Method for removing impurities and extracting vanadium from vanadium slag lixivium

Abstract

The invention discloses a method for removing impurities and extracting vanadium from vanadium slag leachate, which comprises the following steps: S1, adding water and a leaching agent into calcified roasting vanadium slag clinker, and uniformly mixing to obtain first ore pulp; the leaching agent at least consists of 8-hydroxyquinoline, an EDTA (Ethylene Diamine Tetraacetic Acid) solution and acid liquor; s2, the pH value of the first ore pulp is adjusted to be 3-6, leaching is conducted under the preset leaching condition, and second ore pulp is obtained; and S3, the second ore pulp is filtered, and vanadium-containing leaching liquid and leaching residues are obtained. According to the method, impurity calcium ions and aluminum ions in the solution are complexed with 8-hydroxyquinoline to generate precipitates during leaching, so that the impurity ions are removed, the obtained leaching solution is low in impurity content and can be directly used for follow-up vanadium precipitation, calcium and aluminum precipitates are flocculent, vanadium leaching residues are granular, metals such as calcium and aluminum can be separated and recycled, and the method is suitable for industrial production. And the maximization of economic benefits is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of vanadium slag leaching, and particularly to a method for removing impurities and extracting vanadium from vanadium slag leaching solution. Background Art

[0002] Vanadium has many excellent physical and chemical properties and mechanical properties, and is widely used in modern industry. With the rapid development of China's modernization drive, the demand for vanadium and its compounds is increasing, and the requirements for high-purity vanadium and its compounds are getting higher and higher.

[0003] At present, most of the vanadium extraction processes from vanadium slag are roasting processes for recovering vanadium, mainly including sodium roasting and calcium roasting. Among them, sodium roasting accounts for more than 90% of the vanadium extraction capacity from vanadium slag, and it is the mainstream vanadium extraction process adopted by major vanadium compound manufacturers at home and abroad. The process uses sodium salts such as soda ash and salt as additives, and through high-temperature oxidation-sodium roasting, the multivalent vanadium in the vanadium-containing raw material is converted into water-soluble sodium salt of pentavalent vanadium. The roasted product is leached with water to obtain a leaching solution containing vanadium and a small amount of impurities. After the vanadium-containing leaching solution is purified, the solution is adjusted to a certain pH value and then ammonium salt is added to precipitate vanadium as ammonium polyvanadate. The ammonium salt is thermally decomposed to obtain vanadium pentoxide products. However, in this process, vanadium in vanadium slag mainly exists in the form of vanadium iron spinel structure, with stable chemical mineral phase and difficult to decompose, resulting in low leaching efficiency; vanadium slag contains more silicon-containing low-melting-point substances, and increasing the reaction temperature will lead to ring formation, making it difficult to improve the extraction rate of vanadium by increasing the temperature; at the same time, harmful kiln gas will be decomposed during the sodium roasting process.

[0004] To solve the problems such as furnace charge caking and ring formation existing in the sodium roasting process, domestic research is currently underway to break through the sodium roasting process. Among them, in the vanadium products factory constructed with the process of calcium roasting-acid leaching of vanadium slag, calcium roasting can avoid the sintering phenomenon of traditional sodium roasting, and no harmful gases such as Cl 2 and SO 2 are generated during the roasting process, resulting in less environmental pollution; the roasting aids used in calcium roasting (such as CaO, CaCO 3 etc.) have lower costs. Compared with the sodium salts used in sodium roasting, the cost of the vanadium extraction process can be reduced; calcium roasting can effectively convert the vanadium spinel in converter vanadium slag into calcium vanadate, and through the subsequent acid leaching process, the leaching rate of vanadium can be effectively improved.

[0005] However, the vanadium slag after calcium roasting is rich in a large amount of CaO and Al 2 O 3 . During the leaching process, due to poor leaching selectivity, impurities Ca and Al enter the solution along with V. The leaching of impurities not only affects the subsequent vanadium precipitation effect, but also the impurity content in the final product is high, resulting in poor market competitiveness. Moreover, calcium elements in the vanadium solution cannot be recovered, causing a large amount of calcium element loss, and the discharge of calcium-containing wastewater will cause significant pollution to the soil.

