Method for recovering vanadium from titanium tetrachloride vanadium removal slag and application thereof

Abstract

The invention relates to the technical field of titanium tetrachloride production, in particular to a method for recovering vanadium from titanium tetrachloride vanadium removal slag and application of the method. The method for recovering the vanadium from the titanium tetrachloride vanadium-removed slag comprises the following steps: (a) carrying out acid liquor leaching on the vanadium-removed slag to obtain vanadium-containing leachate and leaching slag; (b) adding an oxidizing agent into the vanadium-containing leachate for oxidative hydrolysis and pyrolysis vanadium precipitation to obtain a precipitate and a vanadium precipitation mother solution; (c) leaching the precipitate by using alkali liquor, precipitating vanadium by using a precipitant, and roasting to obtain vanadium pentoxide; and (d) the vanadium precipitation mother liquor is subjected to extraction and reverse extraction, and a vanadium-containing solution is obtained. According to the method for recovering the vanadium from the titanium tetrachloride vanadium removal slag, corrosive gases such as HCl and Cl2 are not generated in the preparation process, a large amount of strong alkaline waste residues are not generated, the method has the advantages of being economical and environmentally friendly, the recovered vanadium pentoxide is good in quality and low in impurity content, and the total recovery rate of the vanadium is high.

Description

Technical Field

[0001] The invention relates to the technical field of titanium tetrachloride production, in particular to a method for recovering vanadium from titanium tetrachloride vanadium-removing slag and an application thereof. Background Art

[0002] Crude titanium tetrachloride contains a certain amount of vanadium, and mineral oil or animal oil needs to be added to obtain refined titanium tetrachloride after a vanadium removal process. While obtaining refined titanium tetrachloride, a large amount of vanadium removal slurry will also be produced. The vanadium removal slurry contains a certain amount of vanadium. If it cannot be reasonably utilized, it will cause a waste of vanadium resources. At the same time, the vanadium removal slurry needs to be treated, which increases costs.

[0003] The existing methods for recovering vanadium from crude titanium tetrachloride vanadium removal slag mostly adopt the oxidation roasting-leaching process. The technical route of this process is as follows: Figure 1 In the existing process, the vanadium removal slag reacts with limestone for washing and dechlorination and then roasting. The oxidation roasting process produces pollutants such as HCl and Cl2, and the alkali leaching slag is highly alkaline and has a large amount of slag. Direct stacking pollutes the environment.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a method for recovering vanadium from titanium tetrachloride vanadium removal slag and its application. The method for recovering vanadium from titanium tetrachloride vanadium removal slag has the advantages of economy, environmental protection, high vanadium yield and the like.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0007] One aspect of the present invention relates to a method for recovering vanadium from titanium tetrachloride vanadium removal slag, comprising the following steps:

[0008] (a) subjecting the vanadium-removing slag to acid leaching to obtain a vanadium-containing leaching solution and leaching slag;

[0009] (b) adding an oxidant to the vanadium-containing leaching solution to carry out oxidative hydrolysis and pyrolysis to precipitate vanadium, thereby obtaining a precipitate and a vanadium precipitation mother liquor;

[0010] (c) subjecting the precipitate to alkali solution leaching, vanadium precipitation with a precipitant and roasting to obtain vanadium pentoxide;

[0011] (d) extracting and stripping the vanadium-precipitated mother liquor to obtain a vanadium-containing solution.

[0012] The method for recovering vanadium from titanium tetrachloride vanadium removal slag does not produce corrosive gases such as HCl and Cl2 during the preparation process, and does not produce a large amount of strongly alkaline waste slag materials. It has economic and environmental advantages, and the recovered vanadium pentoxide has good quality, low impurity content, and high total vanadium recovery rate.

[0013] Another aspect of the present invention also relates to a comprehensive utilization method of titanium tetrachloride vanadium removal slag, including the method of recovering vanadium from titanium tetrachloride vanadium removal slag.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The method for recovering vanadium from titanium tetrachloride vanadium removal slag provided by the present invention does not produce corrosive gases such as HCl and Cl2 during the preparation process, and alkali leaching is carried out during the process of purifying vanadium pentoxide, which does not produce a large amount of strongly alkaline waste slag. It has economic and environmental advantages, and the recovered vanadium pentoxide is of good quality, low impurity content, and high total recovery rate of vanadium.

