Method for preparing vanadium-containing solution from vanadium-containing smelting slag

Abstract

The invention discloses a method for preparing a vanadium-containing solution from vanadium-containing smelting slag. The method for preparing the vanadium-containing solution from the vanadium-containing smelting slag comprises the steps that the vanadium-containing smelting slag and a calcium compound are mixed and roasted, and a calcium roasting product is obtained; leaching the calcified roasting product by adopting a hydrochloric acid solution to obtain an acid leaching solution; an oxidizing agent is added into the acid leaching solution for oxidation, and a pentavalent vanadium solution of an acid chloride system is obtained; extracting pentavalent vanadium by adopting an amide extraction solvent to obtain a vanadium-containing loaded organic phase; then washing the vanadium-containing loaded organic phase to obtain a washed vanadium-containing loaded organic phase; and the washed vanadium-containing loaded organic phase is subjected to back extraction through a back extraction agent, and a vanadium-containing solution is obtained. According to the method, the vanadium-containing smelting slag which is low in grade and difficult to use is subjected to the calcification roasting-acid leaching and solvent extraction coupling technology, the high-purity vanadium-containing solution is obtained, efficient utilization of resources is achieved, and the method has the advantages of being high in leaching rate, high in leaching speed, good in extraction selectivity, economical, environmentally friendly and the like.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal solid waste recycling. Specifically, this invention relates to a method for preparing vanadium-containing solutions from vanadium-containing smelting slag, and further, to a method for obtaining high-purity vanadium-containing solutions using low-grade, difficult-to-utilize vanadium-containing smelting slag as raw material. Background Technology

[0002] Vanadium is mainly used in improving the performance of steel and in emerging green energy storage fields. It is a strategic metal resource in my country. Efficiently extracting vanadium from vanadium-containing smelting slag can enhance the economic value of the entire industrial chain and is also a necessary requirement to ensure a stable supply of vanadium in my country. Sodium roasting-ammonium salt precipitation is currently the mainstream technology for recovering vanadium from vanadium-containing smelting slag. However, the roasting process generates highly corrosive and toxic waste gas and is prone to sintering. The leaching residue also contains a large amount of soluble sodium salts and residual heavy metals. Ammonium salt precipitation requires precise control of pH and valence state, making the process difficult to continue, and the precipitated products have low value. Summary of the Invention

[0003] This invention is based on the inventor's discovery and understanding of the following facts and problems: Sodium roasting-ammonium salt precipitation is currently the mainstream technology for recovering vanadium from vanadium-containing smelting slag. However, the roasting process generates highly corrosive and toxic waste gas and is prone to sintering. The leaching residue also contains a large amount of soluble sodium salt and residual heavy metals. Ammonium salt precipitation requires precise control of pH and valence state, the process is difficult to be continuous, and the value of the precipitated product is low.

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a method for preparing vanadium-containing solutions from vanadium-containing smelting slag. Using low-grade, difficult-to-utilize vanadium-containing smelting slag as raw material, a high-purity vanadium-containing solution is obtained through a coupled technology of calcination roasting-acid leaching and solvent extraction. This achieves efficient resource utilization and has advantages such as high leaching rate, fast leaching speed, good extraction selectivity, and economic and environmental benefits.

[0005] This invention provides a method for preparing a vanadium-containing solution from vanadium-containing smelting slag, comprising the following steps: (1) Mix vanadium-containing smelting slag and calcium compounds and roast them to obtain calcified roasted products; (2) The calcined product is leached with hydrochloric acid solution to obtain an acid leaching solution; (3) An oxidant is added to the acid leaching solution to oxidize it, thereby obtaining a pentavalent vanadium solution in an acidic chloride system; (4) The pentavalent vanadium in the pentavalent vanadium solution of the acidic chloride system is extracted with an amide-based extraction solvent to obtain a vanadium-supported organic phase; (5) Then the vanadium-loaded organic phase is washed to obtain the washed vanadium-loaded organic phase; the washed vanadium-loaded organic phase is back-extracted using a back-extraction agent to obtain a vanadium-containing solution.

[0006] The advantages and technical effects of the method for preparing vanadium-containing solution from vanadium-containing smelting slag in this invention embodiment are as follows: using low-grade, difficult-to-utilize vanadium-containing smelting slag as raw material, a high-purity vanadium-containing solution (vanadium-containing back-extraction liquid) is obtained through a coupling technology of calcination roasting-acid leaching and solvent extraction, realizing efficient utilization of resources, and having advantages such as high leaching rate, fast leaching speed, good extraction selectivity, and being economical and environmentally friendly.

[0007] In this embodiment of the invention, the method for obtaining a high-purity vanadium-containing solution by coupling vanadium-containing smelting slag calcination-acid leaching and solvent extraction uses vanadium-containing smelting slag generated during the smelting process as raw material. Calcium compounds are added and calcined at high temperature to obtain a calcination-roasting product. The calcination-roasting product is leached with hydrochloric acid solution, and an oxidant is added to convert vanadium to a higher valence state, resulting in a pentavalent vanadium solution in an acidic chloride system. The pentavalent vanadium is extracted in this system using an amide-based extraction solvent, and impurities are removed by washing the supported organic phase. The solution is then back-extracted to obtain a high-purity vanadium-containing solution. This method has advantages such as high leaching rate, fast leaching speed, good extraction selectivity, and is economical and environmentally friendly.

[0008] In some embodiments, in step (1), the vanadium-containing smelting slag includes at least one of vanadium slag, vanadium-titanium slag, and vanadium extraction tailings. And / or, before mixing, the vanadium-containing smelting slag is first ground and sieved; preferably, sieved using a 150-300 mesh screen; And / or, the calcium compound includes at least one of inorganic calcium compounds; preferably, the inorganic calcium compound includes at least one of calcium oxide, calcium carbonate, and calcium chloride; And / or, the mass ratio of the vanadium-containing smelting slag to the calcium compound is 100:10 to 50; And / or, the calcination temperature is 600 ℃~1100 ℃; And / or, the calcination time is 0.5 to 10 h.

[0009] In some embodiments, in step (2), the mass ratio of the hydrochloric acid solution to the calcined product is 300-1200:100; And / or, the hydrochloric acid solution contains 10% to 36% HCl by mass; And / or, the leaching temperature is 5–100 °C; And / or, the leaching time is 0.5 to 10 h.

