CN112250110A - A kind of preparation method of ammonium metavanadate without waste water discharge - Google Patents

Abstract

The invention discloses a method for preparing ammonium metavanadate without waste water discharge. back extraction liquid; (2) vanadium precipitation: add a certain amount of ammonium bicarbonate to the desorption liquid or back extraction liquid of step ( ₁ ) or pass _CO and NH in the solution to carry out vanadium precipitation to obtain ammonium metavanadate and crystallization mother liquor; (3) mother liquor transformation: the crystallization mother liquor of step (2) is added one or both in calcium oxide or calcium hydroxide to transform, and the transformed transformed liquor after the transformation returns to carry out the next round of desorption or back extraction . In the present invention, since the crystallization mother liquor can be recycled after conversion, the discharge of waste water is reduced, thus avoiding the discharge of a large amount of ammonia-nitrogen mixed waste water in the process of preparing ammonium metavanadate by the traditional ion exchange and extraction process, and greatly reducing desorption or reverse reaction. The consumption of alkali in the extraction process reduces the production cost and facilitates industrialization.

Description

A kind of preparation method of ammonium metavanadate without waste water discharge

technical field

The invention relates to the technical field of producing ammonium metavanadate, in particular to a method for preparing ammonium metavanadate without waste water discharge.

Background technique

As a rare metal with high melting point, vanadium is widely used in steel, chemical industry, new energy, medicine and other fields because of its various excellent properties, and has the reputation of "modern industrial monosodium glutamate". The main use of vanadium is still in the metallurgical industry. Adding vanadium to steel can significantly improve the mechanical properties of steel and increase plasticity, wear resistance and corrosion resistance.

The reserves and output of vanadium in my country rank first in the world. The main vanadium-containing minerals are vanadium-titanium magnetite and stone coal. With the development of steel, vanadium batteries, and vanadium-titanium alloys in China, the consumption of vanadium resources will continue to increase. increase. my country's vanadium extraction process has been very mature after years of development, but with the increasingly stringent requirements on environmental protection, the traditional vanadium extraction process still needs to be updated and improved.

At present, the main methods of producing vanadium pentoxide at home and abroad are:

Sodium roasting-water leaching method: Vanadium-containing resources are subjected to sodium roasting and then water leaching to obtain leaching solution, and the leaching solution is subjected to acid precipitation to coarsely precipitate vanadium. At this time, there are many impurities in the crude vanadium. Ammonium precipitation of vanadium, the obtained ammonium metavanadate is calcined to obtain qualified vanadium pentoxide.

Direct acid leaching-extraction method: Vanadium-containing resources are directly leached with concentrated sulfuric acid. After the leaching solution is reduced, P204+TBP is used to extract vanadium oxy cations. Vanadium, calcined to obtain vanadium pentoxide.

Calcification roasting-dilute acid leaching: Vanadium-containing resources are leached with dilute sulfuric acid after calcification roasting, the leaching solution is adsorbed by ion exchange or solvent extraction, the obtained loaded resin or loaded organic phase is desorbed or stripped with sodium hydroxide, and the desorption solution or stripped The liquid is impurity-removed with magnesium salt, after impurity removal, ammonium chloride is added to precipitate vanadium, and vanadium pentoxide is obtained by calcining after the precipitation of vanadium.

Oxidative roasting-dilute acid leaching-ion exchange/extraction: Vanadium-containing resources are leached by adding sulfuric acid after oxidative roasting, and the leaching solution is adsorbed or enriched by ion exchange, and the obtained loaded resin or loaded organic phase is desorbed or stripped with sodium hydroxide, The obtained solution is added with ammonium chloride to precipitate vanadium to obtain ammonium metavanadate, and after calcination, vanadium pentoxide is obtained.

In addition to the above several processes, in the current vanadium extraction process, stone coal or vanadium slag is leached after roasting, and the obtained leaching solution is subjected to ammonium salt precipitation after a series of treatments, and ammonium chloride or ammonium sulfate is mostly used in industry. Vanadium precipitation, although this method has good effect of vanadium precipitation, but the crystallization mother liquor after vanadium precipitation is a mixed solution of sodium chloride and ammonium chloride, which belongs to high-salt ammonia nitrogen wastewater. Evaporative crystallization is often used in the industry to treat the above-mentioned waste water, which not only has high cost and energy consumption, but also produces a large amount of mixed salt of sodium chloride and ammonium chloride. This mixed salt may become a dangerous solid waste, and its treatment will further increase cost. Secondly, in order to obtain a higher vanadium precipitation rate and reduce the vanadium concentration in the crystallization mother liquor, the current process needs to add a large excess of ammonium salt, resulting in waste of reagents. As my country's requirements for environmental protection are getting higher and higher, the problems caused by traditional vanadium precipitation need to be solved urgently.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for preparing ammonium metavanadate without waste water discharge, aiming at solving the problem of the discharge of a large amount of ammonia-nitrogen mixed waste water in the process of preparing ammonium metavanadate by traditional ion exchange and extraction process.

