Vanadium precipitation wastewater acid reduction treatment method

Abstract

The present application provides a kind of vanadium precipitation wastewater acid reduction treatment method, belong to vanadium-containing wastewater and environmental protection technical field, including the following processing steps: S1, the preparation of acid reduction regulator, inorganic adsorbent is placed in oxidizing agent solution and is stirred and dispersed, then the bottom precipitate is ground after precipitation, and the acid reduction regulator is obtained after filtration and washing;S2, the collected vanadium precipitation wastewater is initially filtered, and the waste mother liquor is obtained, the acid reduction regulator is added to waste mother liquor, after mixing evenly, vanadium precipitation wastewater is treated by cooling, and the solid-liquid mixture is obtained by standing, wherein the addition amount of acid reduction regulator in waste mother liquor is 3-10%;S3, the solid-liquid mixture is filtered and separated, and the acid root modified acid reduction regulator and qualified mother liquor are obtained, the vanadium extraction operation is carried out on the qualified mother liquor, and the vanadium extraction efficiency is detected, the acid substance in vanadium precipitation wastewater can be effectively removed, the vanadium ion is effectively retained, and further extraction and recovery are facilitated.

Description

Technical Field

[0001] This invention relates to the field of vanadium-containing wastewater and environmental protection technology, specifically to a method for reducing the acidity of vanadium-precipitated wastewater. Background Technology

[0002] Extracting vanadium from ore typically involves multiple steps, including mining, crushing, concentration, extraction, and purification. The most common method for extracting vanadium is using strong acids, such as sulfuric acid or hydrochloric acid. These acids are used to dissolve vanadium from the ore, forming soluble chlorides or sulfates.

[0003] 1-Hydroxyethyl diurea, also known as ethoxyurea, is an organic compound with the chemical formula CHNHCONHCH. It is a white crystalline solid, soluble in water and alcohol. Ethoxyurea has various applications in industries such as chemicals, pharmaceuticals, and agriculture. Considering environmental protection and cost-effectiveness, existing companies primarily use other chemicals, such as ethoxyurea, as extractants to extract vanadium from ores. Ethoxyurea is a relatively environmentally friendly extractant because it does not produce harmful waste or emissions. In contrast, strong acids can be harmful to the environment and require careful handling to avoid pollution. Ethoxyurea is a cost-effective extractant because it is inexpensive and easy to use. Strong acids, on the other hand, can be expensive and require careful handling. When using this method, the extractant forms a soluble complex with vanadium, which can be separated from other metals. The complex can then be further purified by co-precipitation or ion exchange to produce high-purity vanadium products.

[0004] Ethylene diurea can be used as an extractant for the extraction and purification of vanadium from ores or by-products. In this process, ethylene diurea forms a soluble complex with vanadium, which can be separated from other metals. The complex can then be further purified by co-precipitation or ion exchange to produce high-purity vanadium products. This application of ethylene diurea has been widely used in industry, particularly in the processing of vanadium-bearing ores and the recovery of vanadium from by-products of the steel industry.

[0005] Therefore, after adjusting the pH of the vanadium precipitation water, a large amount of vanadium product is obtained. The remaining vanadium precipitation wastewater contains a considerable amount of acid, heavy metals, oxalurone, and vanadium-containing salts. Due to the presence of heavy metals, vanadium and oxalurone cannot complex in an acidic environment. Other acidic substances or metal ions in the solution also compete with vanadium ions to form complexes with oxalurone, leading to competition for coordination sites and the breaking of coordination bonds. This reduces the degree of complexation reaction between oxalurone and vanadium ions. Furthermore, the presence of acidic substances in an overly acidic solution will change the equilibrium position of the complexation reaction, which will inhibit or reduce the formation of oxalurone-vanadium ion complexes. Therefore, it is necessary to reduce the acidity to improve the degree of complexation between oxalurone and vanadium ions.

[0006] pH adjustment is typically achieved using alkaline substances. While both heavy metals and vanadium can react with alkalis, vanadium, being a transition metal, reacts more readily with alkalis due to its unfilled d orbitals, making it easier for it to lose or share electrons. Heavy metals, on the other hand, usually have fully filled d or f orbitals, resulting in lower chemical reactivity compared to transition metals. Therefore, directly using alkaline substances to lower pH makes it less likely for vanadium ions to complex with ethyl urea, leading to alkaline precipitates that increase the difficulty of subsequent separation and extraction, as well as industrial costs. Summary of the Invention

[0007] In view of this, the present invention provides a method for acid reduction treatment of vanadium precipitation wastewater, which can effectively remove acidic substances from vanadium precipitation wastewater, effectively retain vanadium ions, and facilitate further extraction and recovery.

