A method for leaching vanadium from vanadium residue roasting clinker by biological enzyme catalysis

Abstract

The present application relates to a kind of biological enzyme catalysis vanadium residue roasting clinker leaching method for extracting vanadium, the method comprises the following steps: first, the pH of urea buffer solution is adjusted to acidic, and hydrolysis is carried out with urease mixture, obtain hydrolysis solution;Vanadium residue roasting clinker is mixed with the hydrolysis solution and leaching is carried out, and vanadium-containing leaching solution is obtained;The method realizes the efficient leaching of vanadium under mild conditions, and the vanadium leaching rate is preferably as high as 88% or more, the impurity content in leaching solution is as low as 100 ppm or less, and the method process is simple, and the condition is easy to control, solve the problem of existing vanadium residue extraction vanadium process pollution, low extraction efficiency of vanadium.

Description

Technical Field

[0001] This invention relates to the field of vanadium metallurgy, and in particular to a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Background Technology

[0002] Vanadium is a rare metal, often referred to as the "MSG of modern industry." Currently, vanadium-titanium magnetite is the primary raw material for vanadium production. With the rapid development of long-term energy storage and the use of vanadium in the next-generation information industry, the efficient and comprehensive utilization of vanadium-titanium magnetite resources is of great significance.

[0003] Currently, the utilization of vanadium-titanium magnetite mainly involves smelting it in a blast furnace to produce vanadium-containing molten iron, followed by vanadium slag extraction in a converter, and then vanadium extraction from the vanadium slag. Sodium roasting and water leaching of vanadium slag is the most important vanadium extraction technology, but it suffers from the following problems in actual production: alkali metal tailings are difficult to recover and can only be stockpiled, resulting in high environmental remediation costs; vanadium recovery rate is low, while treatment costs are high. While the calcification roasting and acid leaching process for vanadium slag solves the problem of ammonia nitrogen wastewater generated by traditional sodium roasting and water leaching, this technology requires strict control of the calcium-vanadium ratio and high control requirements during the roasting process, leading to difficulties in actual operation, low vanadium recovery rate, and the generation of large amounts of unusable calcium sulfate-containing tailings.

[0004] To address the problems faced by traditional vanadium extraction technologies, some researchers have proposed a new approach: salt-free roasting of vanadium slag followed by leaching with ammonium salts / (ammonium / sodium carbonate mixed salt). However, this approach suffers from issues such as easy decomposition of the leaching agent and difficulty in removing impurities from the leachate. For example, CN104003442A discloses a method for leaching vanadium from vanadium-containing raw materials using ammonium bicarbonate solution after roasting. This method involves leaching the vanadium-containing raw material's clinker after blank roasting in an ammonium bicarbonate solution, allowing vanadium to enter the solution in the form of ammonium vanadate, resulting in leaching residue and vanadium-containing liquid. During the leaching process, ammonium bicarbonate easily decomposes, releasing irritating ammonia gas, leading to a poor operating environment and high ammonium bicarbonate consumption, thus increasing the cost of vanadium extraction.

[0005] For example, CN104831090A discloses a method for vanadium extraction by low-temperature and atmospheric-pressure leaching of vanadium-containing roasted clinker with ammonium bicarbonate solution. This method involves leaching the clinker obtained by salt-free oxidative roasting of vanadium-containing raw materials in ammonium bicarbonate solution, and obtaining vanadium-containing leachate and vanadium extraction tailings after liquid-solid separation. Although this method is carried out at low temperature and atmospheric pressure, the volatilization of ammonia is not completely controlled under the conditions of high liquid-solid ratio and high ammonium salt concentration. Moreover, the consumption of ammonium salt is large and needs to be recycled, resulting in a high overall process cost.

