阅读说明：本技术 利用失效的钒电池正极电解液制取m相vo2的方法 (M-phase VO prepared by using failed vanadium battery positive electrolyte2Method (2) ) 是由 刘波 彭穗 李道玉 于 2019-10-24 设计创作，主要内容包括：本发明公开了一种利用失效的钒电池正极电解液制取M相VO_2的方法,属于二氧化钒技术领域,包括以下步骤：(1)取失效钒电池正极电解液,加入还原剂进行还原反应,还原反应结束后向电解液中加入沉淀剂调节pH至3～6,固液分离,洗涤,得到黑色沉淀；(2)将黑色沉淀煅烧后,得到VO_2粉体。本发明以失效的钒电池电解液为原料,实现了资源回收再利用,降低了VO_2的制备成本；同时本发明的工艺简单,适合工业化应用；制备得到的VO_2纯度高、附加值高、结晶度高,可以广泛的应用于智能窗、光电开关、热敏电阻等领域。(The invention discloses a method for preparing M-phase VO by using a failed vanadium battery positive electrolyte 2 Belonging to the technical field of vanadium dioxide, the method comprises the following steps: (1) adding a reducing agent into the failed vanadium battery positive electrolyte for reduction reaction, adding a precipitator into the electrolyte after the reduction reaction is finished to adjust the pH value to 3-6, and carrying out solid-liquid separation and washing to obtain black precipitate; (2) calcining the black precipitate to obtain VO 2 And (3) powder. The method takes the failed vanadium battery electrolyte as the raw material, realizes the recycling of resources and reduces VO 2 The preparation cost of (2); meanwhile, the method is simple in process and suitable for industrial application; VO obtained by preparation 2 High purity, high added value and high crystallinity, and can be widely applied to the fields of intelligent windows, photoelectric switches, thermistors and the like.)

1. M-phase VO prepared by using failed vanadium battery positive electrolyte₂The method is characterized by comprising the following steps:

(1) adding a reducing agent into the failed vanadium battery positive electrolyte for reduction reaction, adding a precipitator into the electrolyte after the reduction reaction is finished to adjust the pH value to 3-6, and carrying out solid-liquid separation and washing to obtain black precipitate;

(2) calcining the black precipitate to obtain VO₂And (3) powder.

2. The method for preparing M-phase VO by using the spent vanadium battery positive electrolyte according to claim 1₂The method of (2), characterized by: in the step (1), the content of all vanadium in the failed vanadium battery positive electrolyte is 1.6-1.7 mol/L, and SO₄ ^2-The content of (A) is 4.1-4.3 mol/L, the content of pentavalent vanadium is 0.75-0.8 mol/L, and the content of tetravalent vanadium is 0.85-0.9 mol/L.

3. The method for preparing M-phase VO by using the spent vanadium battery positive electrolyte according to claim 1₂The method of (2), characterized by: in the step (1), the reducing agent is one or more of vanadium sulfate, sulfurous acid, oxalic acid, hydrogen sulfide or sulfur dioxide.

4. The method for preparing M-phase VO by using the spent vanadium battery positive electrolyte according to claim 3₂The method of (2), characterized by: in the step (1), reducing agent and V in the electrolyte⁵⁺The molar ratio of (a) to (b) is 0.6 to 1.8: 1.

5. preparation of M-phase VO using spent vanadium battery anolyte according to claim 3 or 4₂The method of (2), characterized by: in the step (1), the step (c),the temperature of the reduction reaction is 30-100 ℃, and the time of the oxidation reaction is 3-12 h.

6. The method for preparing M-phase VO by using the spent vanadium battery positive electrolyte according to claim 1₂The method of (2), characterized by: in the step (1), the precipitant is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonia water or urea.

7. The method for preparing M-phase VO by using the spent vanadium battery positive electrolyte according to claim 1₂The method of (2), characterized by: in the step (2), the calcining temperature is 600-700 ℃, and the calcining time is 3-5 h.

Technical Field

The invention belongs to the technical field of vanadium dioxide, and particularly relates to a method for preparing M-phase VO by using a failed vanadium battery positive electrolyte₂The method of (1).

