阅读说明：本技术 一种偏钒酸铵制备低价钒尾气处理方法 (Method for treating tail gas generated in preparation of low-valence vanadium from ammonium metavanadate ) 是由 张春雨 于 2020-12-28 设计创作，主要内容包括：一种偏钒酸铵制备低价钒的工艺尾气处理方法,包括以下步骤：(1)将粗偏钒酸铵在水中加热溶解,溶解后用氢氧化钠溶液调节pH值至8-9,过滤,得偏钒酸钠溶液；(2)往偏钒酸钠溶液中加入氨水,得偏钒酸铵沉淀；偏钒酸铵沉淀经脱水后用稀氯化铵的水溶液水洗,水洗后再经脱水、焙烧得五氧化二钒；(3)将所得五氧化二钒和碳粉、石墨烯混合均匀,得混合料；(4)将混合料于惰性气体保护下,烧制,得三氧化二钒；(5)收集气体,通入喷淋罐内溶解,喷淋后的气体降温液化。本发明焙烧温度低,焙烧时间短,反应活性高,本发明所得低价钒氧化物中,三氧化二钒的纯度≥99.8%,尾气中检测不到氨气体。(A process tail gas treatment method for preparing low-valence vanadium from ammonium metavanadate comprises the following steps: (1) heating and dissolving crude ammonium metavanadate in water, adjusting the pH value to 8-9 by using a sodium hydroxide solution after dissolving, and filtering to obtain a sodium metavanadate solution; (2) adding ammonia water into the sodium metavanadate solution to obtain ammonium metavanadate precipitate; dehydrating the ammonium metavanadate precipitate, washing with water of a dilute ammonium chloride aqueous solution, dehydrating after washing with water, and roasting to obtain vanadium pentoxide; (3) uniformly mixing the obtained vanadium pentoxide with carbon powder and graphene to obtain a mixture; (4) firing the mixture under the protection of inert gas to obtain vanadium trioxide; (5) collecting gas, introducing into a spraying tank for dissolving, and cooling and liquefying the sprayed gas. The method has the advantages of low roasting temperature, short roasting time and high reaction activity, and in the low-valence vanadium oxide obtained by the method, the purity of vanadium trioxide is more than or equal to 99.8 percent, and ammonia gas cannot be detected in tail gas.)

1. The method for treating tail gas generated in preparation of low-valence vanadium by ammonium metavanadate is characterized by comprising the following steps of:

(1) heating and dissolving crude ammonium metavanadate in water, adjusting the pH value to 8-9 by using a sodium hydroxide solution after dissolving, and filtering to obtain a sodium metavanadate solution; adding sodium hydroxide to generate ammonia gas, and collecting the generated ammonia gas;

(2) adding ammonia water into the sodium metavanadate solution obtained in the step (1) to obtain ammonium metavanadate precipitate; dehydrating the ammonium metavanadate precipitate, washing with water of a dilute ammonium chloride aqueous solution, dehydrating after washing with water, and roasting to obtain vanadium pentoxide; ammonia gas, ammonium chloride gas and hydrogen chloride gas are generated in the operation and reaction processes, and the gases are collected;

(3) uniformly mixing the vanadium pentoxide obtained in the step (2), carbon powder and graphene according to a molar ratio of 2: 1: 0.005-0.01 to obtain a mixture;

(4) firing the mixture obtained in the step (3) for 1-5 h at 500-650 ℃ under the protection of inert gas to obtain vanadium trioxide; a mixed gas of carbon dioxide and inert gas is generated in the step;

(5) and (3) collecting the gas generated in the steps (1), (2) and (4) to obtain mixed gas, firstly introducing the mixed gas into a spraying tank, dissolving and spraying with ferrous sulfate aqueous solution, cooling the sprayed gas to below 5 ℃ for liquefaction, and discharging the cooled and liquefied gas.

2. The method for treating tail gas generated in the preparation of low-valence vanadium by using ammonium metavanadate according to claim 1, wherein in the step (4), the inert gas is nitrogen or argon.