[0006] Therefore, how to provide a novel method for leaching vanadium from vanadium slag roasting clinker, improve the vanadium leaching rate in vanadium slag, reduce the impurity content of the leachate, and at the same time avoid the generation of harmful gases and reduce costs, is a problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. This method solves the problems of high pollution and low vanadium extraction efficiency in existing vanadium slag extraction processes, achieving efficient vanadium leaching under mild conditions, and preventing impurities from easily entering the leachate. The method has a simple operation process, easily controllable conditions, produces no harmful gases during roasting, and has low cost.

[0008] To achieve this objective, the present invention adopts the following technical solution: This invention provides a method for leaching vanadium from vanadium slag clinker using bio-enzymatic catalysis, the method comprising the following steps: (1) Adjust the pH of the urea buffer solution to acidic and mix it with urease for hydrolysis to obtain a hydrolysate; (2) The vanadium slag roasted clinker is mixed with the hydrolysis solution described in step (1) and leached to obtain a vanadium-containing leachate.

[0009] Compared to traditional vanadium extraction processes, the method described in this invention utilizes biological enzymes, which catalyze the hydrolysis of urea to produce NH4-containing compounds. + The vanadium slag clinker is leached in a hydrolysis solution, which causes vanadium to dissolve in the form of ammonium vanadate, while calcium, manganese, and magnesium elements enter the leaching residue in the form of carbonates. This improves the vanadium recovery rate and prevents impurities from entering the leaching solution, thus achieving efficient recovery and utilization of vanadium resources in the vanadium slag.

[0010] Preferably, the urea buffer solution in step (1) is obtained by mixing urea, buffer solution and water.

[0011] Preferably, the concentration of urea in the urea buffer solution in step (1) is 0.5~2 mol / L, for example, it can be 0.5 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L or 2 mol / L, etc.

[0012] Preferably, the buffer includes any one or a combination of at least two of Bis-Tris buffer, MES buffer, PIPES buffer or MOPS buffer, wherein typical but non-limiting combinations include combinations of MES buffer and Bis-Tris buffer, combinations of Bis-Tris buffer and PIPES buffer, and combinations of Bis-Tris buffer and MOPS buffer, etc.

[0013] Preferably, the concentration of the buffer solution is 0.15~0.35 mol / L, for example, it can be 0.15 mol / L, 0.18 mol / L, 0.20 mol / L, 0.22 mol / L, 0.25 mol / L, 0.28 mol / L, 0.30 mol / L, 0.32 mol / L or 0.35 mol / L, etc.

[0014] Preferably, the endpoint of pH adjustment in step (1) is that the pH of the urea buffer solution is 4.5 to 6.5, for example, it can be 4.5, 4.8, 5.0, 5.2, 5.5, 5.8, 6.0, 6.2 or 6.5, etc.

[0015] The method of the present invention further optimizes the pH adjustment in step (1) by setting the pH of the urea buffer solution to 4.5-6.5, which is beneficial for urease to catalyze the hydrolysis of urea. If the corresponding pH is too low or too high, it will lead to a decrease in urease activity and a reduction in the amount of NH4 generated during hydrolysis. + Insufficient concentration leads to a decrease in vanadium leaching rate.

[0016] Preferably, the acid solution used for pH adjustment in step (1) includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid, wherein typical but non-limiting combinations include a combination of sulfuric acid and hydrochloric acid, a combination of hydrochloric acid and nitric acid or a combination of sulfuric acid and nitric acid, etc.

[0017] Preferably, based on the urea buffer solution, the amount of urease added in step (1) is 5~35 mg / L, for example, it can be 5 mg / L, 10 mg / L, 15 mg / L, 20 mg / L, 25 mg / L, 30 mg / L or 35 mg / L, etc.

[0018] The method of the present invention further optimizes the addition of urease in step (1) to 5-35 mg / L, based on the urea buffer solution, which helps to ensure that the concentration of ammonium ions in the resulting hydrolysis solution is sufficient for efficient vanadium extraction. If the amount of urease added is too low, the degree of hydrolysis will be insufficient, the concentration of ammonium ions in the resulting hydrolysis solution will be low, and the vanadium leaching rate will decrease. If the amount of urease added is too high, it will not significantly improve the vanadium leaching rate, but will instead cause waste.