[0010] In some embodiments, in step (3), the oxidant includes at least one of chlorates; preferably, the chlorate includes at least one of sodium chlorate, calcium chlorate, and magnesium chlorate; preferably, the molar ratio of chlorate ions to vanadium ions in the leaching solution is 0.4 to 1:1. And / or, the oxidation temperature is 5–100 °C; And / or, the oxidation time is 0.5 to 10 h; And / or, the oxidation is carried out under stirring.

[0011] In some embodiments, in step (4), the amide extraction solvent includes an amide extractant and a diluent; And / or, the extraction temperature is 5–95 °C; And / or, the extraction ratio O / A is 0.1 to 20; And / or, the extraction time is 1 to 60 min; And / or, the extraction method includes at least one of countercurrent extraction or cross-current extraction; And / or, the extraction stages are 1 to 25.

[0012] In some embodiments, in step (4), the amide extraction solvent contains 5% to 99% by mass of the amide extractant. And / or, in the amide extraction solvent, the mass percentage of the diluent is 1-95%; And / or, the amide extractant is at least one of organic compounds having an amide bond; And / or, the amide extractant includes a monodentate amide extractant; preferably, the amide extractant includes at least one of a primary amide extractant, a secondary amide extractant, and a tertiary amide extractant; And / or, the diluent includes at least one of organic solvents.

[0013] In some embodiments, the structural formula of the primary amide extractant in step (4) is as follows:

[0014] Wherein, R is selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic; And / or, the structural formula of the secondary amide extractant is shown below:

[0015] R1 and R2 are each independently selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic groups, and R1 and R2 may be the same or different; And / or, the structural formula of the tertiary amide extractant is shown below:

[0016] R1, R2 and R3 are each independently selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic groups, and at least two of R1, R2 and R3 are the same or all three are different; And / or, the organic solvent includes at least one of solvent oil, halogenated hydrocarbon compounds, and aromatic compounds.

[0017] In some embodiments, in step (5), a hydrochloric acid solution is used for washing; preferably, the mass percentage of HCl in the hydrochloric acid solution is 3% to 24%. And / or, the washing temperature is 5–95 °C; And / or, the washing ratio is 1 to 20 compared to O / A; And / or, the washing time is 1 to 60 minutes; And / or, the washing method includes at least one of countercurrent washing or crosscurrent washing; And / or, the washing level is 1 to 20.

[0018] In some embodiments, in step (5), a vanadium-containing solution and an organic phase after back-extraction are obtained after back-extraction; And / or, the back-extraction agent includes at least one of water, ammonium carbonate, ammonium bicarbonate, ammonia, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, potassium bicarbonate, and potassium hydroxide solution; And / or, the pH of the back-extraction agent is 7–12; And / or, the temperature of the back-extraction is 5–95 °C; And / or, the O / A ratio for back-extraction is 0.1 to 20; And / or, the back-extraction time is 1 to 60 min; And / or, the back-extraction method includes at least one of countercurrent back-extraction or cross-current back-extraction; And / or, the number of back-extraction stages is 1 to 15.

[0019] In some embodiments, the back-extracted organic phase is regenerated using hydrochloric acid solution to obtain a regenerated organic phase; Preferably, the hydrochloric acid solution contains 3% to 24% HCl by mass. Preferably, the regeneration temperature is 5–95°C; Preferably, the regeneration ratio O / A is 1 to 20; Preferably, the regeneration time is 1 to 60 minutes; Preferably, the regeneration method includes at least one of countercurrent regeneration or crosscurrent regeneration; Preferably, the number of regeneration stages is 1 to 20; Preferably, the regenerated organic phase is recycled during extraction. Attached Figure Description

[0020] Figure 1 These are the XRD patterns of vanadium-titanium slag and vanadium-titanium slag after calcination roasting in Example 1 of this invention.

[0021] Figure 2 These are the infrared spectra of vanadium-titanium slag and vanadium-titanium slag after calcination roasting in Example 1 of this invention.

[0022] Figure 3 The infrared spectra of the blank extraction solvent and the vanadium-containing supported organic phase (extraction solvent after extraction) in Example 5 of this invention are shown. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] A method for preparing a vanadium-containing solution from vanadium-containing smelting slag according to an embodiment of the present invention includes the following steps: (1) Mix vanadium-containing smelting slag and calcium compounds and roast them to obtain calcified roasted products; (2) The calcined product is leached with hydrochloric acid solution to obtain an acid leaching solution; (3) An oxidant is added to the acid leaching solution to oxidize it, thereby obtaining a pentavalent vanadium solution in an acidic chloride system; (4) The pentavalent vanadium in the pentavalent vanadium solution of the acidic chloride system is extracted with an amide-based extraction solvent to obtain a vanadium-supported organic phase; (5) Then the vanadium-loaded organic phase is washed to obtain the washed vanadium-loaded organic phase; the washed vanadium-loaded organic phase is back-extracted using a back-extraction agent to obtain a vanadium-containing solution.

[0025] The method for preparing vanadium-containing solution from vanadium-containing smelting slag in this invention uses low-grade, difficult-to-utilize vanadium-containing smelting slag as raw material. Through a coupled technology of calcination roasting-acid leaching and solvent extraction, a high-purity vanadium-containing solution is obtained, achieving efficient utilization of resources. It has the advantages of high leaching rate, fast leaching speed, good extraction selectivity, and being economical and environmentally friendly.

[0026] In this embodiment of the invention, the method for obtaining a high-purity vanadium-containing solution by coupling vanadium-containing smelting slag calcination-acid leaching and solvent extraction uses vanadium-containing smelting slag generated during the smelting process as raw material. Calcium compounds are added and calcined at high temperature to obtain a calcination-roasting product. The calcination-roasting product is leached with hydrochloric acid solution, and an oxidant is added to convert vanadium to a higher valence state, resulting in a pentavalent vanadium solution in an acidic chloride system. The pentavalent vanadium is extracted in this system using an amide-based extraction solvent, and impurities are removed by washing the supported organic phase. The solution is then back-extracted to obtain a high-purity vanadium-containing solution. This method has advantages such as high leaching rate, fast leaching speed, good extraction selectivity, and is economical and environmentally friendly.

[0027] In some embodiments, in step (1), the present invention does not have any special restrictions on vanadium-containing smelting slag, and any vanadium-containing smelting slag produced during the smelting process is acceptable. For example, the vanadium-containing smelting slag includes at least one of vanadium slag, vanadium-titanium slag, and vanadium extraction tailings.