[0016] (2) The present invention first uses acid solution to leach vanadium from crude titanium tetrachloride vanadium-removing slag, and then oxidizes and precipitates vanadium, thereby recovering vanadium pentoxide, which can reduce the impact on the environment. The leached slag does not change the structure of titanium in the original vanadium-removing slag and can continue to be utilized through a recovery process.

[0017] (3) The present invention uses a dilute acid leaching-oxidative hydrolysis method with a high acid leaching rate to recover vanadium from crude titanium tetrachloride organic vanadium removal slag, optimizes the parameters of oxidative hydrolysis, and uses an extractant N235 to recover vanadium from vanadium precipitation mother liquor. The present invention recovers vanadium from titanium tetrachloride vanadium removal slag with a total vanadium recovery rate of 96% to 98%. Vanadium is expressed as vanadium pentoxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is the technical roadmap for the oxidation roasting-leaching process. DETAILED DESCRIPTION

[0020] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0021] One aspect of the present invention relates to a method for recovering vanadium from titanium tetrachloride vanadium removal slag, comprising the following steps:

[0022] (a) subjecting the vanadium-removing slag to acid leaching to obtain a vanadium-containing leaching solution and leaching slag;

[0023] (b) adding an oxidant to the vanadium-containing leaching solution to carry out oxidative hydrolysis and pyrolysis to precipitate vanadium, thereby obtaining a precipitate and a vanadium precipitation mother liquor;

[0024] (c) subjecting the precipitate to alkali solution leaching, vanadium precipitation with a precipitant and roasting to obtain vanadium pentoxide;

[0025] (d) extracting and stripping the vanadium-precipitated mother liquor to obtain a vanadium-containing solution.

[0026] The method for recovering vanadium from titanium tetrachloride vanadium removal slag does not produce corrosive gases such as HCl and Cl2 during the preparation process, and does not produce a large amount of strongly alkaline waste slag, has economic and environmental advantages, and the recovered vanadium pentoxide has good quality, low impurity content, and high total vanadium recovery rate.

[0027] The present invention firstly performs acid leaching of vanadium from crude titanium tetrachloride vanadium removal slag, and then oxidizes and precipitates vanadium, so as to recover vanadium pentoxide, which can reduce the impact on the environment. The leached slag does not change the structure of titanium in the original vanadium removal slag, and can continue to be utilized through a recovery process. The recovery method can be carried out by adopting existing technology, which is not described in detail in the present invention.

[0028] The present invention uses a dilute acid leaching-oxidation hydrolysis method with a high acid leaching rate to recover vanadium from crude titanium tetrachloride organic matter vanadium removal slag, optimizes the parameters of oxidation hydrolysis, and uses an extractant N235 to recover vanadium from vanadium precipitation mother liquor. The present invention recovers vanadium from titanium tetrachloride vanadium removal slag with a total vanadium recovery rate of 96% to 98%. Vanadium is expressed as vanadium pentoxide.

[0029] Furthermore, the ratio of the vanadium-removing slag to the acid leached from the acid solution is 1kg:0.5-2L, including but not limited to 1kg:0.5L, 1kg:1L, 1kg:1.5L or 1kg:2L.

[0030] Furthermore, the acid leaching is 2 to 5 levels of countercurrent leaching, including but not limited to 2, 3, 4 or 5 levels.

[0031] In some specific embodiments, the ratio of the vanadium removal slag to the acid leaching acid is 1kg:1L, the acid leaching is 3-stage countercurrent leaching, the single-stage leaching rate is about 85%, and the optimized three-stage countercurrent leaching rate is above 98%.

[0032] Furthermore, the acid leaching time is 2 to 6 hours, including but not limited to any one of 2 hours, 3 hours, 4 hours, 5 hours or 6 hours or a range between any two of them.

[0033] Furthermore, the acid concentration of the acid solution leaching is 0.2-1 mol / L, including but not limited to any point value of 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L or any range value between two of them. The acid solution concentration is limited to a certain range, and there is no need to add a large amount of alkali solution to adjust the pH in the pyrolysis vanadium precipitation stage.

[0034] Furthermore, the acid concentration of the acid leaching is 0.5 mol / L.

[0035] Furthermore, the acid leaching acid includes but is not limited to: hydrochloric acid and / or sulfuric acid.

