阅读说明：本技术 一种钠化钒液低铵制备多钒酸铵的方法 (Method for preparing ammonium polyvanadate from sodium vanadium solution with low ammonium content ) 是由 蒋霖 伍珍秀 伍金树 于 2021-08-31 设计创作，主要内容包括：本发明涉及多钒酸铵制备技术领域,公开了一种钠化钒液低铵制备多钒酸铵的方法。该方法包括：(1)向钠化钒液中通入CO-(2),将钠化钒液的pH值调节至8～9,反应后过滤,得到净化液；(2)向步骤(1)所得净化液中加入分散剂和铵盐并搅拌溶解,铵盐的用量为钠化钒液中全钒质量的0.6～1.0倍；(3)将步骤(2)所得溶液的pH值调节至1.8～2.2,然后加热反应并在搅拌条件下进行保温,反应结束后过滤,并对固体产物进行洗涤,得到高密度多钒酸铵。采用本方法制备的多钒酸铵,其堆积密度大于0.7g/cm～(3)；本发明加铵系数K为0.6～1.0,铵盐用量减少50％以上,沉钒率与现有高密度沉钒工艺相当。(The invention relates to the technical field of ammonium polyvanadate preparation, and discloses a method for preparing ammonium polyvanadate from sodium vanadium solution with low ammonium content. The method comprises the following steps: (1) introducing CO into the sodium vanadium solution 2 Adjusting the pH value of the sodium vanadium solution to 8-9, and filtering after reaction to obtain a purified solution; (2) adding a dispersing agent and ammonium salt into the purified liquid obtained in the step (1), stirring and dissolving, wherein the using amount of the ammonium salt is 0.6-1.0 time of the mass of all vanadium in the sodium vanadium solution; (3) and (3) adjusting the pH value of the solution obtained in the step (2) to 1.8-2.2, then heating for reaction, keeping the temperature under the stirring condition, filtering after the reaction is finished, and washing a solid product to obtain the high-density ammonium polyvanadate. The bulk density of the ammonium polyvanadate prepared by the method is more than 0.7g/cm 3 (ii) a The coefficient K of the added ammonium is 0.6-1.0, the dosage of the ammonium salt is reduced by more than 50%, and the vanadium precipitation rate is equivalent to that of the existing high-density vanadium precipitation process.)

1. A method for preparing ammonium polyvanadate from sodium vanadium solution with low ammonium content is characterized by comprising the following steps:

(1) introducing CO into the sodium vanadium solution₂Adjusting the pH value of the sodium vanadium solution to 8-9, and filtering after reaction to obtain a purified solution;

(2) adding a dispersing agent and ammonium salt into the purified liquid obtained in the step (1), and stirring and dissolving, wherein the using amount of the ammonium salt is 0.6-1 time of the mass of all vanadium in the sodium vanadium solution;

(3) and (3) adjusting the pH value of the solution obtained in the step (2) to 1.8-2.2, then heating for reaction, keeping the temperature under the stirring condition, filtering after the reaction is finished, and washing a solid product to obtain the high-density ammonium polyvanadate.

2. The method according to claim 1, wherein in the sodium vanadium solution in the step (1), V is 20-50 g/L, and P is less than 0.015 g/L.

3. The method according to claim 1, wherein in step (2), the dispersant is polyethylene glycol.

4. The method of claim 3, wherein in step (2), the polyethylene glycol has a molecular weight of 1000 or less.

5. The method of claim 4, wherein in step (2), the polyethylene glycol has a molecular weight of 800 or less.

6. The method according to claim 1, wherein in the step (2), the amount of the dispersing agent is 0.04-0.20 g/L based on the volume of the sodium vanadium solution added in the step (1).

7. The method of claim 1, wherein in step (2), the ammonium salt is ammonium sulfate.

8. The method according to claim 1, wherein in step (3), the pH is adjusted with sulfuric acid.

9. The method according to claim 1, wherein in the step (3), the temperature of the heating reaction is 60 to 90 ℃.

10. The method according to claim 1, wherein in the step (3), the holding time of the heating reaction is 30-60 min.

Technical Field

The invention relates to the technical field of ammonium polyvanadate preparation, in particular to a method for preparing ammonium polyvanadate from sodium vanadium solution with low ammonium content.

Background

In the vanadium slag sodium salt vanadium extraction process, vanadium slag is roasted, soaked in water and subjected to impurity removal to obtain qualified sodium salt vanadium liquid, and the qualified sodium salt vanadium precipitation process is adopted to obtain Ammonium Polyvanadate (APV). One of the main uses of ammonium polyvanadate is in the preparation of vanadium oxide products for ferrovanadium smelting, but generally only at densities of 0.6g/cm³The ammonium polyvanadate can meet the requirements of subsequent smelting.

