Method for deep purification and impurity removal of acidic vanadium-containing solution

Abstract

The invention provides a method for deep purification and impurity removal of an acidic vanadium-containing solution. The method comprises the following steps: step 1, detecting the valence state of vanadium in the acidic vanadium-containing solution; when the valence state of vanadium is equal to 5, directly carrying out the step 2; when the vanadium valence state is lower than 5, an oxidizing reagent is added into the acid vanadium-containing solution, and vanadium in the acid vanadium-containing solution is completely converted into pentavalent vanadium; step 2, adding an impurity removal reagent into the acidic vanadium-containing solution, wherein the impurity removal reagent is phosphate, silicate or selenate; and step 3, adding a pH regulator into the acidic vanadium-containing solution, regulating the acidity of the acidic vanadium-containing solution until the hydrogen ion concentration is 10 <-3 > mol / L to 10 <-7 > mol / L, stirring at 25-60 DEG C for 0.5-2 hours to carry out an impurity removal reaction, filtering after impurity removal is finished, and carrying out solid-liquid separation to obtain a vanadium-containing impurity-removed solution and a filter cake. The method for deep purification and impurity removal of the acidic vanadium-containing solution has the advantages of being short in process, easy to operate, good in impurity removal effect and low in vanadium loss rate.

Description

Technical Field

[0001] The invention relates to a nonferrous metal separation and purification technology, and in particular to a method for deep purification and impurity removal of an acidic vanadium-containing solution. Background Art

[0002] Vanadium is a silver-grey metal with a high melting point and boiling point. It is non-magnetic, has good ductility and plasticity. Due to its excellent physical and chemical properties, vanadium is widely used in modern industries such as aerospace, medicine, and national defense. In addition, with the consumption of non-renewable energy and the development of new energy battery and other industries, the application of vanadium in the field of energy storage has increased rapidly, and the requirements for high-purity vanadium and its compounds are getting higher and higher.

[0003] Vanadium exists mainly in the form of vanadium oxide in nature, usually coexisting with elements such as Fe, Ti, Ca, Si, Al, and Mn. More than 70 vanadium-containing minerals have been discovered so far. The main raw materials for vanadium extraction are vanadium-titanium magnetite, stone coal mine, and vanadium shale mine. Among them, vanadium-titanium magnetite is the main raw material for vanadium extraction, storing about 98% of the world's vanadium resources. About 80% of the world's vanadium production comes from vanadium-containing steel slag after iron smelting with vanadium-titanium magnetite. The mature large-scale production processes include sodium roasting-water leaching vanadium extraction and calcium roasting-acid leaching vanadium extraction.

[0004] The sodium roasting-water leaching process has a good vanadium extraction effect, but the roasting process consumes a large amount of sodium chloride industrial salt and produces a large amount of gas such as hydrogen chloride, which pollutes the environment and is gradually replaced by calcium roasting. When the vanadium-containing steel slag adopts the calcium roasting-acid leaching process, the metal impurities such as Fe, Al, Mn, Ti, Zn in it react with the sulfuric acid used for leaching and enter the leachate, so the vanadium-containing acid leaching liquid contains a large amount of impurities and has poor quality. The subsequent preparation of high-purity vanadium chemicals or vanadium flow battery electrolytes requires purification and separation, otherwise it will lead to the risk of rapid battery capacity decay, low energy efficiency and poor high and low temperature stability in vanadium flow batteries.