3. The method for treating tail gas generated in the preparation of low-valence vanadium by using ammonium metavanadate according to claim 1 or 2, wherein in the step (1), the heating and dissolving temperature of the crude ammonium metavanadate in water is 90-100 ℃, and the weight ratio of the crude ammonium metavanadate to the water is 1: 3-4.

4. The method for treating tail gas generated in the preparation of low-valence vanadium by using ammonium metavanadate according to claim 1 or 2, wherein in the step (2), the mass concentration of ammonium chloride in the dilute ammonium chloride aqueous solution is 1% -10%.

5. The method for treating tail gas generated in the preparation of low-valence vanadium by using ammonium metavanadate according to claim 1 or 2, wherein in the step (2), ammonia water is added into the sodium metavanadate solution obtained in the step (1) until no precipitate is generated.

6. The method for treating tail gas generated in the preparation of low-valence vanadium from ammonium metavanadate according to claim 1 or 2, wherein in the step (5), the concentration of ferrous sulfate in the ferrous sulfate aqueous solution is 10-30 g/L.

7. The method for treating tail gas generated in the preparation of low-valence vanadium from ammonium metavanadate according to claim 1 or 2, wherein in the step (5), the sprayed gas is cooled to 0-5 ℃ and liquefied.

Technical Field

The invention relates to the technical field of low-valence vanadium production and tail gas treatment, in particular to a method for treating tail gas generated in preparation of low-valence vanadium by ammonium metavanadate.

Background

The vanadium resource is rich in China, the application of vanadium products is wide, in recent years, along with the technical progress, the industrial production of some downstream high-end technical products of vanadium has higher requirements on the quality of vanadium compounds, and the most introduced attention is the low-valence oxide of vanadium, especially vanadium dioxide (VO)₂) And vanadium (V) oxide₂O₃) When the temperature changes, the vanadium dioxide and the vanadium trioxide have phase changes, namely the arrangement mode of atoms changes, and the phase changes are accompanied by considerable mutation on the magnetic, electric and optical properties of the material, so that the vanadium dioxideVanadium oxide and vanadium trioxide can be used for manufacturing various electronic and optical devices such as current-limiting elements, thermosensitive devices, intelligent window coatings and other application materials, so that upgrading of the production process of low-cost vanadium is very important.

The production method of vanadium trioxide in the prior art is prepared by reducing vanadium pentoxide by hydrogen, carbon or carbon monoxide, or thermally decomposing vanadium pentoxide at 1750 ℃ and calcining ammonium vanadate in the absence of air. However, these production methods have high requirements on the calcination temperature, high cost and complicated operation.

And if the ammonium metavanadate is used for preparing the low-valence vanadium, when the purity of the ammonium metavanadate as a raw material is not high, the purity of the obtained low-valence vanadium is also low, and the application value of the low-valence vanadium is influenced. And a large amount of tail gas can be generated in the production process, and if the tail gas is not treated, the tail gas is directly discharged, so that the environmental pollution is inevitably caused.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and provides a tail gas treatment method for preparing low-valence vanadium from ammonium metavanadate, which has the advantages of lower roasting temperature and tail gas recovery treatment to avoid environmental pollution.

The invention solves the technical problem by adopting the technical scheme that the method for treating the tail gas generated in the preparation of low-valence vanadium by using ammonium metavanadate comprises the following steps:

(1) heating and dissolving crude ammonium metavanadate in water, adjusting the pH value to 8-9 by using a sodium hydroxide solution after dissolving, and filtering to obtain a sodium metavanadate solution; a small amount of ammonia gas is generated after the sodium hydroxide is added, and the generated small amount of ammonia gas is collected;

in the step (1), some soluble impurities or impurities which can be dissolved in the alkali solution sodium hydroxide solution are removed, and the purity of the sodium metavanadate solution is improved.

(2) Adding ammonia water into the sodium metavanadate solution obtained in the step (1) to obtain ammonium metavanadate precipitate; dehydrating the ammonium metavanadate precipitate, washing with water of a dilute ammonium chloride aqueous solution, dehydrating after washing with water, and roasting to obtain vanadium pentoxide; ammonia gas, ammonium chloride gas, hydrogen chloride gas and the like can be generated in the operation and reaction processes, and the gases are collected;

in the step (2), the purity of the ammonium metavanadate precipitate is further improved, and the purity of vanadium pentoxide can be improved and the content of impurities in the vanadium pentoxide can be reduced through water washing.