In the conventional acidic ammonium salt vanadium precipitation process, ammonium sulfate is mostly used as a precipitating agent, the pH value of the precipitate is controlled to be about 2.0, and ammonium polyvanadate is obtained under the boiling condition. In the process of precipitating ammonium polyvanadate, because qualified liquid contains a large amount of sodium ions, in order to improve the vanadium precipitation rate and ensure the product quality, excessive ammonium salt is often added, and in order to obtain high density (rho is more than 0.6 g/cm)³) Ammonium polyvanadate, the amount of ammonium salt used is generally higher. Excessive ammonium salt can enter the vanadium precipitation wastewater to obtain high-ammonia-nitrogen vanadium precipitation wastewater, and the wastewater treatment cost is increased.

In the aspect of preparing high-density ammonium polyvanadate, Liqian (research on morphology control technology of products in ammonium salt vanadium precipitation process) adopts an acidic ammonium salt vanadium precipitation process to precipitate ammonium polyvanadate, and researches on influences of vanadium liquid concentration, precipitation pH value, ammonium salt addition amount, precipitation time and precipitation temperature on morphology of the precipitated ammonium polyvanadate. The results show that: and (3) reacting at the temperature of more than 70 ℃ for 30min under the conditions that the pH value of vanadium precipitation is 2.2 and the ammonium coefficient K is 2.3 (the mass ratio of ammonium sulfate to the total vanadium mass of the solution), so as to obtain a spherical APV product, wherein the vanadium precipitation rate is more than 99%. The method comprises the steps of adding seed crystal which is more than 1/50 times of the mass of the total vanadium and ammonium sulfate which is 1.5-2.5 times of the mass of the total vanadium into solution containing 20-30 g/L vanadium at 60-85 ℃, adjusting the pH to 2.1-2.4 by using sulfuric acid, precipitating for 40min and 20min at the rotating speeds of 350r/min and 200r/min in sequence in a boiling water bath at 95 ℃, obtaining the vanadium precipitation rate of more than 98.5 percent, wherein the bulk density of the dried APV is more than 0.95g/cm³。

Chinese patent CN 104876268B adopts alcohol amine to mix with soluble ammonium salt and vanadium-containing solution, then adjusts pH value to react, obtains high-density ammonium polyvanadate; chinese patent CN 108557884B introduces amino acid as a binding agent to prepare large-particle high-density ammonium polyvanadate; chinese patent CN 1294084C utilizes the reaction of sulfuric acid and ammonia water to synthesize ammonium sulfate, ammonia water and sulfuric acid are added into the solution step by step, and the high-density ammonium polyvanadate product is obtained by controlling the pH value of the solution and adding seed crystals; in the Chinese patent CN 109081374B, the vanadium-containing purification solution is added into a crystallizer, the heating rate is controlled to be 0.1-3 ℃/h, the temperature of the vanadium-containing purification solution is increased to 85-95 ℃, ammonium salt is added in the heating process, and the pH value is adjusted; and after the temperature of the vanadium-containing purification solution reaches a preset value, continuously adding the vanadium-containing purification solution into the crystallizer, controlling the heating rate to be 6-10 ℃/h, keeping the temperature of the vanadium-containing purification solution at 85-95 ℃, adding ammonium salt and adjusting the pH in the heating process, and crystallizing to obtain spherical ammonium polyvanadate with the particle size of more than 150 mu m.

Therefore, the preparation of high-density ammonium polyvanadate requires addition of a large amount of ammonium salt, introduction of other additives or precise control of the operation process, which results in high production cost. In view of the above, the present invention provides a method for obtaining high density ammonium polyvanadate by precipitation with low ammonium salt addition.

Disclosure of Invention

The invention aims to solve the problem that the high-density ammonium polyvanadate is prepared by adding a large amount of ammonium salt, introducing other impurities or accurately controlling the operation process in the prior art, so that the production cost is high.

In order to achieve the aim, the invention provides a method for preparing ammonium polyvanadate from sodium vanadium solution with low ammonium content, which comprises the following steps:

(1) introducing CO into the sodium vanadium solution₂Adjusting the pH value of the sodium vanadium solution to 8-9, and filtering after reaction to obtain a purified solution;

(2) adding a dispersing agent and ammonium salt into the purified liquid obtained in the step (1), and stirring and dissolving, wherein the using amount of the ammonium salt is 0.6-1 time of the mass of all vanadium in the sodium vanadium solution;

(3) and (3) adjusting the pH value of the solution obtained in the step (2) to 1.8-2.2, then heating for reaction, keeping the temperature under the stirring condition, filtering after the reaction is finished, and washing a solid product to obtain the high-density ammonium polyvanadate.

Preferably, in the sodium vanadium solution in the step (1), V is 20-50 g/L, and P is less than 0.015 g/L.

Preferably, in step (2), the dispersant is polyethylene glycol.

