Method for preparing high-purity vanadium pentoxide from acidic calcified vanadium liquid

Abstract

The invention discloses a method for preparing high-purity vanadium pentoxide from acidic calcified vanadium liquid, which comprises the following steps: adding ammonia water into the acidic calcified vanadium liquid to adjust the pH value, adjusting the pH value to 6-8, reacting, settling to obtain vanadium-containing precipitate, washing the vanadium-containing precipitate once, re-dissolving to remove impurities, and removing impurities and calcium through calcium salt to obtain purified vanadium liquid. And finally, cooling and precipitating to obtain sodium metavanadate, and calcining the sodium metavanadate to prepare a high-purity vanadium pentoxide product. According to the method, the acidic calcified vanadium liquid serves as the raw material, vanadium and impurities Mn, Ca, Si, P, K and Na are fully separated through two-stage precipitation-dissolution and efficient chemical impurity removal, the high-purity vanadium pentoxide product with the purity reaching 99.9% or above is prepared, the process is simple, the cost is low, and development of the vanadium slag calcification vanadium extraction process is greatly promoted.

Description

Technical Field

[0001] The invention relates to the technical field of rare metal refining, and in particular to a method for preparing high-purity vanadium pentoxide from acidic calcified vanadium liquid. Background Art

[0002] Vanadium is an important strategic metal resource and is widely used in steel, construction, batteries, catalysis, aerospace and other fields. As an important oxide of vanadium, vanadium pentoxide has become an indispensable material in many fields. At the same time, the purity requirements of vanadium pentoxide in some special application fields are getting higher and higher, so that the vanadium pentoxide sold on the market cannot meet the application standards in these fields.

[0003] The vanadium slag calcification process is currently a mainstream green and clean vanadium slag vanadium extraction technology, but the acidic calcified vanadium liquid obtained by acid leaching has a high impurity content and a wide variety of impurities, such as Mn content up to 10g / L, Ca content up to 0.5g / L, Si content up to 1.0g / L, and other impurities such as P, Fe, Al, etc. The content reaches about 0.1g / L, resulting in the production of vanadium pentoxide products with low purity, which is difficult to exceed 99.0%. Its main impurities are Ca, Fe, Mn, K, Na, P, Si, etc., which seriously restricts the expansion of the process to high-purity fine vanadium chemical products and limits its application and development.

[0004] At present, the mainstream process for preparing high-purity vanadium is to use ammonium metavanadate or vanadium pentoxide as raw materials for deep impurity removal. Therefore, vanadium pentoxide is the main raw material for obtaining high-purity vanadium, but there is currently no industrial production process that can achieve the production of high-purity vanadium pentoxide through acidic calcification vanadium liquid. Although the production of vanadium pentoxide produced by vanadium slag calcification has reached more than 20,000 tons / year, the production demand for high-purity vanadium and fine vanadium chemical products is still very urgent.

[0005] Chinese patent application CN106430307A discloses a method for preparing high-purity vanadium pentoxide, which uses liquid ammonium to hydrolyze vanadium, removes some impurities under acidic conditions, drips diluted sodium hydroxide to dissolve the obtained vanadium hydrolyzate, filters to remove precipitated impurities, and then uses cation exchange resin to remove trace divalent or divalent metal cation impurities. Although this method can prepare high-purity vanadium pentoxide, this method uses ammonium polyvanadate or ammonium metavanadate as raw materials, the cation exchange resin used is relatively expensive, and requires multiple steps and a complicated process.

[0006] Therefore, developing a method for producing high-purity vanadium pentoxide using acidic calcified vanadium liquid as raw material can achieve sufficient separation of vanadium and impurities in the acidic calcified vanadium liquid, and obtain high-purity vanadium pentoxide with a purity of 99.9%, which has very important economic value. Summary of the invention The purpose of the present invention is to provide a method for preparing high-purity vanadium pentoxide from acidic calcified vanadium liquid. The method uses acidic calcified vanadium liquid as raw material, realizes the full separation of vanadium and impurities such as Mn, Ca, Si, P, K and Na through two-stage precipitation-dissolution and efficient chemical impurity removal, and prepares a high-purity vanadium pentoxide product with a purity of more than 99.9%, thereby promoting the development of vanadium slag calcification vanadium extraction process technology.