[0028] In some embodiments, in step (1), the vanadium-containing smelting slag is first ground and sieved before mixing; optionally, grinding equipment is used for grinding, the grinding equipment including at least one of rod mill, ball mill or roller press; optionally, sieving is performed using a 150-300 mesh screen; optionally, vanadium-containing smelting slag of 150-300 mesh or less is mixed with calcium compounds.

[0029] In some embodiments, in step (1), the vanadium-containing smelting slag and calcium compound are mixed using a mixing device; the mixing device includes at least one of a container rotary mixer, a container stationary mixer, and an airflow mixer.

[0030] In some embodiments, in step (1), the calcium compound includes at least one of inorganic calcium compounds; preferably, the inorganic calcium compound includes at least one of calcium oxide, calcium carbonate, and calcium chloride.

[0031] In some embodiments, in step (1), the mass ratio of the vanadium-containing smelting slag to the calcium compound is 100:10 to 50 (e.g., 10, 20, 30, 40, 50), that is, the amount of calcium compound used is 10 g to 50 g per 100 g of vanadium-containing smelting slag.

[0032] In some embodiments, in step (1), the calcination temperature is 600 ℃ to 1100 ℃, specifically, for example, 600 ℃, 700 ℃, 800 ℃, 900 ℃, 1000 ℃, 1100 ℃; the calcination time is 0.5 to 10 h, specifically, for example, 0.5 h, 1 h, 2 h, 5 h, 8 h, 10 h.

[0033] In some embodiments, in step (2), the calcined product is leached with hydrochloric acid solution to obtain an acid leaching solution; Optionally, the mass ratio of the hydrochloric acid solution to the calcined product is 300–1200 (e.g., 300, 400, 500, 600, 800, 1000, 1200):100, that is, the amount of hydrochloric acid solution used is 300 g to 1200 g per 100 g of calcined product. Optionally, the mass percentage of HCl in the hydrochloric acid solution is 10% to 36%, specifically, for example, 10%, 20%, 30%, 36%. Optionally, the leaching temperature is 5–100 °C, specifically, for example, 5 °C, 25 °C, 30 °C, 50 °C, 100 °C; the leaching time is 0.5–10 h, specifically, for example, 0.5 h, 1 h, 2 h, 5 h, 8 h, 10 h.

[0034] In this embodiment of the invention, hydrochloric acid solution is used as the acid leaching agent to form an acidic chloride system.

[0035] In some embodiments, in step (3), an oxidant is added to the acid leaching solution for oxidation to obtain a pentavalent vanadium solution in an acidic chloride system; Optionally, the oxidant includes at least one of chlorates; optionally, the chlorate includes at least one of sodium chlorate, calcium chlorate, and magnesium chlorate; optionally, the molar ratio of chlorate ions to vanadium ions in the acid leaching solution of the chlorate is 0.4 to 1 (e.g., 0.4, 0.5, 0.6, 0.8, 1):1. Optionally, the oxidation temperature is 5–100 °C, specifically, for example, 5 °C, 25 °C, 30 °C, 50 °C, 100 °C; the oxidation time is 0.5–10 h, specifically, for example, 0.5 h, 1 h, 2 h, 5 h, 8 h, 10 h; the oxidation is carried out under stirring.

[0036] In this embodiment of the invention, vanadium in the acid leaching solution is converted to a higher valence state by an oxidizing agent to obtain a pentavalent vanadium solution in an acidic chloride system. To obtain a pentavalent vanadium solution and maintain the chloride system, a chlorate is used as the oxidizing agent, as chlorates have the ability to oxidize low-valence vanadium to pentavalent vanadium.

[0037] In some embodiments, in step (4), the amide extraction solvent includes an amide extractant and a diluent; Optionally, the amide extraction solvent consists of an amide extractant and a diluent; Optionally, the amide extractant is at least one of organic compounds having an amide bond; optionally, the amide extractant includes a monodentate amide extractant; preferably, the amide extractant includes at least one of a primary amide extractant, a secondary amide extractant, and a tertiary amide extractant. Optionally, the structural formula of the primary amide extractant is shown below:

[0038] Wherein, R is selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic; Optionally, the structural formula of the secondary amide extractant is shown below:

[0039] R1 and R2 are each independently selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic groups, and R1 and R2 may be the same or different; Optionally, the structural formula of the tertiary amide extractant is shown below:

[0040] R1, R2 and R3 are each independently selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic groups, and at least two of R1, R2 and R3 are the same or all three are different, that is, R1, R2 and R3 can be the same substituent or different substituents; Optionally, the heteroatomic alkyl group includes an alkoxy group; Optionally, the amide extractant includes , , , , At least one of them; Optionally, the diluent includes at least one of the following organic solvents: the organic solvent includes a low water-soluble inert organic solvent; the organic solvent includes at least one of the following: solvent oil, halogenated hydrocarbon compound, and aromatic compound. Optionally, the diluent includes at least one selected from 1-chlorooctane, 1,2-dichloroethane, toluene, D100 solvent oil, D80 solvent oil, and p-xylene; Optionally, in the amide extraction solvent, the mass percentage of the amide extractant is 5% to 99% (e.g., 5%, 10%, 20%, 50%, 80%, 99%), and in the amide extraction solvent, the mass percentage of the diluent is 1% to 95% (e.g., 1%, 10%, 20%, 50%, 80%, 95%).

[0041] In some embodiments, in step (4), pentavalent vanadium in the pentavalent vanadium solution of the acidic chloride system is extracted with an amide-based extraction solvent to obtain a vanadium-supported organic phase; Optionally, the extraction temperature is 5–95 °C, specifically, for example, 5 °C, 25 °C, 30 °C, 50 °C, 95 °C; the extraction ratio O / A is 0.1–20, specifically, for example, 0.1, 1, 5, 10, 20; the extraction time is 1–60 min, specifically, for example, 1 min, 10 min, 30 min, 60 min; the extraction method includes at least one of countercurrent extraction or cross-current extraction; the number of extraction stages is 1–25, specifically, for example, 1, 5, 10, 25.

