A method for leaching vanadium from vanadium shale by acclimating and inducing bacteria to produce vanadium in vanadium solution

Abstract

The present invention relates to a method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria with a vanadium solution. The technical scheme comprises the following steps: calcining ground vanadium shale at 600-850°C to obtain a decarbonized vanadium shale powder, which is then added to a nitrogen-containing culture medium to produce a bioleaching medium. A bacterial solution of Bacillus mucilaginosus is then mixed with the nitrogen-containing culture medium, followed by multiple chemical mutagenesis cultures with the addition of a mutagen to produce a mutagenized Bacillus mucilaginosus culture. The mutagenized Bacillus mucilaginosus culture is then mixed with the nitrogen-containing culture medium and then acclimated and cultured with a vanadium solution to produce an acclimated mutagenized Bacillus mucilaginosus culture. The acclimated mutagenized Bacillus mucilaginosus culture is then mixed with the bioleaching medium and leached for 20-25 days to produce a vanadium shale bioleaching slurry. Solid-liquid separation is then performed to produce a vanadium-containing leachate. The vanadium leaching rate is 70.36-84.08%. The acclimated mutagenized Bacillus mucilaginosus has enhanced growth and metabolic capacity, shortens the leaching cycle, and improves the leaching efficiency of vanadium from vanadium shale.

Description

Technical Field

[0001] The present invention belongs to the technical field of leaching vanadium from vanadium shale, and specifically relates to a method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria with a vanadium solution. Background Art

[0002] Vanadium is widely used in steel metallurgy, chemical industry, and new energy. Vanadium shale, an important vanadium mineral resource, is abundant in reserves, but the vanadium grade is generally low and the mineral phase composition is complex. Furthermore, most of the vanadium is contained in the crystal lattice of (aluminum) silicate minerals, resulting in a relatively stable structure that is not easily leached. Currently, most vanadium extraction processes for vanadium shale use high-temperature roasting, acid leaching, alkaline leaching, and roasting with various additives such as oxidants and roasting aids. While these methods are efficient and fast, they still suffer from high energy consumption and high costs.

[0003] Bioleaching, a clean metallurgical technology, is gaining increasing attention worldwide due to its low cost, minimal investment, short process flow, simple equipment, and environmental friendliness. Currently, the technology has been successfully applied in the industrial production of metals such as copper, gold, and uranium. Silicate bacteria, as leaching bacteria, can dissolve elements by disrupting the lattice structure of silicate minerals, and are therefore widely used in various metallurgical fields. Bioleaching of vanadium from vanadium shale occurs through the direct dissolution of bacteria and the indirect effects of bacterial growth metabolites, releasing vanadium from the mineral. However, the leaching rate of vanadium is generally low, failing to meet industrial requirements.

[0004] The patented technology, "A Method for Bioleaching Vanadium from Vanadium Shale Using a Composite Nitrogen Source" (CN 112921175 A), targets silicate bacteria leaching vanadium-containing shale. Using a composite nitrogen source composed of (NH4)2SO4 and NH4NO3, the technology enhances bacterial growth and metabolic capacity, increasing bacterial damage to the mineral lattice. While the vanadium leaching efficiency is limited to 66-78%, this technology still suffers from low leaching efficiency and a long leaching cycle.

[0005] Dong Yingbo et al. (Dong Yingbo, Lin Hai, Fu Kaibin, Mo Xiaolan, Wang Han. Effect of bacterial chemical mutagenesis on microbial leaching of low-grade copper tailings [J]. Journal of University of Science and Technology Beijing. Vol. 33 (2011) 532-538) used the dominant strain of Acidithiobacillus ferrooxidans as the original bacteria and used hydroxylamine hydrochloride to chemically mutagenize it. They found that hydroxylamine mutagenesis could cause significant mutations in the bacteria. After mutagenesis, the morphology of the bacteria did not change, but the size changed. At the same time, the cell surface became smooth and a sticky substance appeared. The cell aggregation phenomenon was obvious. After leaching for 30 days, the copper leaching rate of the induced bacteria reached 35%, but the leaching cycle of the induced bacteria was long and the leaching efficiency was low.

[0006] Dong Yingbo et al. (Dong Yingbo, Liu Yue, Lin Hai, Liu Chenjing. Improving vanadium extraction from stone coal via combination of blank roasting and bioleaching by ARTP-mutated Bacillus mucilaginosus[J]. Trans. Nonferrous Met. Soc. China 29(2019)849-858) used a method combining blank roasting and microbial leaching, using Bacillus mucilaginosus as the original bacteria and using plasma technology to induce its mutation. They found that after 20 days of leaching of vanadium-containing stone coal, the vanadium leaching rate of the mutant bacteria BM-50 reached 18.2%, which was an increase compared to the vanadium leaching rate of the original bacteria (15.3%). Blank roasting pretreatment can further improve the vanadium leaching efficiency. After 20 days of leaching, the vanadium leaching rate of the mutant bacteria BM-50 reached 68.3%, which is a significant increase compared to the vanadium leaching rate of the untreated mutant bacteria leaching system. Although this method combined with roasting pretreatment can obtain a higher vanadium leaching rate, the mutant bacteria have not been domesticated and cultured, have poor metabolic capacity, poor dissolution effect on minerals, and low leaching efficiency.

