Alkaline vanadium liquid impurity removal method

Abstract

The method comprises the following steps that carbonate is added into the alkaline vanadium liquid, the concentration of V in the alkaline vanadium liquid ranges from 10 g / L to 30 g / L, the concentration of impurities Al, Ca, Fe, Mn, Si and P does not exceed 1 g / L, and the concentration of other impurities does not exceed 0.05 g / L; adding a calcium salt impurity removing agent to obtain purified vanadium liquid; and oxalate is added into the purified vanadium liquid to obtain deeply-purified vanadium liquid. According to the scheme, Al, Ca, Fe, Mn, Si and P impurities in the alkaline vanadium liquid are deeply removed in a short process, the impurity concentration after purification can be reduced to 0.01 g / L or below, short-process deep impurity removal of the vanadium liquid is achieved, impurity removal slag generated by impurity removal can serve as a calcium salt roasting additive to be returned for use, meanwhile, vanadium is recycled, the vanadium loss rate is low, and the production cost is effectively reduced.

Description

Technical Field

[0001] The invention relates to the field of vanadium liquid treatment, and in particular to a method for removing impurities from alkaline vanadium liquid. Background Art

[0002] The main technologies for removing impurities from vanadium-containing solutions include chemical precipitation, solvent extraction, ion exchange, membrane, etc., which are selected or combined according to the properties of the raw materials, the types and contents of impurities. Among them, solvent extraction and ion exchange have the advantages of good impurity removal and adsorption effects and high product purity, but the purification cost is relatively high. The membrane method has a high cost and is only applicable to low-concentration vanadium solutions. The chemical precipitation method has the widest application range due to its low cost.

[0003] At present, the main technical route for preparing high-purity vanadium pentoxide in industry is still to use crude vanadium such as vanadium pentoxide or industrial-grade vanadate products as raw materials, and obtain it through processes such as dissolution, impurity removal and purification, and vanadium precipitation. When using alkaline solution for dissolution, some impurities are difficult to remove under alkaline conditions. In order to achieve the impurity removal effect, multi-stage alkaline dissolution-precipitation operations are often required, the process flow is long, and the consumption of reagents is large.

[0004] In addition, chemical impurity removal mainly focuses on the removal of Si, P, and Fe, and the impurity removal process is relatively complex and the impurity removal effect is relatively general. It is difficult to reduce the content of Si and P to below 0.01g / L. At the same time, since other impurities such as Al, Ca, Mn and other impurities are difficult to remove chemically, there is currently no effective removal method. Ion exchange and extraction are mainly used for removal, but there are generally problems such as large vanadium loss and high impurity removal costs, making it difficult to carry out industrial application transformation. Summary of the invention

[0005] In view of this, in order to overcome at least one aspect of the above problems, an embodiment of the present invention provides a method for removing impurities from alkaline vanadium liquid, comprising the following steps: Adding carbonate to alkaline vanadium solution, wherein the V concentration in the alkaline vanadium solution is 10-30 g / L, the concentrations of impurities Al, Ca, Fe, Mn, Si, and P are all less than 1 g / L, and the concentrations of other impurities are less than 0.05 g / L; Adding calcium salt impurity remover to obtain purified vanadium liquid; Adding oxalate into the purified vanadium liquid can obtain deeply purified vanadium liquid.

[0006] In some embodiments, adding carbonate to the alkaline vanadium solution further comprises: Add ammonium carbonate and / or ammonium bicarbonate to the alkaline solution, stir until completely dissolved, and then heat to 75-95°C.

[0007] In some embodiments, the amount of ammonium carbonate and / or ammonium bicarbonate added is 10-40 g / L.

[0008] In some embodiments, adding a calcium salt impurity remover to obtain purified vanadium solution further comprises: The liquid temperature is maintained at 75-95° C., a calcium salt impurity remover is added, and after reacting for 15-45 minutes, the solid and liquid are separated to obtain the purified vanadium liquid and a first stage impurity removal slag.

[0009] In some embodiments, the calcium salt impurity remover is calcium oxide and / or calcium hydroxide, and the added amount is 2-10 g / L.

[0010] In some embodiments, it also includes: The first stage impurity removal slag is used as a calcium salt roasting additive for roasting.

[0011] In some embodiments, adding oxalate to the purified vanadium solution to obtain the deeply purified vanadium solution further comprises: The temperature of the purified vanadium liquid is maintained at 75-95° C., the oxalate is added, and after reacting for 30-60 minutes, the solid-liquid separation is performed to obtain the deeply purified vanadium liquid and the second-stage impurity removal slag.

