阅读说明：本技术 钒溶液制备氧化钒及钠、铵循环的方法 (Method for preparing vanadium oxide and circulating sodium and ammonium by using vanadium solution ) 是由 付自碧 彭毅 李明 蒋霖 于 2020-07-06 设计创作，主要内容包括：本发明属于钒的湿法冶金技术领域,具体涉及钒溶液制备氧化钒及钠、铵循环的方法。本发明所要解决的技术问题是提供钒溶液制备氧化钒及钠、铵循环的方法,包括以下步骤：A、钒溶液除硅得到除硅后液,浓缩除硅后液,通CO<Sub>2</Sub>调节体系pH为7.0～9.0,然后在45～80℃进行一次结晶,得到碳酸氢钠；一次结晶母液降温至20～35℃进行二次结晶,得到偏钒酸钠；B、将偏钒酸钠溶于水中,加入氯化铵和碳酸氢铵沉钒得到偏钒酸铵和沉钒上层液；C、沉钒上层液中加入碳酸氢铵并结晶得到碳酸氢钠和结晶母液。本发明方法实现了钠、铵介质的循环利用,减少了试剂的消耗,降低了工艺成本。(The invention belongs to the technical field of vanadium hydrometallurgy, and particularly relates to a method for preparing vanadium oxide and circulating sodium and ammonium by using a vanadium solution. The invention aims to solve the technical problem of providing a method for preparing vanadium oxide and circulating sodium and ammonium by using a vanadium solution, which comprises the following steps: A. removing silicon from vanadium solution to obtain silicon-removed solution, concentrating the silicon-removed solution, introducing CO 2 Adjusting the pH value of the system to 7.0-9.0, and then carrying out primary crystallization at 45-80 ℃ to obtain sodium bicarbonate; cooling the primary crystallization mother liquor to 20-35 ℃ for secondary crystallization to obtain sodium metavanadate; B. dissolving sodium metavanadate in water, adding ammonium chloride and ammonium bicarbonate to precipitate vanadium to obtain ammonium metavanadate and a vanadium precipitation supernatant; C. adding ammonium bicarbonate into the supernatant of the vanadium precipitation and crystallizing to obtain the bicarbonateSodium and crystallization mother liquor. The method realizes the recycling of sodium and ammonium media, reduces the consumption of reagents and reduces the process cost.)

1. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution is characterized by comprising the following steps: the method comprises the following steps:

A. removing silicon from the vanadium solution to obtain a silicon-removed solution, concentrating the silicon-removed solution to a vanadium concentration of 110-160 g/L, introducing CO₂Adjusting the pH value of the system to 7.0-9.0, and then carrying out primary crystallization at 45-80 ℃ to obtain sodium bicarbonate and primary crystallization mother liquor; cooling the primary crystallization mother liquor to 20-35 ℃ for secondary crystallization to obtain sodium metavanadate and secondary crystallization mother liquor;

B. dissolving sodium metavanadate in water, adding ammonium chloride and ammonium bicarbonate to precipitate vanadium to obtain ammonium metavanadate and vanadium precipitation supernatant, and calcining ammonium metavanadate to obtain vanadium pentoxide;

C. and B, adding ammonium bicarbonate into the upper layer solution of the precipitated vanadium obtained in the step B, and crystallizing to obtain sodium bicarbonate and crystallization mother liquor.

2. The method for preparing vanadium oxide and recycling sodium and ammonium by using the vanadium solution as claimed in claim 1, is characterized in that: c, the crystallization mother liquor obtained in the step C is returned to be used for dissolving sodium metavanadate in the step B; preferably, when the crystallization mother liquor is returned for dissolving sodium metavanadate, the mole number of the added sodium metavanadate is controlled to be +/-5% different from the mole number of the ammonium bicarbonate added into the vanadium precipitation upper-layer liquor when the crystallization mother liquor is prepared; more preferably the same.