[0019] Preferably, the NH4+ in the hydrolysis solution of step (1) + The concentration is 40~65 g / L, for example, it can be 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L or 65 g / L, etc.

[0020] Preferably, the hydrolysis temperature in step (1) is 40~70℃, for example, it can be 40℃, 45℃, 50℃, 55℃, 60℃, 65℃ or 70℃.

[0021] Preferably, the hydrolysis time in step (1) is 0.5 to 2.5 h, for example, it can be 0.5 h, 1 h, 1.5 h, 2 h or 2.5 h.

[0022] Preferably, the hydrolysis process in step (1) is accompanied by a first stirring.

[0023] Preferably, the rotation speed of the first stirring is 100~400 r / min, for example, it can be 100 r / min, 200 r / min, 300 r / min or 400 r / min, etc.

[0024] Preferably, the vanadium slag roasted clinker in step (2) is obtained by roasting vanadium-containing raw materials.

[0025] Preferably, the roasting includes any one or a combination of at least two of salt-free roasting, calcification roasting, or sodium roasting, wherein typical but non-limiting combinations include a combination of salt-free roasting and calcification roasting, a combination of calcification roasting and sodium roasting, or a combination of salt-free roasting and sodium roasting, etc., with salt-free roasting being the preferred option.

[0026] The salt-free roasting described in this invention refers to roasting the vanadium-containing raw material directly without adding any additives.

[0027] Preferably, the calcium source used in the calcination roasting includes calcium oxide and / or calcium carbonate.

[0028] Preferably, during the calcification roasting, the molar ratio of V in the vanadium-containing raw material to Ca in the calcium source is (0.5~2):1, for example, it can be 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1, etc.

[0029] Preferably, the sodium source used in the sodium roasting includes sodium carbonate and / or sodium chloride.

[0030] Preferably, during the sodium roasting, the molar ratio of V in the vanadium-containing raw material to Na in the sodium source is (0.5~2):1, for example, it can be 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1, etc.

[0031] Preferably, the vanadium-containing raw material includes any one or a combination of at least two of vanadium-titanium magnetite, coal shale, vanadium slag, or vanadium-containing catalyst. Typical but non-limiting combinations include combinations of vanadium-titanium magnetite and coal shale, combinations of vanadium-titanium magnetite and vanadium slag, or combinations of vanadium-titanium magnetite and vanadium-containing catalyst.

[0032] Preferably, based on the total mass of the vanadium-containing raw materials as 100wt%, the vanadium-containing raw materials include V2O5: 10~25wt%, TFe: 25~54wt%, CaO: 0.7~3wt%, MgO: 1~5wt%, SiO2: 9~22wt%, MnO2: 2~20wt%, TiO2: 1~15wt%, Cr2O3: 1~11wt%, Al2O3: 1~3wt%, and P2O5: 0.2~0.4wt%.

[0033] Among them, V₂O₅: 10~25wt%, for example, it can be 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 22wt%, or 25wt%, etc.; TFe: 25~54wt%, for example, it can be 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, or 54wt%, etc.; CaO: 0.7~3wt%, for example, it can be 0.7wt%, 1.2wt%, 1.5wt%, 2wt%, 2.5wt%, or... 3wt%, etc.; MgO: 1~5wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, or 5wt%, etc.; SiO2: 9~22wt%, for example, it can be 9wt%, 12wt%, 15wt%, 18wt%, 20wt%, or 22wt%, etc.; MnO: 2~20wt%, for example, it can be 2wt%, 5wt%, 10wt%, 15wt%, or 20wt%, etc.; TiO2: 1~15wt%, for example, it can be 1wt%, 5wt%, 10wt%, etc. wt%, 12 wt% or 15 wt%, etc.; Cr2O3: 1~11 wt%, for example, it can be 1 wt%, 5 wt%, 8 wt% or 11 wt%, etc.; Al2O3: 1~3 wt%, for example, it can be 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt% or 3 wt%, etc.; P2O5: 0.2~0.4 wt%, for example, it can be 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt% or 0.4 wt%, etc.