(3) Uniformly mixing the vanadium pentoxide obtained in the step (2), carbon powder and graphene according to a molar ratio of 2: 1: 0.005-0.01 to obtain a mixture;

(4) firing the mixture obtained in the step (3) for 1-5 h at 500-650 ℃ under the protection of inert gas to obtain vanadium trioxide; a mixed gas of carbon dioxide and inert gas is generated in the step;

(5) and (3) collecting the gas generated in the steps (1), (2) and (4) to obtain mixed gas, firstly introducing the mixed gas into a spraying tank, dissolving and spraying with ferrous sulfate aqueous solution, cooling the sprayed gas to below 5 ℃ (preferably 0-5 ℃) for liquefaction, and discharging the cooled and liquefied gas.

The mixed gas is firstly introduced into a spraying tank, ferrous sulfate aqueous solution is used for dissolving and spraying, most of ammonia gas, ammonium chloride and hydrogen chloride which are easily dissolved in water can be dissolved in water, and the ferrous sulfate aqueous solution is used as a solvent, so that the dissolving speed can be accelerated, and the dissolving amount can be improved. The sprayed gas is cooled to below 5 ℃ for liquefaction, the gas coming out of the ferrous sulfate aqueous solution can be liquefied at low temperature, and the cooled and liquefied gas basically only contains inert gas and carbon dioxide and can be discharged.

Further, in the step (4), the inert gas may be nitrogen, argon, or the like.

Further, in the step (5), the concentration of the ferrous sulfate in the ferrous sulfate aqueous solution is 10-30 g/L. The concentration of the ferrous sulfate is too low, so that the ferrous sulfate does not greatly assist in dissolution, and the depth of the ferrous sulfate is too high, so that the waste of resources is caused, and the dissolution of gas is not facilitated.

Researches show that graphene has very good heat conduction performance, trace graphene is added into solid powder, so that the material is heated uniformly, and the affinity of the graphene helps to form a nano-pore structure; and (4) improving the activity of the reaction of the material at the lower roasting temperature and the shorter roasting time in the step (4), forming a stable structure, obtaining a target product and improving the purity of the vanadium trioxide. Moreover, the addition of graphene is superior to the addition of graphite, probably because of the special structure inside graphene, which graphite does not have such structure and performance.

Further, in the step (1), the heating and dissolving temperature of the crude ammonium metavanadate in water is 90-100 ℃, and the weight ratio of the crude ammonium metavanadate to the water is 1: 3-4.

Further, in the step (2), the mass concentration of ammonium chloride in the dilute ammonium chloride aqueous solution is 1% -10%.

Further, in the step (2), ammonia water is added to the sodium metavanadate solution obtained in the step (1) until no precipitate is generated.

The invention has the beneficial effects that:

1. the vanadium trioxide produced by the method has high purity and few impurities, and completely meets the production requirements of some high-end products.

2. The method has the advantages of short process flow, simple equipment, low cost, high benefit, low roasting temperature, short roasting time and high reaction activity, and is very suitable for large-scale industrial production.

3. The invention can recycle and treat the tail gas in the production process to be harmless and then discharge the tail gas into the air, thereby avoiding environmental pollution, and the ammonia in the tail gas can be recycled.

In the low-valence vanadium oxide obtained by the method, the purity of vanadium trioxide is more than or equal to 99.8%.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

The method for treating tail gas generated in the preparation of low-valence vanadium from ammonium metavanadate comprises the following steps:

(1) heating and dissolving the crude ammonium metavanadate in water, adjusting the pH value to 8 by using a sodium hydroxide solution after dissolving, and filtering to obtain a sodium metavanadate solution; a small amount of ammonia gas is generated after the sodium hydroxide is added, and the generated small amount of ammonia gas is collected;

in the step (1), some soluble impurities or impurities which can be dissolved in the alkali solution sodium hydroxide solution are removed, and the purity of the sodium metavanadate solution is improved.