Background

The vanadium dioxide has a plurality of crystal phases of A phase, M phase, B phase, R phase and the like, wherein,m-phase VO₂Has phase transition characteristic at about 68 ℃, changes from monoclinic structure M phase to tetragonal rutile structure R phase, and is reversible along with the process of temperature rise and reduction, and simultaneously, the transmission rate, the reflectivity, the resistivity, the magnetic susceptibility and the like of the phase transition are all changed suddenly along with the phase transition, so VO₂The method is widely applied to the fields of intelligent windows, photoelectric switches, thermistors and the like.

At present, VO₂The preparation method of the powder mainly comprises a hydrothermal method, a thermal decomposition method, a sol-gel method, a vapor deposition method, a chemical deposition method and the like. The first category is that a pentavalent vanadium source is added with a reducing agent, most of the reducing agent are alcohols, organic acids and the like, and VO is prepared by reduction through a hydrothermal method₂(ii) a The second kind is that quadrivalent vanadium source is used as raw material, hydrolysate is obtained through chemical precipitation or hydrothermal method, and finally VO is obtained through high-temperature heat treatment₂(ii) a The third category is direct high-temperature thermal decomposition of tetravalent vanadium products, such as vanadyl sulfate, vanadyl oxalate and the like; the fourth type is that vanadium-containing organic matter is used as a base material, and target products such as vanadium isopropoxide, vanadium acetylacetonate, vanadium triacetylacetonate and the like are obtained through high-temperature thermal decomposition.

CN102910675A discloses VO₂Preparation and application of nanosheet material, wherein one or more of ethylene glycol, glycerol, erythritol, xylitol, mannitol, sorbitol, fructose, glucose and the like is/are used as a reducing agent, and V is used as a reducing agent₂O₅，NH₄VO₃，VOPO₄，VOCl₃，VO(C₃H₇O)₃One or more of which is a source of vanadium. The reduction temperature is 100 ℃ and 180 ℃, and the reaction time is 10-40 hours. High-quality VO with single crystalline phase and uniform appearance is prepared by hydrothermal reaction₂A nanosheet material.

CN105819508A discloses a method for preparing VO by spray pyrolysis₂Adding ammonium metavanadate into glycol solvent, heating and stirring to finally form a precursor solution with the concentration of 0.02mol/L, atomizing the precursor into small droplets by using an atomizer, spraying the small droplets onto a heated substrate by using carrier gas, and enabling the precursor to be in the substrateDecomposing on the bottom, depositing for a period of time, and collecting the product to obtain VO₂(M) a powder or a film.

CN104071843A discloses a preparation method of monodisperse M-phase vanadium dioxide nanoparticles, wherein vanadium pentoxide, oxalic acid dihydrate and water are mixed according to a molar ratio of 1-2.5: 1: 500-800 to obtain a precursor solution, placing the precursor solution in a closed state, reacting at least 1d at the temperature of 200-260 ℃ to obtain orthogonal vanadium dioxide powder, then placing the orthogonal vanadium dioxide powder in a nitrogen atmosphere, and annealing at 300-600 ℃ for at least 0.5h to obtain the monodisperse M-phase vanadium dioxide nanoparticles with the particle size of 60-80 nm.

Preparation of VO as mentioned above₂In the method, firstly, the requirements on the purity of raw materials are high, because certain nonspecific impurity ions in the vanadium dioxide can deteriorate the phase change function of the vanadium dioxide, and then the use function of the material is influenced. Secondly, if a pentavalent vanadium source is adopted as a raw material, a reduction step is required to be added, the process is complex, and the flow is long; if a tetravalent vanadium source such as vanadyl sulfate, vanadyl oxalate and the like is adopted, the raw material is difficult to prepare and has high requirement on purity; VO is generated if an organic vanadium source is adopted₂The preparation cost is too high.

Vanadium battery positive electrode (VO)₂)SO₄ ^-/VOSO₄An electric pair with negative electrode V³⁺/V²⁺Electric pair, after the battery is charged, the positive electrode material is V⁵⁺Ionic solution with negative electrode of V²⁺An ionic solution; after discharge, the positive and negative electrodes are V respectively⁴⁺And V³⁺An ionic solution. After the vanadium battery electrolyte is recycled for a long time, the concentration of vanadium ions and the concentration of sulfuric acid are seriously out of standard, the valence state of the vanadium ions is not matched, the energy attenuation is serious, and further the vanadium battery electrolyte is invalid and cannot be used.