[0007] In summary, in the vanadium shale vanadium extraction system, the bacterial activity of ordinary Bacillus subtilis bacteria is poor and the metabolic capacity is not strong; the bacteria induced by the existing mutagenesis method have too low a mutation degree and have not undergone acclimation and cultivation. The leaching cycle is too long and the vanadium extraction effect is poor. Summary of the Invention

[0008] The present invention aims to overcome the defects of the prior art and has the objective of proposing a method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria with a vanadium solution with a short leaching cycle. The method can enhance bacterial growth and metabolism and the degree of bacterial destruction of mineral crystal lattices under the dual effects of chemical mutagenesis and vanadium solution acclimation, thereby improving the leaching efficiency of vanadium from vanadium shale.

[0009] To achieve the above purpose, the technical solution adopted by the present invention comprises the following specific steps:

[0010] Step 1: Pretreatment of vanadium shale

[0011] The vanadium shale is crushed and ground to a particle size of ≤0.074 mm accounting for more than 60%; and then roasted at 600-850 DEG C for 30-60 minutes to obtain vanadium shale decarbonization powder.

[0012] Step 2: Prepare basal culture medium solution

[0013] Sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are dissolved in distilled water to obtain a basic culture medium solution; in the basic culture medium solution, the concentrations of sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are 5 to 10 kg·m -3 , 1~2Kg·m -3 , 0.005~0.01Kg·m -3 , 0.5~0.8Kg·m -3 and 0.1~0.2Kg·m -3 .

[0014] Step 3: Prepare solid culture medium

[0015] The concentration of agar powder in the basic culture medium solution is 15-20 kg·m -3 , adding the agar powder to the basic culture medium solution, adjusting the pH to 6.5-8.0; then keeping warm at 100-121° C. for 10-20 minutes, cooling at 0-40° C., solidifying, and obtaining a solid culture medium.

[0016] Step 4: Prepare nitrogen-containing culture medium solution

[0017] The concentration of nitrogen source in the basic culture medium solution is 1-4 kg·m -3 , adding the nitrogen source to the basal culture medium solution to obtain a nitrogen-containing culture medium solution.

[0018] Step 5: Prepare bioleaching medium

[0019] The concentration of the vanadium shale decarbonization powder in the nitrogen-containing culture medium solution is 10-100 kg·m -3 The vanadium shale decarbonized powder is added to the nitrogen-containing culture medium solution, and the pH is adjusted to 6.5-8.0 to obtain a bioleaching culture medium.

[0020] Step 6: Bacterial mutagenesis

[0021] The Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20) to 100 to obtain a mixed solution I; the concentration of the mutagen is 0.05-0.7 kg·m -3 , add a mutagen to the mixed solution I, and then chemically mutagenize and culture at 28-35° C. and a shaking speed of 180-220 r / min for 6-8 days to obtain a first-generation mutagenized Bacillus subtilis bacterial solution.

[0022] The volume ratio of the first generation mutagenic Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is (5-20):100, and the first generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution II; the concentration of the mutagen in the mixed solution II is 0.05-0.7 kg·m -3 , add a mutagen to the mixed solution II, and then chemically culture at 28-35°C and a shaking speed of 180-220 r / min for 6-8 days to obtain a second-generation mutagenic Bacillus subtilis bacterial solution.

[0023] And so on;

[0024] The n-1 generation mutagenic Bacillus mucilaginosus bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20) to 100 to obtain a mixed solution N; a mutagen is added to the mixed solution N at a concentration of 0.05-0.7 kg·m-3 in the mutagen mixed solution N, and then chemical mutagenesis culture is carried out at 28-35° C. and a shaking table speed of 180-220 r / min for 6-8 days to obtain an n-generation mutagenic Bacillus mucilaginosus bacterial solution.

[0025] n is a natural number from 3 to 10; N is the same natural number as n.

[0026] Step 7: Bacterial domestication

[0027] The n-generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20):100 to obtain a mixed solution A; and a vanadium solution is added to the mixed solution A to obtain a mixed solution B, wherein the vanadium concentration in the mixed solution B is 0.5-5 kg·m -3 ; Then, the mixture was acclimated and cultured at 28-35° C. and a shaking speed of 180-220 r / min for 3-4 days to obtain an acclimated mucilaginous Bacillus subtilis mutagenic bacterial liquid.

[0028] Step 8. Bacteria Screening

[0029] The bacteria in the acclimated mutagenic Bacillus subtilis bacterial liquid are transferred to the solid culture medium for cultivation at a temperature of 28-32° C., and acclimated mutagenic Bacillus subtilis colonies are obtained by screening.