[0008] This invention provides a method for reducing the acidity of vanadium-precipitated wastewater, comprising the following treatment steps:

[0009] S1. Preparation of acid-lowering agent: The inorganic adsorbent is placed in an oxidant solution and stirred and dispersed. Then, the bottom precipitate is ground after precipitation, and the acid-lowering agent is obtained after filtration and washing.

[0010] S2. The collected vanadium precipitation wastewater is initially filtered to obtain waste mother liquor. Acid-reducing agent is added to the waste mother liquor and mixed evenly. The vanadium precipitation wastewater is then cooled and allowed to stand to obtain a solid-liquid mixture. The amount of acid-reducing agent added to the waste mother liquor is 3-10%.

[0011] S3. The solid-liquid mixture is filtered and separated to obtain an acid-modified deacidifying agent and a qualified mother liquor. Vanadium is extracted from the qualified mother liquor, and the vanadium extraction efficiency is tested.

[0012] The technical solution of this invention mainly involves the activation of hydroxyl groups on the surface of the adsorbent to react with acidic substances in the waste mother liquor, consuming hydrogen ions and attaching corresponding acid radicals to the surface of the adsorbent, thereby reducing the acidity value of the waste mother liquor. Simultaneously, the vanadium-precipitated wastewater is cooled during the reaction. Lowering the temperature reduces the kinetics of the reaction between the activated hydroxyl groups and vanadium ions, making the reaction more difficult to occur. The lower temperature also reduces collisions between vanadium ions and activated hydroxyl groups, thus slowing down the reaction rate. The reaction between hydrogen ions and activated hydroxyl groups is almost unaffected because the vanadium-precipitated wastewater contains strong acids and other substances that can act as acid catalysts, catalyzing acid-base reactions and increasing their rate.

[0013] Furthermore, the inorganic adsorbent includes activated carbon, clay, cartilage carbon, and inorganic oxides that do not react with acids, wherein the inorganic oxides are silicon dioxide, titanium dioxide, or aluminum oxide.

[0014] The aforementioned adsorbents typically do not react with vanadium ions because vanadium ions do not undergo physical or chemical adsorption on the surface of activated carbon. Furthermore, the chemical properties of vanadium ions do not match the composition of clay, and the size of vanadium ions is relatively large compared to the particle size of cartilage carbon, making it difficult for them to pass through the pores of cartilage carbon and enter the surface adsorption sites.

[0015] Furthermore, the particle size of the inorganic adsorbent is 100 nm-10 μm.

[0016] Furthermore, the oxidant solution includes hydrogen peroxide, potassium permanganate, and nitric acid.

[0017] Chemical oxidation is a common method that introduces hydroxyl functional groups onto the surface of cartilage carbon. Alternatively, strong acids and reducing agents such as sulfuric acid and ferrous chloride can be used to reduce cartilage carbon and introduce hydroxyl functional groups. Physical methods include plasma modification and ultraviolet irradiation. Plasma treatment can form hydroxyl functional groups on the surface of cartilage carbon through gas discharge. Ultraviolet irradiation can break down some molecules on the surface of cartilage carbon, forming hydroxyl functional groups.

[0018] Furthermore, in S1, the grinding is performed by adding an external grinding pestle, and the grinding machine used is a double-peg electric mortar and pestle grinder, and the grinding time is 2 hours.

[0019] Furthermore, the cleaning agent used in the cleaning step of S1 is pure water.

[0020] Furthermore, in the cooling process step S2, the temperature is reduced to below 5°C, and the cooling method is external coil water-coal cooling.

[0021] Through actual production implementation, it was found that temperature is very necessary for acid reduction operations at low temperatures. When the temperature is too high, although the acidity value decreases, the content of vanadium ions decreases significantly during subsequent extraction and separation. Therefore, low temperature can effectively inhibit the combination between vanadium ions and activated hydroxyl groups.

[0022] Furthermore, the settling time in S2 is 5-10 hours.

