Method for separating vanadium product from tailings by using microorganisms

Abstract

The invention provides a method for separating and obtaining a vanadium product from tailings by utilizing microorganisms, and aims to solve the problems that vanadium is generally extracted by roasting vanadium slag externally matched with sodium salt, calcium salt, magnesium salt and manganese salt, the generated tailings are complex in component and difficult to treat, and a biological leaching method can solve the problems. The method for extracting the vanadium from the tailings through the biological leaching method is an environment-friendly and economical method, and the method mainly depends on the metabolic activity of microorganisms to oxidize and dissolve vanadium compounds; efficient and low-cost vanadium recycling can be realized by optimizing selection of microorganisms, controlling reaction conditions and improving treatment steps of leachate; and the current situations of tailing accumulation and resource waste are solved.

Description

Technical Field

[0001] The invention belongs to the field of separation technology and relates to a method for obtaining vanadium products by separating tailings using microorganisms. Background Art

[0002] Vanadium metal has important value in alloys, chemicals, energy storage, superconductors, nuclear industry, medical treatment and other fields, and is a key material for the development of modern industry and science and technology; for example: ① High-strength alloy application: used to manufacture high-strength alloys such as vanadium steel, advantages: improve strength, toughness, wear resistance and corrosion resistance, widely used in aerospace, automobile and construction fields. ② Chemical catalyst application: used as a catalyst for sulfuric acid production, petroleum refining and organic synthesis, advantages: improve reaction efficiency, reduce energy consumption and pollution. ③ Energy storage material application: used for all-vanadium liquid flow battery (VRFB), advantages: suitable for large-scale energy storage, support the stable use of renewable energy. ④ Superconducting material application: used to manufacture superconducting materials such as vanadium gallium (V3Ga), advantages: achieve zero resistance at low temperature, used in magnetic resonance imaging (MRI) and particle accelerators. ⑤ Nuclear industry application: used for structural materials and coolants of nuclear reactors, advantages: good radiation resistance and high temperature stability. ⑥ Medical field application: used to manufacture artificial joints and bone repair materials, advantages: good biocompatibility and strong corrosion resistance. ⑦Other applications: used to manufacture electronic components, optical glass and pigments. Advantages: improve product performance and expand application scope.

[0003] The way to obtain vanadium is relatively simple. Vanadium usually coexists with metal ores such as iron, titanium, lead, and manganese, and carbonaceous ores such as crude oil and oil shale. At present, the main vanadium-containing minerals are vanadium-titanium magnetite, vanadium mica ore, green sulfur vanadium ore, and vanadium-lead-zinc ore, and the vanadium content in ores is less than 2%. According to the latest data from the United States Bureau of Geology and Mineral Resources (USGS), China's vanadium production in 2022 will account for 70% of the global total production, making it the world's largest vanadium producer. Vanadium is used in various forms, such as ferrovanadium, vanadium nitrogen, vanadium iron nitride, etc. Such alloys are added to steel or catalyst production to enhance the properties of the products of the above production process. In order to meet the huge demand for metallic vanadium and its alloys in different fields, it is necessary to accelerate the research process of vanadium extraction from primary and secondary resources containing vanadium.

[0004] In the future, the development of new processes for extracting vanadium from converter vanadium slag should pay more attention to solving the resource and environmental problems existing in current technologies, such as the large amount of salt-containing wastewater generated, the difficulty in treating ammonium-containing sodium sulfate, and the difficulty in utilizing the high sodium content in vanadium extraction tailings.