Preferably, in step (2), the molecular weight of the polyethylene glycol is 1000 or less.

Preferably, in step (2), the molecular weight of the polyethylene glycol is less than or equal to 800.

Preferably, in the step (2), the dosage of the dispersant is 0.04-0.20 g/L based on the volume of the sodium vanadium solution added in the step (1).

Preferably, in step (2), the ammonium salt is ammonium sulfate.

Preferably, in step (3), the pH is adjusted with sulfuric acid.

Preferably, in the step (3), the temperature of the heating reaction is 60-90 ℃.

Preferably, in the step (3), the heat preservation time of the heating reaction is 30-60 min.

Compared with the prior art, the invention has the following advantages: (1) the method is suitable for qualified sodium vanadium liquid (c) (P) is less than 0.015g/L) with the V concentration of 20-50 g/L, and has wide application range; (2) the bulk density of the ammonium polyvanadate prepared by the method is more than 0.7g/cm³(ii) a (3) The ammonium addition coefficient K (the ratio of the using amount of ammonium salt to the mass of all vanadium in the sodium vanadium solution) is 0.6-1.0, the using amount of ammonium salt is reduced by more than 50%, the production cost is obviously reduced, the vanadium precipitation rate is equivalent to that of the existing high-density vanadium precipitation process, and NH in the upper-layer filtrate₄ ⁺The concentration is about 5g/L (K is 0.8), which is beneficial to simplifying the subsequent wastewater treatment process.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a method for preparing ammonium polyvanadate from sodium vanadium solution with low ammonium content, which comprises the following steps:

(1) introducing CO into the sodium vanadium solution₂Adjusting the pH value of the sodium vanadium solution to 8-9, and filtering after reaction to obtain a purified solution;

(2) adding a dispersing agent and ammonium salt into the purified liquid obtained in the step (1), and stirring and dissolving, wherein the using amount of the ammonium salt is 0.6-1 time of the mass of all vanadium in the sodium vanadium solution;

(3) and (3) adjusting the pH value of the solution obtained in the step (2) to 1.8-2.2, then heating for reaction, keeping the temperature under the stirring condition, filtering after the reaction is finished, and washing a solid product to obtain the high-density ammonium polyvanadate.

In general, the sodium vanadium solution contains impurity P, which affects the vanadium precipitation process and product quality, so before the acidic ammonium salt vanadium precipitation, the sodium vanadium solution is dephosphorized. Therefore, the main impurities in the sodium vanadium solution are silicon and contain more sodium, although the silicon has little influence on the vanadium precipitation process, the inventor finds that the density of the product can be influenced after the silicon enters the ammonium polyvanadate product, and the quality of the product can be influenced after the sodium impurity enters the ammonium polyvanadate product. Based on the method, the invention provides a preparation method of high-density ammonium polyvanadate, the product quality is high, the impurities are few, and NH in the obtained waste liquid₄ ⁺The concentration is low, which is beneficial to the treatment of subsequent wastewater.

The method adopts the technical scheme that: firstly introducing CO into the sodium vanadium solution₂Adjusting the pH value of the sodium vanadium solution to a certain range to separate out impurity Si, and simultaneously removing partial Na (namely sodium pre-desiliconized) in the solution, wherein the chemical reaction formula is Na₂SiO₃+2CO₂+2H₂O＝2NaHCO₃+H₂SiO₃↓; then adding a dispersant and a small amount of ammonium salt into the filtered purified liquid, and adding polyethylene glycol before vanadium precipitation to control the vanadium precipitation rate and avoid forming fine ammonium polyvanadate particles due to too fast nucleationAnd granulating to obtain high-density ammonium polyvanadate.

In a specific embodiment of the method, in the sodium vanadium solution in the step (1), V is 20-50 g/L (for example, 20g/L, 25g/L, 30g/L, 35g/L, 40g/L, 45g/L or 50g/L), and P is less than 0.015 g/L. The method has wide application range and can be applied to the sodium vanadium solution with V concentration in a wider range.

In a specific embodiment, in the step (1), CO is introduced into the sodium vanadium solution₂The pH of the sodium vanadium solution can be adjusted to 8, 8.2, 8.4, 8.6, 8.8, or 9.

In a specific embodiment, in step (2), the dispersant may be polyethylene glycol, preferably polyethylene glycol having a molecular weight of 1000 or less, for example, a molecular weight of 200, 400, 600, 800, 1000, etc. In a more preferred embodiment, the polyethylene glycol has a molecular weight of 800 or less.

In a preferred embodiment, in the step (2), the amount of the dispersant is 0.04-0.20 g/L, for example, 0.04g/L, 0.06g/L, 0.08g/L, 0.1g/L, 0.12g/L, 0.14g/L, 0.16g/L, 0.18g/L or 0.20g/L based on the volume of the sodium vanadium solution added in the step (1).