[0023] In summary, this application has at least one of the following beneficial technical effects compared with the prior art:

[0024] This invention primarily uses an acid-reducing agent to lower the acidity of waste mother liquor. To avoid the reaction between vanadium ions and the acid-reducing agent, it not only uses activated hydroxyl groups to combine acid and base and consume hydrogen ions, but also uses low temperature to slow down the consumption of vanadium ions. This maximizes the retention of vanadium ions in the mother liquor, allowing for continued vanadium extraction from the subsequently acidified mother liquor. This increases the efficiency of vanadium extraction, reduces the likelihood of interference from other salts, and lowers production costs. Attached Figure Description

[0025] Figure 1 The graph shows the vanadium extraction efficiency trend of the embodiments and comparative examples of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings of the embodiments of the present invention. Figure 1 The technical solutions of the embodiments of the present invention will be clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment applies the technical means of this application to the vanadium-precipitated mother liquor after vanadium extraction. The initial vanadium extraction efficiency is 84%, and the target vanadium content in the vanadium-precipitated waste liquor is 16%. The specific implementation method of this embodiment is as follows:

[0029] Step 1: Weigh 8 kg of cartilage charcoal and place it in a 10% (v / v) hydrogen peroxide solution for stirring and dispersion. The hydrogen peroxide solution should just cover the cartilage charcoal. After settling, use a double-pepper electric mortar grinder to grind the cartilage charcoal sediment at the bottom at a speed of 60 rpm. After filtering through a filter screen, activated cartilage charcoal is obtained. The activated cartilage charcoal is then washed with purified water to obtain an acid-lowering agent. The washing standard is that the pH value of the washing water is ≤10.

[0030] The second step involves pre-filtering the vanadium-containing wastewater after the vanadium extraction process to remove waste residue and insoluble impurities, resulting in vanadium-containing wastewater without precipitates. The activated cartilage carbon obtained in the first step is then added to the vanadium-containing wastewater at a ratio of 8 kg of cartilage carbon to 100 kg of vanadium-containing wastewater. After stirring and mixing evenly with a stirring spoon, a serpentine coil with refrigerant is immersed in the vanadium-containing wastewater to cool it down. The wastewater is then allowed to stand for 10 hours at a refrigerant temperature of 3°C to obtain a solid-liquid mixture.

[0031] The third step involves using a filtration device to separate the solid-liquid mixture, obtaining cartilage carbon containing acid radical modification and qualified mother liquor. Vanadium is extracted from the qualified mother liquor, and the amount of remaining vanadium is 14.2%, which is 88.75% compared to the 16% vanadium content in the total vanadium precipitated waste liquid.

[0032] Example 2

[0033] The difference between this embodiment and Embodiment 1 is that the amount of acid-reducing agent added to the waste mother liquor has been changed. The specific changes are as follows:

[0034] In the first step, 3 kg of cartilage carbon was weighed and dispersed accordingly. The oxidant solvent used was a 10% volume fraction hydrogen peroxide solution.

[0035] In the second step, the activated cartilage carbon obtained in the first step is added to the vanadium precipitation wastewater at a ratio of 3 kg of cartilage carbon to 100 kg of vanadium precipitation wastewater.

[0036] Based on the changes in the above two steps, the amount of vanadium extracted in the third step was 13.5%, which is 84.8% compared to the 16% vanadium content in the total vanadium precipitate waste liquid.

[0037] Example 3

[0038] The difference between this embodiment and Embodiment 1 is that the amount of acid-reducing agent added to the waste mother liquor has been changed. The specific changes are as follows:

[0039] In the first step, 10 kg of cartilage carbon was weighed and dispersed accordingly. The oxidant solvent used was a 10% volume fraction hydrogen peroxide solution.

[0040] In the second step, the activated cartilage carbon obtained in the first step is added to the vanadium precipitation wastewater at a ratio of 10 kg of cartilage carbon to 100 kg of vanadium precipitation wastewater.

[0041] Based on the changes in the above two steps, the amount of vanadium extracted in the third step was 13.6%, which is 86.88% compared to the 16% vanadium content in the total vanadium precipitate waste liquid.

[0042] Example 4

[0043] The difference between this embodiment and the previous one is that the type of inorganic adsorbent has been changed; activated carbon is used in the preparation of the acid-lowering agent. The specific changes are as follows:

[0044] In this embodiment, the vanadium content of the target vanadium-precipitated waste liquid is 14%.