In order to achieve the above object, the present invention proposes a method for preparing ammonium metavanadate without waste water discharge, comprising the following steps:

(1) desorption or stripping: desorption or stripping of the vanadium-adsorbed loaded resin or the loaded organic phase through the transformation liquid, to obtain a desorption liquid or stripping solution;

(2) vanadium precipitation: add a certain amount of ammonium bicarbonate in the desorption solution of step (1) or the stripping liquid or pass into CO in solution and NH Carry out vanadium precipitation, obtain ammonium metavanadate and crystallization mother liquor;

(3) mother liquor transformation: the crystallization mother liquor of step (2) is added one or both of calcium oxide or calcium hydroxide to transform, and the transformed transformed liquor after the transformation returns to carry out the next round of desorption or back extraction.

Preferably, in step (1), the loaded resin is a weakly basic ion exchange resin.

Preferably, in step (1), the loaded organic phase is a weakly alkaline extractant.

Preferably, the weakly basic extractant includes a tertiary amine extractant, a primary amine extractant or a secondary amine extractant.

Preferably, in step (1), the conversion solution is a mixture of one or both of sodium carbonate solution or sodium hydroxide solution.

Preferably, in the step (2), the amount of ammonium bicarbonate added is 1-3 times the theoretical amount, the vanadium precipitation time is 0.1-5h, and the vanadium precipitation temperature is 0-60°C.

Preferably, the addition amount of one or both of calcium oxide or calcium hydroxide in step (3) is 1-3 times the theoretical amount, the conversion time is 0.5-4h, and the conversion temperature is 20-100°C.

Preferably, one or both of sodium carbonate or sodium hydroxide is supplemented during the next round of desorption or stripping of the transformed liquid.

Compared with the prior art, the method for preparing ammonium metavanadate without waste water discharge proposed by the present invention has at least the following beneficial effects: no ammonia nitrogen waste water and waste salts are produced, the consumption of reagents is low, the operation is simple, and the equipment requirements are low. , the cost is low, the recycling of resources is realized, and it is easy to realize industrialization.

Description of drawings

Fig. 1 is the flow chart of a kind of ammonium metavanadate preparation method without waste water discharge proposed by the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. These implementations are only used to illustrate the present invention and not to limit the scope of the present invention.

Preparation of experimental materials:

A certain concentration of vanadium-containing raw material solution is adjusted to pH=2-4, and the vanadium-containing raw material solution is one or more of stone coal acid leaching solution, vanadium-containing waste catalyst acid leaching solution and vanadium-titanium magnetite slag leaching solution.

Example Preparation of loaded resin: take the prepared vanadium-containing raw material solution, V ₂ O ₅ =13.84g/L, pH = 2.5, and adsorb with weakly basic anion resin to obtain a loaded resin (per 1 ml of resin is loaded with about 220 mg of V ₂ O ₅ ).

Please refer to Fig. 1 for the flow chart of the specific ammonium metavanadate preparation method without waste water discharge.

Example 1

(1) The prepared loaded resin is used as the raw material, and the sodium carbonate with a concentration of 1 mol/L is used as the desorbent to desorb.

(2) statically desorb the obtained loaded resin under the condition that the liquid-solid ratio is 10:1, the desorption time is 2h, the temperature is 25°C, and the desorption rate is over 99%.

(3) Add ammonium bicarbonate to the solution after desorption to precipitate vanadium, the amount of ammonium bicarbonate added is 1.5 times the theoretical amount, the temperature is 25°C, the time for vanadium precipitation is 40min, the pH is about 9.8, and the rate of vanadium precipitation reaches 95.6% .

(4) The crystallization mother liquor after vanadium precipitation is transformed, the amount of calcium oxide added is 1 times the theoretical amount, the transformation temperature is 80 ° C, the transformation time is 2h, the transformed solution is a sodium carbonate solution, and the liquid-solid ratio is 5 : 1 to desorb the loaded resin, and the desorption rate is greater than 99%.

Embodiment 2

(1) Using the prepared loaded resin as a raw material, desorb with a mixed solution of sodium carbonate with a concentration of 0.5 mol/L and sodium hydroxide with a concentration of 0.5 mol/L as a desorbent.

(2) Under the condition that the liquid-solid ratio is 5:1, the obtained loaded resin is statically desorbed, the desorption time is 2h, the temperature is 25°C, and the desorption rate is greater than 99%.

(3) in the solution after desorption, add ammonium bicarbonate for vanadium precipitation, the amount of ammonium bicarbonate added is 1.5 times the theoretical amount, the temperature is 25 ° C, the vanadium precipitation time is 40min, the pH is more than 10, and the vanadium precipitation rate reaches 97.7% .

(4) The crystallization mother liquor after vanadium precipitation is transformed, the amount of calcium oxide added is 1 times the theoretical amount, the transformation temperature is 80 ° C, the transformation time is 2h, the transformed solution is a sodium carbonate solution, and the liquid-solid ratio is 5 : 1 to desorb the loaded resin, and the desorption rate is greater than 99%.