[0034] Preferably, the roasting temperature is 850~950℃, for example, it can be 850℃, 880℃, 900℃, 920℃ or 950℃.

[0035] Preferably, the calcination time is 0.5 to 2 hours, for example, 0.5 hours, 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours or 2 hours.

[0036] Preferably, the roasting atmosphere includes an oxygen-containing atmosphere.

[0037] Preferably, the liquid-solid ratio of the hydrolysis solution in step (2) to the vanadium slag roasted clinker is (5~20):1, for example, it can be 5:1, 8:1, 10:1, 12:1, 15:1, 18:1 or 20:1, etc.

[0038] Preferably, the leaching temperature in step (2) is 35~70℃, for example, it can be 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃ or 70℃, etc.

[0039] Preferably, the leaching time in step (2) is 0.5 to 3 hours, for example, it can be 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours.

[0040] Preferably, the leaching process in step (2) is accompanied by a second stirring.

[0041] Preferably, the second stirring speed is 200~500 r / min, for example, it can be 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min or 500 r / min, etc.

[0042] Preferably, the method further includes crushing the vanadium slag roasted clinker before the mixing in step (2).

[0043] Preferably, the crushing process includes crushing the vanadium slag clinker to a particle size of 38~75.0 µm, for example, it can be 38.0 µm, 45.0 µm, 48.0 µm, 58.0 µm or 75.0 µm.

[0044] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzymes. This method utilizes bio-enzymes to hydrolyze urea under the catalysis of urease to obtain ammonium ions. The resulting hydrolysate is then used to efficiently leach vanadium from the vanadium slag roasting clinker, while simultaneously preventing impurities from entering the leachate. This achieves highly efficient vanadium leaching from the vanadium slag, with a preferred vanadium leaching rate of over 88% and an impurity content in the leachate as low as 100 ppm. Furthermore, the roasting method is optimized to be salt-free roasting, avoiding the generation of harmful gases. The method also features mild and easily controllable conditions and low cost. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0046] As a specific embodiment of the present invention, a method for leaching vanadium from vanadium slag roasting clinker catalyzed by bio-enzymes is provided, the method comprising the following steps: (I) The vanadium-containing raw material is roasted at 850~950℃ in an oxygen-containing atmosphere for 0.5~2 h to obtain vanadium slag roasted clinker, which is then crushed to a particle size of 38~75.0 µm; the roasting includes any one or a combination of at least two of salt-free roasting, calcification roasting or sodium roasting; the calcium source used in the calcification roasting includes calcium oxide and / or calcium carbonate; the molar ratio of V in the vanadium-containing raw material to Ca in the calcium source is (0.5~2):1; the sodium source used in the sodium roasting includes sodium carbonate and / or sodium chloride; the sodium source used in the sodium roasting includes sodium carbonate and / or sodium chloride; the molar ratio of V in the vanadium-containing raw material to Na in the sodium source is (0.5~2):1; (II) Mix urea, buffer solution, and water to obtain a urea buffer solution, and adjust the pH of the urea buffer solution to 4.5-6.5 with acid solution. Then add 5-35 mg / L urease and hydrolyze for 0.5-2.5 h under the first stirring condition of 40-70℃ and 100-400 r / min to obtain NH4. + A hydrolysis solution with a concentration of 40~65 g / L; The urea buffer solution contains urea at a concentration of 0.5–2 mol / L, and the buffer solution comprises any one or a combination of at least two of Bis-Tris buffer, MES buffer, PIPES buffer, or MOPS buffer; the concentration of the buffer solution is 0.15–0.35 mol / L; the acid solution comprises any one or a combination of at least two of sulfuric acid, hydrochloric acid, phosphoric acid, or nitric acid. (III) The hydrolysis solution in step (II) is mixed with the crushed vanadium slag clinker in step (I) at a liquid-to-solid ratio of (5~20):1. The mixture is then leached for 0.5~3 h under the second stirring conditions of 35~70℃ and 200~500 r / min. The vanadium-containing leachate and leaching residue are obtained by solid-liquid separation.