[0045] Step 1: Weigh 8 kg of activated carbon and place it in a 10% (v / v) hydrogen peroxide solution. Stir and disperse the activated carbon, ensuring the solution just covers it. After settling, use a double-pounder electric mortar grinder to grind the activated carbon at the bottom at 60 rpm. Filter the mixture through a filter to obtain activated carbon. Wash the activated carbon with purified water to obtain an acid-lowering agent. The washing standard is that the pH of the washing water should be ≤10.

[0046] The second step involves pre-filtering the vanadium-containing wastewater after the vanadium extraction process to remove waste residue and insoluble impurities, resulting in vanadium-containing wastewater without precipitates. The activated carbon obtained in the first step is then added to the vanadium-containing wastewater at a ratio of 8 kg of activated carbon to 100 kg of vanadium-containing wastewater. After stirring and mixing evenly with a stirring spoon, a serpentine coil with refrigerant is immersed in the vanadium-containing wastewater to cool it down. The wastewater is then allowed to stand for 10 hours at a refrigerant temperature of 3°C to obtain a solid-liquid mixture.

[0047] The third step involves using a filtration device to separate the solid-liquid mixture, obtaining activated carbon containing acid radical modification and qualified mother liquor. Vanadium is extracted from the qualified mother liquor, and the amount of remaining vanadium extracted is 11.6%, which is 82.86% compared to the 14% vanadium content in the total vanadium precipitated waste liquid.

[0048] Example 5

[0049] The difference between this embodiment and the previous one is that the type of inorganic adsorbent has been changed. Clay is used to prepare the acid-lowering agent. The specific changes are as follows:

[0050] In this embodiment, the vanadium content of the target vanadium-precipitated waste liquid is 14%.

[0051] Step 1: Weigh 8 kg of clay and place it in a 10% (v / v) hydrogen peroxide solution for stirring and dispersion. The hydrogen peroxide solution should just cover the clay. After settling, use a double-pounder electric mortar grinder to grind the clay at the bottom sediment at 60 rpm. Filter the mixture through a filter to obtain activated clay. Wash the activated clay with purified water to obtain an acid-lowering agent. The washing standard is that the pH value of the washing water should be ≤10.

[0052] The second step involves pre-filtering the vanadium-containing wastewater after the vanadium extraction process to remove waste residue and insoluble impurities, resulting in vanadium-containing wastewater without precipitates. The activated clay obtained in the first step is then added to the vanadium-containing wastewater at a ratio of 8 kg of clay to 100 kg of vanadium-containing wastewater. After mixing evenly with a stirring spoon, a serpentine coil with refrigerant is submerged in the vanadium-containing wastewater to cool it down. The mixture is then allowed to stand for 10 hours at a refrigerant temperature of 3°C to obtain a solid-liquid mixture.

[0053] The third step involves using a filtration device to separate the solid-liquid mixture, obtaining clay containing acid radical modification and a qualified mother liquor. Vanadium is then extracted from the qualified mother liquor, and the amount of vanadium remaining is 10.8%, which is 77.14% compared to the 14% vanadium content in the total vanadium-precipitated waste liquid.

[0054] Example 6

[0055] The difference between this embodiment and the previous one is that the type of inorganic adsorbent has been changed. Silica is used instead to prepare the acid-lowering agent. The specific changes are as follows:

[0056] In this embodiment, the vanadium content of the target vanadium-precipitated waste liquid is 14%.

[0057] Step 1: Weigh 8 kg of silica and place it in a 10% (v / v) hydrogen peroxide solution and stir to disperse it. The hydrogen peroxide solution should just cover the silica. After settling, use a double-pepper electric mortar grinder to grind the silica at the bottom at 60 rpm. Filter the silica through a filter to obtain activated silica. Wash the activated silica with purified water to obtain an acid-lowering agent. The washing standard is that the pH value of the washing water should be ≤10.

[0058] The second step involves pre-filtering the vanadium-containing wastewater after the vanadium extraction process to remove waste residue and insoluble impurities, resulting in vanadium-containing wastewater without precipitates. The activated silica obtained in the first step is then added to the vanadium-containing wastewater at a ratio of 8 kg of silica to 100 kg of vanadium-containing wastewater. After stirring and mixing evenly with a stirring spoon, a serpentine coil with refrigerant is immersed in the vanadium-containing wastewater to cool it down. The wastewater is then allowed to stand for 10 hours at a refrigerant temperature of 3°C to obtain a solid-liquid mixture.