[0006] In view of this, improvements should be made to the existing technology. Summary of the Invention

[0007] The main object of the present invention is to provide a method for removing impurities and extracting vanadium from vanadium slag leaching solution. During leaching, impurity calcium ions and aluminum ions in the solution are complexed to form precipitates, thereby removing impurity ions. Therefore, the obtained leaching solution has a low impurity content and can be directly used for subsequent vanadium precipitation. Moreover, the calcium and aluminum precipitates are flocculent, and the vanadium leaching residue is granular, enabling the separation and recovery of metals such as calcium and aluminum, maximizing economic benefits.

[0008] According to one aspect of the present invention, a method for removing impurities and extracting vanadium from vanadium slag leaching solution is provided, which includes the following steps: S1. Add water and a leaching agent to calcined vanadium slag clinker, and mix evenly to obtain a first pulp; the leaching agent consists of at least 8-hydroxyquinoline, an EDTA solution, and an acid solution; S2. Adjust the pH value of the first pulp to 3 - 6, and perform leaching under predetermined leaching conditions to obtain a second pulp; S3. Filter the second pulp to obtain a vanadium-containing leaching solution and a leaching residue.

[0009] According to an embodiment of the present invention, the calcined vanadium slag clinker is prepared by the method of slag making through converter blowing of blast furnace molten iron.

[0010] According to an embodiment of the present invention, the calcined vanadium slag clinker contains V 2 O 5 : 11 - 12 wt%, CaO: 8 - 9 wt%, Al 2 O 3 : 5 - 6 wt%.

[0011] According to an embodiment of the present invention, before step S1, the method further includes: grinding the calcined vanadium slag clinker to a particle size such that the portion less than 0.07 mm accounts for more than 80 wt%.

[0012] According to an embodiment of the present invention, the leaching agent consists of at least 8-hydroxyquinoline with a purity of 98 - 99%, an EDTA solution with a concentration of 0.04 - 0.06 mol / L, and a sulfuric acid solution with a concentration of 0.04 - 0.06 mol / L.

[0013] According to an embodiment of the present invention, the mass ratio of 8-hydroxyquinoline with a purity of 98 - 99%, the EDTA solution, and the sulfuric acid solution is 5:2:(10 - 20).

[0014] According to an embodiment of the present invention, the addition amount of the leaching agent is 10 - 18 wt% of the calcined vanadium slag clinker.

[0015] According to an embodiment of the present invention, adjusting the pH value of the pulp includes adding an acidic solution and / or an alkaline solution and / or a buffer solution to adjust the pH value of the pulp, and then stirring and leaching at 60-90°C for 30-90 minutes.

[0016] According to an embodiment of the present invention, the predetermined adjusted leaching conditions include that the range of the leaching stirring rate is 400-800 r / min.

[0017] According to an embodiment of the present invention, filtration includes rinsing with an EDTA solution as a washing agent.

[0018] In a method for removing impurities and extracting vanadium from a vanadium slag leaching solution according to an embodiment of the present invention, impurities such as calcium ions and aluminum ions in the solution are complexed to form precipitates during leaching, thereby removing the impurity ions. Therefore, the obtained leaching solution has a low impurity content and can be directly used for subsequent vanadium precipitation. Moreover, the calcium and aluminum precipitates are flocculent, and the vanadium leaching residue is granular, so metals such as calcium and aluminum can be separated and recovered, maximizing the economic benefits. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 Shows a process flow diagram of a method for removing impurities and extracting vanadium from a vanadium slag leaching solution according to an exemplary embodiment of the present invention; Figure 2 Shows another process flow diagram of a method for removing impurities and extracting vanadium from a vanadium slag leaching solution according to an exemplary embodiment of the present invention. Detailed Description of the Embodiments

[0021] The following detailed description of the embodiments is used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention. The present invention can be implemented in many different forms, not limited to the specific embodiments disclosed herein, but including all technical solutions falling within the scope of the claims.

[0022] The present invention provides these embodiments to make the present disclosure thorough and complete, and to fully convey the scope of the present invention to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangements of the components and steps, the components of the materials, the numerical expressions and values described in these embodiments should be interpreted as merely exemplary, rather than as limitations.

