[0055] Comparative Example 4 uses the same raw ore, the same grinding particle size, the same flocculation adjusting agent and the first high gradient magnetic separation conditions as Examples 1 and 2, and then uses common hydrofluoric acid for leaching, and the leaching conditions are the same as those of Example 2. It is found that after leaching in Comparative Example 4, the niobium-tantalum ore is leached into the solution while the hematite remains in the leaching residue, making it difficult to recover niobium-tantalum from the solution later. This shows that the implementation effect of conventional leaching agents is not good.

[0056] By comparing comparative examples 1-4 with examples 1 and 2, it can be seen that due to the influence of limonite, it is difficult to obtain a high-grade niobium-tantalum concentrate by non-dissolving direct magnetic separation process, and it is difficult to achieve selective dissolution of limonite by using conventional leaching agents. Using selective leaching in Example 2, after mineralogy analysis of the leaching slag, the residual limonite in the leaching slag is less than 2%, and the loss rate of niobium-tantalum ore before and after leaching is only 3%, indicating that the use of selective leaching agents has better achieved the selective leaching of limonite, creating conditions for subsequent magnetic separation to obtain high-grade niobium-tantalum concentrate. In addition, due to the extremely fine distribution of the target mineral (niobium-tantalum mineral), the magnetic separation recovery rate is extremely low, and niobium-tantalum resources are seriously wasted. The process technology of the present invention can obtain a niobium-tantalum concentrate product with a grade of ≥30% (Nb2O5+Ta2O5), which overcomes the problem that such extremely fine niobium-tantalum ores are difficult to effectively enrich and recover, and the implementation effect is good.

[0057] Example 3

[0058] A method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore, comprising the following steps:

[0059] Preparation of the first high gradient magnetic separation raw material: ultra-fine niobium-tantalum ore is ground to a particle size of -0.045 mm, accounting for 98% of the total ore mass ratio. At this time, the dissociation degree of niobium-tantalum mineral monomers is 92%. Polyferric chloride and polyaluminium chloride are added to the slurry after grinding (slurry concentration is 25%). The total mass of the two is 45 g / ton relative to the mass of the original ore, and the mass ratio between the two is 0.7:1. The slurry after adding polyferric chloride and polyaluminium chloride is then mixed with polyacrylamide, and the mass ratio of the total mass of polyferric chloride and polyaluminium chloride to polyacrylamide is 45:1.

[0060] The first high gradient magnetic separation: the prepared raw material with the adjusting agent added is fed into the high gradient magnetic separator for magnetic separation. The magnetic field strength is 1.6 Tesla. The high gradient magnetic separation operation is a combination of a roughing selection and a scavenging selection.

[0061] Comparative Example 5

[0062] The difference between the recovery method of Comparative Example 5 and Example 3 is that no polyferric chloride, polyaluminium chloride and polyacrylamide are added, that is, no adjusting agent is added, and other conditions are consistent with Example 3.

[0063] The first high gradient magnetic separation test was conducted using the niobium-tantalum ore dressing and recovery method provided in Example 3 of the present invention, and a comparative test was conducted with the non-flocculation direct high gradient magnetic separation provided in Comparative Example 5. The raw ore used was a volcanic rock type ultra-fine-grained niobium-tantalum ore from Ankang, Shaanxi. The niobium-tantalum iron ore in the ore had an embedded particle size of -5 microns and a content of 84%. The comparative magnetic separation test process is as follows: Figure 1 The comparative test results are shown in Table 2.

[0064] Table 2 Comparison of the first high gradient magnetic separation test results of an extremely fine niobium-tantalum ore in Shaanxi

[0065]

[0066] The niobium and tantalum recoveries in the magnetic concentrate obtained by the slurry preparation + first high gradient magnetic separation process provided in Example 3 of the present invention are 35.79% and 41.62%, respectively, which are significantly higher than those of the direct magnetic separation without flocculation and slurry preparation in Comparative Example 5.

[0067] Example 4

[0068] Process such as Figure 2 As shown, based on Example 3, the following steps are also included:

[0069] Selective leaching: A leaching agent is added to the magnetic concentrate obtained by the first high gradient magnetic separation in Example 3 in Table 2, and the leaching agent is mainly composed of concentrated hydrochloric acid and ferric chloride, and the mass ratio of the two is 0.9:1. The liquid-solid mass ratio of the leaching is 4:1, the temperature of the leaching reaction is controlled to be 80 degrees Celsius, the stirring speed is 140 rpm, and the leaching time is 3 hours.

[0070] Second high gradient magnetic separation: The leached residue obtained by selective leaching is slurried with water to a pulp concentration of 23%, and fed into the second high gradient magnetic separator for magnetic separation. The magnetic field strength is 1.3 Tesla, and the high gradient magnetic separation is a combination of a roughing separation and a scavenging separation. The final niobium-tantalum concentrate (Nb2O5+Ta2O5) has a grade of 30.4%, a Nb2O5 recovery rate of 25.36%, and a Ta2O5 recovery rate of 28.17%.

[0071] Recovery of ferric hydroxide: adding sodium hydroxide solution to the leachate obtained by selective leaching to precipitate a crude ferric hydroxide product with a TFe grade of 44%, the mass volume ratio of the added sodium hydroxide relative to the leachate is 800 g / L, and the concentration of the sodium hydroxide solution is 30%.