[0012] In some embodiments, the oxalate is one or more of oxalic acid, ammonium oxalate, sodium oxalate, and potassium oxalate.

[0013] In some embodiments, the amount of oxalate added is 1-5 g / L.

[0014] In some embodiments, it also includes: The second-stage impurity removal slag is used as a calcium salt roasting additive for roasting.

[0015] The present invention has one of the following beneficial technical effects: the short process proposed by the present invention can realize deep removal of Al, Ca, Fe, Mn, Si and P impurities in alkaline vanadium liquid, and the impurity concentration can be reduced to below 0.01 g / L after purification, thereby realizing deep impurity removal of vanadium liquid in a short process, and the impurity removal slag produced by the impurity removal can be returned for use as a calcium salt roasting additive, while realizing the recovery and utilization of vanadium, with low vanadium loss rate and effectively reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic flow chart of a method for removing impurities from alkaline vanadium liquid provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] 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 combination with specific embodiments and with reference to the accompanying drawings.

[0019] 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.

[0020] According to one aspect of the present invention, an embodiment of the present invention provides a method for removing impurities from alkaline vanadium liquid, such as Figure 1 As shown, it may include the steps of: Adding carbonate to alkaline vanadium solution, wherein the V concentration in the alkaline vanadium solution is 10-30 g / L, the concentrations of impurities Al, Ca, Fe, Mn, Si, and P are all less than 1 g / L, and the concentrations of other impurities are less than 0.05 g / L; Adding calcium salt impurity remover to obtain purified vanadium liquid; Adding oxalate into the purified vanadium liquid can obtain deeply purified vanadium liquid.

[0021] At present, the main impurity removal technologies for vanadium-containing solutions include chemical precipitation, solvent extraction, ion exchange, membrane method, etc., which are selected or combined according to the properties of raw materials, impurity types and contents. Among them, solvent extraction and ion exchange have the advantages of good impurity removal and adsorption effect and high product purity, but the purification cost is relatively high. The membrane method has high cost and is only applicable to low-concentration vanadium solutions. The chemical precipitation method has the widest application range due to its low cost. At present, the main technical route for industrial preparation of high-purity vanadium pentoxide is still to use crude vanadium such as vanadium pentoxide or industrial-grade vanadate products as raw materials, and obtain it through processes such as dissolution, impurity removal, purification, and vanadium precipitation. When using alkaline solution for dissolution, it is difficult to remove some impurities under alkaline conditions. In order to achieve the impurity removal effect, multi-stage alkaline dissolution-precipitation operations are often required, and the process flow is long and the reagent consumption is large. For example, in CN102430266B, the method contacts the vanadium-containing solution with an acidic cation exchange resin to perform ion exchange to remove metal cations in the vanadium-containing solution; in CN201910476311, after adding ferrous sulfate and a silicon precipitant to the vanadium-containing solution to remove impurities, the solution is adsorbed once with an aminophosphoric acid resin, and then the solution is adsorbed twice with an iminodiacetic acid chelating resin, and finally vanadium is precipitated to obtain an ammonium polyvanadate product. However, the process flow is long and the reagent consumption is large. In CN102888512A, Zhang Lin et al. of Panzhihua Iron and Steel Group Xichang Steel and Vanadium Co., Ltd. disclosed a method for removing impurities from a vanadium solution, wherein an oxidant (potassium permanganate, hydrogen peroxide, etc.) is added to oxidize the divalent iron ions after adjusting the pH of the vanadium solution, and then a precipitant is added to remove impurities to obtain a purified vanadium solution for vanadium precipitation. In CN111690826A, vanadium mud containing aluminum-based impurity remover and polyacrylamide is mixed with vanadium slag alkaline leaching liquid for impurity removal, and the impurity removal liquid is crystallized and calcined to obtain vanadium pentoxide with a purity of >99.5%. In CN102251113 A, a method for purifying and removing impurities from vanadium leaching liquid is disclosed, wherein a vanadium-containing clinker leaching liquid with a pH value of 5-8 is heated to 60°C to 100°C, a phosphorus removal purifier is added, an acid is added to adjust the pH value, a silicon removal purifier is added again, and after cooling and standing, a vanadium liquid with a low silicon and phosphorus content is obtained by filtering, thereby achieving the removal of Si and P impurities. In CN101709399, a method for purifying and removing impurities from vanadium-containing leaching liquid is disclosed, wherein magnesium sulfate and alum are added to the vanadium liquid at a certain temperature and pH to remove P and Si, and the Si concentration in the vanadium liquid can be controlled to be below 0.05g / L and the P concentration to be controlled to be 0.015g / L. CN116656949A discloses a method for removing impurities from a carbonated vanadium leaching solution. After the pH value of the carbonated vanadium-containing leaching solution is adjusted to 10.5-12.5, a zinc source such as zinc sulfate is added and the temperature is raised to 90-100°C for stirring reaction to remove impurities, thereby reducing the iron and zinc contents in the vanadium solution to below 0.005 g / L.