[0023] It should be noted that in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is greater than or equal to two; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", etc. is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0024] It should also be noted that in the description of the present invention, unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. When it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0025] All terms used in the present invention have the same meanings as those understood by ordinary skilled artisans in the field to which the present disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as those, should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless specifically defined as such here.

[0026] Technologies, methods, and devices known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, these technologies, methods, and devices should be regarded as part of the specification.

[0027] As Figure 1 shown, the present invention provides a method for removing impurities and extracting vanadium from vanadium slag leaching solution, which includes the following steps: S1. Add water and a leaching agent to the calcined vanadium slag clinker, and after mixing evenly, obtain a first pulp; the leaching agent is at least composed of 8-hydroxyquinoline, an EDTA solution, and an acid solution; S2. Adjust the pH value of the first pulp to 3 - 6, and perform leaching under predetermined leaching conditions to obtain a second pulp; S3. Filter the second pulp to obtain a vanadium-containing leaching solution and a leaching residue.

[0028] In the method for removing impurities and extracting vanadium from vanadium slag leaching solution according to an embodiment of the present invention, impurities such as calcium ions and aluminum ions in the solution are complexed to form precipitates during leaching, thereby removing impurity ions. Therefore, the obtained leaching solution has a low impurity content and can be directly used for subsequent vanadium precipitation. Moreover, the calcium and aluminum precipitates are flocculent, and the vanadium leaching residue is granular, enabling the separation and recovery of metals such as calcium and aluminum, maximizing economic benefits.

[0029] In some specific embodiments, the calcined vanadium slag clinker is prepared by the converter slag-making method using blast furnace hot metal.

[0030] Based on the above embodiments, the calcined vanadium slag clinker contains V 2 O 5 : 11 - 12 wt%, CaO: 8 - 9 wt%, Al 2 O 3 : 5 - 6 wt%.

[0031] In some specific embodiments, before step S1, the method further includes: grinding the calcined vanadium slag clinker to a particle size where the portion less than 0.07 mm accounts for more than 80 wt%. Among them, the calcined vanadium slag clinker is ground by ball milling. After grinding, the particles of the vanadium slag clinker become smaller, and the specific surface area increases significantly, resulting in a substantial increase in the contact area between the solvent and the vanadium slag clinker. During the leaching process, more target substances such as vanadate can fully contact and react with the leaching agent, thereby accelerating the leaching reaction rate and enabling more rapid transfer of valuable elements such as vanadium from the clinker to the leaching solution.

[0032] As Figure 2 shown, based on the above embodiments, the leaching agent is composed of at least 8-hydroxyquinoline with a purity of 98 - 99%, an EDTA solution with a concentration of 0.04 - 0.06 mol / L, and a sulfuric acid solution with a concentration of 0.04 - 0.06 mol / L. Preferably, the leaching agent includes 8-hydroxyquinoline with a purity of 98%, EDTA with a concentration of 0.05 mol / L, and sulfuric acid with a concentration of 0.05 mol / L.

[0033] As a chelating agent, 8-hydroxyquinoline can form stable complexes with metal ions. During the leaching process, it can selectively bind to target metal ions, making it easier for metal ions to dissolve from solid materials, thereby increasing the leaching rate of metal ions.

[0034] EDTA is a very strong complexing agent with multiple coordinating atoms and can form stable chelates with various metal ions.

[0035] Sulfuric acid has strong acidity and can provide a large amount of hydrogen ions. During the leaching process, hydrogen ions can react chemically with metal oxides in solid materials to convert metal ions into soluble salts, thereby enabling the metal ions to enter the leaching solution.

[0036] In some specific embodiments, the mass ratio of 8-hydroxyquinoline, EDTA solution, and sulfuric acid solution with a purity of 98 - 99% is 5:2:(10 - 20).

[0037] Generally, for the extraction of vanadium from vanadium slag by leaching, usually various ions are first leached out, and then impurity ions are removed by methods such as extraction, precipitation, and resin ion exchange to increase the concentration of vanadium ions in the solution; finally, vanadium is precipitated to obtain V 2 O 5 .