[0047] In the methods provided in the following examples or comparative examples, step (I) of salt-free roasting means roasting directly without adding any additives.

[0048] I. Implementation Examples Example 1 This embodiment provides a method for leaching vanadium from vanadium slag clinker using bio-enzymatic catalysis, the method comprising the following steps: (I) Vanadium-titanium magnetite was roasted at 900℃ in air atmosphere for 1 h without salt to obtain vanadium slag roasted clinker, which was then crushed to a particle size of 48.0~75.0 µm; (II) A urea buffer solution was prepared by mixing urea (1 mol / L), Bis-Tris buffer (0.3 mol / L), and water. The pH of the urea buffer solution was adjusted to 5.5 with sulfuric acid (15 wt%). Then, 20 mg / L of urease was added, and the solution was hydrolyzed for 2 h under the first stirring condition of 50 °C and 300 r / min to obtain NH4. + A hydrolysis solution with a concentration of 50 g / L; (III) The hydrolysis solution and the vanadium slag roasted clinker are mixed in a liquid-solid ratio of 10:1. The mixture is then leached for 2 hours under the second stirring condition of 60°C and 300 r / min. After cooling, the mixture is filtered to obtain the vanadium-containing leachate and leaching residue.

[0049] The composition and content of the vanadium-titanium magnetite described in this embodiment are shown in Table 1; Table 1 Example 2 This embodiment provides a method for leaching vanadium from vanadium slag clinker using bio-enzymatic catalysis, the method comprising the following steps: (I) Vanadium slag is mixed with calcium oxide and calcined at 850°C in air atmosphere for 2 h to obtain vanadium slag calcined clinker, which is then crushed to a particle size of 38.0~45.0 µm; wherein the molar ratio of V in the vanadium slag to Ca in the calcium oxide is 1:1; (II) A urea buffer solution was prepared by mixing urea (0.5 mol / L), Bis-Tris buffer (0.15 mol / L), and water. The pH of the urea buffer solution was adjusted to 4.5 with sulfuric acid (17 wt%). Then, 5 mg / L of urease was added, and the solution was hydrolyzed for 2.5 h under the first stirring condition of 40 °C and 400 r / min to obtain NH4. + A hydrolysis solution with a concentration of 40 g / L; (III) The hydrolysis solution and the vanadium slag roasted clinker are mixed in a liquid-solid ratio of 5:1. The mixture is then leached for 3 h under the second stirring condition of 35°C and 500 r / min. After cooling, the mixture is filtered to obtain the vanadium-containing leachate and leaching residue.

[0050] The composition and content of the vanadium slag described in this embodiment are shown in Table 2. Table 2 Example 3 This embodiment provides a method for leaching vanadium from vanadium slag clinker using bio-enzymatic catalysis, the method comprising the following steps: (I) Mix coal stone with sodium carbonate and roast at 950°C in air for 0.5 h to obtain vanadium slag roasted clinker, and then crush it to a particle size of 45.0~48.0 µm; wherein the molar ratio of V in the coal stone to Na in the sodium carbonate is 1.2:1; (II) A urea buffer solution was prepared by mixing urea (2 mol / L), Bis-Tris buffer (0.35 mol / L), and water. The pH of the urea buffer solution was adjusted to 6.5 with sulfuric acid (20 wt%). Then, 35 mg / L urease was added, and the solution was hydrolyzed for 0.5 h under the first stirring condition of 70 °C and 200 r / min to obtain NH4. + A hydrolysis solution with a concentration of 65 g / L; (III) The hydrolysis solution in step (II) is mixed with the crushed vanadium slag clinker in step (I) at a liquid-to-solid ratio of 20:1. The mixture is then leached for 0.5 h under the second stirring condition of 70 °C and 200 r / min. After cooling, the mixture is filtered to obtain the vanadium-containing leachate and leaching residue.