[0005] In the prior art, the common method of extracting vanadium is to roast vanadium slag with calcium salt, manganese salt, magnesium salt or sodium salt:

[0006] For example, in CN113913620A "Method for extracting vanadium from sodium slag", sodium bisulfate is used as a sodium additive. After sodium roasting, a sodium clinker with water-soluble sodium vanadate as the main vanadium-containing phase is obtained. Although the application states that the technical solution can be (1) realized by directly replacing sodium carbonate with sodium bisulfate in the sodium roasting process of vanadium slag without any modification; (2) the sulfur oxide treatment technology produced by the roasting process is mature and can be directly adopted; (3) the oxidation roasting temperature of vanadium slag sodium bisulfate can be greatly reduced; (4) in the process of wastewater evaporation and crystallization, only the process parameter pH value needs to be adjusted to crystallize sodium bisulfate; (5) the recycling of sodium salt is realized, solving the problem of disposing low-value sodium sulfate in the current process. However, this technical solution does not get rid of the problem of high investment cost and difficult subsequent residue treatment. Therefore, the field should find a more appropriate technical solution to balance the possible environmental problems while solving some obvious technical problems.

[0007] For another example, patent CN109097567A “Secondary Acid Leaching Process for Calcified Roasted Clinker from Vanadium Slag” discloses a technical solution, which uses a secondary acid leaching process for calcified roasted clinker from vanadium slag, through re-leaching and liquid-solid separation of the primary vanadium extraction tailings, and returning the obtained vanadium-containing filtrate to the vanadium extraction system for recycling. It is claimed that the purpose of reducing the vanadium content in the vanadium extraction tailings can be achieved, and it is also claimed that the vanadium extraction yield can be increased. However, the acid added in the secondary acid leaching process is dilute sulfuric acid, and the patent document discloses that “dilute sulfuric acid is added to adjust the pH value of the solution in the pulping tank to 1.0-1.4”, which means that the entire leaching system is in a strong acid state, which will undoubtedly increase the risk in the production operation process, and there is still room for improvement.

[0008] The above-mentioned vanadium extraction method of roasting vanadium slag with calcium salt, manganese salt, magnesium salt or sodium salt includes three stages: decomposition of olivine, oxidation of vanadium spinel and formation of sodium vanadate. The difficulty lies in the complex material changes in the roasting process, high temperature and high energy consumption, uneven oxidation rate, long roasting time, etc.

[0009] Taking vanadium titanium magnetite vanadium slag as an example, the external additive is sodium salt, and the oxidation process of its main vanadium-containing phase vanadium spinel during roasting can be divided into an initial rapid oxidation stage and a later slow oxidation stage: the oxidation temperature of vanadium spinel is about 500℃, and when the fayalite crystal is dismembered, the vanadium spinel monomer particles are completely exposed. Under the external force of the internal and external oxygen concentration difference, the Fe inside the lattice quickly migrates outward, and Fe0 inclusions are also formed at the edge of the vanadium spinel; when the roasting temperature and time are further increased, the thickness of the inclusion increases, and it is difficult for oxygen to enter the interior of the vanadium spinel. In the low-oxygen environment, Fe no longer migrates outward inside the lattice, and the internal lattice distribution begins to show an induction. As the temperature continues to rise, "hole" defects begin to appear at the edges of the lattice-shaped grain boundaries, and intermediates such as rice-shaped tantalum, FeO, MnVO, FeVO and micropores gradually form inside; the formation and increase of micropores change the oxygen concentration inside and outside the crystal, causing the newly formed tantalum, FeO, FeVO and other cryptocrystalline minerals to gradually grow during the heating process, and the oxidation rate of this process is significantly reduced. Eventually, the regular polygonal vanadium spinel crystal shape is destroyed and dismembered. The formation of sodium vanadate begins at the end of the dismemberment of vanadium spinel. Sodium carbonate, as an additive, gradually enters the interior of vanadium spinel and reacts with the generated cryptocrystalline compounds, which is mainly manifested as the conversion of vanadium oxides and sodium carbonate into vanadates in a local oxygen-rich atmosphere.