[0030] Step 9: Bacterial enrichment culture

[0031] The acclimated mutagenic Bacillus subtilis colony is inoculated into the nitrogen-containing culture medium solution, and cultured to the logarithmic phase under the conditions of 28-35° C. and a shaking speed of 180-220 r / min to obtain a logarithmic phase acclimated mutagenic Bacillus subtilis bacterial liquid.

[0032] Step 10: Vanadium Shale Bioleaching

[0033] The volume ratio of the mutagenic Bacillus microbial liquid after logarithmic phase acclimation to the biological leaching medium is (5-20):100, the mutagenic Bacillus microbial liquid after logarithmic phase acclimation and the biological leaching medium are mixed, leaching is carried out for 20-25 days at 28-35° C. and a shaking table speed of 180-220 r / min, and solid-liquid separation is performed to obtain a vanadium-containing leaching solution.

[0034] The V2O5 content in the vanadium shale is 0.5-1.8 wt%.

[0035] The mutagen is one of hydroxylamine hydrochloride, sodium nitrite and nitrosoguanidine.

[0036] The vanadium solution is a solution containing tetravalent vanadium ions and pentavalent vanadium ions.

[0037] The nitrogen source is one of yeast extract powder, ammonium sulfate and ammonium nitrate.

[0038] Due to the adoption of the above technical solution, the present invention has the following positive effects compared with the prior art:

[0039] 1. The present invention induces genetic mutations in Bacillus mucilaginosus under the action of a mutagen, thereby obtaining mutated Bacillus mucilaginosus. The size and shape of the mutated Bacillus mucilaginosus change, the base pairs undergo a conversion from GC to AT, the functions of proteins controlling acid production are enhanced, and the total organic acid content produced by the mutated Bacillus mucilaginosus is almost three times that of the original bacteria. As a result, the growth and metabolic capacity of the mutated Bacillus mucilaginosus are enhanced, and the ability of the mutated Bacillus mucilaginosus to produce acid and extracellular polymers is enhanced, which improves the dissolution of minerals by the mutated Bacillus mucilaginosus itself and enhances the indirect effects of bacterial metabolites on minerals.

[0040] 2. The present invention obtains a mutagenic Bacillus colloidus with high tolerance and activity through culturing in vanadium solution. When using the mutagenic Bacillus colloidus for leaching, the leaching cycle is shortened. After 25 days of leaching, the vanadium leaching rate for low-grade vanadium shale is increased from 60-70% of the original bacteria to 70.36-84.08%. This accelerates leaching efficiency and improves the vanadium leaching efficiency of vanadium shale. The performance of the mutagenic Bacillus colloidus for leaching vanadium shale is significantly improved.

[0041] Therefore, the present invention has a short cycle, can enhance bacterial growth and metabolism under the dual action conditions of chemical mutagenesis and vanadium solution acclimation, strengthen the degree of bacterial destruction of mineral lattices, and improve the vanadium leaching efficiency in vanadium shale. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with specific embodiments, which does not limit the scope of protection thereof.

[0043] A method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria with a vanadium solution. The steps of the method described in this specific embodiment are:

[0044] Step 1: Pretreatment of vanadium shale

[0045] The vanadium shale is crushed and ground to a particle size of ≤0.074 mm accounting for more than 60%; and then roasted at 600-850 DEG C for 30-60 minutes to obtain vanadium shale decarbonization powder.

[0046] Step 2: Prepare basal culture medium solution

[0047] Sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are dissolved in distilled water to obtain a basic culture medium solution; in the basic culture medium solution, the concentrations of sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are 5 to 10 kg·m -3 , 1~2Kg·m -3 , 0.005~0.01Kg·m -3 , 0.5~0.8Kg·m -3 and 0.1~0.2Kg·m -3 .

[0048] Step 3: Prepare solid culture medium

[0049] The concentration of agar powder in the basic culture medium solution is 15-20 kg·m -3 , adding the agar powder to the basic culture medium solution, adjusting the pH to 6.5-8.0; then keeping warm at 100-121° C. for 10-20 minutes, cooling at 0-40° C., solidifying, and obtaining a solid culture medium.

[0050] Step 4: Prepare nitrogen-containing culture medium solution

[0051] The concentration of nitrogen source in the basic culture medium solution is 1-4 kg·m -3 , adding the nitrogen source to the basal culture medium solution to obtain a nitrogen-containing culture medium solution.

[0052] Step 5: Prepare bioleaching medium

[0053] The concentration of the vanadium shale decarbonization powder in the nitrogen-containing culture medium solution is 10-100 kg·m -3 The vanadium shale decarbonized powder is added to the nitrogen-containing culture medium solution, and the pH is adjusted to 6.5-8.0 to obtain a bioleaching culture medium.