[0007] In order to achieve the above object, the present invention provides a method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution, comprising the following steps: Step (1): adding ammonia water to the acidic vanadium calcification solution to adjust the pH value to 6-8, stirring at room temperature, reacting for 15-60 minutes and then allowing to settle to obtain a vanadium-containing precipitate; Step (2): mixing pure water and vanadium-containing precipitate at a liquid-solid ratio of 2-5:1 mL / g for pulping and washing, and then performing solid-liquid separation to obtain a primary vanadium-containing precipitate after washing; Step (3): mixing the carbonate solution and the primary vanadium-containing precipitate at a liquid-to-solid ratio of 15-30:1 mL / g, stirring evenly, heating to 75-95° C. and reacting for 15-60 min to obtain a vanadium-containing solution; Step (4): maintaining the temperature at 75-95°C, adding a calcium salt impurity remover to the vanadium-containing return solution, reacting for 15-60 minutes, and then separating the solid and liquid to obtain a vanadium-containing purified solution; Step (5): adding oxalate to the vanadium-containing purified liquid, maintaining the reaction temperature at 75-95°C for 30-90 minutes, and performing solid-liquid separation to obtain a deeply purified vanadium liquid; Step (6): cooling the deeply purified vanadium liquid to 5-35° C., stirring the reaction for 180-360 min, and performing solid-liquid separation to obtain ammonium metavanadate; Step (7): mixing pure water and ammonium metavanadate at a liquid-solid ratio of 2-5:1 mL / g for slurry washing, and then separating the solid and liquid to obtain ammonium polyvanadate; Step (8): After drying the ammonium polyvanadate, the temperature is raised to 500-600° C. in an oxidizing atmosphere, and the temperature is kept to calcine for 60-150 minutes to obtain a vanadium pentoxide product.

[0008] The method of the invention uses acidic calcified vanadium liquid as a raw material, adds ammonia water to the acidic calcified vanadium liquid to adjust the pH value to 6-8, obtains vanadium-containing precipitates through sedimentation after reaction, washes the vanadium-containing precipitates once and then dissolves them for impurity removal, then obtains purified vanadium liquid after impurity removal and calcium removal through calcium salt, and finally cools and precipitates to obtain sodium metavanadate, and prepares a high-purity vanadium pentoxide product through calcination of the sodium metavanadate, realizes the full separation of vanadium and impurities Mn, Ca, Si, P, K and Na, and prepares a high-purity vanadium pentoxide product with a purity of more than 99.9%, thereby greatly promoting the development of vanadium slag calcification vanadium extraction technology.

[0009] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of the present invention, preferably, in the step (3), the carbonate solution is one or more of ammonium carbonate and ammonium bicarbonate, and the addition amount is 10-40 g / L.

[0010] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of the present invention, preferably, in the step (3), the amount of carbonate added is 10-40 g / L.

[0011] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of the present invention, preferably, in step (4), the calcium salt impurity remover is one or more of calcium oxide and calcium hydroxide.

[0012] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of the present invention, preferably, in the step (4), the amount of calcium salt impurity remover added is 2-10 g / L.

[0013] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid of the present invention, preferably, in step (5), the oxalate is one or more of oxalic acid, ammonium oxalate, sodium oxalate and potassium oxalate.

[0014] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of the present invention, preferably, in the step (5), the amount of oxalate added is 1-5 g / L.

[0015] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of the present invention, preferably, in step (2) and step (7), the washing conditions are: washing at 10-30° C. for 10-60 min.

[0016] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid of the present invention, preferably, the acidic calcified vanadium liquid is obtained by a vanadium slag calcification vanadium extraction process, has a pH value of 2.0-4.0, and a vanadium concentration of 10-30 g / L.

[0017] According to the method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid of the present invention, preferably, in the acidic calcified vanadium liquid, the Mn concentration is 5-10 g / L, the Ca concentration is 0.1-0.5 g / L, the Si concentration is 0.1-1 g / L, the K concentration is 0.5-2 g / L, the Na concentration is 0.5-2 g / L, and the concentrations of other impurities do not exceed 0.1 g / L.