[0022] Summarizing the existing research on impurity removal of alkaline vanadium liquid, it can be found that the current chemical impurity removal is mainly focused on the removal of Si, P, and Fe, and the impurity removal process is relatively complicated, the impurity removal effect is relatively general, and the Si and P contents are difficult to reduce to below 0.01g / L. At the same time, since other impurities such as Al, Ca, Mn and other impurities are difficult to remove chemically, there is currently no effective removal method. The main methods used are ion exchange and extraction for removal, but there are generally problems of large vanadium loss and high impurity removal costs, which are difficult to be transformed into industrial applications. The solution proposed in the present invention is to add carbonate to the alkaline vanadium liquid, wherein the V concentration in the alkaline vanadium liquid is 10~30g / L, the impurity Al, Ca, Fe, Mn, Si, and P concentrations are all no more than 1g / L, and the concentrations of other impurities are no more than 0.05g / L; a calcium salt impurity remover is added to obtain a purified vanadium liquid; and oxalate is added to the purified vanadium liquid to obtain a deep purified vanadium liquid. This short process can achieve deep removal of Al, Ca, Fe, Mn, Si, and P impurities in alkaline vanadium liquid. The impurity concentration can be reduced to below 0.01g / L after purification, realizing deep impurity removal of vanadium liquid in a short process. The impurity removal slag produced by the impurity removal can be returned for use as a calcium salt roasting additive, while realizing the recovery and utilization of vanadium. The vanadium loss rate is low, effectively reducing production costs.

[0023] In some embodiments, adding carbonate to the alkaline vanadium solution further comprises: Add ammonium carbonate and / or ammonium bicarbonate to the alkaline solution, stir until completely dissolved, and then heat to 75-95°C.

[0024] In some embodiments, the amount of ammonium carbonate and / or ammonium bicarbonate added is 10-40 g / L.

[0025] In some embodiments, adding a calcium salt impurity remover to obtain purified vanadium solution further comprises: The liquid temperature is maintained at 75-95° C., a calcium salt impurity remover is added, and after reacting for 15-45 minutes, the solid and liquid are separated to obtain the purified vanadium liquid and a first stage impurity removal slag.

[0026] In some embodiments, the calcium salt impurity remover is calcium oxide and / or calcium hydroxide, and the added amount is 2-10 g / L.

[0027] In some embodiments, it also includes: The first stage impurity removal slag is used as a calcium salt roasting additive for roasting.

[0028] In some embodiments, adding oxalate to the purified vanadium solution to obtain the deeply purified vanadium solution further comprises: The temperature of the purified vanadium liquid is maintained at 75-95° C., the oxalate is added, and after reacting for 30-60 minutes, the solid-liquid separation is performed to obtain the deeply purified vanadium liquid and the second-stage impurity removal slag.

[0029] In some embodiments, the oxalate is one or more of oxalic acid, ammonium oxalate, sodium oxalate, and potassium oxalate.

[0030] In some embodiments, the amount of oxalate added is 1-5 g / L.

[0031] In some embodiments, it also includes: The second-stage impurity removal slag is used as a calcium salt roasting additive for roasting.

[0032] Specifically, firstly, carbonate is added to the alkaline vanadium liquid, stirred until completely dissolved, and then the temperature is raised to 75-95°C; then the temperature of the vanadium liquid is maintained at 75-95°C, calcium salt impurity remover is added, and after reacting for 15-45 minutes, solid-liquid separation is performed to obtain purified vanadium liquid and first-stage impurity removal slag; then oxalate is added to the purified vanadium liquid, the temperature of the vanadium liquid is maintained at 75-95°C, and after reacting for 30-60 minutes, solid-liquid separation is performed to obtain deeply purified vanadium liquid and second-stage impurity removal slag; the last-stage impurity removal slag and second-stage impurity removal slag can be used as calcium salt roasting additives and returned to roasting for use to realize vanadium recovery. The impurity concentrations of Al, Ca, Fe, Mn, Si, and P in the alkaline vanadium liquid after impurity removal and purification can be reduced to below 0.01g / L, realizing deep removal of impurities.