[0005] Conventional methods for removing iron and aluminum mainly include chemical precipitation and hydrothermal hydrolysis. If chemical precipitation is used to remove iron and aluminum, the pH value of the solution needs to be adjusted to 5-10 when iron hydroxide and aluminum hydroxide are precipitated and removed. During the pH adjustment process, acid needs to be added to adjust the pH to 2.5-3.0 after impurities are removed for acidification and reduction, so as to prepare high-purity VOSO4 through subsequent extraction process. This process consumes a large amount of acid and alkali and is costly. At the same time, the hydrated hydroxides of iron and aluminum easily adsorb vanadium during the precipitation and impurity purification process, resulting in a large amount of vanadium loss. Although the hydrothermal hydrolysis method avoids the problem of large acid and alkali consumption, the hydrothermal process requires a higher temperature, and the same vanadium is also prone to hydrolysis to precipitate red vanadium, resulting in a large loss of vanadium. The method for removing impurity copper in acidic solution is mainly to remove copper by displacement reduction, using reducing iron powder to reduce the copper in the solution to precipitate copper element, but it will introduce new impurity iron. The removal process of titanium in acidic vanadium-containing solution is to extract titanium. By utilizing the difference in the extraction capacity of the extractant for vanadium and titanium, organic phosphoric acid extractants and amine extractants are used for synergistic extraction, which can effectively separate vanadium and titanium, and then use alkaline solutions such as sodium hydroxide or sodium carbonate for stripping to regenerate the organic phase. This method requires the use of a large amount of alkali, and produces a lot of wastewater, which is costly. The methods for removing manganese in acidic solutions include chemical precipitation, oxidative precipitation, and ion exchange. The chemical precipitation method requires the solution pH to be adjusted to 8-11 so that manganese is precipitated and removed in the form of manganese hydroxide, which consumes a large amount of alkali, and vanadium will also precipitate; the oxidative precipitation method requires the use of strong oxidizing substances such as hydrogen peroxide, sodium persulfate or potassium permanganate to oxidize the manganese in the solution to trivalent, and then through the disproportionation reaction of manganese itself, manganese is removed by forming manganese dioxide, but the main problem of this method is that the amount of oxidant is usually more than 10 times the theoretical amount and the manganese removal is not thorough. Ion exchange is only applicable to solutions with low manganese content, but not to solutions with higher manganese concentrations. Ion exchange is also only applicable to solutions with low manganese concentrations. During the process, a large amount of acidic solution will be produced, forming a new source of pollution that cannot be treated and is costly. Summary of the invention

[0006] The purpose of the present invention is to propose a method for deep purification and impurity removal of acidic vanadium-containing solutions in order to address the problems that the above-mentioned existing acidic vanadium-containing solutions have high impurity content, are difficult to remove, are costly, and cannot directly use extraction processes to produce high-purity VOSO4. The method has the advantages of short process, simple operation, good impurity removal effect, and low vanadium loss rate.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for deep purification and impurity removal of an acidic vanadium-containing solution, comprising the following steps:

[0008] Step 1, detecting the valence state of vanadium in an acidic vanadium-containing solution;

[0009] When the vanadium valence is equal to 5, proceed directly to step 2;

[0010] When the vanadium valence is lower than 5, an oxidant is added to the acidic vanadium-containing solution, and an oxidation reaction is carried out by stirring at pH = 2.0 to 3.0 and 20 to 90° C. to convert all vanadium in the acidic vanadium-containing solution into pentavalent vanadium, and then step 2 is performed;

[0011] Step 2, adding an impurity-removing agent to the acidic vanadium-containing solution, stirring and reacting at 25° C. to 50° C. for 0.5 h to 6 h to completely dissolve the impurity-removing agent, wherein the impurity-removing agent is a phosphate;

[0012] Step 3: Add a pH regulator to the acidic vanadium-containing solution to adjust the acidity of the acidic vanadium-containing solution to a hydrogen ion concentration of 10 -4 mol / L~10 -7 mol / L, stirred at 25℃~60℃ for 0.5h~2h to carry out impurity removal reaction, filtered after impurity removal, and solid-liquid separation to obtain vanadium-containing impurity-removed liquid and filter cake.

[0013] Furthermore, the acidic vanadium-containing solution is obtained by leaching sulfuric acid from tailings after ironmaking of calcified roasted vanadium-titanium magnetite, vanadium slag clinker or stone coal.

[0014] Furthermore, the vanadium concentration in the acidic vanadium-containing solution in step 1 is 4g / L to 70g / L. When the acidic vanadium-containing solution is a solution after leaching from stone coal mine, its vanadium concentration is 4g / L to 10g / L; when the acidic vanadium-containing solution is a leaching solution of tailings after iron smelting of vanadium-containing titanium magnetite, its vanadium concentration is 20g / L to 50g / L.

[0015] Furthermore, the hydrogen ions (H + ) concentration is 10 -2 mol / L~10 -3 mol / L.

[0016] Furthermore, the metal impurities in the acidic vanadium-containing solution in step 1 are Fe 3+ 、Al 3+ , Cu 2+ 、Zn 2+ 、Ti 2+ , Pb 2+ and Mn 2+ One or more of .

[0017] Furthermore, the iron concentration in the acidic vanadium-containing solution in step 1 is greater than or equal to 0.1 g / L, preferably 0.1 g / L to 2 g / L.

[0018] Furthermore, the aluminum concentration in the acidic vanadium-containing solution in step 1 is greater than or equal to 0.1 g / L, preferably 0.1 g / L to 2 g / L.