[0018] The beneficial effects of the present invention are: The method provided by the present invention comprises the following steps: adding ammonia water to the acidic calcified vanadium liquid to adjust the pH value, adjusting the pH value to 6-8, obtaining a vanadium-containing precipitate by sedimentation after the reaction, washing the vanadium-containing precipitate once and then dissolving it back to remove impurities, then removing impurities and removing calcium by calcium salt to obtain a purified vanadium liquid, and finally cooling and precipitating it to obtain sodium metavanadate, and preparing a high-purity vanadium pentoxide product by calcining the sodium metavanadate, realizing the full separation of vanadium and impurities Mn, Ca, Si, P, K and Na, preparing a high-purity vanadium pentoxide product with a purity of more than 99.9%, and promoting the high-end development of vanadium slag calcification vanadium extraction process products. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments.

[0020] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0021] The acidic calcified vanadium liquid used in the embodiment of the present invention is obtained by vanadium slag calcification vanadium extraction process, and the pH value is 2.8. The concentrations of vanadium and other major impurities in the acidic calcified vanadium liquid are shown in Table 1, and the concentrations of other impurities do not exceed 0.1 g / L.

[0022] Table 1 Main impurity components of common acidic vanadium calcification liquid raw materials g / L V Approx Feb Mr K So P Si Cr 25.36 0.72 0.04 9.18 0.35 1.32 0.03 0.41 0.02 Example 1 The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of Example 1 comprises the following steps: Step (1): adding ammonia water to the acidic vanadium calcification solution to adjust the pH value to 7.0, stirring the solution at room temperature for 30 minutes and then allowing the solution to settle to obtain a vanadium-containing precipitate.

[0023] Step (2): Pure water and the vanadium-containing precipitate are mixed at a liquid-solid ratio of 3:1 mL / g for pulping and washing, and after washing at 20° C. for 30 min, solid-liquid separation is performed to obtain a primary vanadium-containing precipitate.

[0024] Step (3): mixing the carbonate solution and the primary vanadium-containing precipitate at a liquid-to-solid ratio of 20:1 mL / g, stirring evenly, heating to 85° C. and reacting for 30 min to obtain a vanadium-containing solution; wherein the carbonate is ammonium bicarbonate, and the amount of ammonium bicarbonate added is 30 g / L.

[0025] Step (4): maintaining the temperature at 85° C., adding a calcium salt impurity remover to the vanadium-containing return solution, reacting for 30 minutes, and then performing solid-liquid separation to obtain a vanadium-containing purified solution; wherein the calcium salt impurity remover is calcium hydroxide, and the amount of calcium hydroxide added is 6 g / L.

[0026] Step (5): adding oxalate to the vanadium-containing purified liquid, maintaining the temperature of the vanadium liquid at 85° C. for 45 minutes, and performing solid-liquid separation to obtain a deeply purified vanadium liquid; wherein the oxalate is ammonium oxalate, and the amount of ammonium oxalate added is 2 g / L.

[0027] Step (6): Cool the deeply purified vanadium solution to 10° C., stir and react for 240 minutes, and then perform solid-liquid separation to obtain ammonium metavanadate.

[0028] Step (7): Pure water and ammonium metavanadate are mixed and slurried at a liquid-to-solid ratio of 3:1 mL / g for washing, and then washed at 15° C. for 30 min and then separated into solid and liquid to obtain ammonium polyvanadate.

[0029] Step (8): After drying the ammonium polyvanadate, the temperature is raised to 550° C. in an oxidizing atmosphere and calcined for 90 minutes to obtain a vanadium pentoxide product.

[0030] The purity of the vanadium pentoxide product prepared in Example 1 reaches 99.91%, the vanadium yield reaches 82%, the main impurities Mn content is 0.001%, Ca content is 0.002%, Si content is 0.005%, P content is 0.001%, K content is 0.004%, Na content is 0.002%, and the content of other impurities does not exceed 0.002%.

[0031] Example 2 A method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution in Example 2 comprises the following steps: Step (1): adding ammonia water to the acidic vanadium calcification solution to adjust the pH value to 6.0, stirring the solution at room temperature for 60 minutes and then allowing the solution to settle to obtain a vanadium-containing precipitate.

[0032] Step (2): Pure water and the vanadium-containing precipitate are mixed at a liquid-to-solid ratio of 5:1 mL / g for pulping and washing, and after washing at 20° C. for 30 min, solid-liquid separation is performed to obtain a primary vanadium-containing precipitate.