[0038] However, the present invention adopts a process of selective acid leaching of vanadium from calcined vanadium slag for vanadium extraction. During the acid leaching of vanadium slag, impurity ion calcium in the solution forms a precipitate by complexing with 8-hydroxyquinoline, where EDTA is a masking agent to avoid the formation of vanadium precipitate and maintain the stability of the precipitate under acidic conditions. The present invention completes the removal of impurity ions during leaching, reduces subsequent impurity removal processes, and shortens the process flow.

[0039] Under acidic conditions, 8-hydroxyquinoline undergoes a complexation reaction with calcium and aluminum ions (Ca 2+ / Al 3+ ), and under the action of the masking agent EDTA, calcium ions form a stable precipitate. 8-hydroxyquinoline is a bidentate ligand that can deprotonate under acidic conditions to form a ligand in the Q− form, and then coordinate with metal ions such as Al 3+ or Ca 2+ to form a complex. The chemical reactions involved in the leaching process are as follows:

[0040]

[0041] Currently, for the extraction of vanadium from vanadium-titanium magnetite, the converter blowing slag-making method is mainly used to produce vanadium slag from hot metal in a blast furnace, that is, by using the principle of selective oxidation, high-speed pure oxygen jets are used to stir the vanadium-containing hot metal in the converter to oxidize the vanadium in the hot metal into high-valence stable vanadium oxides to obtain vanadium slag. After roasting the vanadium slag, the trivalent vanadium in vanadium iron spinel is converted into acid-soluble tetravalent and pentavalent vanadium compounds, which can be efficiently leached out in a sulfuric acid solution medium. After the vanadium-containing leaching solution is purified, it can be separated by cooling crystallization to obtain sodium metavanadate products.

[0042] On the basis of the above embodiments, the addition amount of the leaching agent is 10-18 wt% of the calcined vanadium slag clinker. Preferably, the addition amount of the leaching agent is 16 wt% of the calcined vanadium slag clinker.

[0043] In some specific embodiments, adjusting the pH value of the pulp includes adding an acidic solution and / or a basic solution and / or a buffer solution to adjust the pH value of the pulp, and then stirring and leaching for 30-90 min under the condition of 60-90 °C. For example, a 0.01 mol / L NaOH solution or a 0.01 mol / L H 2 SO 4 solution can be used to adjust the pH value of the pulp. Preferably, stir and leach for 60 min at 80 °C.

[0044] On the basis of the above embodiments, the predetermined leaching conditions include that the leaching stirring rate ranges from 400 to 800 r / min. Preferably, the rotation speed is 500 r / min.

[0045] On the basis of the above embodiments, filtration includes rinsing with an EDTA solution as a washing agent. The concentration of the EDTA solution is 0.01 mol / L. EDTA (ethylenediaminetetraacetic acid) is a strong complexing agent, which can form stable complexes with various metal ions. During the rinsing and filtration process, the formation of these complexes can effectively dissolve the metal ions adsorbed on the solid surface into the solution.

[0046] The method for selectively leaching vanadium from calcined vanadium slag disclosed in the present invention solves the technical problems that the acid leaching selectivity of the existing calcined vanadium slag is poor, resulting in complex and costly purification processes for subsequent impurities Ca and Al. The steps include adding water and a leaching agent to the calcined vanadium slag clinker, adjusting the pH value to 3-6, performing leaching, and finally separating the solid and liquid of the pulp obtained after the leaching. The leaching agent is a mixture composed of 8-hydroxyquinoline, EDTA and sulfuric acid in proportion. The leaching rate of vanadium in the present invention is greater than 99%, the vanadium concentration in the obtained vanadium-containing leaching solution is about 35-47 g / L, the calcium concentration is less than 0.05 g / L, and the aluminum concentration is less than 0.01 g / L. The impurity content in the leaching solution is low and can be directly used for subsequent vanadium precipitation.

[0047] The following is an illustration of the present application through specific embodiments.