[0019] Furthermore, the copper concentration in the acidic vanadium-containing solution in step 1 is greater than or equal to 0.01 g / L, preferably 0.01 g / L to 0.1 g / L.

[0020] Furthermore, the zinc concentration in the acidic vanadium-containing solution in step 1 is greater than or equal to 0.02 g / L, preferably 0.02 g / L to 1 g / L.

[0021] Furthermore, the titanium concentration in the acidic vanadium-containing solution in step 1 is greater than or equal to 0.005 g / L, preferably 0.005 g / L to 0.5 g / L.

[0022] Furthermore, the lead concentration in the acidic vanadium-containing solution in step 1 is greater than or equal to 0.001 g / L, preferably 0.001 g / L to 0.1 g / L.

[0023] Furthermore, the manganese concentration in the acidic vanadium-containing solution in step 1 is greater than or equal to 0.02 g / L, preferably 0.02 g / L to 0.15 g / L.

[0024] Furthermore, the pH adjustment in step 1 adopts one or more of sodium hydroxide, potassium hydroxide, calcium oxide, calcium hydroxide, ammonia water and calcium carbonate.

[0025] The acidic vanadium-containing solution is difficult to remove impurities, mainly due to the following reasons:

[0026] (1) The acidic vanadium-containing solution mainly contains Fe 3+ 、Al 3+ , Cu 2+ 、Zn 2+ 、Ti 2+ , Pb 2+ , Mn 2+ Metal impurities such as H + The concentration is 10 -2 mol / L~10 -3 Under mol / L conditions, the various salts of the above-mentioned metal impurities have good solubility and are difficult to form precipitation for removal.

[0027] (2) When removing impurities from an acidic vanadium-containing solution, + The concentration is 10 -2 mol / L~10 -3 mol / L, when the vanadium concentration is high, H2V 10 O 28 4- It exists in the form of vanadium and is easy to co-precipitate with the precipitate formed by impurities, causing serious vanadium loss.

[0028] Furthermore, the oxidant in step 1 is one or more of hydrogen peroxide, O3, sodium peroxide, calcium peroxide, sodium persulfate and ammonium persulfate.

[0029] Furthermore, the amount of the oxidant added in step 1 is, by mole, 1.2 to 3.0 times the theoretical amount for oxidizing vanadium in the solution to 5-valent vanadium.

[0030] Furthermore, the oxidation reaction temperature in step 1 is 50° C. to 90° C., and the stirring reaction time is 1.0 h to 2.0 h.

[0031] Furthermore, the stirring speed in step 1 is 300 rpm to 1000 rpm.

[0032] Furthermore, the amount of the impurity-removing agent added in step 2 is 1.2 to 8.0 times the total amount of impurities in the acidic vanadium-containing solution in terms of molar amount.

[0033] Furthermore, the impurity removal agent in step 2 is one or more of phosphate, silicate and selenate.

[0034] Furthermore, step 2 is stirred and reacted at 25° C. to 60° C. for 1 h to 3 h.

[0035] Furthermore, the stirring speed in step 2 is 500 rpm to 1000 rpm, so that the impurity removal agent is fully dissolved.

[0036] Furthermore, in step 3, the pH regulator is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water and calcium carbonate.

[0037] Furthermore, when the pH value of the acidic vanadium-containing solution is adjusted to 4.0-5.0 using a pH adjuster, Al, Cu, and Pb in the solution can be removed to 0.005 g / L, 0.0005 g / L, 0.0001 g / L and below, respectively.

[0038] Furthermore, when the pH value of the acidic vanadium-containing solution is adjusted to the range of 5.0 to 6.0 using a pH adjuster, Fe, Zn and Ti in the solution can be removed to 0.015 g / L, 0.001 g / L, 0.001 g / L and below, respectively.

[0039] Furthermore, when the pH value of the acidic vanadium-containing solution is adjusted to a range of 6.0 to 6.5 using a pH adjuster, Mn in the solution can be removed to 0.02 g / L or less.

[0040] Furthermore, the stirring speed in step 3 is 500rpm to 1000rpm.

[0041] Furthermore, step 3 is reacted at 25°C to 40°C for 1.5h to 3h.

[0042] Furthermore, the Fe concentration in the vanadium-containing impurity-removed liquid is reduced to 0.015 g / L and below, and / or the Al concentration is reduced to 0.005 g / L and below, and / or the Cu concentration is reduced to 0.0005 g / L and below, the Zn concentration is reduced to 0.001 g / L and below, and / or the Ti concentration is reduced to 0.001 g / L and below, and / or the Pb concentration is reduced to 0.0001 g / L and below, and / or the Mn concentration is reduced to 0.02 g / L and below.