[0042] In some embodiments, in step (5), the vanadium-supported organic phase is then washed to obtain a washed vanadium-supported organic phase; Optionally, a hydrochloric acid solution is used for washing; optionally, the mass percentage of HCl in the hydrochloric acid solution is 3% to 24%, specifically, for example, 3%, 10%, 20%, or 24%. Optionally, the washing temperature is 5–95 °C, specifically, for example, 5 °C, 25 °C, 30 °C, 50 °C, 95 °C; the washing ratio O / A is 1–20, specifically, for example, 1, 5, 10, 20; the washing time is 1–60 min, specifically, for example, 1 min, 10 min, 30 min, 60 min; the washing method includes at least one of countercurrent washing or crosscurrent washing; the number of washing levels is 1–20, specifically, for example, 1, 5, 10, 20.

[0043] In this embodiment of the invention, impurities are removed by washing.

[0044] In some embodiments, in step (5), the washed vanadium-loaded organic phase is back-extracted using a back-extraction agent to obtain a vanadium-containing solution; specifically, the back-extraction yields a vanadium-containing solution and a back-extracted organic phase. Optionally, the stripping agent comprises at least one selected from water, ammonium carbonate, ammonium bicarbonate, ammonia, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, potassium bicarbonate, and potassium hydroxide solution; alternatively, the stripping agent comprises at least one selected from water, ammonium carbonate solution, ammonium bicarbonate solution, ammonia, sodium carbonate solution, sodium bicarbonate solution, sodium hydroxide solution, potassium carbonate solution, potassium bicarbonate solution, and potassium hydroxide solution; the solution comprises an aqueous solution; the pH of the stripping agent is 7-12, specifically, for example, 7, 8, 9, 10, 11, or 12; Optionally, the back-extraction temperature is 5–95 °C, specifically, for example, 5 °C, 25 °C, 30 °C, 50 °C, 95 °C; the back-extraction ratio O / A is 0.1–20, specifically, for example, 0.1, 1, 5, 10, 20; the back-extraction time is 1–60 min, specifically, for example, 1 min, 10 min, 30 min, 60 min; the back-extraction method includes at least one of countercurrent back-extraction or cross-current back-extraction; the number of back-extraction stages is 1–15, specifically, for example, 1, 5, 10, 15.

[0045] In some embodiments, the back-extracted organic phase is regenerated using hydrochloric acid solution to obtain a regenerated organic phase; Optionally, the mass percentage of HCl in the hydrochloric acid solution is 3% to 24%, specifically, for example, 3%, 10%, 20%, 24%. Optionally, the regeneration temperature is 5–95°C, specifically, for example, 5°C, 25°C, 30°C, 50°C, 95°C; the regeneration ratio O / A is 1–20, specifically, for example, 1, 5, 10, 20; the regeneration time is 1–60 min, specifically, for example, 1 min, 10 min, 30 min, 60 min; the regeneration method includes at least one of countercurrent regeneration or crosscurrent regeneration; the number of regeneration stages is 1–20, specifically, for example, 1, 5, 10, 20. Optionally, the regenerated organic phase is recycled during extraction.

[0046] In some embodiments, a method for preparing a vanadium-containing solution from vanadium-containing smelting slag includes the following steps: 1) Grinding and screening vanadium-containing smelting slag: The vanadium-containing smelting slag is thoroughly ground using grinding equipment and then screened using a 150-300 mesh screen; 2) Calcification roasting of vanadium-containing smelting slag: Weigh the sieve material obtained in step 1), mix it with at least one of the inorganic calcium compounds such as calcium oxide, calcium carbonate and calcium chloride per 100 g of vanadium-containing smelting slag using a mixing device, roast at a temperature of 600 ℃ to 1100 ℃ for 0.5 to 10 h to obtain the calcification roasting product; 3) Leaching of calcined roasted product: Weigh the calcined roasted product obtained in step 2), use hydrochloric acid solution as the acid leaching agent, add 300 g to 1200 g of hydrochloric acid solution per 100 g of calcined roasted product, the mass percentage of HCl in the hydrochloric acid solution is 10% to 36%, the leaching temperature is 5 to 100 ℃, and the time is 0.5 to 10 h to obtain acid leaching solution; 4) Pre-oxidation of acid leaching solution: Take the acid leaching solution obtained in step 3), add at least one of sodium chlorate, calcium chlorate and magnesium chlorate, etc., according to the molar ratio of chlorate to vanadium ions of 0.4 to 1, and stir. The stirring temperature is 5 to 100 °C and the stirring time is 0.5 to 10 h to obtain a pentavalent vanadium solution in an acidic chloride system. 5) Preparation of extraction solvent: The extraction solvent consists of an amide extractant and a diluent. The amide extractant includes at least one of monodentate amide extractants such as primary amide extractants, secondary amide extractants, and tertiary amide extractants. The diluent includes at least one of low water-soluble inert organic solvents. The two are mixed to form the extraction solvent as the organic phase. The mass percentage of the amide extractant is 5% to 99%, and the mass percentage of the diluent is 1% to 95%. 6) Vanadium extraction: Take the extraction solvent from step 5) to extract the pentavalent vanadium solution from the acidic chloride system in step 4). The extraction temperature is 5–95 °C, the phase O / A ratio is 0.1–20, the extraction time is 1–60 min, the extraction method is countercurrent extraction or cross-current extraction, and the number of extraction stages is 1–25 to obtain a vanadium-loaded organic phase. 7) Washing and back-extraction of vanadium-supported organic phase: Wash the vanadium-supported organic phase obtained in step 6) with hydrochloric acid solution. The mass percentage of HCl in the hydrochloric acid solution is 3% to 24%, the washing temperature is 5 to 95 ℃, the washing phase O / A ratio is 1 to 20, the washing time is 1 to 60 min, the washing method is countercurrent washing or cross-current washing, and the number of washing stages is 1 to 20, to obtain the washed organic phase; The vanadium-loaded organic phase after back-extraction and washing is subjected to a back-extraction solution with a pH of 7–12, a back-extraction temperature of 5–95 °C, a back-extraction phase O / A ratio of 0.1–20, a back-extraction time of 1–60 min, and either countercurrent or cross-current back-extraction. The number of back-extraction stages is 1–15, resulting in a high-purity vanadium-containing solution and the back-extracted organic phase. 8) Regeneration of extraction solvent: Take hydrochloric acid solution to regenerate the back-extracted organic phase obtained in step 7). The mass percentage of HCl in the hydrochloric acid solution is 3% to 24%. The regeneration temperature is 5 to 95°C. The regeneration phase O / A ratio is 1 to 20. The regeneration time is 1 to 60 min. The regeneration method is countercurrent regeneration or cross-current regeneration. The number of regeneration stages is 1 to 20. The regenerated organic phase is then recycled in step 6).