Disclosure of Invention

The invention aims to provide a method for preparing M-phase VO by using a failed vanadium battery positive electrolyte₂The method comprises the following steps:

(1) adding a reducing agent into the failed vanadium battery positive electrolyte for reduction reaction, adding a precipitator into the electrolyte after the reduction reaction is finished to adjust the pH value to 3-6, and carrying out solid-liquid separation and washing to obtain black precipitate;

(2) calcining the black precipitate to obtain VO₂And (3) powder.

Wherein, the M-phase VO is prepared by using the failed vanadium battery positive electrolyte₂In the step (1), the content of all vanadium in the failed vanadium battery positive electrolyte is 1.6-1.7 mol/L, and SO is added₄ ^2-The content of (A) is 4.1-4.3 mol/L, the content of pentavalent vanadium is 0.75-0.8 mol/L, and the content of tetravalent vanadium is 0.85-0.9 mol/L.

Wherein, the M-phase VO is prepared by using the failed vanadium battery positive electrolyte₂In the step (1), the reducing agent is one or more of vanadium sulfate, sulfurous acid, oxalic acid, hydrogen sulfide or sulfur dioxide.

Wherein, the M-phase VO is prepared by using the failed vanadium battery positive electrolyte₂The method of (1), wherein the reducing agent and V are contained in the electrolyte⁵⁺The molar ratio of (a) to (b) is 0.6 to 1.8: 1.

wherein, the M-phase VO is prepared by using the failed vanadium battery positive electrolyte₂In the step (1), the temperature of the reduction reaction is 30-100 ℃, and the time of the oxidation reaction is 3-12 h.

Wherein, the M-phase VO is prepared by using the failed vanadium battery positive electrolyte₂In the step (1), the precipitant is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonia water or urea.

Wherein, the M-phase VO is prepared by using the failed vanadium battery positive electrolyte₂In the step (2), the calcining temperature is 600-700 ℃, and the calcining time is 3-5 hours.

The invention has the beneficial effects that:

the method takes the failed vanadium battery electrolyte as a raw material, so that the resource recycling is realized; VO is prepared by taking ineffective vanadium battery electrolyte as raw material₂In the process, the process method is simple, low in cost and easy to popularize and apply; at the same time, the invention preparesVO (a) of₂The method has the advantages of high purity, high added value, high crystallinity and the like, and can be widely applied to the fields of intelligent windows, photoelectric switches, thermistors and the like.

Drawings

FIG. 1 shows M-phase VO obtained by the present invention₂X-ray diffraction pattern of the powder;

FIG. 2 shows M-phase VO obtained by the present invention₂SEM image of powder.

Detailed Description

The failed vanadium battery positive electrode electrolyte is mainly characterized in that the concentration of tetravalent vanadium and pentavalent vanadium ions is not matched in the charging and discharging process, a small amount of precipitate is generated (mainly vanadium pentoxide hydrate), and the capacity efficiency is as low as 40%. The pentavalent vanadium ions have strong oxidizing property, SO that the reducing agent can be added, SO as not to introduce metal cation impurities, the invention adopts SO₂、H₂SO₃、H₂S, solid vanadium sulfate and oxalic acid are used as reducing agents, and solid precipitated from electrolyte is completely dissolved and reduced into a tetravalent product VO (OH) through reduction reaction₂Then VO (OH)₂Obtaining VO after calcination₂And (3) powder.

In the method, because the used reducing agent is easy to volatilize and decompose, such as sulfur dioxide, oxalic acid and the like, the dosage of the reducing agent is set to be excessive, and if the dosage of the reducing agent is less than the range defined by the invention, pentavalent vanadium ions cannot be completely reduced; if the amount of the reducing agent is more than the range defined by the present invention, additional waste may be caused. Therefore, the invention mixes the reducing agent with V in the electrolyte⁵⁺The molar ratio of (a) to (b) is 0.6 to 1.8: 1.

the following examples are provided to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention.

Taking 1.5L of failure vanadium battery electrolyte for standby (1#), and detecting [ TV []＝1.65mol/L，[V⁵⁺]＝0.76mol/L，[SO₄ ^2-]＝4.21mol/L。