[0051] The composition and content of the coal stone described in this embodiment are shown in Table 3. Table 3 Example 4 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for step (II), in which sulfuric acid is used to adjust the pH of the urea buffer solution to 4.3, the method is the same as in Example 1.

[0052] Example 5 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for step (II), in which sulfuric acid is used to adjust the pH of the urea buffer solution to 6.8, the method is the same as in Example 1.

[0053] Example 6 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for step (II), where the amount of urease added is 2 mg / L, the method is the same as in Example 1.

[0054] Example 7 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for step (II), where the amount of urease added is 40 mg / L, the method is the same as in Example 1.

[0055] Example 8 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for step (II), where the concentration of urea in the urea buffer solution is 0.3 mol / L, the method is the same as in Example 1.

[0056] Example 9 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for step (II), where the concentration of urea in the urea buffer solution is 2.5 mol / L, the method is the same as in Example 1.

[0057] Example 10 This embodiment provides a method for leaching vanadium from vanadium slag roasted clinker using bio-enzyme catalysis. Except for step (III), where the liquid-to-solid ratio of the hydrolysis solution to the vanadium slag roasted clinker is 4:1, the method is the same as in Example 1.

[0058] Example 11 This embodiment provides a method for leaching vanadium from vanadium slag roasted clinker using bio-enzyme catalysis. Except for the liquid-to-solid ratio of the hydrolysis solution to the vanadium slag roasted clinker in step (III) being 22:1, the method is the same as in Example 1.

[0059] Example 12 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for the leaching temperature of 30°C in step (III), the method is the same as in Example 1.

[0060] Example 13 This embodiment provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for the leaching temperature of 75°C in step (III), the method is the same as in Example 1.

[0061] II. Comparative Example Comparative Example 1 This comparative example provides a method for leaching vanadium from vanadium slag roasting clinker using bio-enzyme catalysis. Except for step (II), which does not adjust the pH of the urea buffer solution to acidity, but instead directly mixes the urea buffer solution with urease at pH 7.0 for hydrolysis, the method is the same as in Example 1.

[0062] Comparative Example 2 This comparative example provides a method for leaching vanadium from vanadium slag roasted clinker. The method is carried out using the method provided in Example 1 of CN104003442A, namely, vanadium slag salt-free roasting-ammonium bicarbonate solution leaching.

[0063] III. Tests and Results The vanadium leaching rate and the impurity content in the obtained vanadium-containing leachate were tested or calculated using the methods provided in the above embodiments or comparative examples, and the results are shown in Table 4. Table 4 The data in Table 4 shows that: (1) As can be seen from Examples 1 to 3, the method for leaching vanadium from vanadium slag using bio-enzyme catalysis provided by the present invention achieves efficient vanadium leaching from vanadium slag, with a vanadium leaching rate of over 88%, and the impurity content in the resulting vanadium-containing leachate is as low as 100 ppm.

[0064] (2) As can be seen from Examples 1 and 4 to 9, the present invention further optimizes the pH of the urea buffer solution to 4.5-6.5, or further optimizes the amount of urease added to 5-35 mg / L, or further optimizes the concentration of urea in the urea buffer solution to 0.5-2 mol / L, which is beneficial for urease to catalyze the hydrolysis of urea, thereby ensuring that the solution contains sufficient NH4. + This process allows vanadium to dissolve in the form of ammonium vanadate, thereby further increasing the vanadium leaching rate.