3. The method for preparing vanadium oxide and recycling sodium and ammonium from vanadium solution according to claim 1 or 2, characterized in that: and (C) returning the sodium bicarbonate obtained in the step (A) and/or the step (C) to be used for the leaching process of the clinker after the vanadium slag roasting.

4. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution according to any one of claims 1 to 3, characterized by comprising the following steps: and B, returning the secondary crystallization mother liquor obtained in the step A to be mixed with the liquid after silicon removal, and repeating the step A to concentrate, crystallize and separate sodium bicarbonate and sodium metavanadate.

5. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution as claimed in any one of claims 1 to 4, wherein the method comprises the following steps: in the step A, sodium aluminate is adopted for silicon removal; further, the silicon removal temperature is 50-90 ℃; the time is 10-60 min.

6. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution as claimed in any one of claims 1 to 4, wherein the method comprises the following steps: in the step B, the adding amount of the ammonium chloride is NH according to the molar ratio₄ ⁺the/V is 2-4: 1; the adding amount of ammonium bicarbonate is calculated as HCO according to molar ratio₃ ^-/Na＝1.0～1.5:1。

7. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution as claimed in any one of claims 1 to 4, wherein the method comprises the following steps: in the step B, the vanadium precipitation temperature is between normal temperature and 50 ℃.

8. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution as claimed in any one of claims 1 to 4, wherein the method comprises the following steps: in the step C, the difference between the adding amount of the ammonium bicarbonate and the mole number of the sodium metavanadate is +/-5 percent; further, the number of moles was the same.

9. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution as claimed in any one of claims 1 to 4, wherein the method comprises the following steps: in the step C, the crystallization temperature is 5-30 ℃.

10. The method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution according to any one of claims 1 to 9, wherein the method comprises the following steps: in the step A, the vanadium solution is obtained by calcifying and roasting vanadium slag to obtain roasted clinker, and the roasted clinker is obtained by leaching sodium-containing carbonate;

further, the calcific roasting step comprises: at least one of the following is satisfied:

the particle size of the vanadium slag is-0.125 mm;

the amount of the calcium salt for calcification roasting is 0 to 8 percent of the mass of the vanadium slag by taking CaO as the weight;

the temperature of the calcification roasting is 800-950 ℃; the time is 40-200 min;

further, the sodium carbonate leaching step: at least one of the following is satisfied:

the sodium-containing carbonate is sodium carbonate or sodium bicarbonate;

the concentration of the sodium bicarbonate is 130-220 g/L;

the solid-to-solid ratio of the leaching solution is 1.5-5.0 mL:1 g;

the leaching temperature is 80-100 ℃; the leaching time is 30-150 min.

Technical Field

The invention belongs to the technical field of vanadium hydrometallurgy, and particularly relates to a method for preparing vanadium oxide and circulating sodium and ammonium by using a vanadium solution.

Background

The vanadium slag is a main raw material for preparing vanadium oxide, and the traditional production process is sodium roasting-water vanadium extraction. In the vanadium extraction process, the vanadium extraction tailings containing about 6 percent of sodium oxide can be generated, the vanadium extraction tailings are difficult to be reused, and a vanadium-chromium reduction filter cake and a large amount of solid waste sodium sulfate are difficult to treat, so that the environmental protection hidden danger is large; a large amount of sodium carbonate is consumed in the vanadium extraction process, and the process cost is high. In order to reduce the production cost of vanadium oxide and eliminate the hidden trouble of environmental protection, the process idea of preparing vanadium oxide by calcifying roasting-carbonating leaching of vanadium slag is provided.