[0033] Step (3): the carbonate solution and the primary vanadium-containing precipitate are mixed at a liquid-to-solid ratio of 30:1 mL / g, stirred evenly, and then heated to 75° C. for reaction for 60 min to obtain a vanadium-containing solution; wherein the carbonate is ammonium carbonate, and the amount of ammonium carbonate added is 10 g / L.

[0034] Step (4): maintaining the temperature at 75° C., adding a calcium salt impurity remover to the vanadium-containing return solution, reacting for 60 minutes, and then performing solid-liquid separation to obtain a vanadium-containing purified solution; wherein the calcium salt impurity remover is calcium hydroxide, and the amount of calcium hydroxide added is 2 g / L.

[0035] Step (5): adding oxalic acid to the vanadium-containing purified liquid, maintaining the temperature of the vanadium liquid at 75° C. for 90 minutes, and performing solid-liquid separation to obtain a deeply purified vanadium liquid; wherein the oxalate is oxalic acid, and the amount of oxalic acid added is 2 g / L.

[0036] Step (6): Cool the deeply purified vanadium solution to 5°C, stir and react for 180 minutes, and then perform solid-liquid separation to obtain ammonium metavanadate.

[0037] Step (7): Pure water and ammonium metavanadate are mixed and slurried at a liquid-to-solid ratio of 2:1 mL / g for washing, and then washed at 30° C. for 30 min, followed by solid-liquid separation to obtain ammonium polyvanadate.

[0038] Step (8): After drying the ammonium polyvanadate, the temperature is raised to 600° C. in an oxidizing atmosphere and calcined for 60 minutes to obtain a vanadium pentoxide product.

[0039] The purity of the vanadium pentoxide product prepared in Example 2 reached 99.94%, the vanadium yield reached 81%, the main impurities Mn content was 0.001%, Ca content was 0.004%, Si content was 0.004%, P content was 0.001%, K content was 0.005%, Na content was 0.001%, and the contents of other impurities did not exceed 0.002%.

[0040] Example 3 The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution of Example 3 comprises the following steps: Step (1): adding ammonia water to the acidic vanadium calcification solution to adjust the pH value to 8.0, stirring the solution at room temperature for 15 minutes and then allowing the solution to settle to obtain a vanadium-containing precipitate.

[0041] Step (2): Pure water and the vanadium-containing precipitate are mixed at a liquid-solid ratio of 2:1 mL / g for pulping and washing, and after washing at 20° C. for 30 min, solid-liquid separation is performed to obtain a primary vanadium-containing precipitate.

[0042] Step (3): Mix the carbonate solution and the first-level vanadium-containing precipitate at a liquid-solid ratio of 15:1 mL / g, stir evenly, and heat to 95° C. for 15 min to obtain a vanadium-containing solution; wherein the carbonate is ammonium carbonate, and the amount added is 40 g / L.

[0043] Step (4): maintaining 95° C., adding a calcium salt impurity remover to the vanadium-containing return solution, reacting for 15 minutes, and then separating the solid and liquid to obtain a vanadium-containing purified solution; wherein the calcium salt impurity remover is calcium oxide, and the amount added is 10 g / L.

[0044] Step (5): adding oxalate to the vanadium-containing purified liquid, maintaining the temperature of the vanadium liquid at 95° C. for 30 minutes, and performing solid-liquid separation to obtain a deeply purified vanadium liquid; wherein the oxalate is sodium oxalate, and the amount added is 5 g / L.

[0045] Step (6): Cool the deeply purified vanadium solution to 35° C., stir and react for 360 min, and then perform solid-liquid separation to obtain ammonium metavanadate.

[0046] Step (7): Pure water and ammonium metavanadate are mixed and slurried at a liquid-to-solid ratio of 5:1 mL / g for washing, and then washed at 30° C. for 30 min and then separated into solid and liquid to obtain ammonium polyvanadate.

[0047] Step (8): After drying the ammonium polyvanadate, the temperature is raised to 500° C. in an oxidizing atmosphere and calcined for 150 minutes to obtain a vanadium pentoxide product.

[0048] The purity of the vanadium pentoxide product prepared in Example 3 reached 99.92%, the vanadium yield reached 80%, the main impurities Mn content was 0.001%, Ca content was 0.006%, Si content was 0.006%, P content was 0.001%, K content was 0.003%, Na content was 0.001%, and the contents of other impurities did not exceed 0.002%.