[0059] The third step involves using a filtration device to separate the solid-liquid mixture, obtaining silica containing acid radicals and a qualified mother liquor. Vanadium is then extracted from the qualified mother liquor, and the amount of vanadium remaining is 11.3%, which is 80.71% compared to the 14% vanadium content in the total vanadium-precipitated waste liquid.

[0060] Example 7

[0061] The difference between this embodiment and Embodiment 1 is that potassium permanganate is selected as the oxidant solution.

[0062] The remaining steps are the same as in the example. The amount of vanadium extracted was 13.8%, which is 86.25% compared to the 16.0% vanadium content in the total vanadium precipitate waste liquid.

[0063] Example 8

[0064] The difference between this embodiment and Embodiment 1 is that nitric acid is used as the oxidizing agent solution.

[0065] The remaining steps were the same as in the example, and the amount of vanadium extracted was 13.2%, which is 82.5% compared to the 16.0% vanadium content in the total vanadium precipitate waste liquid.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 1 is that, instead of using an inorganic adsorbent to adjust the acidity of the vanadium-precipitated wastewater, an alkaline solution is used directly for acid adjustment. The specific differences are as follows:

[0068] 0.8 kg of 20% sodium hydroxide solution was added to 100 kg of vanadium-precipitated wastewater to reduce acidity. After filtration, vanadium was extracted from the remaining mother liquor. The amount of vanadium extracted was 2.6 kg, which is 16.25% compared to the 16% vanadium content in the total vanadium-precipitated wastewater.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 1 is that an inorganic adsorbent is directly used to treat vanadium-precipitated wastewater, without the preparation of an acid-reducing agent. The specific differences are as follows:

[0071] Step 1: Weigh 8 kg of cartilage charcoal and place it in clean water for stirring and dispersion. After settling, use a double-pepper electric mortar grinder to grind the cartilage charcoal sediment at the bottom at a speed of 60 rpm. Filter the mixture through a filter screen to obtain cartilage charcoal.

[0072] The second step involves pre-filtering the vanadium-containing wastewater after the vanadium extraction process to remove waste residue and insoluble impurities, resulting in vanadium-containing wastewater without precipitates. The cartilage carbon obtained in the first step is then added to the vanadium-containing wastewater at a ratio of 8 kg of cartilage carbon to 100 kg of vanadium-containing wastewater. After stirring and mixing evenly with a stirring spoon, a serpentine coil with refrigerant is immersed in the vanadium-containing wastewater to cool it down. The wastewater is then allowed to stand for 10 hours at a refrigerant temperature of 3°C to obtain a solid-liquid mixture.

[0073] The third step involves using a filtration device to separate the solid-liquid mixture, obtaining cartilage carbon containing acid radical modification and qualified mother liquor. Vanadium is extracted from the qualified mother liquor, and the amount of remaining vanadium is 3.1%, which is 19.38% compared to the 16% vanadium content in the total vanadium precipitated waste liquid.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 1 is that the vanadium precipitation wastewater was not cooled. The specific changes are as follows:

[0076] The second step is to perform preliminary filtration on the vanadium-containing wastewater after the vanadium extraction process to remove waste residue and insoluble impurities, and obtain vanadium-containing wastewater without precipitates. The activated cartilage carbon obtained in the first step is added to the vanadium-containing wastewater at a ratio of 8 kg of cartilage carbon to 100 kg of vanadium-containing wastewater. After stirring and mixing evenly with a stirring spoon, the mixture is allowed to stand for 10 hours at a standing temperature of 25°C to obtain a solid-liquid mixture.

[0077] The third step involves using a filtration device to separate the solid-liquid mixture, obtaining cartilage carbon containing acid radical modification and qualified mother liquor. Vanadium is extracted from the qualified mother liquor, and the amount of remaining vanadium is 9.8%, which is 61.25% compared to the 16% vanadium content in the total vanadium precipitated waste liquid.

[0078] Comparative Example 4

[0079] The difference between this comparative example and Example 1 is that an excessive amount of acid-reducing agent was used. Compared with the amount used in Example 1 and Example 3, this comparative example used 15 kg of acid-reducing agent. The remaining steps are basically the same as those in the examples. The amount of vanadium extracted was 9.9%, which is 61.88% compared with the 16% vanadium content in the total vanadium precipitate waste liquid.