[0047] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0048] Example 1 A method for preparing a vanadium-containing solution from vanadium-containing smelting slag includes the following steps: 1) Grinding and screening vanadium-containing smelting slag: The vanadium-titanium slag is thoroughly ground using a ball mill and then screened using a 300-mesh sieve; 2) Calcification roasting of vanadium-containing smelting slag: Weigh the sieved material obtained in step 1), mix it with 40g of calcium oxide per 100g of vanadium-titanium slag using a rotary mixer, and roast at 900℃ for 1 h to obtain calcified roasted vanadium-titanium slag; the XRD patterns of the vanadium-titanium slag and the calcified roasted vanadium-titanium slag are shown below. Figure 1 As shown, the infrared spectra of vanadium-titanium slag and calcined roasted vanadium-titanium slag are as follows: Figure 2 As shown; 3) Leaching of calcified roasted product: Weigh the calcified roasted vanadium-titanium slag obtained in step 2), use hydrochloric acid solution as acid leaching agent, add 700 g of hydrochloric acid solution per 100 g of calcified roasted vanadium-titanium slag, the mass ratio of HCl in the hydrochloric acid solution is 20%, the leaching temperature is 85 ℃, and the time is 2 h to obtain acid leaching solution. 4) Pre-oxidation of acid leaching solution: Take the acid leaching solution obtained in step 3), add sodium chlorate at a molar ratio of chlorate to vanadium ions of 0.6, stir at 75 ℃ for 2 h to obtain a pentavalent vanadium solution in an acidic chloride system. 5) Preparation of the extraction solvent: The extraction solvent consists of an amide extractant and a diluent. The amide extractant is... The diluent is 1-chlorooctane, and the two are mixed to form the extraction solvent as the organic phase. The mass ratio of the amide extractant is 20%, and the mass ratio of 1-chlorooctane is 80%. 6) Vanadium extraction: Take the extraction solvent from step 5) to extract the pentavalent vanadium solution from the acidic chloride system in step 4). The extraction temperature is 25 °C, the phase O / A ratio is 2, the extraction time is 12 min, the extraction method is countercurrent extraction, and the extraction stage is 6 stages to obtain a vanadium-loaded organic phase. 7) Washing and back-extraction of vanadium-supported organic phase: Wash the vanadium-supported organic phase obtained in step 6) with hydrochloric acid solution. The mass percentage of HCl in the hydrochloric acid solution is 15%, the washing temperature is 65 ℃, the washing ratio of O / A is 3, the washing time is 8 min, the washing method is cross-flow washing, and the number of washing stages is 3, to obtain the washed organic phase. The vanadium-loaded organic phase after back-extraction and washing was treated with potassium carbonate solution as the back-extraction agent, pH 8, back-extraction temperature 65℃, back-extraction phase O / A ratio 8, back-extraction time 30 min, cross-flow back-extraction method, and 4 back-extraction stages. High-purity vanadium-containing solution and back-extracted organic phase were obtained, with a total vanadium recovery rate of 95.2%. 8) Regeneration of extraction solvent: Take hydrochloric acid solution to regenerate the back-extracted organic phase obtained in step 7). The hydrochloric acid solution contains 5% HCl by mass, the regeneration temperature is 15 ℃, the regeneration phase O / A ratio is 8, the regeneration time is 22 min, the regeneration method is cross-flow regeneration, and the number of regeneration stages is 10. The regenerated organic phase is obtained and recycled in step 6).

[0049] Example 2 A method for preparing a vanadium-containing solution from vanadium-containing smelting slag includes the following steps: 1) Grinding and screening vanadium-containing smelting slag: The vanadium extraction tailings are thoroughly ground by a roller press and then screened using a 150-mesh screen; 2) Calcification roasting of vanadium-containing smelting slag: Weigh the sieve material obtained in step 1), mix it with 20g of calcium chloride per 100g of vanadium extraction tailings using a container rotary mixer, roast at 700℃ for 5 h to obtain calcified roasted vanadium extraction tailings. 3) Leaching of calcified roasting products: Weigh the calcified roasting vanadium extraction tailings obtained in step 2), use hydrochloric acid solution as the acid leaching agent, add 800 g of hydrochloric acid solution per 100 g of calcified roasting vanadium extraction tailings, the mass ratio of HCl in the hydrochloric acid solution is 30%, the leaching temperature is 70 ℃, and the time is 6 h to obtain the acid leaching solution. 4) Pre-oxidation of acid leaching solution: Take the acid leaching solution obtained in step 3), add sodium chlorate and calcium chlorate (mass ratio of sodium chlorate to calcium chlorate is 40:60) at a molar ratio of chlorate to vanadium ions of 0.55, stir at a stirring temperature of 75 ℃ for 4 h to obtain a pentavalent vanadium solution in an acidic chloride system. 5) Preparation of the extraction solvent: The extraction solvent consists of an amide extractant and a diluent. The amide extractant is... The diluent is 1,2-dichloroethane, and the two are mixed to form the extraction solvent as the organic phase. The mass ratio of the amide extractant is 50%, and the mass ratio of the diluent is 50%. 6) Vanadium extraction: Take the extraction solvent from step 5) to extract the pentavalent vanadium solution from the acidic chloride system in step 4). The extraction temperature is 40 °C, the phase O / A ratio is 16, the extraction time is 45 min, the extraction method is cross-flow extraction, and the extraction stage is 7 stages to obtain a vanadium-loaded organic phase. 7) Washing and back-extraction of vanadium-supported organic phase: Wash the vanadium-supported organic phase obtained in step 6) with hydrochloric acid solution. The mass percentage of HCl in the hydrochloric acid solution is 16%, the washing temperature is 70 ℃, the washing ratio of O / A is 15, the washing time is 40 min, the washing method is cross-flow washing, and the washing stage is 11 stages to obtain the washed organic phase. The vanadium-loaded organic phase after back-extraction and washing was treated with sodium hydroxide solution at pH 10, at a temperature of 60 °C, with an O / A ratio of 7, a back-extraction time of 40 min, and a countercurrent back-extraction method with 12 stages. This yielded a high-purity vanadium-containing solution and the back-extracted organic phase, with a total vanadium recovery rate of 91.4%. 8) Regeneration of extraction solvent: Take hydrochloric acid solution to regenerate the back-extracted organic phase obtained in step 7). The HCl mass ratio in the hydrochloric acid solution is 10%, the regeneration temperature is 20 ℃, the regeneration phase O / A ratio is 13, the regeneration time is 50 min, the regeneration method is cross-flow regeneration, and the number of regeneration stages is 3. The regenerated organic phase is obtained and recycled in step 6).