[0010] Its main bonding phase and secondary vanadium-containing phase is fayalite. The morphological change law during the roasting process plays an important role in the distribution of the spatial embedding relationship of the main vanadium-containing phase in the roasting slag, and its spatial embedding relationship directly affects the difficulty of subsequent vanadium recovery. With the increase of roasting time, the contents of fayalite and calcium-ferrous olivine in the roasted slag gradually decreased, while the contents of albite and calcium silicate increased significantly; when the roasting time was 360 min, with the large amount of precipitation of iron oxide, the fayalite crystal began to completely dismember and transformed into albite, calcium feldspar and iron oxide; when the roasting time and temperature were further increased, some of the newly generated small particles of albite began to aggregate to form low-melting sodium silicate, and the sodium silicate and albite sintered together to form a tight inclusion; the reaction change of the phase in the roasted slag also started with olivine first. The difference in the reaction process is that sodium salt is added to the vanadium-chromium slag. When the temperature reaches about 600°C, Na begins to enter the fayalite and the first phase albite solid solution is formed; and with the increase of roasting time, the albite solid solution is gradually transformed into pyroxene and sodium silicate; as the temperature further increases, the sodium silicate content will gradually increase.

[0011] In summary, the existing technical solutions all have more or less technological defects and cannot respond to the call for low-cost, green and efficient recovery of vanadium resources from converter-smelted vanadium slag. In addition, in the case of high demand for vanadium products, the solid wastes such as ore waste residues generated by the above-mentioned vanadium extraction processes are also quite significant. To ensure the sustainable development of the vanadium industry, there is an urgent need in this field for a new process to solve the above problems and make the processes in the vanadium extraction series develop in the direction of greenness, low cost, short process flow and high yield. Summary of the Invention

[0012] In view of the shortcomings of the existing technology, the present invention provides a method for separating vanadium products from tailings by using microorganisms. For the treatment of vanadium extraction tailings with solid waste recycling, the leaching rate of vanadium in the production line of roasting vanadium slag with externally added salts varies from about 91.42% to 94.03% due to different combinations of salt components. That is to say, there are still quite a few unextracted vanadium elements in the tailings, especially the tailings remaining from multiple production lines. The solid waste components of the tailings include:

[0013] ① Calcium oxide (CaO) and magnesium oxide (MgO); ② Silicon dioxide (SiO 2 ); ③ Iron oxide (Fe 2 O 3 or Fe 3 O 4 ): Vanadium slag usually contains a relatively high proportion of iron. Some iron may be oxidized to ferric iron or magnetite during roasting and remain in the waste residue, accounting for about 15% - 35%; ④ Unreacted sodium salts: such as sodium sulfate (Na 2 SO 4 ), sodium carbonate (Na 2 CO 3 ), etc., which depend on the amount of sodium salt added and the degree of reaction completion; ⑤ Residual vanadium compounds; ⑥ Other metal oxides: such as titanium (TiO 2 ), aluminum (Al 2 O 3 ), etc.; Trace impurities: including but not limited to elements in the form of phosphorus (P 2 O 5 ), sulfur (S), etc., which are approximately less than 1%.

[0014] And the above components show the presence of obvious ferrous ions in the tailings, that is to say, the tailings soil itself is suitable for the growth of Acidithiobacillus ferrooxidans bacteria, so samples can be directly taken and cultivated.

[0015] To achieve the above object, the present invention adopts the following technical solutions: A method for separating vanadium products from tailings by using microorganisms, comprising the following steps:

[0016] 1) Tail residue pretreatment:

[0017] Weigh, crush, and screen the tail residue until the particle size of the tail residue reaches 150 - 80 μm;

[0018] 2) Microbial cultivation:

[0019] Take 5 grams of the tail residue particles from step 1) and further grind them to 60 - 45 μm. Place the ground tail residue particles in a sterile petri dish, pour in the solid inorganic salt basal medium at 33 - 37 °C, and cultivate at 30 °C for 5 - 7 days to isolate single colonies; the composition of the solid inorganic salt basal medium is 0.4 g of ammonium sulfate, 0.4 g of potassium hydrogen phosphate, 0.4 g of magnesium sulfate heptahydrate, 0.01 g of potassium nitrate, 5 g of ferric sulfate heptahydrate, 15 g of agar, add distilled water to a volume of 1000 milliliters, and adjust the pH value to 1.6 - 2.0;