[0036] Furthermore, the amount of the oxidant added is 1.2 to 1.8 times the mass of vanadium in the vanadium-containing leaching solution, including but not limited to any one of 1.2, 1.4, 1.6 or 1.8 times or a range between any two of the points.

[0037] Furthermore, the oxidant includes but is not limited to: sodium chlorate.

[0038] Furthermore, the pH of the pyrolysis-precipitated vanadium is 1-2, including but not limited to any one of 1, 1.2, 1.4, 1.6, 1.8 or 2 or a range between any two of them.

[0039] Furthermore, the pH of the pyrolysis vanadium precipitation is 1.0 to 1.4. Oxidative hydrolysis converts all iron ions into trivalent ions. In order to control the iron content in red vanadium, the preferred pH range is 1.1 to 1.4. High iron content affects the leaching rate of alkaline solution leaching. If the iron content is not controlled, it will reach 10% to 15%.

[0040] Furthermore, the temperature of the pyrolysis vanadium precipitation is 95-100° C., including but not limited to any point value of 95° C., 96° C., 97° C., 98° C., 99° C. or 100° C. or any range value between two of them. Limiting the temperature of the pyrolysis vanadium precipitation to a certain range can ensure a higher precipitation rate.

[0041] Furthermore, the time for pyrolysis precipitation of vanadium is 1 to 2 hours, including but not limited to any one of 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours or 2 hours or a range between any two of them.

[0042] Furthermore, the pH of the precipitant for vanadium precipitation is 8-9, including but not limited to any one of 8, 8.2, 8.4, 8.6, 8.8 or 9 or a range between any two of them.

[0043] Furthermore, the precipitant for vanadium precipitation includes but is not limited to: ammonium salt.

[0044] Furthermore, the calcination temperature is 500-550°C.

[0045] Furthermore, the calcination time is 2 to 3 hours.

[0046] Furthermore, the extractant for the extraction comprises: 20 vol% to 40 vol% N235 and 60 vol% to 80 vol% sulfonated kerosene. The N235 extractant is also known as tri-octyl-decyl tertiary amine or tri-n-octylamine.

[0047] Furthermore, the volume ratio of the extractant to water is 1:1 to 1.5, including but not limited to 1:1, 1:1.1, 1:1.2, 1:1.3 or 1:1.5.

[0048] Furthermore, the extraction pH is 1.2 to 1.6, including but not limited to any point value of 1.2, 1.3, 1.4, 1.5 or 1.6 or any range value between two of them. The vanadium content in the vanadium precipitation mother liquor is 1.5 to 2.5 g / L, the iron content is 5 to 10 g / L, the extraction end point pH is controlled to be 1.2 to 1.6, and the vanadium extraction rate is above 85%.

[0049] Furthermore, the stripping agent for the stripping includes but is not limited to: sodium carbonate solution.

[0050] Furthermore, the concentration of the sodium carbonate solution is 5wt% to 15wt%, including but not limited to any one of 5wt%, 7wt%, 9wt%, 11wt%, 13wt% or 15wt% or a range between any two of them.

[0051] Furthermore, the vanadium-containing solution is returned to adjust the pH of the pyrolysis vanadium precipitation, and the reuse of the vanadium-containing solution can increase the yield of vanadium.

[0052] Furthermore, the method for recovering vanadium from titanium tetrachloride vanadium-removing slag also includes:

[0053] The leached residue is acid-leached to obtain a titanium concentrate. After removing ash from the titanium concentrate, the titanium content (TiO2) can reach 70% to 78%.

[0054] Furthermore, the acid solution for acid leaching includes but is not limited to: 0.2-1 mol / L hydrochloric acid solution.

[0055] The source of the vanadium removal slag involved in the present invention is: titanium tetrachloride plus mineral oil or animal oil is subjected to a vanadium removal process to obtain refined titanium tetrachloride and vanadium removal slurry, and the vanadium removal slurry is subjected to rapid evaporation to recover titanium tetrachloride and obtain vanadium removal slag at the same time.

[0056] Another aspect of the present invention also relates to a comprehensive utilization method of titanium tetrachloride vanadium removal slag, including the method of recovering vanadium from titanium tetrachloride vanadium removal slag.