[0065] (3) As can be seen from the combined examples 1 and 10 to 13, the present invention further optimizes the liquid-solid ratio of the hydrolysis solution to the vanadium slag roasting clinker to (5~20):1, or further optimizes the leaching temperature to 35~70℃, which is more conducive to vanadium leaching.

[0066] (4) It can be seen from the combined results of Example 1 and Comparative Examples 1 and 2 that, since the pH of the urea buffer solution in Comparative Example 1 was not adjusted to acidity, the urease activity decreased, and the NH4+ in the hydrolysis solution decreased. + The drawback is that the vanadium leaching rate is relatively low. Because the process of leaching with ammonium bicarbonate solution was used in Comparative Example 2, the leaching agent is prone to decomposition when the temperature is too high. This shows that the method for leaching vanadium from vanadium slag roasting clinker provided by the present invention has excellent vanadium leaching effect and has both high leaching rate and high selectivity.

[0067] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for leaching vanadium from vanadium slag clinker using bio-enzyme catalysis, characterized in that, The method includes the following steps: (1) Adjust the pH of the urea buffer solution to acidic and mix it with urease for hydrolysis to obtain a hydrolysate; (2) The vanadium slag roasted clinker is mixed with the hydrolysis solution described in step (1) and leached to obtain a vanadium-containing leachate.

2. The method according to claim 1, characterized in that, The urea buffer solution described in step (1) is obtained by mixing urea, buffer solution, and water; Preferably, the concentration of urea in the urea buffer solution in step (1) is 0.5~2 mol / L; Preferably, the buffer solution includes any one or a combination of at least two of Bis-Tris buffer, MES buffer, PIPES buffer, or MOPS buffer; Preferably, the concentration of the buffer solution is 0.15~0.35 mol / L.

3. The method according to claim 1 or 2, characterized in that, The endpoint of pH adjustment in step (1) is that the pH of the urea buffer solution is 4.5 to 6.5; Preferably, the acid solution used for pH adjustment in step (1) includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, phosphoric acid, or nitric acid.

4. The method according to any one of claims 1 to 3, characterized in that, Based on the urea buffer solution, the amount of urease added in step (1) is 5~35 mg / L; Preferably, the NH4+ in the hydrolysis solution of step (1) + The concentration is 40~65g / L.

5. The method according to any one of claims 1 to 4, characterized in that, The hydrolysis temperature in step (1) is 40~70℃; Preferably, the hydrolysis time in step (1) is 0.5~2.5 h; Preferably, the hydrolysis process in step (1) is accompanied by a first stirring; Preferably, the first stirring speed is 100~400 r / min.

6. The method according to any one of claims 1 to 5, characterized in that, The vanadium slag roasted clinker in step (2) is obtained by roasting vanadium-containing raw materials; Preferably, the roasting includes any one or a combination of at least two of salt-free roasting, calcification roasting, or sodium roasting, with salt-free roasting being the most preferred.

7. The method according to claim 6, characterized in that, The vanadium-containing raw materials include any one or a combination of at least two of vanadium-titanium magnetite, coal shale, vanadium slag, or vanadium-containing catalysts.

8. The method according to claim 6 or 7, characterized in that, The roasting temperature is 850~950℃; Preferably, the roasting time is 0.5~2 h; Preferably, the roasting atmosphere includes an oxygen-containing atmosphere.

9. The method according to any one of claims 1 to 8, characterized in that, The liquid-solid ratio of the hydrolysis solution to the vanadium slag roasted clinker in step (2) is (5~20):1; Preferably, the leaching temperature in step (2) is 35~70℃; Preferably, the leaching time in step (2) is 0.5 to 3 hours; Preferably, the leaching process in step (2) is accompanied by a second stirring; Preferably, the second stirring speed is 200~500 r / min.

10. The method according to any one of claims 1 to 9, characterized in that, The method further includes crushing the vanadium slag roasted clinker before the mixing in step (2); Preferably, the crushing process includes crushing the vanadium slag clinker to a particle size of 38~75.0 µm.

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