[0054] Step 6: Bacterial mutagenesis

[0055] The Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20) to 100 to obtain a mixed solution I; the concentration of the mutagen is 0.05-0.7 kg·m -3 , add a mutagen to the mixed solution I, and then chemically mutagenize and culture at 28-35° C. and a shaking speed of 180-220 r / min for 6-8 days to obtain a first-generation mutagenized Bacillus subtilis bacterial solution.

[0056] The volume ratio of the first generation mutagenic Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is (5-20):100, and the first generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution II; the concentration of the mutagen in the mixed solution II is 0.05-0.7 kg·m -3 , add a mutagen to the mixed solution II, and then chemically culture at 28-35°C and a shaking speed of 180-220 r / min for 6-8 days to obtain a second-generation mutagenic Bacillus subtilis bacterial solution.

[0057] And so on;

[0058] The n-1 generation mutagenic Bacillus mucilaginosus bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20) to 100 to obtain a mixed solution N; a mutagen is added to the mixed solution N at a concentration of 0.05-0.7 kg·m-3 in the mutagen mixed solution N, and then chemical mutagenesis culture is carried out at 28-35° C. and a shaking table speed of 180-220 r / min for 6-8 days to obtain an n-generation mutagenic Bacillus mucilaginosus bacterial solution.

[0059] n is a natural number from 3 to 10; N is the same natural number as n.

[0060] Step 7: Bacterial domestication

[0061] The n-generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20):100 to obtain a mixed solution A; and a vanadium solution is added to the mixed solution A to obtain a mixed solution B, wherein the vanadium concentration in the mixed solution B is 0.5-5 kg·m -3 ; Then, the mixture was acclimated and cultured at 28-35° C. and a shaking speed of 180-220 r / min for 3-4 days to obtain an acclimated mucilaginous Bacillus subtilis mutagenic bacterial liquid.

[0062] Step 8. Bacteria Screening

[0063] The bacteria in the acclimated mutagenic Bacillus subtilis bacterial liquid are transferred to the solid culture medium for cultivation at a temperature of 28-32° C., and acclimated mutagenic Bacillus subtilis colonies are obtained by screening.

[0064] Step 9: Bacterial enrichment culture

[0065] The acclimated mutagenic Bacillus subtilis colony is inoculated into the nitrogen-containing culture medium solution, and cultured to the logarithmic phase under the conditions of 28-35° C. and a shaking speed of 180-220 r / min to obtain a logarithmic phase acclimated mutagenic Bacillus subtilis bacterial liquid.

[0066] Step 10: Vanadium Shale Bioleaching

[0067] The volume ratio of the mutagenic Bacillus microbial liquid after logarithmic phase acclimation to the biological leaching medium is (5-20):100, the mutagenic Bacillus microbial liquid after logarithmic phase acclimation and the biological leaching medium are mixed, leaching is carried out for 20-25 days at 28-35° C. and a shaking table speed of 180-220 r / min, and solid-liquid separation is performed to obtain a vanadium-containing leaching solution.

[0068] The V2O5 content in the vanadium shale is 0.5-1.8 wt%.

[0069] The mutagen is one of hydroxylamine hydrochloride, sodium nitrite and nitrosoguanidine.

[0070] The nitrogen source is one of yeast extract powder, ammonium sulfate and ammonium nitrate.

[0071] In this specific implementation mode:

[0072] The vanadium solution is a solution containing tetravalent vanadium ions and pentavalent vanadium ions.

[0073] The details will not be described in detail in the embodiments.

[0074] Example 1

[0075] A method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria with a vanadium solution. The steps of the method described in this embodiment are:

[0076] Step 1: Pretreatment of vanadium shale

[0077] The vanadium shale is crushed and ground to a particle size of ≤0.074 mm accounting for more than 60%; and then calcined at 600° C. for 30 minutes to obtain vanadium shale decarbonization powder.

[0078] Step 2: Prepare basal culture medium solution

[0079] Sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are dissolved in distilled water to obtain a basal culture medium solution; in the basal culture medium solution, the concentrations of sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are 5 kg·m -3 , 1Kg·m -3 , 0.005Kg·m -3 , 0.5Kg·m -3 and 0.1 kg·m -3 .

[0080] Step 3: Prepare solid culture medium

[0081] The concentration of agar powder in the basic culture medium solution is 15 kg·m -3 , adding the agar powder to the basic culture medium solution, adjusting the pH to 6.5; then keeping warm at 100° C. for 10 minutes, cooling at 0° C., and solidifying to obtain a solid culture medium.

[0082] Step 4: Prepare nitrogen-containing culture medium solution

[0083] The concentration of nitrogen source in the basic culture medium solution is 1 kg·m -3 , adding the nitrogen source to the basal culture medium solution to obtain a nitrogen-containing culture medium solution.

[0084] Step 5: Prepare bioleaching medium

[0085] The concentration of the vanadium shale decarbonized powder in the nitrogen-containing culture medium solution is 10 kg·m -3 , adding the vanadium shale decarbonized powder to the nitrogen-containing culture medium solution, adjusting the pH to 6.5, and obtaining a bioleaching culture medium.