[0072] Comparative Example 6

[0073] The magnetic separation concentrate obtained by the direct high gradient magnetic separation process without flocculation and slurry adjustment in Comparative Example 5 in Table 2 is further subjected to magnetic separation and concentration (without selective leaching, and the magnetic separation conditions are the same as those in Example 4), but it is difficult to further improve the niobium and tantalum grade, and the niobium and tantalum concentrate (Nb2O5+Ta2O5) finally obtained has a grade of 3.36%, which is equivalent to the grade of the first magnetic separation concentrate obtained by the direct high gradient magnetic separation process without flocculation and slurry adjustment in Table 2. Therefore, the comparison shows that the method provided in Examples 3 and 4 significantly improves the grade and recovery rate of the niobium and tantalum concentrate, and the implementation effect is significantly better.

[0074] Comparative Example 7

[0075] Comparative Example 7 uses the same raw ore, the same grinding particle size, the same flocculation adjusting agent and the first high gradient magnetic separation conditions as Examples 3 and 4, and then uses commonly used concentrated sulfuric acid for leaching, and the leaching conditions are the same as those of Example 4. It is found that after leaching in Comparative Example 7, both niobium-tantalum ore and limonite are leached into the solution, and the result that limonite is selectively leached into the solution and niobium-tantalum ore is leached into the leaching residue is not achieved, resulting in the subsequent difficulty in separating the two. This shows that the conventional leaching agent has poor selectivity.

[0076] Comparative Example 8

[0077] Comparative Example 8 uses the same raw ore, the same grinding particle size, the same flocculation adjusting agent and the first high gradient magnetic separation conditions as Examples 3 and 4, and then uses common hydrofluoric acid for leaching, and the leaching conditions are the same as those of Example 4. It is found that after leaching in Comparative Example 8, the niobium-tantalum ore is leached into the solution while the hematite remains in the leaching residue, making it difficult to recover niobium-tantalum from the solution later. This shows that the implementation effect of conventional leaching agents is also not good.

[0078] By comparing Examples 5-8 with Examples 3 and 4, it can be seen that the process of combining flocculation, selective leaching and magnetic separation adopted by the present invention overcomes the problem that the magnetic separation recovery rate is extremely low, the niobium and tantalum resources are wasted, and the hematite and niobium and tantalum ore are difficult to be further separated by magnetic separation to obtain high-grade niobium and tantalum concentrate. The process technology of the present invention can obtain a niobium and tantalum concentrate product with a grade of (Nb2O5+Ta2O5) ≥30%, and the implementation effect is good.

[0079] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for the recovery of volcanic rock type ultra-fine-grained niobium-tantalum ore, characterized in that: The following steps are involved: S1. Grinding: Grinding the volcanic rock type ultra-fine-grained niobium-tantalum ore to a particle size of -0.045 mm, which accounts for ≥95% of the total ore mass ratio; S2, first magnetic separation: adding a conditioning agent to the slurry obtained after grinding and stirring evenly, and performing the conditioned slurry for the first high gradient magnetic separation to obtain a magnetically separated coarse concentrate and tailings 1; Among them, the adjuster includes adjuster 1 and polyacrylamide in a mass ratio range of 20 to 50:1, the adjuster 1 is polyferric chloride and / or polyaluminium chloride, and the usage of the adjuster is 10 to 50 grams per ton of raw ore; the magnetic field intensity of the first high gradient magnetic separation is 0.8 to 1.6 Tesla.

2. The method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 1, characterized in that: The following steps are also included: S3, leaching: adding a selective leaching agent to the magnetically separated coarse concentrate slurry for leaching to obtain leaching residue and leaching liquid; S4, second magnetic separation: directly adding water to the leached residue for slurry preparation, and performing a second high gradient magnetic separation to obtain a niobium-tantalum concentrate product and tailings 2; The selective leaching agent is composed of concentrated hydrochloric acid and ferric chloride in a mass ratio of 0.5 to 1:1; the magnetic field strength of the second high gradient magnetic separation is 0.8 to 1.6 Tesla; S5. Adding sodium hydroxide solution into the leaching solution to precipitate and obtain a crude iron hydroxide product.

3. A method for recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 1 or 2, characterized in that: The niobium-tantalum mineral embedded particle size of the volcanic rock type ultra-fine-grained niobium-tantalum ore is 0.1 to 50 nanometers, wherein the content of 0.1 to 10 nanometer particles is ≥50%.

4. A method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 1 or 2, characterized in that: In step S1, the dissociation degree of useful mineral monomers after grinding reaches more than 85%.

5. A method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 1 or 2, characterized in that: In step S2, the concentration of the ore pulp obtained after grinding is 20-35%.

6. A method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 1 or 2, characterized in that: In step S2, the first high gradient magnetic separation is a roughing separation or a combination of a roughing separation and a scavenging separation.

7. The method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 2, characterized in that: In step S3, the liquid-solid mass ratio of the leaching is 2-5:1, the reaction temperature is 50-80 degrees Celsius, the stirring speed is 50-150 rpm, and the reaction time is 0.5-3 hours.

8. The method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 2, characterized in that: In step S4, the second high gradient magnetic separation is a one-stage roughing separation or a combination of a one-stage roughing separation and a one-stage scavenging separation.

9. The method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 2, characterized in that: In step S4, the leached residue is slurried with water to obtain a slurry concentration of 15-30%.

10. The method for beneficiating and recovering volcanic rock type ultra-fine-grained niobium-tantalum ore according to claim 2, characterized in that: In step S5, the concentration of the sodium hydroxide solution is 10-30%, and the mass volume ratio of sodium hydroxide to the leaching solution is 100-1000 g / L.

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