Embodiment 3

(1) The prepared loaded resin is used as the raw material, and the sodium hydroxide with a concentration of 1 mol/L is used as the desorbent to desorb.

(2) statically desorb the obtained loaded resin under the condition that the liquid-solid ratio is 2:1, the desorption time is 2h, the temperature is 25°C, and the desorption rate is greater than 99%.

(3) in the solution after desorption, add ammonium bicarbonate for vanadium precipitation, the amount of ammonium bicarbonate added is 1.6 times the theoretical amount, the temperature is 25 ° C, the time for vanadium precipitation is 40min, the adjustment pH is about 9, and the vanadium precipitation rate reaches 98 %.

(4) The crystallization mother liquor after vanadium precipitation is transformed, the amount of calcium oxide added is 1 times the theoretical amount, the transformation temperature is 80 ° C, the transformation time is 2h, the transformed solution is a sodium carbonate solution, and the liquid-solid ratio is 5 : 1 to desorb the loaded resin, and the desorption rate is greater than 99%.

Embodiment 4

(1) Using the prepared loaded organic phase (100 mg V ₂ O ₅ per 1 ml of extractant) as a raw material, and using sodium hydroxide with a concentration of 1 mol/L as a desorbent to desorb.

(2) carrying out back-extraction on the obtained loaded organic phase under the condition that the ratio is 2:1, the back-extraction time is 10min, the temperature is 25°C, and the back-extraction rate is greater than 99%.

(3) in the solution after desorption, add ammonium bicarbonate for vanadium precipitation, the amount of ammonium bicarbonate added is 1.6 times the theoretical amount, the temperature is 25 ° C, the time for vanadium precipitation is 40min, the pH is adjusted to be about 9, and the vanadium precipitation rate reaches 95 %.

(4) the crystallization mother liquor after the vanadium precipitation is transformed, the amount of calcium oxide added is 1 times of the theoretical amount, the transformation temperature is 80 ° C, the transformation time is 2h, and the transformed solution is a sodium carbonate solution, and the ratio is 2: Under the condition of 1, the loaded organic phase is back-extracted, and the back-extraction rate is greater than 99%.

The invention utilizes the leaching solution containing vanadium resources as raw material, and removes cationic impurities while extracting vanadium through weakly basic anion exchange resin adsorption or weakly basic extraction agent. At the same time, ammonium bicarbonate is used for vanadium precipitation, which further reduces the introduction of anions. The crystallization mother liquor after vanadium precipitation is causticized by adding calcium oxide or calcium hydroxide, realizing the recycling of crystallization mother liquor, reducing the production of high-salt wastewater, reducing environmental pollution, low reagent consumption, low cost and simple operation , easy to industrialize.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still understand the foregoing embodiments. The technical solutions described are modified, or some technical features thereof are equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. A method for preparing ammonium metavanadate without wastewater discharge is characterized by comprising the following steps:

(1) desorption or back extraction: desorbing or back-extracting the loaded resin or loaded organic phase adsorbing vanadium by using conversion solution to obtain desorption solution or back-extraction solution;

(2) and (3) vanadium precipitation: adding a certain amount of ammonium bicarbonate into the desorption solution or the strip solution in the step (1) or introducing CO into the solution₂And NH₃Precipitating vanadium to obtain ammonium metavanadate and crystallization mother liquor;

(3) mother liquor conversion: and (3) adding the crystallization mother liquor obtained in the step (2) into one or two of calcium oxide or calcium hydroxide for conversion, and returning the converted conversion liquor for next round of desorption or back extraction.

2. The method for preparing ammonium metavanadate without waste water discharge according to claim 1, wherein in the step (1), the loaded resin is a weakly basic ion exchange resin.

3. The method for preparing ammonium metavanadate without waste water discharge according to claim 1, wherein in the step (1), the loaded organic phase is a weakly alkaline extractant.

4. The method for preparing ammonium metavanadate without wastewater discharge according to claim 3, wherein the weakly basic extractant comprises a tertiary amine extractant, a primary amine extractant or a secondary amine extractant.

5. The method for preparing ammonium metavanadate without waste water discharge according to claim 1, wherein in the step (1), the conversion solution is one or a mixture of sodium carbonate solution and sodium hydroxide solution.

6. The method for preparing ammonium metavanadate without wastewater discharge according to claim 1, wherein the addition amount of ammonium bicarbonate in the step (2) is 1-3 times of the theoretical amount, the vanadium precipitation time is 0.1-5h, and the vanadium precipitation temperature is 0-60 ℃.

7. The method for preparing ammonium metavanadate without wastewater discharge according to claim 1, wherein the addition amount of one or both of calcium oxide or calcium hydroxide in the step (3) is 1 to 3 times of the theoretical amount, the conversion time is 0.5 to 4 hours, and the conversion temperature is 20 to 100 ℃.

8. The method according to claim 1, wherein one or both of sodium carbonate and sodium hydroxide are supplemented during the process of returning the converted solution to the next round of desorption or stripping.

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