[0086] Step 6: Bacterial mutagenesis

[0087] The volume ratio of the Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is 5:100, and the Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution I; the concentration of the mutagen is 0.05 kg·m -3 , a mutagen was added to the mixed solution I, and then chemical mutagenesis culture was carried out at 28° C. and a shaking speed of 180 r / min for 6 days to obtain a first-generation mutagenic Bacillus subtilis bacterial solution.

[0088] The volume ratio of the first generation mutagenic Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is 5:100, and the first generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution II; the concentration of the mutagenic agent in the mixed solution II is 0.05 kg·m -3, a mutagen was added to the mixed solution II, and then chemical mutagenesis culture was carried out at 28°C and a shaking speed of 180 r / min for 6 days to obtain the second generation of mutagenic Bacillus subtilis bacterial solution.

[0089] The second-generation mutagenic Bacillus subtilis bacterial liquid and the nitrogen-containing culture medium solution are mixed at a volume ratio of 5:100 to obtain a mixed solution III; a mutagen is added to the mixed solution III at a concentration of 0.05 kg·m-3 in the mutagen mixed solution III, and then chemical mutagenesis culture is carried out at 28° C. and a shaking speed of 180 r / min for 6 days to obtain a third-generation mutagenic Bacillus subtilis bacterial liquid.

[0090] Step 7: Bacterial domestication

[0091] The third-generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution were mixed at a volume ratio of 5:100 to obtain a mixed solution A; and a vanadium solution was added to the mixed solution A to obtain a mixed solution B, wherein the vanadium concentration in the mixed solution B was 0.5 kg·m -3 ; Then, the culture was carried out at 28°C and a shaking speed of 180 r / min for 3 days to obtain the acclimated mucilaginous Bacillus subtilis mutagenic bacterial liquid.

[0092] Step 8. Bacteria Screening

[0093] The bacteria in the acclimated mutagenic Bacillus subtilis bacterial liquid were transferred to the solid culture medium for cultivation at a temperature of 28° C., and acclimated mutagenic Bacillus subtilis colonies were obtained by screening.

[0094] Step 9: Bacterial enrichment culture

[0095] The acclimated mutagenic Bacillus subtilis colony is inoculated into the nitrogen-containing culture medium solution, and cultured at 28° C. and a shaking speed of 180 r / min until the logarithmic phase, thereby obtaining a logarithmic phase acclimated mutagenic Bacillus subtilis bacterial solution.

[0096] Step 10: Vanadium Shale Bioleaching

[0097] The logarithmically-acclimated mutagenic Bacillus microbial strain liquid and the bioleaching medium were mixed at a volume ratio of 5:100, and the mixture was leached for 20 days at 28° C. and a shaking speed of 180 rpm, followed by solid-liquid separation to obtain a vanadium-containing leachate. The vanadium leaching rate of the vanadium-containing leachate was 81.91%.

[0098] The V2O5 content in the vanadium shale is 0.5 wt%.

[0099] The mutagen is hydroxylamine hydrochloride.

[0100] The nitrogen source is yeast extract powder.

[0101] Example 2

[0102] A method for leaching vanadium from vanadium shale by acclimating and inducing bacteria to undergo vanadium solution leaching.

[0103] The steps of the method described in this specific embodiment are:

[0104] Step 1: Pretreatment of vanadium shale

[0105] The vanadium shale is crushed and ground to a particle size of ≤0.074 mm accounting for more than 60%; and then roasted at 750° C. for 50 minutes to obtain vanadium shale decarbonization powder.

[0106] Step 2: Prepare basal culture medium solution

[0107] Sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are dissolved in distilled water to obtain a basal culture medium solution; in the basal culture medium solution, the concentrations of sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are 7 kg·m -3 , 1.5Kg·m -3 , 0.007Kg·m -3 , 0.6Kg·m -3 and 0.15 kg·m -3 .

[0108] Step 3: Prepare solid culture medium

[0109] The concentration of agar powder in the basic culture medium solution is 17 kg·m -3 , adding the agar powder to the basic culture medium solution, adjusting the pH to 7.5; then keeping warm at 110° C. for 15 minutes, cooling at 20° C., and solidifying to obtain a solid culture medium.

[0110] Step 4: Prepare nitrogen-containing culture medium solution

[0111] The concentration of nitrogen source in the basic culture medium solution is 2 kg·m -3 , adding the nitrogen source to the basal culture medium solution to obtain a nitrogen-containing culture medium solution.

[0112] Step 5: Prepare bioleaching medium

[0113] The concentration of the vanadium shale decarbonized powder in the nitrogen-containing culture medium solution is 50 kg·m -3, adding the vanadium shale decarbonized powder to the nitrogen-containing culture medium solution, adjusting the pH to 7.5, and obtaining a bioleaching culture medium.