[0043] Furthermore, the vanadium-containing impurity-removed liquid can be directly used to produce high-purity vanadium chemicals such as APV, AMV, V2O5, or directly prepare high-purity vanadium energy storage media through extraction process.

[0044] Furthermore, the vanadium-containing impurity-removed liquid is extracted to produce vanadium electrolyte VOSO4. The extraction process is divided into three steps, namely extraction, washing, and stripping, all of which involve aqueous phase and oil phase. The raw material aqueous phase of the extraction process can be divided into pentavalent vanadium solution and tetravalent vanadium solution (obtained by reducing the pentavalent vanadium solution). The corresponding oil phase is different for different valence states of vanadium. Taking tetravalent vanadium as an example, extraction: SO2, sulfurous acid, sodium metabisulfite or other organic reducing agents are used to reduce the vanadium in the solution from pentavalent to tetravalent to obtain VOSO4 solution, and the pH of the solution is adjusted to between 2.5 and 3.0 using liquid alkali or other pH adjusting agents, and mixed with cationic extractants such as organic phase P204 and P507 to transfer vanadium from the aqueous phase to the oil phase. Water washing: Use pure water, secondary water or dilute acid to wash the vanadium-loaded oil phase to remove entrained impurities. Stripping: Use sulfuric acid of a specific concentration to mix with the vanadium-containing oil phase, and the hydrogen ions in the aqueous phase react with the VO in the oil phase. 2+ Ions are exchanged to transfer vanadium from the oil phase to the water phase to prepare VOSO4 electrolyte.

[0045] The method for deep purification and impurity removal of the acidic vanadium-containing solution of the present invention has the following advantages compared with the prior art:

[0046] 1) The method for deep purification and impurity removal of acidic vanadium-containing solution of the present invention can achieve deep impurity removal of vanadium-containing solution, and the impurities of iron, aluminum, copper, zinc, titanium, lead and manganese can be reduced to 0.015g / L, 0.005g / L, 0.0005g / L, 0.001g / L, 0.001g / L, 0.0001g / L, 0.02g / L and below, respectively, and the vanadium loss rate of the whole process is ≤1%.

[0047] 2) The method for deep purification and impurity removal of the acidic vanadium-containing solution of the present invention has a short impurity removal process, the impurity removal reagent is cheap and easy to obtain, the operation is simple, and it is easy to expand industrialization. The acidic vanadium-containing solution after impurity removal can be directly subjected to the extraction process to produce vanadium electrolyte VOSO4, and the waste water can be recycled and used for sulfuric acid leaching of vanadium slag clinker or stone coal mine after calcification roasting. It effectively solves the problems of high impurities, many types, and small application fields of acidic vanadium-containing raw materials.

[0048] 3) The method for deep purification and impurity removal of the acidic vanadium-containing solution of the present invention selectively removes designated metal impurities by controlling the pH at the reaction endpoint, removes and recovers metals in steps, and increases the added value of raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The present invention is a flow chart of the method for deep purification and impurity removal of acidic vanadium-containing solution. DETAILED DESCRIPTION

[0050] The following is a further description of the present invention in conjunction with an implementation example:

[0051] Example 1

[0052] This embodiment discloses a method for deep purification and impurity removal of an acidic vanadium-containing solution, such as Figure 1 As shown, the following steps are included:

[0053] Step 1: Measure 1L of vanadium-containing steel slag acidic leaching solution to carry out an impurity removal test. The vanadium concentration in the acidic vanadium-containing leaching solution (acidic vanadium-containing solution) is 47.25g / L, and the impurities are: iron concentration is 0.1236g / L, aluminum concentration is 0.1618g / L, copper concentration is 0.0513g / L, zinc concentration is 0.0356g / L, titanium concentration is 0.1219mg / L, lead concentration is 0.08g / L, manganese concentration is 14.8731g / L, and hydrogen ion concentration is 1.995×10 -3 mol / L.

[0054] Step 2, adding 33.2 g of disodium hydrogen phosphate with a molar content of 1.2 times the impurity content to the acidic vanadium-containing solution, and dissolving at 25° C. and a stirring speed of 600 rpm;

[0055] Step 3: Use ammonia water to adjust the hydrogen ion concentration in the solution to 3.162×10 -7 mol / L, the solution was reacted at 25°C and 1000rpm stirring speed for 1h; after solid-liquid separation, the vanadium-containing impurity-free liquid and filter cake were obtained. The vanadium-containing impurity-free liquid can be directly used in vanadium precipitation process or extraction process to produce high-purity vanadium chemicals after adjusting the acidity with sulfuric acid.