CN102560086A discloses a vanadium extraction method for leaching vanadium slag clinker with ammonium carbonate, which comprises leaching with 200-800 g/L ammonium carbonate solution and vanadium slag clinker at 60-98 ℃ according to a liquid-solid ratio of 5: 1-30: 1. The method has the advantages of high leaching agent consumption and high production cost; because the solubility of ammonium metavanadate is low, in order to avoid vanadium from precipitating into residues in the form of ammonium metavanadate, a larger liquid-solid ratio needs to be controlled, and the concentration of vanadium in the obtained leachate is lower; in addition, a large amount of ammonia escapes in the leaching process, so that the operating environment is influenced.

CN110106344A discloses a method for cleanly extracting vanadium by carbonating and leaching vanadium slag, which adopts the mixed leaching of sodium-containing carbonate and ammonium-containing carbonate to solve the problems caused by the single leaching of the ammonium-containing carbonate, and the clinker can be directly leached out by circulating the supernatant of the precipitated vanadium, but the leaching of the ammonium-containing carbonate can generate ammonia gas to influence the operating environment.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for preparing vanadium oxide and circulating sodium and ammonium by using a vanadium solution. The method comprises the following steps:

A. removing silicon from the vanadium solution to obtain a silicon-removed solution, concentrating the silicon-removed solution to a vanadium concentration of 110-160 g/L, introducing CO₂Adjusting the pH value of the system to 7.0-9.0, and then carrying out primary crystallization at 45-80 ℃ to obtain sodium bicarbonate and primary crystallization mother liquor; cooling the primary crystallization mother liquor to 20-35 ℃ for secondary crystallization to obtain sodium metavanadate and secondary crystallization mother liquor;

B. dissolving sodium metavanadate in water, adding ammonium chloride and ammonium bicarbonate to precipitate vanadium to obtain ammonium metavanadate and vanadium precipitation supernatant, and calcining ammonium metavanadate to obtain vanadium pentoxide;

C. and B, adding ammonium bicarbonate into the upper layer solution of the precipitated vanadium obtained in the step B, and crystallizing to obtain sodium bicarbonate and crystallization mother liquor.

Further, in the method for preparing vanadium oxide and recycling sodium and ammonium by using the vanadium solution, the crystallization mother liquor obtained in the step C is returned to be used for dissolving sodium metavanadate in the step B. When the crystallization mother liquor is returned for dissolving sodium metavanadate, the mole number of the added sodium metavanadate is preferably controlled to be similar to the mole number of the ammonium bicarbonate added into the vanadium precipitation upper layer liquor when the crystallization mother liquor is prepared, and the difference is +/-5%. More preferably the same. The crystallization mother liquor can dissolve sodium metavanadate without adding ammonium chloride and ammonium bicarbonate, and the sodium metavanadate can be directly dissolved to precipitate vanadium.

Further, in the method for preparing vanadium oxide and recycling sodium and ammonium by using the vanadium solution, the sodium bicarbonate obtained in the step A and/or the step C is returned to be used in the leaching process of the clinker after roasting the vanadium slag.

Further, in the method for preparing vanadium oxide and recycling sodium and ammonium by using the vanadium solution, the secondary crystallization mother liquor obtained in the step A is returned to be mixed with the liquid after silicon removal, and the step A is repeated to concentrate, crystallize and separate sodium bicarbonate and sodium metavanadate.

Specifically, in the step a of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, sodium aluminate is used for silicon removal.

Further, in the step A of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the silicon removal temperature is 50-90 ℃. The time is 10-60 min.

Specifically, in the step B of the method for preparing vanadium oxide and recycling sodium and ammonium from the vanadium solution, the addition amount of the water is such that the concentration of the sodium metavanadate is 30-50 g/L.

Specifically, in the step B of the method for preparing vanadium oxide by using the vanadium solution and circulating sodium and ammonium, the adding amount of the ammonium chloride is NH calculated according to the molar ratio₄ ⁺and/V is 2-4: 1. The adding amount of ammonium bicarbonate is calculated as HCO according to molar ratio₃ ^-/Na＝1.0～1.5:1。

Specifically, in the step B of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the vanadium precipitation temperature is between normal temperature and 50 ℃.