[0114] Step 6: Bacterial mutagenesis

[0115] The volume ratio of the Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is 10:100, and the Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution I; the concentration of the mutagen is 0.2 kg·m -3 , a mutagen was added to the mixed solution I, and then chemical mutagenesis culture was carried out at 32° C. and a shaking speed of 200 r / min for 7 days to obtain a first-generation mutagenic Bacillus subtilis bacterial solution.

[0116] The volume ratio of the first generation mutagenic Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is 10:100, and the first generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution II; the concentration of the mutagenic agent in the mixed solution II is 0.2 kg·m -3 , a mutagen was added to the mixed solution II, and then chemical mutagenesis culture was carried out at 32°C and a shaking speed of 200 r / min for 7 days to obtain the second generation of mutagenic Bacillus subtilis bacterial solution.

[0117] And so on;

[0118] The sixth-generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of 10:100 to obtain a mixed solution VII; a mutagen is added to the mixed solution VII at a concentration of 0.2 kg·m-3 in the mutagen mixed solution VII, and then chemical mutagenesis culture is carried out at 32° C. and a shaking speed of 200 r / min for 7 days to obtain a seventh-generation mutagenic Bacillus subtilis bacterial solution.

[0119] Step 7: Bacterial domestication

[0120] The 7th generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution were mixed at a volume ratio of 10:100 to obtain a mixed solution A; and a vanadium solution was added to the mixed solution A to obtain a mixed solution B. The vanadium concentration in the mixed solution B was 2 kg·m -3 ; Then, the culture was carried out at 32°C and a shaking speed of 200 r / min for 4 days to obtain the acclimated mucilaginous Bacillus subtilis mutagenic bacterial liquid.

[0121] Step 8. Bacteria Screening

[0122] The bacteria in the acclimated mutagenic Bacillus subtilis bacterial liquid were transferred to the solid culture medium for cultivation at a temperature of 30° C., and acclimated mutagenic Bacillus subtilis colonies were obtained by screening.

[0123] Step 9: Bacterial enrichment culture

[0124] The acclimated mutagenic Bacillus subtilis colony is inoculated into the nitrogen-containing culture medium solution, and cultured at 32° C. and a shaking speed of 200 r / min until the logarithmic phase, thereby obtaining a logarithmic phase acclimated mutagenic Bacillus subtilis bacterial solution.

[0125] Step 10: Vanadium Shale Bioleaching

[0126] The logarithmically-acclimated mutagenic Bacillus microbial strain liquid and the bioleaching medium were mixed at a volume ratio of 10:100, and leached for 22 days at 32° C. and a shaking speed of 200 r / min, followed by solid-liquid separation to obtain a vanadium-containing leachate. The vanadium leaching rate of the vanadium-containing leachate was 84.08%.

[0127] The V2O5 content in the vanadium shale is 1.0 wt%.

[0128] The mutagen is sodium nitrite.

[0129] The nitrogen source is ammonium sulfate.

[0130] Example 3

[0131] A method for leaching vanadium from vanadium shale by acclimating and inducing bacteria to undergo vanadium solution leaching.

[0132] The steps of the method described in this specific embodiment are:

[0133] Step 1: Pretreatment of vanadium shale

[0134] The vanadium shale is crushed and ground to a particle size of ≤0.074 mm accounting for more than 60%; and then roasted at 850° C. for 60 minutes to obtain vanadium shale decarbonization powder.

[0135] Step 2: Prepare basal culture medium solution

[0136] Sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are dissolved in distilled water to obtain a basic culture medium solution; in the basic culture medium solution, the concentrations of sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are 10 kg·m -3 , 2Kg·m -3 , 0.01Kg·m -3 , 0.8Kg·m -3and 0.2 kg·m -3 .

[0137] Step 3: Prepare solid culture medium

[0138] The concentration of agar powder in the basic culture medium solution is 20 kg·m -3 , adding the agar powder to the basic culture medium solution, adjusting the pH to 8.0; then keeping warm at 121° C. for 20 minutes, cooling at 40° C., and solidifying to obtain a solid culture medium.

[0139] Step 4: Prepare nitrogen-containing culture medium solution

[0140] The concentration of nitrogen source in the basic culture medium solution is 4 kg·m -3 , adding the nitrogen source to the basal culture medium solution to obtain a nitrogen-containing culture medium solution.

[0141] Step 5: Prepare bioleaching medium

[0142] The concentration of the vanadium shale decarbonized powder in the nitrogen-containing culture medium solution is 100 kg·m -3 , adding the vanadium shale decarbonized powder to the nitrogen-containing culture medium solution, adjusting the pH to 8.0, and obtaining a bioleaching culture medium.

[0143] Step 6: Bacterial mutagenesis

[0144] The volume ratio of the Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is 20:100, and the Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution I; the concentration of the mutagen is 0.7 kg·m -3 , a mutagen was added to the mixed solution I, and then chemical mutagenesis culture was carried out at 35° C. and a shaking speed of 220 r / min for 8 days to obtain a first-generation mutagenic Bacillus subtilis bacterial solution.