[0056] After testing, the iron in the vanadium-containing impurity removal solution was removed to 0.0127 g / L, the aluminum was removed to 0.0006 g / L, the copper was removed to 0.0001 g / L, the zinc was removed to 0.0001 g / L, the titanium was removed to 0.0009 g / L, the lead was removed to 0.0001 g / L, and the manganese was removed to 0.015 g / L, and the vanadium loss rate was less than 1%. The specific test results are shown in Table 1.

[0057] Table 1 Example 1 Solution vanadium and impurity detection results before and after impurity removal

[0058]

[0059] Example 2

[0060] This embodiment discloses a method for deep purification and impurity removal of an acidic vanadium-containing solution, comprising the following steps:

[0061] Step 1: Measure 1L of vanadium-containing steel slag acidic leaching solution to carry out an impurity removal test. The vanadium concentration in the acidic vanadium-containing leaching solution (acidic vanadium-containing solution) is 62.54 g / L, and the impurities are: iron concentration is 0.3670 g / L, aluminum concentration is 0.2192 g / L, copper concentration is 0.072 g / L, zinc concentration is 1.360 g / L, titanium concentration is 0.2951 mg / L, lead concentration is 0.083 g / L, manganese concentration is 12.9354 g / L, and hydrogen ion concentration is 2.32×10 -3 mol / L;

[0062] Step 2, adding 11.4 g of sodium silicate in an amount 2.2 times the molar content of the impurities other than manganese mentioned above to the acidic vanadium-containing solution, and dissolving at 25° C. and a stirring speed of 600 rpm;

[0063] Step 3: Use sodium hydroxide to adjust the hydrogen ion concentration in the solution to 1.26×10 -6 mol / L, the solution was reacted at 25°C and 1000rpm stirring speed for 0.5h; after solid-liquid separation, the vanadium-containing impurity-free liquid and filter cake were obtained. The vanadium-containing impurity-free liquid can be directly used in vanadium precipitation process or extraction process to produce high-purity vanadium chemicals after adjusting the acidity with sulfuric acid.

[0064] It has been tested that without removing manganese, iron can be removed to 0.0135g / L, aluminum can be removed to 0.0021g / L, copper can be removed to 0.0001g / L, zinc can be removed to 0.0005g / L, titanium can be removed to 0.0008g / L, and lead can be removed to 0.00g / L, and the vanadium loss rate is less than 1%.

[0065] Table 2 Example 2 Solution vanadium and impurity detection results before and after impurity removal

[0066]

[0067] Example 3

[0068] This embodiment discloses a method for deep purification and impurity removal of an acidic vanadium-containing solution, comprising the following steps:

[0069] Step 1, measuring 15L of vanadium-containing steel slag acidic leaching solution for impurity removal test, the vanadium concentration in the acidic vanadium-containing leaching solution (acidic vanadium-containing solution) is 39.31g / L, wherein the impurities are: iron concentration is 0.1489g / L, aluminum concentration is 0.1149g / L, copper concentration is 0.0570g / L, zinc concentration is 0.0257g / L, titanium concentration is 0.042mg / L, lead concentration is 0.085g / L, manganese concentration is 14.5524g / L, and hydrogen ion concentration is 2.17×10-3mol / L;

[0070] Step 2, adding 102.5 g of sodium selenite in an amount 4.0 times the molar content of the impurities other than manganese mentioned above to the acidic vanadium-containing solution, and dissolving at 25° C. and a stirring speed of 600 rpm;

[0071] Step 3: Use calcium hydroxide to adjust the hydrogen ion concentration in the solution to 6.31×10 -6 mol / L, the solution was reacted at 25°C and 1000rpm stirring speed for 1h; after solid-liquid separation, the vanadium-containing impurity-free liquid and filter cake were obtained. The vanadium-containing impurity-free liquid can be directly used in vanadium precipitation process or extraction process to produce high-purity vanadium chemicals after adjusting the acidity with sulfuric acid.

[0072] After testing, iron can be removed to 0.013g / L, aluminum can be removed to 0.0006mg / L, copper can be removed to 0.0001g / L, zinc can be removed to 0.0009g / L, titanium can be removed to 0.0009g / L, lead can be removed to 0.00g / L, and the vanadium loss rate is less than 1%.