Preferably, in step C of the method for preparing vanadium oxide from the vanadium solution and recycling sodium and ammonium, the addition amount of ammonium bicarbonate is within ± 5% of the mole number of sodium metavanadate. Preferably the same.

Specifically, in the step C of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the crystallization temperature is 5-30 ℃.

Specifically, in the step A of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the vanadium solution is obtained by calcifying and roasting vanadium slag to obtain roasted clinker, and the roasted clinker is obtained by leaching sodium-containing carbonate. The vanadium slag is common vanadium slag or high-calcium high-phosphorus vanadium slag obtained by oxidizing and converting vanadium-containing molten iron.

Further, in the step A of the method for preparing vanadium oxide by using the vanadium solution and circulating sodium and ammonium, the granularity of the vanadium slag is-0.125 mm.

Further, in the step A of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the amount of the calcium salt for calcification roasting is 0-8% of the mass of the vanadium slag by taking CaO as a reference.

Further, in the step A of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the temperature of calcification roasting is 800-950 ℃. The time is 40-200 min.

Further, in step a of the method for preparing vanadium oxide from the vanadium solution and circulating sodium and ammonium, the sodium-containing carbonate is sodium carbonate or sodium bicarbonate.

Further, in the step A of the method for preparing vanadium oxide by using the vanadium solution and recycling sodium and ammonium, the concentration of the sodium bicarbonate is 130-220 g/L.

Further, in the step A of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the solid-to-solid ratio of the leaching solution is 1.5-5.0 mL:1 g.

Further, in the step A of the method for preparing vanadium oxide and circulating sodium and ammonium by using the vanadium solution, the leaching temperature is 80-100 ℃. The leaching time is 30-150 min.

The method adopts ammonium chloride and ammonium bicarbonate to precipitate vanadium together, not only improves the vanadium precipitation effect, but also solves the problem that the sodium salt can not be recovered in the form of sodium bicarbonate by single ammonium chloride vanadium precipitation, and also solves the problem that the quality of vanadium products is influenced by the high concentration of hydrogen carbonate in the solution and the common precipitation of ammonium metavanadate and sodium bicarbonate during the single ammonium bicarbonate vanadium precipitation. Because of the introduction of chloride ions, bicarbonate radical in the solution can be reduced, and the crystallization of the sodium bicarbonate in the vanadium precipitation process can be controlled. When the ammonium bicarbonate is supplemented into the vanadium precipitation upper layer liquid after vanadium precipitation to further crystallize sodium bicarbonate, the concentration of vanadium in the upper layer liquid is low, and ammonium metavanadate is not easy to separate out; further, since the solubility of sodium bicarbonate is low due to the increase of bicarbonate, sodium is easily crystallized and precipitated, and thus sodium is recovered as sodium bicarbonate.

The crystallization mother liquor can be returned to be directly used for dissolving sodium metavanadate, and when the mole numbers of ammonium bicarbonate and sodium metavanadate added into the vanadium precipitation upper layer liquor are controlled to be similar, the crystallization mother liquor can be recycled to dissolve the sodium metavanadate of the next batch all the time, and ammonium chloride and ammonium bicarbonate are not required to be added additionally. The sodium bicarbonate obtained in the two parts of the method can be returned to be used for the leaching procedure of the roasted clinker.

The method adopts vanadium slag blank or calcified roasting, and reduces the cost of roasting the additive. The leachate is crystallized and separated from sodium bicarbonate and sodium metavanadate step by step, so that the problem that subsequent vanadium precipitation is influenced by the high ratio of sodium to vanadium in the leachate is solved. The sodium metavanadate solution utilizes ammonium chloride and ammonium bicarbonate to precipitate vanadium, so that the vanadium precipitation rate and the recovery rate are improved, sodium salt is recovered, the cyclic utilization of ammonium salt is realized, and the generation of ammonia-containing gas is avoided.