[0057] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0058] The vanadium in the vanadium removal slag used in the following examples is mainly present in tetravalent form and is soluble in water. The main components are shown in Table 1.

[0059] Table 1

[0060] <![CDATA[V2O5]]> <![CDATA[TiO2]]> Fe Cl C Al 20.89％ 23.39％ 1.93％ 30.74％ 20.36％ 0.17％

[0061] Example 1

[0062] The method for recovering vanadium from titanium tetrachloride vanadium-removing slag provided in this embodiment comprises the following steps:

[0063] Step 1. placing the vanadium removal slag in 0.5 mol / L dilute hydrochloric acid for acid leaching, the ratio of the vanadium removal slag to the acid is 1 kg:1 L, the acid leaching is 3-stage countercurrent leaching, leaching for 4 hours, filtering, and obtaining vanadium-containing leaching solution and leaching slag;

[0064] Step 2. adding sodium chlorate as an oxidant to the vanadium-containing leachate for oxidative hydrolysis, wherein the amount of the oxidant added is 1.4 times the mass of vanadium in the vanadium-containing leachate, adding alkali solution to the reaction system after oxidative hydrolysis to adjust the pH to 1.2, heating the reaction system to 97° C. for 1.5 h to pyrolyze and precipitate vanadium, filtering to obtain precipitated red vanadium and vanadium precipitation mother liquor;

[0065] Step 3. The polyvanadic acid (red vanadium) obtained in step 2 is subjected to alkaline solution leaching, vanadium is precipitated with a precipitant under the condition of pH 8.4, and ammonium metavanadate is roasted to obtain vanadium pentoxide;

[0066] Step 4. Leaching the leached residue in step 1 with 1.2 mol / L hydrochloric acid to obtain a titanium enriched product;

[0067] Step 5. The mother liquor of vanadium precipitation in step 2 is treated with 35 vol% N235 + 70 vol% sulfonated kerosene at a ratio of 1:1.3 to recover vanadium, the extraction pH is controlled at 1.4, and sodium carbonate solution is used for stripping to obtain a vanadium-containing solution which can be returned to step 2 for oxidation and then the pH of vanadium precipitation by pyrolysis is adjusted.

[0068] Example 2

[0069] The method for recovering vanadium from titanium tetrachloride vanadium-removing slag provided in this embodiment comprises the following steps:

[0070] Step 1. Place the vanadium removal slag in 0.7 mol / L dilute sulfuric acid for acid leaching, the ratio of vanadium removal slag to acid is 1 kg: 1.4 L, the acid leaching is 4-stage countercurrent leaching, leaching for 5 hours, filtering, and obtaining vanadium-containing leaching solution and leaching slag;

[0071] Step 2. adding sodium chlorate as an oxidant to the vanadium-containing leachate for oxidative hydrolysis, wherein the amount of the oxidant added is 1.6 times the mass of vanadium in the vanadium-containing leachate, adding alkali solution to the reaction system after oxidative hydrolysis to adjust the pH to 1.4, heating the reaction system to 98° C. for 1.5 h to pyrolyze and precipitate vanadium, filtering to obtain precipitated red vanadium and vanadium precipitation mother liquor;

[0072] Step 3. The polyvanadic acid (red vanadium) obtained in step 2 is subjected to alkaline solution leaching, vanadium is precipitated with a precipitant under the condition of pH 8.6, and ammonium metavanadate is roasted to obtain vanadium pentoxide;

[0073] Step 4. Leaching the leached residue in step 1 with 1 mol / L hydrochloric acid to obtain a titanium enriched product;

[0074] Step 5. The vanadium-containing solution obtained in step 2 is recovered from the vanadium-precipitated mother liquor with 35 vol% N235+65 vol% sulfonated kerosene at a ratio of 1:1.4, the extraction pH is controlled at 1.5, and the solution is stripped with sodium carbonate solution to obtain a vanadium-containing solution which can be returned to step 2 for oxidation and then the pH of the vanadium-precipitated pyrolysis is adjusted.