[0080] Comparative Example 5

[0081] The difference between this comparative example and Example 1 is that a very small amount of acid-reducing agent was used. Compared with the amount used in Example 1 and Example 2, this comparative example used 1 kg of acid-reducing agent. The remaining steps are basically the same as those in the examples. The amount of vanadium extracted was 6.7%, which is 41.88% compared with the 16% vanadium content in the total vanadium precipitate waste liquid.

[0082] A trend chart was generated to show the extraction efficiency of the above embodiments and comparative examples. The results are as follows: Figure 1 As shown in Examples 1, 2, 3, 4, and 5, the dosage of the acid-lowering agent tends to be within a certain range. Too much acid-lowering agent, after combining with acid and alkali, can partially affect the balance of the remaining vanadium ions, resulting in the absence of vanadium ions. On the other hand, too little acid-lowering agent will not combine with the acidic substances in the waste liquid enough to achieve the effect intended by this invention.

[0083] As can be seen from Examples 1, 4, 5, and 6, the technical means of this application can perform similar operations on activated carbon, clay, and inorganic oxides, thereby achieving the acid reduction effect without affecting the stable existence of vanadium ions.

[0084] As shown in Comparative Example 1, directly using alkaline substances to acidify wastewater will cause vanadium ions to precipitate directly with the alkaline substances, thus preventing a large number of vanadium ions from being properly recovered.

[0085] As shown in Comparative Example 2, without modifying and activating the inorganic adsorbent, acidic substances in wastewater cannot be effectively stripped away. This leads to other heavy metals and vanadium ions competing with oxalate to form complexes, resulting in competition for coordination sites and the breaking of coordination bonds, thus reducing the degree of complexation reaction between oxalate and vanadium ions.

[0086] According to Comparative Example 3, the use of cooling methods can significantly slow down the binding of vanadium ions with the acid-lowering agent, thereby allowing acidic substances to fully bind with the activated hydroxyl groups on the acid-lowering agent.

[0087] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for deacidifying vanadium-precipitated wastewater, characterized in that, The following processing steps are included: S1. Preparation of the acid-reducing agent: An inorganic adsorbent is placed in an oxidant solution and stirred and dispersed. The bottom precipitate is then ground after precipitation, followed by filtration and washing to obtain the acid-reducing agent. The inorganic adsorbent includes activated carbon, clay, cartilage carbon, and inorganic oxides that do not react with acids, such as silicon dioxide, titanium dioxide, or aluminum oxide. S2. The collected vanadium-precipitated wastewater is initially filtered to obtain a mother liquor. The acid-reducing agent is added to the mother liquor, mixed thoroughly, and then the vanadium-precipitated wastewater is cooled and allowed to stand to obtain a solid-liquid mixture. The amount of acid-reducing agent added to the mother liquor is 3-10%. S3. The solid-liquid mixture is filtered and separated to obtain an acid-modified deacidifying agent and a qualified mother liquor. Vanadium is extracted from the qualified mother liquor, and the vanadium extraction efficiency is tested.

2. The method for reducing acidity in vanadium-precipitated wastewater as described in claim 1, characterized in that: The inorganic adsorbent has a particle size of 100 nm to 10 μm.

3. The method for reducing acidity in vanadium-precipitated wastewater as described in claim 1, characterized in that: The oxidant solution includes hydrogen peroxide, potassium permanganate, and nitric acid.

4. The method for reducing acidity in vanadium-precipitated wastewater as described in claim 1, characterized in that: The grinding in S1 is performed by adding an external grinding pestle. The grinding machine used is a double-peg electric mortar and pestle grinder, and the grinding time is 2 hours.

5. The method for reducing acidity in vanadium-precipitated wastewater as described in claim 1, characterized in that: The cleaning agent used in the cleaning step S1 is pure water.

6. The method for reducing acidity in vanadium-precipitated wastewater as described in claim 1, characterized in that: In the cooling process of S2, the temperature is reduced to below 5°C, and the cooling method is external coil water-coal cooling.

7. The method for reducing acidity in vanadium-precipitated wastewater as described in claim 1, characterized in that: The settling time in S2 is 5-10 hours.

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