[0050] Example 3 A method for preparing a vanadium-containing solution from vanadium-containing smelting slag includes the following steps: 1) Grinding and screening vanadium-containing smelting slag: The vanadium slag is thoroughly ground using a ball mill and then screened using a 200-mesh sieve; 2) Calcification roasting of vanadium-containing smelting slag: Weigh the sieve material obtained in step 1), mix it with 35g of calcium carbonate and calcium chloride per 100g of vanadium slag (the mass ratio of calcium carbonate to calcium chloride is 10:90) using a container-fixed mixer, roast at 650℃ for 4.5 h to obtain calcified roasted vanadium slag. 3) Leaching of calcified roasted vanadium slag obtained in step 2): Weigh the calcified roasted vanadium slag obtained in step 2), use hydrochloric acid solution as the acid leaching agent, add 900 g of hydrochloric acid solution per 100 g of calcified roasted vanadium slag, the mass ratio of HCl in the hydrochloric acid solution is 18%, the leaching temperature is 45 ℃, and the time is 3 h to obtain the acid leaching solution. 4) Pre-oxidation of acid leaching solution: Take the acid leaching solution obtained in step 3), add calcium chlorate at a molar ratio of chlorate to vanadium ions of 0.8, stir at 60 ℃ for 7 h to obtain a pentavalent vanadium solution in an acidic chloride system. 5) Preparation of the extraction solvent: The extraction solvent consists of an amide extractant and a diluent. The amide extractant is... The diluent is toluene, the mass percentage of the amide extractant is 60%, and the mass percentage of the diluent is 40%. 6) Vanadium extraction: Take the extraction solvent from step 5) to extract the pentavalent vanadium solution from the acidic chloride system in step 4). The extraction temperature is 15 °C, the ratio of O / A is 0.5, the extraction time is 15 min, the extraction method is cross-flow extraction, and the number of extraction stages is 12, to obtain a vanadium-loaded organic phase. 7) Washing and back-extraction of vanadium-supported organic phase: Wash the vanadium-supported organic phase obtained in step 6) with hydrochloric acid solution. The mass percentage of HCl in the hydrochloric acid solution is 12%, the washing temperature is 55 ℃, the washing ratio of O / A is 7, the washing time is 35 min, the washing method is cross-flow washing, and the number of washing stages is 5, to obtain the washed organic phase. The vanadium-loaded organic phase after back-extraction and washing was used as the back-extraction agent solution, which was a mixed solution of sodium carbonate and sodium bicarbonate (mass ratio of sodium carbonate to sodium bicarbonate 70:30), with a pH of 10.5. The back-extraction temperature was 35 ℃, the O / A ratio of the back-extraction phase was 14, the back-extraction time was 45 min, the back-extraction method was countercurrent back-extraction, and the number of back-extraction stages was 5. A high-purity vanadium-containing solution and the back-extracted organic phase were obtained, with a total vanadium recovery rate of 91.8%. 8) Regeneration of extraction solvent: Take hydrochloric acid solution to regenerate the back-extracted organic phase obtained in step 7). The HCl mass ratio in the hydrochloric acid solution is 21%, the regeneration temperature is 80℃, the O / A ratio in the regeneration phase is 16, the regeneration time is 50 min, the regeneration method is cross-flow regeneration, and the number of regeneration stages is 5. The regenerated organic phase is obtained and recycled in step 6).

[0051] Example 4 A method for preparing a vanadium-containing solution from vanadium-containing smelting slag includes the following steps: 1) Grinding and screening vanadium-containing smelting slag: The vanadium slag is thoroughly ground using a rod mill and then screened using a 150-mesh sieve; 2) Calcification roasting of vanadium-containing smelting slag: Weigh the sieve material obtained in step 1), mix it with 45 g of calcium chloride per 100 g of vanadium slag using an airflow mixer, and roast at 1050 ℃ for 6.5 h to obtain calcified roasted vanadium slag. 3) Leaching of calcified roasted vanadium slag obtained in step 2): Weigh the calcified roasted vanadium slag obtained in step 2), use hydrochloric acid solution as the acid leaching agent, add 1000 g of hydrochloric acid solution per 100 g of calcified roasted vanadium slag, the mass percentage of HCl in the hydrochloric acid solution is 22%, the leaching temperature is 85 ℃, and the time is 3 h to obtain the acid leaching solution. 4) Pre-oxidation of acid leaching solution: Take the acid leaching solution obtained in step 3), add magnesium chlorate at a molar ratio of chlorate to vanadium ions of 1, stir at a stirring temperature of 55 ℃ for 6 h to obtain a pentavalent vanadium solution in an acidic chloride system. 5) Preparation of the extraction solvent: The extraction solvent consists of an amide extractant and a diluent. The amide extractant is... The diluent is D100 solvent oil, and the two are mixed to form the extraction solvent as the organic phase. The mass ratio of the amide extractant is 20%, and the mass ratio of the diluent is 80%. 6) Vanadium extraction: Take the extraction solvent from step 5) to extract the pentavalent vanadium solution from the acidic chloride system in step 4). The extraction temperature is 75 °C, the phase O / A ratio is 1, the extraction time is 50 min, the extraction method is cross-flow extraction, and the extraction stage is 6 stages to obtain a vanadium-loaded organic phase. 7) Washing and back-extraction of vanadium-supported organic phase: Wash the vanadium-supported organic phase obtained in step 6) with hydrochloric acid solution. The mass percentage of HCl in the hydrochloric acid solution is 10%, the washing temperature is 15 ℃, the washing ratio of O / A is 8, the washing time is 50 min, the washing method is countercurrent washing, and the washing stage is 12 stages to obtain the washed organic phase. The vanadium-loaded organic phase after back-extraction and washing was subjected to ammonia solution as the back-extraction agent, with a pH of 11. The back-extraction temperature was 30℃, the O / A ratio of the back-extraction phase was 16, the back-extraction time was 45 min, the back-extraction method was cross-flow back-extraction, and the number of back-extraction stages was 4. A high-purity vanadium-containing solution and the back-extracted organic phase were obtained, with a total vanadium recovery rate of 90.8%. 8) Regeneration of extraction solvent: Take hydrochloric acid solution to regenerate the back-extracted organic phase obtained in step 7). The HCl mass ratio in the hydrochloric acid solution is 16%, the regeneration temperature is 70 ℃, the regeneration phase O / A ratio is 7, the regeneration time is 50 min, the regeneration method is cross-flow regeneration, and the number of regeneration stages is 8. The regenerated organic phase is obtained and recycled in step 6).