[0075] Example 3

[0076] The method for recovering vanadium from titanium tetrachloride vanadium-removing slag provided in this embodiment comprises the following steps:

[0077] Step 1. Place the vanadium removal slag in 0.2 mol / L dilute hydrochloric acid for acid leaching, the ratio of the vanadium removal slag to the acid is 1 kg: 0.5 L, the acid leaching is a two-stage countercurrent leaching, the leaching is for 2 hours, and the leaching is filtered to obtain a vanadium-containing leaching solution and leaching slag;

[0078] Step 2. adding sodium chlorate as an oxidant to the vanadium-containing leachate for oxidative hydrolysis, wherein the amount of the oxidant added is 1.2 times the mass of vanadium in the vanadium-containing leachate, adding alkali solution to the reaction system after oxidative hydrolysis to adjust the pH to 1, heating the reaction system to 95° C. for 1.5 h to pyrolyze and precipitate vanadium, filtering to obtain precipitated red vanadium and vanadium precipitation mother liquor;

[0079] Step 3. The polyvanadic acid (red vanadium) obtained in step 2 is subjected to alkaline solution leaching, vanadium is precipitated with a precipitant under the condition of pH 8, and ammonium metavanadate is roasted to obtain vanadium pentoxide;

[0080] Step 4. Leaching the leached residue in step 1 with 0.5 mol / L hydrochloric acid to obtain a titanium enriched product;

[0081] Step 5. The mother liquor of vanadium precipitation in step 2 is treated with 20 vol% N235 + 80 vol% sulfonated kerosene in a ratio of 1:1 to recover vanadium, the extraction pH is controlled at 1.2, and sodium carbonate solution is used for stripping to obtain a vanadium-containing solution which can be returned to step 2 for oxidation and then the pH of pyrolysis vanadium precipitation is adjusted.

[0082] Example 4

[0083] The method for recovering vanadium from titanium tetrachloride vanadium-removing slag provided in this embodiment comprises the following steps:

[0084] Step 1. placing the vanadium removal slag in 1 mol / L dilute sulfuric acid for acid leaching, the ratio of the vanadium removal slag to the acid is 1 kg: 2 L, the acid leaching is 5-level countercurrent leaching, leaching for 6 hours, filtering, and obtaining vanadium-containing leaching solution and leaching slag;

[0085] Step 2. adding sodium chlorate as an oxidant to the vanadium-containing leachate for oxidative hydrolysis, wherein the amount of the oxidant added is 1.8 times the mass of vanadium in the vanadium-containing leachate, adding alkali solution to the reaction system after oxidative hydrolysis to adjust the pH to 2, heating the reaction system to 100° C. for 1.5 h to pyrolyze and precipitate vanadium, filtering to obtain precipitated red vanadium and vanadium precipitation mother liquor;

[0086] Step 3. The polyvanadic acid (red vanadium) obtained in step 2 is subjected to alkaline solution leaching, vanadium is precipitated with a precipitant under the condition of pH 9, and ammonium metavanadate is roasted to obtain vanadium pentoxide;

[0087] Step 4. Leaching the leached residue in step 1 with 2 mol / L hydrochloric acid to obtain a titanium enriched product;

[0088] Step 5. The vanadium-containing solution obtained in step 2 is recovered from the vanadium-precipitated mother liquor with 40 vol% N235+60 vol% sulfonated kerosene at a ratio of 1:1.5, the extraction pH is controlled at 1.6, and the solution is stripped with sodium carbonate solution to obtain a vanadium-containing solution which can be returned to step 2 for oxidation and then the pH of the vanadium-precipitated pyrolysis is adjusted.

[0089] Comparative Example 1

[0090] The vanadium removal slag and sodium carbonate were mixed in a mass ratio of 100g:35g, placed in a muffle furnace and roasted at 700°C for 3h, leached with 100mL of water, filtered and the filtrate was adjusted to pH=8.5, 32g of ammonium chloride was added to precipitate ammonium metavanadate solid, and roasted at 500°C for 2h.

[0091] Comparative Example 2

[0092] The difference between this comparative example and Example 1 is that the acid concentration of the acid solution leached is 2 mol / L.

[0093] Comparative Example 3

[0094] The difference between this comparative example and Example 1 is that the pH of the pyrolysis vanadium precipitation in step 2 is 2.5.

[0095] Comparative Example 4

[0096] The difference between this comparative example and Example 1 is only that the pH of the extraction is 2.

[0097] Experimental example

[0098] The components of the red vanadium obtained in each embodiment and comparative example were analyzed, and the results are shown in Table 2.