[0073] Table 3 Detection results of vanadium and impurities in solution before and after impurity removal in Example 3

[0074]

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for deep purification and impurity removal of an acidic vanadium-containing solution, characterized in that: The following steps are involved: Step 1, detecting the valence state of vanadium in an acidic vanadium-containing solution; When the vanadium valence is equal to 5, proceed directly to step 2; When the vanadium valence is lower than 5, an oxidant is added to the acidic vanadium-containing solution, and an oxidation reaction is carried out by stirring at pH = 2.0 to 3.0 and 20 to 90° C. to convert all vanadium in the acidic vanadium-containing solution into pentavalent vanadium, and then step 2 is performed; Step 2, adding an impurity removal agent to the acidic vanadium-containing solution, stirring and reacting at 25° C. to 50° C. for 0.5 h to 6 h to completely dissolve the impurity removal agent; Step 3: Add a pH regulator to the acidic vanadium-containing solution to adjust the acidity of the acidic vanadium-containing solution to a hydrogen ion concentration of 10 -3 mol / L~10 -7 mol / L, stirred at 25℃~60℃ for 0.5h~2h to carry out impurity removal reaction, filtered after impurity removal, and solid-liquid separation to obtain vanadium-containing impurity-removed liquid and filter cake.

2. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1, characterized in that: The hydrogen ion concentration in the acidic vanadium-containing solution in step 1 is 10 -2 mol / L~10 -3 mol / L; And / or, the vanadium concentration in the acidic vanadium-containing solution in step 1 is 4 g / L to 70 g / L; And / or, the metal impurity in the acidic vanadium-containing solution in step 1 is Fe 3+ 、Al 3+ , Cu 2+ 、Zn 2+ 、Ti 2+ , Pb 2+ and Mn 2+ One or more of .

3. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1 or 2, characterized in that: The iron concentration in the acidic vanadium-containing solution of step 1 is greater than or equal to 0.1 g / L; and / or, the aluminum concentration in the acidic vanadium-containing solution of step 1 is greater than or equal to 0.1 g / L; and / or, the copper concentration in the acidic vanadium-containing solution of step 1 is greater than or equal to 0.01 g / L; and / or, the zinc concentration in the acidic vanadium-containing solution of step 1 is greater than or equal to 0.02 g / L; and / or, the titanium concentration in the acidic vanadium-containing solution of step 1 is greater than or equal to 0.005 g / L; and / or, the lead concentration in the acidic vanadium-containing solution of step 1 is greater than or equal to 0.001 g / L; and / or, the manganese concentration in the acidic vanadium-containing solution of step 1 is greater than or equal to 0.02 g / L.

4. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1, characterized in that: The oxidant in step 1 is one or more of hydrogen peroxide, O3, sodium peroxide, calcium peroxide, sodium persulfate and ammonium persulfate; And / or, the amount of the oxidant added is, in molar amount, 1.2 to 3.0 times the theoretical amount for oxidizing vanadium in the solution to 5-valent vanadium.

5. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1, characterized in that: The pH in step 1 is adjusted by one or more of sodium hydroxide, potassium hydroxide, calcium oxide, calcium hydroxide, ammonia water and calcium carbonate.

6. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1, characterized in that: The amount of the impurity-removing agent added in step 2 is 1.2 to 8.0 times the total amount of impurities in the acidic vanadium-containing solution in terms of molar amount.

7. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1, characterized in that: The impurity removal agent in step 2 is one or more of phosphate, silicate and selenate.

8. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1 or 7, characterized in that: The impurity removal agent is one of disodium hydrogen phosphate, sodium dihydrogen phosphate, trisodium phosphate, sodium hypophosphite, sodium metaphosphate, potassium phosphate, ammonium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, sodium silicate, potassium silicate, aluminum silicate, sodium metasilicate and sodium selenite.

9. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1, characterized in that: In step 3, the pH regulator is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water and calcium carbonate.

10. The method for deep purification and impurity removal of an acidic vanadium-containing solution according to claim 1, characterized in that: The Fe concentration in the vanadium-containing impurity-removed liquid is reduced to 0.015 g / L and below; and / or, the Al concentration is reduced to 0.005 g / L and below; and / or, the Cu concentration is reduced to 0.0005 g / L and below; and / or, the Zn concentration is reduced to 0.001 g / L and below; and / or, the Ti concentration is reduced to 0.001 g / L and below; and / or, the Pb concentration is reduced to 0.0001 g / L and below; and / or, the Mn concentration is reduced to 0.02 g / L and below.

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