[0020] Transfer the isolated single colonies to four solid inorganic salt basal medium plates containing 0.5 - 1.0% (weight / volume) of vanadinite Pb 5 (VO 4 ) 3 Cl, 1 - 1.5% (weight / volume) of ammonium metavanadate NH 4 VO 3 , 1 - 2.0% (weight / volume) of spinel vanadate VAl 2 O 4 , and 1 - 1.5% (weight / volume) of sodium metavanadate NaVO 3 , and cultivate at 30 °C for 5 - 7 days. According to the formation of dissolution zones of the indicator compounds in the plates, select the bacterial strains that can form obvious dissolution zones;

[0021] Then shake - cultivate in the liquid inorganic salt basal medium containing the above - mentioned insoluble indicator compounds at 150 revolutions per minute for 6 - 8 days, and measure the soluble vanadium content and pH value in the culture solution; screen out the bacterial strain with the strongest acid - producing ability and the best vanadium leaching effect;

[0022] 3) Cleaning and drying:

[0023] Clean and dry the remaining part of the tail residue in step 1) after sampling in step 2);

[0024] 4) Inoculation and leaching reaction:

[0025] Inoculate the bacterial strains isolated in step 2) into the leaching system of the remaining part of the tail residue treated in step 3), stir to ensure full contact, and oxidize the low - valence vanadium to high - valence vanadium;

[0026] 5) Leachate treatment:

[0027] In step 4), an alkaline substance is added to adjust the pH value of the leaching solution system to promote the precipitation of vanadium -- to precipitate vanadium in the form of metavanadate. After the precipitation is completed, the leaching system is filtered and separated;

[0028] 6) Purify and concentrate the separated liquid to obtain high-purity metavanadate;

[0029] 7) Obtain a pure vanadium product from the metavanadate obtained in step 6) by an acidification method or a direct precipitation method.

[0030] Adopting the above technical solution, the pretreatment can remove the excess soluble salts encapsulated inside the tailings residues that have been crushed and screened into small particles, reduce the influencing factors of impurities on inoculation and leaching, and ensure the high efficiency of leaching conditions;

[0031] The particle size range of the tailings residues in step 1) can not only provide a sufficient specific surface area, but also avoid difficulties in operation caused by overly fine particles, such as subsequent filtration and separation problems; it can also avoid the problem that overly fine particles of the tailings residues may cause difficulties in microbial attachment, thereby affecting their activity.

[0032] Preferably, the microorganism is Thiobacillus ferrooxidans.

[0033] Adopting the above technical solution, Thiobacillus ferrooxidans can further oxidize the trace ferrous ions (Fe 2+ ) remaining in the tailings residues into ferric ions (Fe 3+ ), and release protons (H + ) in this process, further increasing the acidity of the leaching solution system; the obtained ferric ions (Fe 3+ ) can, as a strong oxidant, oxidize the low-valent vanadium in the tailings residues into high-valent soluble vanadium compounds. For example: 4Fe 2+ +O 2 +4H + →4Fe 3+ +2H 2 O 4 Fe 2+ +O 2 +4H + →4Fe 3+ +2H 2 O.

[0034] Preferably, the tailings residues are selected from the solid residues remaining after roasting vanadium slag with externally added calcium salts, manganese salts, magnesium salts or sodium salts.

[0035] Adopting the above technical solution, the multi-range sampling of the tailings residues can verify the applicability of the microbial extraction technology from multiple angles. The tailings residues of various production lines have diverse compositions and complex impurity situations, which can further consider the treatment ability of Thiobacillus ferrooxidans on the tailings residues.

[0036] Preferably, the alkaline substance in step 5) is NaOH or ammonia water.

[0037] Preferably, the leaching time in step 4) is 80 - 120 min.

[0038] Preferably, the leaching solid - liquid ratio in step 4) is 1:2.