[0033] The pH value of the alkaline vanadium solution is between 7.5 and 10, the V concentration is 10 to 30 g / L, the main impurities are Al, Ca, Fe, Mn, Si, and P, the concentrations of which are all less than 1 g / L, and the concentrations of other impurities are less than 0.05 g / L; the carbonate is one or more of ammonium carbonate and ammonium bicarbonate, and the addition amount is 10-40 g / L; the calcium salt impurity remover is one or more of calcium oxide and calcium hydroxide, and the addition amount is 2-10 g / L; the oxalate is one or more of oxalic acid, ammonium oxalate, sodium oxalate, and potassium oxalate, and the addition amount is 1-5 g / L.

[0034] Example 1 Step 1, add carbonate to the alkaline vanadium solution, stir until completely dissolved, and heat to 95°C; Step 2: Keep the temperature of the vanadium liquid at 95°C, add a calcium salt impurity remover, react for 15 minutes, separate the solid and the liquid, and obtain a purified vanadium liquid and a first-stage impurity-removing slag; Step 3, adding oxalate to the purified vanadium liquid, maintaining the temperature of the vanadium liquid at 95°C, reacting for 30 minutes, and then separating the solid and the liquid to obtain a deeply purified vanadium liquid and a second-stage impurity removal slag; Step 4: The first stage impurity removal slag and the second stage impurity removal slag can be returned to the roasting as calcium salt roasting additives to achieve vanadium recovery; The alkaline vanadium solution has a pH value of 9.8, a V concentration of 29.7 g / L, a main impurity Al concentration of 0.10 g / L, a Ca concentration of 0.15 g / L, a Fe concentration of 0.18 g / L, a Mn concentration of 0.28 g / L, a Si concentration of 0.61 g / L, a P concentration of 0.03 g / L, and other impurity concentrations not exceeding 0.05 g / L; The carbonate is ammonium bicarbonate, and the addition amount is 40g / L; The calcium salt impurity remover is calcium hydroxide, and the addition amount is 5g / L; The oxalate is ammonium oxalate, and the addition amount is 5g / L; After impurity removal and purification, the Al concentration in the alkaline vanadium liquid is 0.002g / L, the Ca concentration is 0.009g / L, the Fe concentration is 0.001g / L, the Mn concentration is 0.001g / L, the Si concentration is 0.009g / L, and the P concentration is 0.001g / L, achieving deep removal of impurities.

[0035] Example 2 Step 1, add carbonate to the alkaline vanadium solution, stir until completely dissolved, and heat to 85°C; Step 2, maintaining the temperature of the vanadium liquid at 85° C., adding a calcium salt impurity remover, reacting for 30 minutes, and then separating the solid and the liquid to obtain a purified vanadium liquid and a first-stage impurity-removing slag; Step 3, adding oxalate to the purified vanadium liquid, maintaining the temperature of the vanadium liquid at 85°C, reacting for 45 minutes, and then separating the solid and the liquid to obtain a deeply purified vanadium liquid and a second-stage impurity-removing slag; Step 4: The first stage impurity removal slag and the second stage impurity removal slag can be returned to the roasting as calcium salt roasting additives to achieve vanadium recovery; The alkaline vanadium solution has a pH value of 8.5, a V concentration of 20.6 g / L, a main impurity Al concentration of 0.05 g / L, a Ca concentration of 0.16 g / L, a Fe concentration of 0.11 g / L, a Mn concentration of 0.11 g / L, a Si concentration of 0.41 g / L, a P concentration of 0.04 g / L, and other impurity concentrations not exceeding 0.05 g / L; The carbonate is ammonium carbonate, and the addition amount is 25g / L; The calcium salt impurity remover is calcium oxide, and the addition amount is 10g / L; The oxalate is oxalic acid, and the added amount is 5g / L; After impurity removal and purification, the Al concentration in the alkaline vanadium liquid is 0.001g / L, the Ca concentration is 0.008g / L, the Fe concentration is 0.002g / L, the Mn concentration is 0.002g / L, the Si concentration is 0.008g / L, and the P concentration is 0.001g / L, achieving deep removal of impurities.