[0145] The volume ratio of the first generation mutagenic Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is 20:100, and the first generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution II; the concentration of the mutagenic agent in the mixed solution II is 0.7 kg·m -3 , a mutagen was added to the mixed solution II, and then chemical mutagenesis culture was carried out at 35°C and a shaking speed of 220 r / min for 8 days to obtain the second generation of mutagenic Bacillus subtilis bacterial solution.

[0146] And so on;

[0147] The 9th generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of 20:100 to obtain a mixed solution X; a mutagen is added to the mixed solution X at a concentration of 0.7 kg·m-3 in the mutagen mixed solution X, and then chemical mutagenesis culture is carried out at 35° C. and a shaking speed of 220 r / min for 8 days to obtain a 10th generation mutagenic Bacillus subtilis bacterial solution.

[0148] Step 7: Bacterial domestication

[0149] The 10th generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution were mixed at a volume ratio of 20:100 to obtain a mixed solution A; and a vanadium solution was added to the mixed solution A to obtain a mixed solution B. The vanadium concentration in the mixed solution B was 5 kg·m -3 ; Then, the culture was carried out at 35°C and a shaking speed of 220 r / min for 4 days to obtain the acclimated mucilaginous Bacillus subtilis mutagenic bacterial liquid.

[0150] Step 8. Bacteria Screening

[0151] The bacteria in the acclimated mutagenic Bacillus subtilis bacterial liquid were transferred to the solid culture medium for cultivation at a temperature of 32° C., and acclimated mutagenic Bacillus subtilis colonies were obtained by screening.

[0152] Step 9: Bacterial enrichment culture

[0153] The acclimated mutagenic Bacillus subtilis colony is inoculated into the nitrogen-containing culture medium solution, and cultured at 35° C. and a shaking speed of 220 r / min until the logarithmic phase, thereby obtaining a logarithmic phase acclimated mutagenic Bacillus subtilis bacterial solution.

[0154] Step 10: Vanadium Shale Bioleaching

[0155] The logarithmically-acclimated mutagenic Bacillus microbial strain liquid and the bioleaching medium were mixed at a volume ratio of 20:100, and the mixture was leached at 35° C. and a shaking speed of 220 r / min for 25 days, followed by solid-liquid separation to obtain a vanadium-containing leachate. The vanadium leaching rate of the vanadium-containing leachate was 70.36%.

[0156] The V2O5 content in the vanadium shale is 1.8 wt%.

[0157] The mutagen is nitrosoguanidine.

[0158] The nitrogen source is ammonium nitrate.

[0159] Compared with the prior art, this embodiment has the following positive effects:

[0160] 1. In this specific embodiment, under the action of a mutagen, Bacillus mucilaginosus undergoes genetic mutation, resulting in a mutated Bacillus mucilaginosus. The size and shape of the mutated Bacillus mucilaginosus change, the base pairs undergo a conversion from GC to AT, the function of the proteins controlling acid production is enhanced, and the total organic acid content produced by the mutated Bacillus mucilaginosus is almost three times that of the original bacteria. As a result, the growth and metabolic capacity of the mutated Bacillus mucilaginosus are enhanced, and the ability of the mutated Bacillus mucilaginosus to produce acid and extracellular polymers is enhanced, which improves the dissolution effect of the mutated Bacillus mucilaginosus itself on minerals and enhances the indirect effect of bacterial metabolites on minerals.

[0161] 2. This specific embodiment, through culturing with vanadium solution, produces a mutagenic Bacillus mucilaginosus with high tolerance and activity. When using this mutagenic Bacillus mucilaginosus for leaching, the leaching cycle is shortened. After 25 days of leaching, the vanadium leaching rate for low-grade vanadium shale increases from 60-70% of the original bacteria to 70.36-84.08%. This accelerates leaching efficiency and improves the vanadium leaching efficiency of vanadium shale, significantly enhancing the performance of the mutagenic Bacillus mucilaginosus for leaching vanadium shale.

[0162] Therefore, this specific embodiment has a short cycle, can enhance bacterial growth and metabolism under the dual conditions of chemical mutagenesis and vanadium solution acclimation, strengthen the degree of bacterial destruction of mineral lattices, and improve the vanadium leaching efficiency in vanadium shale.