[0052] Example 5 A method for preparing a vanadium-containing solution from vanadium-containing smelting slag includes the following steps: 1) Grinding and screening vanadium-containing smelting slag: The vanadium-titanium slag is thoroughly ground by passing it through a roller press and a ball mill, and then screened using a 250-mesh screen; 2) Calcification roasting of vanadium-containing smelting slag: Weigh the sieve material obtained in step 1), mix it with 25g of calcium oxide per 100g of vanadium-titanium slag using a container rotary mixer, and roast at 950℃ for 8 hours to obtain calcified roasted vanadium-titanium slag. 3) Leaching of calcified roasted product: Weigh the calcified roasted vanadium-titanium slag obtained in step 2), use hydrochloric acid solution as the acid leaching agent, add 1000 g of hydrochloric acid solution per 100 g of calcified roasted vanadium-titanium slag, the mass ratio of HCl in the hydrochloric acid solution is 30%, the leaching temperature is 90 ℃, and the time is 7.5 h to obtain acid leaching solution. 4) Pre-oxidation of acid leaching solution: Take the acid leaching solution obtained in step 3), add calcium chlorate at a molar ratio of chlorate to vanadium ions of 0.8, stir at a stirring temperature of 95 ℃ for 1.5 h to obtain a pentavalent vanadium solution in an acidic chloride system. 5) Preparation of the extraction solvent: The extraction solvent consists of an amide extractant and a diluent. The amide extractant is... The diluent is D80 solvent oil, and the two are mixed to form the extraction solvent as the organic phase. The mass ratio of the amide extractant is 40%, and the mass ratio of the diluent is 60%. 6) Vanadium extraction: The extraction solvent from step 5) was used to extract the pentavalent vanadium solution from the acidic chloride system in step 4). The extraction temperature was 20 °C, the O / A ratio was 4, the extraction time was 35 min, the extraction method was cross-flow extraction, and the extraction stage was 10 stages, yielding a vanadium-loaded organic phase. The infrared spectra of the blank extraction solvent and the extracted vanadium-loaded organic phase (extraction solvent after extraction) are shown below. Figure 3 As shown; 7) Washing and back-extraction of vanadium-supported organic phase: Wash the vanadium-supported organic phase obtained in step 6) with hydrochloric acid solution. The mass percentage of HCl in the hydrochloric acid solution is 20%, the washing temperature is 80 ℃, the washing ratio of O / A is 6, the washing time is 50 min, the washing method is countercurrent washing, and the washing stage is 6 stages to obtain the washed organic phase. The vanadium-supported organic phase after back-extraction and washing was subjected to an ammonium carbonate solution with a pH of 9, a back-extraction temperature of 10℃, a back-extraction phase O / A ratio of 12, a back-extraction time of 45 min, a cross-flow back-extraction method, and a three-stage back-extraction process. This yielded a high-purity vanadium-containing solution and the back-extracted organic phase, with a total vanadium recovery rate of 94.6%. 8) Regeneration of extraction solvent: Take hydrochloric acid solution to regenerate the back-extracted organic phase obtained in step 7). The HCl mass ratio in the hydrochloric acid solution is 11%, the regeneration temperature is 30℃, the regeneration phase O / A ratio is 8, the regeneration time is 50 min, the regeneration method is cross-flow regeneration, and the number of regeneration stages is 12. The regenerated organic phase is obtained and recycled in step 6).

[0053] Example 6 A method for preparing a vanadium-containing solution from vanadium-containing smelting slag includes the following steps: 1) Grinding and screening vanadium-containing smelting slag: The vanadium extraction tailings are thoroughly ground using a rod mill and then screened using a 220-mesh sieve; 2) Calcification roasting of vanadium-containing smelting slag: Weigh the undersize obtained in step 1), and mix it with 40 g of calcium carbonate per 100 g of vanadium extraction tailings using a container rotary mixer and an airflow mixer. The roasting temperature is 1100 ℃ and the roasting time is 7 h to obtain calcified roasted vanadium extraction tailings. 3) Leaching of calcified roasting products: Weigh the calcified roasting vanadium extraction tailings obtained in step 2), use hydrochloric acid solution as the acid leaching agent, add 450 g of hydrochloric acid solution per 100 g of calcified roasting vanadium extraction tailings, the mass percentage of HCl in the hydrochloric acid solution is 12%, the leaching temperature is 85 ℃, and the time is 6.5 h to obtain the acid leaching solution. 4) Pre-oxidation of acid leaching solution: Take the acid leaching solution obtained in step 3), add sodium chlorate at a molar ratio of chlorate to vanadium ions of 0.85, stir at 90 ℃ for 3.5 h to obtain a pentavalent vanadium solution in an acidic chloride system. 5) Preparation of the extraction solvent: The extraction solvent consists of an amide extractant and a diluent. The amide extractant is... The diluent is p-xylene, the amide extractant accounts for 80% by mass, and the diluent accounts for 20% by mass. 6) Vanadium extraction: Take the extraction solvent from step 5) to extract the pentavalent vanadium solution from the acidic chloride system in step 4). The extraction temperature is 80 °C, the phase O / A ratio is 5, the extraction time is 20 min, the extraction method is countercurrent extraction, and the extraction stage is 12 stages to obtain a vanadium-loaded organic phase. 7) Washing and back-extraction of vanadium-supported organic phase: Wash the vanadium-supported organic phase obtained in step 6) with hydrochloric acid solution. The mass percentage of HCl in the hydrochloric acid solution is 10%, the washing temperature is 80 ℃, the washing ratio of O / A is 7, the washing time is 20 min, the washing method is cross-flow washing, and the number of washing stages is 2, to obtain the washed organic phase. The vanadium-loaded organic phase after back-extraction and washing was treated with potassium hydroxide solution at pH 11.5, at 80 °C, with an O / A ratio of 11, for 5 min. The back-extraction method was countercurrent back-extraction with four stages, resulting in a high-purity vanadium-containing solution and the back-extracted organic phase. The total vanadium recovery rate was 89.8%. 8) Regeneration of extraction solvent: Take hydrochloric acid solution to regenerate the back-extracted organic phase obtained in step 7). The HCl mass ratio in the hydrochloric acid solution is 10%, the regeneration temperature is 15 ℃, the regeneration phase O / A ratio is 8, the regeneration time is 50 min, the regeneration method is cross-flow regeneration, and the number of regeneration stages is 4. The regenerated organic phase is obtained and recycled in step 6).