[0048] Example 1 In the calcined vanadium slag clinker, V 2 O 5 is 11.2 wt%, CaO is 8.6 wt%, Al 2 O 3It is 5.9 wt%. The calcined vanadium slag clinker is ground to a particle size less than 0.070 mm accounting for 80 wt% to obtain the ground clinker; 0.2 kg of the ground clinker is taken and added to 1 L of water, and then a leaching agent is added. The leaching agent is a mixture composed of 98% 8-hydroxyquinoline, 0.05 mol / L EDTA, and 0.05 mol / L sulfuric acid in a mass ratio of 5:2:10. The addition amount of the leaching agent is 10 wt% of the ground clinker; the pH value of the pulp is adjusted to 3, and then it is stirred at 60 °C for 30 min to obtain the reacted pulp; the leaching stirring rate is 500 r / min. After the reaction, it is separated and filtered to obtain a vanadium-containing leaching solution and leaching residue.

[0049] In this example, the leaching rate of vanadium is 96.38%, and the vanadium concentration in the obtained vanadium-containing leaching solution is 35.29 g / L, the calcium concentration is 0.43 g / L, and the aluminum concentration is 0.36 g / L.

[0050] Example 2 In the calcined vanadium slag clinker, V 2 O 5 is 11.2 wt%, CaO is 8.6 wt%, Al 2 O 3 is 5.9 wt%. The calcined vanadium slag clinker is ground to a particle size less than 0.070 mm accounting for 80 wt% to obtain the ground clinker; 0.2 kg of the ground clinker is taken and added to 1 L of water, and then a leaching agent is added. The leaching agent is a mixture composed of 98% 8-hydroxyquinoline, 0.05 mol / L EDTA, and 0.05 mol / L sulfuric acid in a mass ratio of 5:2:15. The addition amount of the leaching agent is 10 wt% of the ground clinker; the pH value of the pulp is adjusted to 3, and then it is stirred at 60 °C for 30 min to obtain the reacted pulp; the leaching stirring rate is 500 r / min. After the reaction, it is separated and filtered to obtain a vanadium-containing leaching solution and leaching residue.

[0051] In this example, the leaching rate of vanadium is 97.81%, and the vanadium concentration in the obtained vanadium-containing leaching solution is 43.16 g / L, the calcium concentration is 0.37 g / L, and the aluminum concentration is 0.30 g / L.

[0052] Example 3 In the calcined vanadium slag clinker, V 2 O 5 is 11.2 wt%, CaO is 8.6 wt%, Al 2 O 3It is 5.9 wt%. The calcined vanadium slag clinker is ground to a particle size less than 0.070 mm accounting for 80 wt% to obtain the ground clinker; 0.2 kg of the ground clinker is added to 1 L of water, and then a leaching agent is added. The leaching agent is a mixture of 98% 8-hydroxyquinoline, 0.05 mol / L EDTA, and 0.05 mol / L sulfuric acid combined in a mass ratio of 5:2:15. The addition amount of the leaching agent is 10 wt% of the ground clinker; the pH value of the pulp is adjusted to 3, and then it is stirred at 60 °C for 60 min to obtain the reacted pulp; the leaching stirring rate is 500 r / min. After the reaction, it is separated and filtered to obtain a vanadium-containing leaching solution and leaching residues.

[0053] In this example, the leaching rate of vanadium is 99.15%, and the vanadium concentration in the obtained vanadium-containing leaching solution is 43.88 g / L, the calcium concentration is 0.079 g / L, and the aluminum concentration is 0.018 g / L.

[0054] Example 4 In the calcined vanadium slag clinker, V 2 O 5 is 11.2 wt%, CaO is 8.6 wt%, Al 2 O 3 is 5.9 wt%. The calcined vanadium slag clinker is ground to a particle size less than 0.070 mm accounting for 80 wt% to obtain the ground clinker; 0.2 kg of the ground clinker is added to 1 L of water, and then a leaching agent is added. The leaching agent is a mixture of 98% 8-hydroxyquinoline, 0.05 mol / L EDTA, and 0.05 mol / L sulfuric acid combined in a mass ratio of 5:2:15. The addition amount of the leaching agent is 10 wt% of the ground clinker; the pH value of the pulp is adjusted to 6, and then it is stirred at 80 °C for 60 min to obtain the reacted pulp; the leaching stirring rate is 500 r / min. After the reaction, it is separated and filtered to obtain a vanadium-containing leaching solution and leaching residues.