[0049] It can be seen from Examples 1-3 that the method disclosed in the present invention uses acidic calcified vanadium liquid as a raw material to prepare high-purity vanadium pentoxide with a purity of more than 99.91%, achieving full separation of vanadium from other impurities, and making an important contribution to promoting the development of high-purity fine vanadium chemical products.

[0050] It should be particularly pointed out that the various components or steps in the above-mentioned embodiments can be cross-linked, replaced, added, or deleted with each other. Therefore, the combinations formed by these reasonable arrangements and combinations should also fall within the scope of protection of the present invention, and the scope of protection of the present invention should not be limited to the embodiments.

[0051] The above are exemplary embodiments disclosed in the present invention. The order disclosed in the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages 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 disclosed in the embodiments of the present invention (including the claims) is limited to these examples. Various changes and modifications may be made without departing from the scope defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0052] A person skilled 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 the 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 in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium solution, characterized in that: The steps include: Step (1): adding ammonia water to the acidic vanadium calcification solution to adjust the pH value to 6-8, stirring at room temperature, reacting for 15-60 minutes and then allowing static sedimentation to obtain a vanadium-containing precipitate; Step (2): mixing pure water and vanadium-containing precipitate at a liquid-solid ratio of 2-5:1 mL / g for pulping and washing, and then performing solid-liquid separation to obtain a primary vanadium-containing precipitate after washing; Step (3): mixing the carbonate solution and the primary vanadium-containing precipitate at a liquid-to-solid ratio of 15-30:1 mL / g, stirring evenly, heating to 75-95° C. and reacting for 15-60 min to obtain a vanadium-containing solution; Step (4): maintaining the temperature at 75-95°C, adding a calcium salt impurity remover to the vanadium-containing return solution, reacting for 15-60 minutes, and then separating the solid and liquid to obtain a vanadium-containing purified solution; Step (5): adding oxalate to the vanadium-containing purified liquid, maintaining the reaction temperature at 75-95°C for 30-90 minutes, and performing solid-liquid separation to obtain a deeply purified vanadium liquid; Step (6): cooling the deeply purified vanadium solution to 5-35°C, stirring the reaction for 180-360 minutes, and then performing solid-liquid separation to obtain ammonium metavanadate; Step (7): mixing pure water and ammonium metavanadate in a liquid-solid ratio of 2-5:1 mL / g for slurry washing, and then separating the solid and liquid to obtain ammonium polyvanadate; Step (8): After drying the ammonium polyvanadate, the temperature is raised to 500-600° C. in an oxidizing atmosphere, and the temperature is kept to calcine for 60 min-150 min to obtain a vanadium pentoxide product.

2. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 1, characterized in that: In the step (3), the carbonate is one or more of ammonium carbonate and ammonium bicarbonate, and the added amount is 10-40 g / L.

3. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 2, characterized in that: In the step (3), the amount of carbonate added is 10-40 g / L.

4. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 1, characterized in that: In the step (4), the calcium salt impurity remover is one or more of calcium oxide and calcium hydroxide.

5. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 4, characterized in that: In the step (4), the amount of calcium salt impurity remover added is 2-10 g / L.

6. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 1, characterized in that: In the step (5), the oxalate is one or more of oxalic acid, ammonium oxalate, sodium oxalate, and potassium oxalate.

7. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 6, characterized in that: In the step (5), the amount of oxalate added is 1-5 g / L.

8. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 1, characterized in that: In step (2) and step (7), the washing conditions are: washing at 10-30°C for 10-60 minutes.

9. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 1, characterized in that: The acidic calcified vanadium liquid is obtained by vanadium slag calcification vanadium extraction process, with a pH value of 2.0-4.0 and a vanadium concentration of 10-30g / L.

10. The method for preparing high-purity vanadium pentoxide from an acidic calcified vanadium liquid according to claim 9, characterized in that: In the acidic calcified vanadium solution, the Mn concentration is 5-10g / L, the Ca concentration is 0.1-0.5g / L, the Si concentration is 0.1-1g / L, the K concentration is 0.5-2g / L, the Na concentration is 0.5-2g / L, and the concentrations of other impurities do not exceed 0.1g / L.