The method solves the problems of high process cost and difficult utilization of solid waste tailings, vanadium-chromium reduction filter cakes and sodium sulfate in the traditional vanadium slag sodium salt roasting-water vanadium extraction, and realizes low-cost clean production of vanadium oxide.

Detailed Description

The invention provides a method for preparing vanadium oxide and circulating sodium and ammonium from vanadium slag, which comprises the following steps:

a. roasting: adding 0-8% (by mass, calculated as CaO) of calcium salt into vanadium slag with the particle size of-0.125 mm, uniformly mixing, and roasting at 800-950 ℃ for 40-200 min to obtain roasted clinker;

b. leaching: adding the roasted clinker into 130-220 g/L sodium bicarbonate solution, stirring and leaching at 80-100 ℃ for 30-150 min according to a liquid-solid ratio of 1.5-5.0: 1mL/g, and performing solid-liquid separation to obtain a leaching solution;

c. silicon removal: adding sodium aluminate into the leachate, stirring and reacting at 50-90 ℃ for 10-60 min to remove silicon, and carrying out solid-liquid separation to obtain a silicon-removed solution;

d. fractional crystallization: concentrating the desiliconized solution to the vanadium concentration of 110-160 g/L, introducing CO₂Adjusting the pH value to 7.0-9.0, and carrying out primary crystallization at 45-80 ℃ to obtain sodium bicarbonate solid and primary crystallization mother liquor; cooling the primary crystallization mother liquor to 20-35 ℃ for secondary crystallization to obtain sodium metavanadate solid and secondary crystallization mother liquor;

e. vanadium product preparation and sodium and ammonium circulation: dissolving sodium metavanadate solid in water, adding ammonium chloride and ammonium bicarbonate to precipitate ammonium metavanadate, and calcining ammonium metavanadate to obtain a vanadium pentoxide product; adding ammonium bicarbonate into the vanadium precipitation supernatant, and cooling and crystallizing to obtain sodium bicarbonate and crystallization mother liquor.

In the step a of the method, in order to fully expose the ferrovanadium spinel in the vanadium slag, facilitate the oxidation of the ferrovanadium spinel and the full contact reaction of the vanadium slag and calcium salt, the vanadium slag is crushed, and the vanadium slag with the granularity of less than 0.125mm is selected. Because the solubility of calcium metavanadate in water is larger than that of calcium pyrovanadate and calcium orthovanadate, the calcium metavanadate is beneficial to leaching, and in order to control the vanadium in the calcified roasting clinker to mainly exist in the form of calcium metavanadate, the amount of added calcium salt is 0-8 percent of the mass of the vanadium slag calculated by CaO.

In the step b of the method, the roasting clinker is leached by carbonate containing sodium, and the carbonation leaching is adopted because the solubility of calcium carbonate is lower than that of calcium metavanadate, calcium pyrovanadate and calcium n-vanadate, calcium ions and carbonate are combined into slag, and vanadium enters solution.

In step c of the method, sodium aluminate is used for removing silicon in the leaching solution.

In the step d of the method, the concentration of the solution after silicon removal is to improve the concentration of sodium and vanadium, the solubility of sodium metavanadate is far greater than that of sodium bicarbonate, sodium can be crystallized out in the form of sodium bicarbonate by introducing carbon dioxide into the concentrated solution, and the concentration of vanadium is controlled to be 110-160 g/L, and the primary crystallization temperature is controlled to be 45-80 ℃ to avoid the crystallization of sodium metavanadate; the primary crystallization mother liquor after sodium bicarbonate separation is cooled to 20-35 ℃ to crystallize sodium metavanadate and control sodium bicarbonate precipitation.

In the step d of the method, the secondary crystallization mother liquor can be returned to be mixed with the next batch of the liquid after the silicon removal, and the operation of concentrating, crystallizing and separating the sodium bicarbonate and the sodium metavanadate in the step d is continuously carried out.