[0055] In this example, the leaching rate of vanadium is 99.76%, and the vanadium concentration in the obtained vanadium-containing leaching solution is 46.59 g / L, the calcium concentration is 0.049 g / L, and the aluminum concentration is 0.016 g / L.

[0056] The vanadium extraction process by selective acid leaching of calcined vanadium slag in the present invention has remarkable beneficial effects. During the acid leaching process, the complexation reaction between 8-hydroxyquinoline and the impurity ion calcium in the solution is ingeniously utilized to promote the formation of calcium precipitate, thereby effectively removing the impurity ion calcium, greatly reducing the content of impurities in the solution, and creating good conditions for subsequent vanadium extraction. At the same time, EDTA plays a key role. As a masking agent, it precisely avoids the formation of vanadium precipitation during leaching, ensures the stable existence of vanadium in the solution, and can also maintain the stability of the formed precipitate under acidic conditions, further optimizing the leaching effect. Particularly importantly, the present invention realizes the simultaneous removal of impurity ions during leaching. This innovative measure greatly reduces the subsequent complicated impurity removal processes, avoids problems such as vanadium loss and cost increase caused by multiple impurity removal operations, significantly shortens the entire process flow, improves production efficiency, reduces production costs, and provides a more advantageous technical solution for the efficient extraction of vanadium.

[0057] The above are exemplary embodiments disclosed by the present invention. The order of disclosure of the above embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of disclosure of the embodiments of the present invention (including the claims) is limited to these examples. Without departing from the scope defined by the claims, various changes and modifications can be made. The functions, steps, and / or actions of the method claims according to the disclosed embodiments herein do not need to be performed in any specific order. In addition, although the elements disclosed in the embodiments of the present invention can be described or claimed in individual form, they can also be understood as multiple unless explicitly limited to the singular.

[0058] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features between the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for removing impurities and extracting vanadium from vanadium slag leaching solution, characterized in that: The following steps are involved: S1. Adding water and a leaching agent to the calcified roasted vanadium slag clinker, and mixing them evenly to obtain a first slurry; wherein the leaching agent is composed of at least 8-hydroxyquinoline, EDTA solution and acid solution; S2, adjusting the pH value of the first slurry to 3-6, and leaching under predetermined leaching conditions to obtain a second slurry; S3. Filter the second slurry to obtain a vanadium-containing leaching solution and leaching residue.

2. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 1, characterized in that: The calcified roasted vanadium slag clinker is prepared by a slag-making method using molten iron from a blast furnace through a converter blowing process.

3. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 1, characterized in that: The calcified roasted vanadium slag clinker comprises V2O5: 11-12wt%, CaO: 8-9wt%, and Al2O3: 5-6wt%.

4. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 1, characterized in that: Before step S1, the method further comprises: grinding the calcified roasted vanadium slag clinker to a particle size of less than 0.07 mm accounting for more than 80 wt%.

5. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 1, characterized in that: The leaching agent at least consists of 8-hydroxyquinoline with a purity of 98-99%, an EDTA solution with a concentration of 0.04-0.06 mol / L, and a sulfuric acid solution with a concentration of 0.04-0.06 mol / L.

6. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 5, characterized in that: The mass ratio of the 8-hydroxyquinoline with a purity of 98-99%, the EDTA solution and the sulfuric acid solution is 5:2:(10-20).

7. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 6, characterized in that: The added amount of the leaching agent is 10-18 wt % of the calcified roasted vanadium slag clinker.

8. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 1, characterized in that: Adjusting the pH value of the slurry includes adding an acidic solution and / or an alkaline solution and / or a buffer solution to adjust the pH value of the slurry, and then stirring and leaching at 60-90° C. for 30-90 minutes.

9. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 1, characterized in that: The predetermined adjusted leaching conditions include a leaching stirring rate ranging from 400 to 800 r / min.

10. The method for removing impurities and extracting vanadium from vanadium slag leaching solution according to claim 1, characterized in that: The filtration includes washing using an EDTA solution as a washing agent.

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