Claims

1. A method for leaching vanadium from vanadium shale by acclimating and inducing bacteria to produce vanadium in a vanadium solution, characterized in that The steps of the method are: Step 1: Pretreatment of vanadium shale The vanadium shale is crushed and ground to a particle size of ≤0.074 mm, accounting for more than 60%; and then roasted at 600-850° C. for 30-60 minutes to obtain vanadium shale decarbonization powder. Step 2: Prepare basal culture medium solution Sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are dissolved in distilled water to obtain a basic culture medium solution; in the basic culture medium solution, the concentrations of sucrose, disodium hydrogen phosphate, anhydrous ferric chloride, magnesium sulfate heptahydrate and calcium carbonate are 5 to 10 kg·m -3 , 1~2Kg·m -3 , 0.005~0.01Kg·m -3 , 0.5~0.8Kg·m -3 and 0.1~0.2Kg·m -3 ; Step 3: Prepare solid culture medium The concentration of agar powder in the basic culture medium solution is 15-20 kg·m -3 , adding the agar powder to the basal culture medium solution, adjusting the pH to 6.5-8.0; then keeping warm at 100-121° C. for 10-20 minutes, cooling at 0-40° C., and solidifying to obtain a solid culture medium; Step 4: Prepare nitrogen-containing culture medium solution The concentration of nitrogen source in the basic culture medium solution is 1-4 kg·m -3 , adding the nitrogen source to the basal culture medium solution to obtain a nitrogen-containing culture medium solution; Step 5: Prepare bioleaching medium The concentration of the vanadium shale decarbonization powder in the nitrogen-containing culture medium solution is 10-100 kg·m -3 , adding the vanadium shale decarbonized powder to the nitrogen-containing culture medium solution, adjusting the pH to 6.5-8.0, to obtain a bioleaching culture medium; Step 6: Bacterial mutagenesis The Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20) to 100 to obtain a mixed solution I; the concentration of the mutagen is 0.05-0.7 kg·m -3 , adding a mutagen to the mixed solution I; then chemically incubating the mixture at 28-35° C. and a shaking speed of 180-220 r / min for 6-8 days to obtain a first-generation mutagenic Bacillus subtilis solution; The volume ratio of the first generation mutagenic Bacillus subtilis bacterial solution to the nitrogen-containing culture medium solution is (5-20):100, and the first generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed to obtain a mixed solution II; the concentration of the mutagen in the mixed solution II is 0.05-0.7 kg·m -3 , adding a mutagen to the mixed solution II; then chemically incubating the mixture at 28-35°C and a shaking speed of 180-220 r / min for 6-8 days to obtain a second-generation mutagenic Bacillus subtilis bacterial solution; And so on; The n-1 generation mutagenic Bacillus mucilaginosus bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20) to 100 to obtain a mixed solution N; a mutagen is added to the mixed solution N at a concentration of 0.05-0.7 kg·m-3, and then chemically mutagenized and cultured at 28-35° C. and a shaking speed of 180-220 r / min for 6-8 days to obtain an n-generation mutagenic Bacillus mucilaginosus bacterial solution; n is a natural number from 3 to 10, and N is the same natural number as n; Step 7: Bacterial domestication The n-generation mutagenic Bacillus subtilis bacterial solution and the nitrogen-containing culture medium solution are mixed at a volume ratio of (5-20):100 to obtain a mixed solution A; and a vanadium solution is added to the mixed solution A to obtain a mixed solution B, wherein the vanadium concentration in the mixed solution B is 0.5-5 kg·m -3 ; Then, the mixture was cultured at 28-35°C and a shaking speed of 180-220 r / min for 3-4 days to obtain an acclimated mucoid Bacillus subtilis mutagenic bacterial solution; Step 8. Bacteria Screening Transferring the bacteria in the acclimated mutagenic Bacillus subtilis bacterial solution to the solid culture medium for cultivation at a temperature of 28-32° C., and screening to obtain acclimated mutagenic Bacillus subtilis colonies; Step 9: Bacterial enrichment culture Inoculating the acclimated mutagenic Bacillus subtilis colony into the nitrogen-containing culture medium solution, and culturing the culture medium at 28-35° C. and a shaking speed of 180-220 r / min until the logarithmic phase, thereby obtaining a logarithmic phase acclimated mutagenic Bacillus subtilis bacterial solution; Step 10: Vanadium Shale Bioleaching The volume ratio of the mutagenic Bacillus microbial liquid after logarithmic phase acclimation to the biological leaching medium is (5-20):100, the mutagenic Bacillus microbial liquid after logarithmic phase acclimation and the biological leaching medium are mixed, leaching is carried out for 20-25 days at 28-35° C. and a shaking table speed of 180-220 r / min, and solid-liquid separation is performed to obtain a vanadium-containing leaching solution.

2. The method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria in vanadium solution according to claim 1, characterized in that The V2O5 content in the vanadium shale is 0.5-1.8 wt%.

3. The method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria in vanadium solution according to claim 1, characterized in that The mutagen is one of hydroxylamine hydrochloride, sodium nitrite and nitrosoguanidine.

4. The method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria in vanadium solution according to claim 1, characterized in that The vanadium solution is a solution containing tetravalent vanadium ions and pentavalent vanadium ions.

5. The method for leaching vanadium from vanadium shale by acclimating and mutagenizing bacteria in vanadium solution according to claim 1, characterized in that The nitrogen source is one of yeast extract powder, ammonium sulfate and ammonium nitrate.