[0099] Table 2 Red vanadium element analysis %

[0100]

[0101] As can be seen from Table 2, the red vanadium obtained by the process of the present invention has a low impurity iron content and a high vanadium content.

[0102] The vanadium pentoxide obtained in each embodiment and comparative example was analyzed for components, and the yield was calculated. The yield was calculated as (mass of product vanadium pentoxide*vanadium content) / total mass of vanadium pentoxide*100%, and the total mass of vanadium pentoxide was the mass of product vanadium pentoxide*vanadium pentoxide content+mass of leached slag*vanadium pentoxide content of leached slag+volume of vanadium precipitation mother liquor*vanadium pentoxide content after extraction+volume of solution after precipitating vanadium with precipitant*vanadium pentoxide content after precipitation. The results are shown in Table 3.

[0103] Table 3 Product vanadium pentoxide %

[0104]

[0105]

[0106] It can be seen from Table 3 that the yield of vanadium pentoxide of the present invention is 96-98%, which is high.

[0107] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for recovering vanadium from titanium tetrachloride vanadium removal slag, characterized in that: The following steps are involved: (a) subjecting the vanadium-removing slag to acid leaching to obtain a vanadium-containing leaching solution and leaching slag; (b) adding an oxidant to the vanadium-containing leaching solution to carry out oxidative hydrolysis and pyrolysis to precipitate vanadium, thereby obtaining a precipitate and a vanadium precipitation mother liquor; (c) subjecting the precipitate to alkali solution leaching, vanadium precipitation with a precipitant and roasting to obtain vanadium pentoxide; (d) extracting and stripping the vanadium-precipitated mother liquor to obtain a vanadium-containing solution.

2. The method for recovering vanadium from titanium tetrachloride vanadium removal slag according to claim 1, characterized in that: Includes at least one of the following technical features: (1) The ratio of the vanadium removal slag to the acid leached from the acid solution is 1 kg: 0.5-2 L; (2) The acid leaching is 2 to 5 levels of countercurrent leaching; (3) The acid concentration of the acid solution leached is 0.2 to 1 mol / L.

3. The method for recovering vanadium from titanium tetrachloride vanadium removal slag according to claim 1, characterized in that: Includes at least one of the following technical features: (1) The amount of the oxidant added is 1.2 to 1.8 times the mass of vanadium in the vanadium-containing leaching solution; (2) The oxidant includes sodium chlorate.

4. The method for recovering vanadium from titanium tetrachloride vanadium removal slag according to claim 1, characterized in that: Includes at least one of the following technical features: (1) The pH of the pyrolysis vanadium precipitation is 1 to 2; (2) The temperature of the pyrolysis vanadium precipitation is 95-100°C; (3) The time for pyrolysis precipitation of vanadium is 1 to 2 hours.

5. The method for recovering vanadium from titanium tetrachloride vanadium removal slag according to claim 1, characterized in that: The pH value of vanadium precipitation by the precipitant is 8-9.

6. The method for recovering vanadium from titanium tetrachloride vanadium-removing slag according to claim 1, characterized in that: Includes at least one of the following technical features: (1) The extraction agent comprises: 20 vol% to 40 vol% N235 and 60 vol% to 80 vol% sulfonated kerosene; (2) The volume ratio of the extractant to water is 1:1 to 1.5; (3) The pH of the extraction is 1.2 to 1.6; (4) The stripping agent for stripping includes: sodium carbonate solution.

7. The method for recovering vanadium from titanium tetrachloride vanadium-removing slag according to claim 1, characterized in that: The vanadium-containing solution is returned to adjust the pH of the pyrolysis-precipitated vanadium.

8. The method for recovering vanadium from titanium tetrachloride vanadium-removing slag according to claim 1, characterized in that: The method for recovering vanadium from titanium tetrachloride vanadium removal slag also includes: The leached residue is subjected to acid leaching to obtain a titanium-enriched product.

9. The method for recovering vanadium from titanium tetrachloride vanadium-removing slag according to claim 8, characterized in that: The acid solution for acid leaching includes: 0.5-2 mol / L hydrochloric acid solution.

10. A comprehensive utilization method of titanium tetrachloride vanadium removal slag, characterized in that: The invention comprises the method for recovering vanadium from titanium tetrachloride vanadium-removing slag as described in any one of claims 1 to 9.

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