[0039] Preferably, the pH value of the culture solution in step 2) is 2.2 - 3.5.

[0040] Preferably, the vanadium product is vanadyl sulfate.

[0041] Preferably, the bio - leaching method in step 4) adopts the direct contact mechanism.

[0042] Adopting the above - mentioned technical solution, in the direct contact mechanism, microorganisms attach to the surface of mineral tailing particles to form a biofilm; these microorganisms fix themselves by secreting extracellular polymeric substances (EPS) and can directly act on the minerals by being in close contact with the mineral surface, promoting the release of vanadium ions; and secrete organic acids or other metabolites, such as secreting organic acids like oxalic acid and citric acid, and these acids can dissolve vanadium compounds in the minerals; more importantly, the bacterial colonies can catalyze chemical reactions on the surface of mineral tailing particles, further promoting the release of vanadium.

[0043] Advantages of the present invention:

[0044] It can treat tailings for various types of vanadium - containing ore bodies. The bio - leaching method for extracting vanadium from vanadium slag is an environmentally friendly and economical method, mainly relying on the metabolic activities of microorganisms to oxidize and dissolve vanadium compounds; by optimizing the selection of microorganisms, controlling reaction conditions, and improving the treatment steps of leaching solutions, efficient and low - cost vanadium recovery can be achieved, and the bio - leaching method has a very broad application prospect in industry. Specific embodiments

[0045] The present invention will be further described below through specific embodiments, but it does not limit the scope of the present invention.

[0046] Example 1:

[0047] 1) Pretreatment of tailings:

[0048] Weigh, crush, and screen the tailings after sodium roasting until the particle size of the tailings reaches 150 μm;

[0049] 2) Microorganism culture:

[0050] Take 5 g of the tailing particles in step 1) and further grind them to 60 μm. Place the ground tailing particles in a sterile petri dish, pour in the solid inorganic salt basal medium at 33 - 37 °C, and culture at 30 °C for 5 - 7 days to isolate single colonies. The composition of the solid inorganic salt basal medium is 0.4 g of ammonium sulfate, 0.4 g of potassium hydrogen phosphate, 0.4 g of magnesium sulfate heptahydrate, 0.01 g of potassium nitrate, 5 g of ferric sulfate heptahydrate, 15 g of agar, add distilled water to a volume of 1000 ml, and adjust the pH value to 1.6 - 2.0;

[0051] Transfer the isolated single colonies to four solid inorganic salt basal medium plates containing 0.5 - 1.0% (weight / volume) of vanadinite Pb 5 (VO 4 ) 3 Cl, 1 - 1.5% (weight / volume) of ammonium metavanadate NH 4 VO 3 , 1 - 2.0% (weight / volume) of spinel vanadate VAl 2 O 4 , and 1 - 1.5% (weight / volume) of sodium metavanadate NaVO 3 . Culture at 30 °C for 6 days. According to the formation of dissolution zones of the indicator compounds in the plates, select the bacterial strains that can form obvious dissolution zones;

[0052] Then shake - culture in the liquid inorganic salt basal medium containing the above - mentioned insoluble indicator compounds at 150 rpm for 7 days, measure the soluble vanadium content and pH value of the culture solution to be 2.2 - 3.5; Screen out the Thiobacillus ferrooxidans bacterial strain with the strongest acid - producing ability and the best vanadium leaching effect;

[0053] 3) Cleaning and drying:

[0054] Wash and dry the remaining part of the tailings except for the sample taken in step 2) in step 1);

[0055] 4) Inoculation and leaching reaction:

[0056] Inoculate the bacterial strains isolated in step 2) into the tailings leaching system of the remaining part treated in step 3), with a solid - liquid ratio of 1:2, stir for 120 min to ensure full contact, and oxidize the low - valence vanadium to high - valence vanadium;

[0057] 5) Treatment of the leaching solution:

[0058] Add the alkaline substance NaOH in step 4) to adjust the pH value of the leaching solution system to promote the precipitation of vanadium - precipitate vanadium in the form of metavanadate. After precipitation, filter and separate the leaching system;

[0059] 6) Purify and concentrate the separated liquid to obtain sodium metavanadate with high purity;

[0060] 7) Obtain pure vanadium products from the metavanadate obtained in step 6) through acidification.