[0054] In summary, the method of this invention can efficiently recover vanadium-containing smelting slag, including vanadium slag, vanadium-titanium slag, and vanadium extraction tailings, to produce high-purity vanadium-containing solutions, with a total vanadium recovery rate of not less than 89%.

[0055] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0056] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A method for preparing a vanadium-containing solution from vanadium-containing smelting slag, characterized in that, Includes the following steps: (1) Mix vanadium-containing smelting slag and calcium compounds and roast them to obtain calcified roasted products; (2) The calcined product is leached with hydrochloric acid solution to obtain an acid leaching solution; (3) An oxidant is added to the acid leaching solution to oxidize it, thereby obtaining a pentavalent vanadium solution in an acidic chloride system; (4) The pentavalent vanadium in the pentavalent vanadium solution of the acidic chloride system is extracted with an amide-based extraction solvent to obtain a vanadium-supported organic phase; (5) Then the vanadium-loaded organic phase is washed to obtain the washed vanadium-loaded organic phase; the washed vanadium-loaded organic phase is back-extracted using a back-extraction agent to obtain a vanadium-containing solution.

2. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 1, characterized in that, In step (1), the vanadium-containing smelting slag includes at least one of vanadium slag, vanadium-titanium slag, and vanadium extraction tailings. And / or, before mixing, the vanadium-containing smelting slag is first ground and sieved; preferably, sieved using a 150-300 mesh screen; And / or, the calcium compound includes at least one of inorganic calcium compounds; preferably, the inorganic calcium compound includes at least one of calcium oxide, calcium carbonate, and calcium chloride; And / or, the mass ratio of the vanadium-containing smelting slag to the calcium compound is 100:10 to 50; And / or, the calcination temperature is 600 ℃~1100 ℃; And / or, the calcination time is 0.5 to 10 h.

3. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 1, characterized in that, In step (2), the mass ratio of the hydrochloric acid solution to the calcined product is 300-1200:

100. And / or, the hydrochloric acid solution contains 10% to 36% HCl by mass; And / or, the leaching temperature is 5–100 °C; And / or, the leaching time is 0.5 to 10 h.

4. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 1, characterized in that, In step (3), the oxidant includes at least one of chlorates; preferably, the chlorate includes at least one of sodium chlorate, calcium chlorate, and magnesium chlorate; preferably, the molar ratio of chlorate ions to vanadium ions in the acid leaching solution is 0.4 to 1:

1. And / or, the oxidation temperature is 5–100 °C; And / or, the oxidation time is 0.5 to 10 h; And / or, the oxidation is carried out under stirring.

5. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 1, characterized in that, In step (4), the amide extraction solvent includes an amide extractant and a diluent; And / or, the extraction temperature is 5–95 °C; And / or, the extraction ratio O / A is 0.1 to 20; And / or, the extraction time is 1 to 60 min; And / or, the extraction method includes at least one of countercurrent extraction or cross-current extraction; And / or, the extraction stages are 1 to 25.

6. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 5, characterized in that, In step (4), the amide extraction solvent contains 5% to 99% by mass of the amide extractant. And / or, in the amide extraction solvent, the mass percentage of the diluent is 1-95%; And / or, the amide extractant is at least one of organic compounds having an amide bond; And / or, the amide extractant includes a monodentate amide extractant; preferably, the amide extractant includes at least one of a primary amide extractant, a secondary amide extractant, and a tertiary amide extractant; And / or, the diluent includes at least one of organic solvents.

7. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 6, characterized in that, In step (4), the structural formula of the primary amide extractant is as follows: Wherein, R is selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic; And / or, the structural formula of the secondary amide extractant is shown below: R1 and R2 are each independently selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic groups, and R1 and R2 may be the same or different; And / or, the structural formula of the tertiary amide extractant is shown below: R1, R2 and R3 are each independently selected from alkyl, aromatic, heteroatom-containing alkyl or heteroaromatic groups, and at least two of R1, R2 and R3 are the same or all three are different; And / or, the organic solvent includes at least one of solvent oil, halogenated hydrocarbon compounds, and aromatic compounds.

8. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 1, characterized in that, In step (5), a hydrochloric acid solution is used for washing; preferably, the mass percentage of HCl in the hydrochloric acid solution is 3% to 24%. And / or, the washing temperature is 5–95 °C; And / or, the washing ratio is 1 to 20 compared to O / A; And / or, the washing time is 1 to 60 minutes; And / or, the washing method includes at least one of countercurrent washing or crosscurrent washing; And / or, the washing level is 1 to 20.

9. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 1, characterized in that, In step (5), a vanadium-containing solution and an organic phase after back-extraction are obtained after back-extraction. And / or, the back-extraction agent includes at least one of water, ammonium carbonate, ammonium bicarbonate, ammonia, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, potassium bicarbonate, and potassium hydroxide solution; And / or, the pH of the back-extraction agent is 7–12; And / or, the temperature of the back-extraction is 5–95 °C; And / or, the O / A ratio for back-extraction is 0.1 to 20; And / or, the back-extraction time is 1 to 60 min; And / or, the back-extraction method includes at least one of countercurrent back-extraction or cross-current back-extraction; And / or, the number of back-extraction stages is 1 to 15.

10. The method for preparing vanadium-containing solution from vanadium-containing smelting slag according to claim 9, characterized in that, The extracted organic phase is regenerated using hydrochloric acid solution to obtain a regenerated organic phase; Preferably, the hydrochloric acid solution contains 3% to 24% HCl by mass. Preferably, the regeneration temperature is 5–95°C; Preferably, the regeneration ratio O / A is 1 to 20; Preferably, the regeneration time is 1 to 60 minutes; Preferably, the regeneration method includes at least one of countercurrent regeneration or crosscurrent regeneration; Preferably, the number of regeneration stages is 1 to 20; Preferably, the regenerated organic phase is recycled during extraction.

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