[0036] Example 3 Step 1, add carbonate to the alkaline vanadium solution, stir until completely dissolved, and heat to 75°C; Step 2, maintaining the temperature of the vanadium liquid at 75° C., adding a calcium salt impurity remover, reacting for 45 minutes, and then separating the solid and the liquid to obtain a purified vanadium liquid and a first-stage impurity-removing slag; Step 3, adding oxalate to the purified vanadium liquid, maintaining the temperature of the vanadium liquid at 75° C., reacting for 60 minutes, and then separating the solid and the liquid to obtain a deeply purified vanadium liquid and a second-stage impurity-removing slag; Step 4: The first stage impurity removal slag and the second stage impurity removal slag can be returned to the roasting as calcium salt roasting additives to achieve vanadium recovery; The alkaline vanadium solution has a pH value of 7.5, a V concentration of 10.9 g / L, a main impurity Al concentration of 0.09 g / L, a Ca concentration of 0.11 g / L, a Fe concentration of 0.17 g / L, a Mn concentration of 0.09 g / L, a Si concentration of 0.39 g / L, a P concentration of 0.06 g / L, and other impurity concentrations not exceeding 0.05 g / L; The carbonate is ammonium bicarbonate, and the addition amount is 10g / L; The calcium salt impurity remover is calcium hydroxide, and the addition amount is 2g / L; The oxalate is oxalic acid, and the added amount is 1 g / L; After impurity removal and purification, the Al concentration in the alkaline vanadium liquid is 0.001g / L, the Ca concentration is 0.007g / L, the Fe concentration is 0.001g / L, the Mn concentration is 0.001g / L, the Si concentration is 0.009g / L, and the P concentration is 0.002g / L, achieving deep removal of impurities.

[0037] The short process proposed in the present invention can achieve deep removal of Al, Ca, Fe, Mn, Si and P impurities in alkaline vanadium liquid. The impurity concentration can be reduced to below 0.01 g / L after purification, thereby achieving deep impurity removal of vanadium liquid in a short process. The impurity removal slag produced by the impurity removal can be returned for use as a calcium salt roasting additive, while vanadium recovery is achieved. The vanadium loss rate is low, and the production cost is effectively reduced.

[0038] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope disclosed in the embodiments of the present invention as 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.

[0039] It should be understood that, as used herein, the singular forms "a", "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations including one or more of the associated listed items.

[0040] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0041] 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 above embodiments of the present invention, 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 removing impurities from alkaline vanadium liquid, characterized in that: The following steps are involved: Adding carbonate to alkaline vanadium solution, wherein the V concentration in the alkaline vanadium solution is 10-30 g / L, the concentrations of impurities Al, Ca, Fe, Mn, Si, and P are all less than 1 g / L, and the concentrations of other impurities are less than 0.05 g / L; Adding calcium salt impurity remover to obtain purified vanadium liquid; Adding oxalate into the purified vanadium liquid can obtain deeply purified vanadium liquid.

2. The method according to claim 1, characterized in that Adding carbonate to the alkaline vanadium solution further comprises: Add ammonium carbonate and / or ammonium bicarbonate to the alkaline solution, stir until completely dissolved, and then heat to 75-95°C.

3. The method according to claim 2, characterized in that The amount of ammonium carbonate and / or ammonium bicarbonate added is 10-40 g / L.

4. The method according to claim 1, characterized in that Adding a calcium salt impurity remover to obtain purified vanadium liquid further comprises: The liquid temperature is maintained at 75-95° C., a calcium salt impurity remover is added, and after reacting for 15-45 minutes, the solid and liquid are separated to obtain the purified vanadium liquid and a first stage impurity removal slag.

5. The method according to claim 4, characterized in that The calcium salt impurity remover is calcium oxide and / or calcium hydroxide, and the added amount is 2-10 g / L.

6. The method according to claim 4, characterized in that Also includes: The first stage impurity removal slag is used as a calcium salt roasting additive for roasting.

7. The method according to claim 1, characterized in that Adding oxalate to the purified vanadium liquid to obtain deeply purified vanadium liquid further comprises: The temperature of the purified vanadium liquid is maintained at 75-95° C., the oxalate is added, and after reacting for 30-60 minutes, the solid-liquid separation is performed to obtain the deeply purified vanadium liquid and the second-stage impurity removal slag.

8. The method according to claim 7, characterized in that The oxalate is one or more of oxalic acid, ammonium oxalate, sodium oxalate and potassium oxalate.

9. The method according to claim 7, characterized in that The added amount of the oxalate is 1-5 g / L.

10. The method according to claim 7, characterized in that Also includes: The second-stage impurity removal slag is used as a calcium salt roasting additive for roasting.

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