[0061] Example 2:

[0062] 1) Pretreatment of tailings:

[0063] Weigh, crush, and screen the calcined tailings until the particle size of the tailings reaches 80 μm;

[0064] 2) Microbial culture:

[0065] Take 5 grams of the tailings particles in step 1) and further grind them to 45 μm. Place the ground tailings particles in a sterile petri dish, pour in the solid inorganic salt basal medium at 33 - 37 °C, and culture at 30 °C for 5 - 7 days to isolate single colonies; the composition of the solid inorganic salt basal medium is 0.4 g of ammonium sulfate, 0.4 g of potassium hydrogen phosphate, 0.4 g of magnesium sulfate heptahydrate, 0.01 g of potassium nitrate, 5 g of ferric sulfate heptahydrate, 15 g of agar, add distilled water to a volume of 1000 ml, and adjust the pH value to 1.6 - 2.0;

[0066] Transfer the separated single colonies to four solid inorganic salt basal medium plates containing 0.5 - 1.0% (weight / volume) of vanadinite Pb 5 (VO 4 ) 3 Cl, 1 - 1.5% (weight / volume) of ammonium metavanadate NH 4 VO 3 , 1 - 2.0% (weight / volume) of spinel VAl 2 O 4 , and 1 - 1.5% (weight / volume) of sodium metavanadate NaVO 3 , and culture at 30 °C for 6 days. According to the formation of dissolution zones of the indicator compounds in the plates, select the bacterial strains that can form obvious dissolution zones;

[0067] Then shake - culture in the liquid inorganic salt basal medium containing the above - mentioned insoluble indicator compounds at 150 revolutions per minute for 7 days, measure the soluble vanadium content and pH value in the culture solution to be 2.2 - 3.5; screen out the Thiobacillus ferrooxidans bacterial strain with the strongest acid - producing ability and the best vanadium leaching effect;

[0068] 3) Cleaning and drying:

[0069] Clean and dry the remaining part of the tailings in step 1) except for the sample taken in step 2);

[0070] 4) Inoculation and leaching reaction:

[0071] Inoculate the bacterial strain isolated in step 2) into the remaining tailing leaching system treated in step 3), with a solid-liquid ratio of 1:2, and stir for 80 min to ensure sufficient contact, oxidizing low-valence vanadium to high-valence vanadium;

[0072] 5) Leachate treatment:

[0073] Add the alkaline substance ammonia water in step 4) to adjust the pH value of the leachate system to 9.0 to promote the precipitation of vanadium - causing vanadium to precipitate in the form of metavanadate. After the precipitation is completed, filter and separate the leaching system;

[0074] 6) Purify and concentrate the separated liquid to obtain high-purity ammonium metavanadate;

[0075] 7) Obtain a pure vanadium product from the metavanadate obtained in step 6) by the direct precipitation method.

[0076] Example 3:

[0077] Replace the tailings from sodium roasting in Example 1 with the tailings from a production line with externally added magnesium salts, and the rest remains unchanged.

[0078] Example 4:

[0079] Replace the tailings from sodium roasting in Example 2 with the tailings from a production line with externally added manganese salts, and the rest remains unchanged.

[0080] Under the conditions of the above several different examples, consider the leaching rate and the purity of the leached matter of each example. The results are shown in the following table:

[0081] Leaching rate Extract purity Example 1 appropriate high Example 2 appropriate high Example 3 appropriate high Example 4 appropriate high

[0082] The above examples show that the technical solution of the present application can directly leach insoluble vanadium from tailings obtained by general production methods such as sodium roasting or similar methods. Moreover, by adopting the microbial leaching method, the leaching rate is considerable and the purity of the leached matter is high. Although the particle size of the tailings after crushing and screening will affect the leaching rate (generally, the smaller the particles, the faster the leaching), in the above treatment method, maintaining the tailings particle size at 80 - 150 microns can meet general leaching conditions, achieve the preset leaching effect, and because microorganisms can more easily contact the effective substances in the waste residue, an appropriate particle size does not affect the viscosity of the leaching solution, maintaining a stable mass transfer efficiency, which is also friendly to subsequent separation.