In the method of the present invention, the ammonium salt may be a common acidic ammonium salt, such as ammonium sulfate, ammonium chloride, sodium nitrate, etc., but in consideration of the difficulty in post-treating wastewater with anions such as chloride, nitrate, etc., in a preferred embodiment, in step (2), ammonium sulfate is used as the ammonium salt.

In particular embodiments, considering that the introduction of sulfate ions into the waste stream is easier to handle than other common anions, in a preferred embodiment, in step (3), the pH is adjusted with sulfuric acid.

In a specific embodiment, in step (3), the pH of the solution obtained in step (2) may be adjusted to 1.8, 1.9, 2, 2.1 or 2.2.

In the method of the present invention, in order to increase the vanadium precipitation rate and the density of the obtained ammonium polyvanadate product on the basis of adding a dispersant and a small amount of ammonium salt, in a preferred embodiment, in the step (3), the temperature of the heating reaction is 60 to 90 ℃, for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃ or 90 ℃. In a preferred embodiment, in the step (3), the heat preservation time of the heating reaction is 30-60 min, such as 30min, 35min, 40min, 45min, 50min, 55min or 60 min.

The ammonium polyvanadate prepared by the method has higher density (more than 0.6 g/cm)³) And the subsequent smelting requirements can be met.

The present invention will be described in detail by way of examples, but the scope of the present invention is not limited thereto.

TABLE 1 Components and contents/g.L of qualified vanadium liquid for sodium modification in examples 1 to 3^-1。

Examples	V	Cr	P	Si	Na
						Example 1	20.74	2.04	＜0.01	0.56	22.84
Example 2	30.13	2.64	＜0.01	0.79	31.82
						Example 3	49.76	3.89	＜0.01	1.80	48.57
Comparative example 1	33.92	2.31	＜0.01	0.64	36.17

Example 1

Introducing CO into 1000mL of qualified sodium vanadium solution₂Gas, so that the pH value of the solution is reduced to 8.0; filtering to obtain purified vanadium liquid; adding 0.04g of polyethylene glycol (molecular weight is 1000, the dosage of the polyethylene glycol is 0.04g/L) and 20.74g of ammonium sulfate (the dosage of the ammonium sulfate is 1 time of the total vanadium mass in the sodium vanadium solution), stirring and dissolving, and then adjusting the pH value of the solution to 1.8 by adopting sulfuric acid; heating to 90 deg.C, reacting under stirring for 60min, filtering, and washing to obtain ammonium polyvanadate with vanadium precipitation rate of 99.05% and bulk density of 0.75g/cm³。

Example 2

Introducing CO into 600mL of qualified sodium vanadium solution₂Gas, so that the pH value of the solution is reduced to 9.0; filtering to obtain purified vanadium liquid; adding 0.1g polyethylene glycol (molecular weight 600, polyethylene glycol dosage is 0.17g/L) and 14.46g ammonium sulfate (ammonium salt dosage is 0.8 times of total vanadium mass in sodium vanadium solution), stirring for dissolving,then adjusting the pH value of the solution to 2 by adopting sulfuric acid; heating to 80 deg.C, reacting under stirring for 30min, filtering, and washing to obtain ammonium polyvanadate with vanadium precipitation rate of 99.38% and bulk density of 0.81g/cm³。

Example 3

Introducing CO into 1500mL of qualified sodium vanadium solution₂Gas, so that the pH value of the solution is reduced to 8.4; filtering to obtain purified vanadium liquid; adding 0.2g of polyethylene glycol (the molecular weight is 400, and the dosage of the polyethylene glycol is 0.13g/L) and 8.96g of ammonium sulfate (the dosage of the ammonium salt is 0.6 times of the total vanadium mass in the sodium vanadium solution), stirring and dissolving, and then adjusting the pH value of the solution to 2.2 by adopting sulfuric acid; heating to 60 deg.C, reacting under stirring for 45min, filtering, and washing to obtain ammonium polyvanadate with vanadium precipitation rate of 99.57% and bulk density of 0.83g/cm³。

Comparative example 1

Adding 33.92g of ammonium sulfate (the dosage of ammonium salt is 2.0 times of the total vanadium mass in the sodium vanadium solution) into 500mL of sodium-treated qualified vanadium solution, stirring for dissolving, and then adjusting the pH value of the solution to 2.0 by adopting sulfuric acid; heating to boiling, reacting for 45min under stirring, filtering, and washing to obtain ammonium polyvanadate with vanadium precipitation rate of 99.81% and bulk density of 0.78g/cm³。

It can be seen from examples 1 to 3 and comparative example 1 that the amount of ammonium salt used in the examples was reduced by 50% or more than that in comparative example 1, but the vanadium deposition rate and the bulk density of ammonium polyvanadate in the examples were comparable to those in comparative example 1.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.