In the step e of the method, the sodium metavanadate is precipitated by ammonium chloride and ammonium bicarbonate at the normal temperature of 50 ℃, on one hand, the ammonium chloride has better vanadium precipitation effect, the pH value of the precipitated vanadium can be controlled to be lower, and the method is favorable for improving the vanadium precipitation rate and controlling the volatilization of ammonia; on the other hand, ammonium bicarbonate provides partial ammonium and keeps certain bicarbonate concentration, which is beneficial to adding ammonium bicarbonate to the subsequent vanadium precipitation supernatant to crystallize sodium bicarbonate.

In the step e of the method, sodium metavanadate is dissolved in water, ammonium chloride and ammonium bicarbonate are adopted to precipitate vanadium to form ammonium metavanadate, and the supernatant of the precipitated vanadium contains ammonium ions and chloride ions in the ammonium chloride, bicarbonate ions in the ammonium bicarbonate and sodium ions in the sodium metavanadate. When adding ammonium bicarbonate into the upper layer liquid of the precipitated vanadium, sodium ions and bicarbonate ions in the system are promoted to form sodium bicarbonate to crystallize due to the increase of bicarbonate ions and the low solubility of the sodium bicarbonate, and the crystallization mother liquid contains ammonium ions and chloride ions in ammonium chloride and ammonium ions in the ammonium bicarbonate. And e, forming ammonium ions in the ammonium metavanadate and forming bicarbonate ions in the sodium bicarbonate, wherein the ammonium ions in the ammonium metavanadate and the bicarbonate ions in the sodium bicarbonate are equivalent to the ammonium bicarbonate added into the vanadium precipitation supernatant from the step e, and the metavanadate ions in the ammonium metavanadate and the sodium ions in the sodium bicarbonate are equivalent to the sodium metavanadate. The ammonium chloride and ammonium bicarbonate added simultaneously in step e is not consumed. Therefore, in order to maintain the stability of sodium and ammonium ions in the solution and recycle the crystallization mother liquor, the ammonium bicarbonate added in the vanadium precipitation supernatant liquid treated in the step e and the dissolved sodium metavanadate have similar mole numbers (difference is +/-5%, preferably the same). Namely, the ammonium bicarbonate added in the step e for treating the vanadium precipitation supernatant is preferably controlled to be similar to the dissolved sodium metavanadate of the batch in mole number (different by +/-5%, preferably the same). That is, when the crystallization mother liquor is preferably controlled to dissolve the sodium metavanadate of the next batch, the adding amount of the sodium metavanadate is similar to the mol number of the ammonium bicarbonate added in the upper vanadium precipitation layer liquid processed in the step e of the previous batch (the difference is +/-5%, preferably the same). And e, returning the crystallization mother liquor generated in the step e to be used for dissolving the next batch of sodium metavanadate, and directly dissolving the sodium metavanadate to precipitate vanadium without adding ammonium chloride and ammonium bicarbonate additionally.

In the step e of the method, ammonium chloride and ammonium bicarbonate are adopted for precipitating vanadium together, and the introduction of chloride ions can reduce bicarbonate radical in the solution, thereby being beneficial to controlling the crystallization of the sodium bicarbonate in the vanadium precipitation process. When the ammonium bicarbonate is supplemented into the vanadium precipitation upper layer liquid after vanadium precipitation to further crystallize sodium bicarbonate, the concentration of vanadium in the upper layer liquid is low, and ammonium metavanadate is not easy to separate out; further, since the solubility of sodium bicarbonate is low due to the increase of bicarbonate, sodium is easily crystallized and precipitated, and thus sodium is recovered as sodium bicarbonate.

The sodium bicarbonate obtained in the step d and/or the step e of the method can be returned to be used for the leaching process of the roasted clinker of the vanadium slag in the step b.

The present invention will be further illustrated by the following specific examples.