[0083] The biological leaching method using the Thiobacillus ferrooxidans bacterial strain selected in the present invention has a good leaching effect on insoluble vanadium in tailings. The whole process is green and low-cost, can adapt to vanadium-extracted tailings from various production methods, and achieves the purpose of resource recycling.

Claims

1. A method for separating vanadium products from tailings using microorganisms, characterized in that: The steps include: 1) Tailings pretreatment: Weigh, crush and screen the tailings until the tailings particle size reaches 150-80 μm; 2) Microbial culture: 5 g of the tailings particles in step 1) are further ground to 60-45 μm, the ground tailings particles are placed in a sterile culture dish, a solid inorganic salt basal medium at 33-37° C. is poured into the culture dish, and a single colony is isolated; the solid inorganic salt basal medium is composed of 0.4 g ammonium sulfate, 0.4 g potassium hydrogen phosphate, 0.4 g magnesium sulfate heptahydrate, 0.01 g potassium nitrate, 5 g ferric sulfate heptahydrate, and 15 g agar, and distilled water is added to a volume of 1000 ml, and the pH value is adjusted to 1.6-2.0; The isolated single colonies were respectively transferred to four solid inorganic salt basal culture medium plates containing 0.5-1.0% by weight / volume of vanadium calcium calcium Pb5(VO4)3Cl, 1-1.5% by weight / volume of ammonium metavanadate NH4VO3, 1-2.0% by weight / volume of aluminum vanadium spinel VAl2O4, and 1-1.5% by weight / volume of sodium metavanadate NaVO3, and cultured at 30°C for 5-7 days, and the bacterial strains that can form obvious dissolution zones were selected according to the formation of dissolution zones by the indicator compounds in the plates; Then, the culture is cultured in a liquid inorganic salt basal culture medium containing the above-mentioned insoluble indicator compound at 150 revolutions per minute for 6-8 days, and the soluble vanadium content and pH value in the culture solution are determined; and the bacterial strain with the strongest acid production ability and the best vanadium leaching effect is screened; 3) Cleaning and drying: Wash and dry the remaining tailings in step 1) except for the sample taken in step 2); 4) Inoculation and leaching reaction: Inoculating the bacterial strain separated in step 2) into the remaining tailings leaching system treated in step 3), stirring to ensure full contact, and oxidizing the low-valent vanadium to high-valent vanadium; 5) Leachate treatment: In step 4), an alkaline substance is added to adjust the pH value of the leaching solution system to promote the precipitation of vanadium, that is, to precipitate the vanadium in the form of metavanadate, and after the precipitation is completed, the leaching system is filtered and separated; 6) purifying and concentrating the separated liquid to obtain high-purity metavanadate; 7) The meta-vanadium salt obtained in step 6) is subjected to an acidification method or a direct precipitation method to obtain a pure vanadium product.

2. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: The microorganism is Thiobacillus ferrooxidans.

3. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: The tailings are selected from the solid residues remaining after roasting vanadium slag with calcium salt, manganese salt, magnesium salt or sodium salt.

4. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: In step 5), the alkaline substance is NaOH or ammonia water.

5. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: The leaching time in step 4) is 80-120 min.

6. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: The leaching solid-liquid ratio in step 4) is 1:

2.

7. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: The pH value of the culture solution in step 2) is 2.2-3.

5.

8. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: The bioleaching method in step 4) is a direct contact mechanism.

9. The method for separating vanadium products from tailings using microorganisms according to claim 1, characterized in that: The vanadium product in step 7) is vanadyl sulfate.