In the step (1), the heating and dissolving temperature of the crude ammonium metavanadate in water is 90 ℃, and the weight ratio of the crude ammonium metavanadate to the water is 1: 3.

(2) Adding ammonia water into the sodium metavanadate solution obtained in the step (1) to obtain ammonium metavanadate precipitate; dehydrating the ammonium metavanadate precipitate, washing with water of a dilute ammonium chloride aqueous solution, dehydrating after washing with water, and roasting to obtain vanadium pentoxide; ammonia gas, ammonium chloride gas, hydrogen chloride gas and the like can be generated in the operation and reaction processes, and the gases are collected;

in the step (2), the purity of the ammonium metavanadate precipitate is further improved, and the purity of vanadium pentoxide can be improved and the content of impurities in the vanadium pentoxide can be reduced through water washing.

In the step (2), the mass concentration of ammonium chloride in the dilute ammonium chloride aqueous solution is 5%.

In the step (2), ammonia water is added into the sodium metavanadate solution obtained in the step (1) until no precipitate is generated.

(3) Uniformly mixing the vanadium pentoxide obtained in the step (2), carbon powder and graphene according to a molar ratio of 2: 1: 0.005 to obtain a mixture;

(4) firing the mixture obtained in the step (3) for 1h at 500 ℃ under the protection of argon gas to obtain vanadium trioxide; a mixed gas of carbon dioxide and inert gas is generated in the step;

(5) and (3) collecting the gas generated in the steps (1), (2) and (4) to obtain mixed gas, firstly introducing the mixed gas into a spraying tank, dissolving and spraying with ferrous sulfate aqueous solution, cooling the sprayed gas to 5 ℃ for liquefaction, and discharging the cooled and liquefied gas.

The concentration of ferrous sulfate in the ferrous sulfate aqueous solution is 10 g/L.

Researches show that graphene has very good heat conduction performance, trace graphene is added into solid powder, so that the material is heated uniformly, and the affinity of the graphene helps to form a nano-pore structure; and (4) improving the activity of the reaction of the material at the lower roasting temperature and the shorter roasting time in the step (4), forming a stable structure, obtaining a target product and improving the purity of the vanadium trioxide. Moreover, the addition of graphene is superior to the addition of graphite, probably because of the special structure inside graphene, which graphite does not have such structure and performance.

In the low-valence vanadium oxide obtained in the embodiment, the purity of vanadium trioxide is 99.9%. Gases such as ammonia are not detected in the discharged gas.

Example 2

The method for treating tail gas generated in the preparation of low-valence vanadium from ammonium metavanadate comprises the following steps:

(1) heating and dissolving the crude ammonium metavanadate in water, adjusting the pH value to 9 by using a sodium hydroxide solution after dissolving, and filtering to obtain a sodium metavanadate solution; a small amount of ammonia gas is generated after the sodium hydroxide is added, and the generated small amount of ammonia gas is collected;

in the step (1), some soluble impurities or impurities which can be dissolved in the alkali solution sodium hydroxide solution are removed, and the purity of the sodium metavanadate solution is improved.

(2) Adding ammonia water into the sodium metavanadate solution obtained in the step (1) to obtain ammonium metavanadate precipitate; dehydrating the ammonium metavanadate precipitate, washing with water of a dilute ammonium chloride aqueous solution, dehydrating after washing with water, and roasting to obtain vanadium pentoxide; ammonia gas, ammonium chloride gas, hydrogen chloride gas and the like can be generated in the operation and reaction processes, and the gases are collected;

in the step (2), the purity of the ammonium metavanadate precipitate is further improved, and the purity of vanadium pentoxide can be improved and the content of impurities in the vanadium pentoxide can be reduced through water washing.

(3) Uniformly mixing the vanadium pentoxide obtained in the step (2), carbon powder and graphene according to a molar ratio of 2: 1: 0.01 to obtain a mixture;

(4) firing the mixture obtained in the step (3) for 2 hours at 500 ℃ under the protection of argon inert gas to obtain vanadium trioxide; a mixed gas of carbon dioxide and inert gas is generated in the step;

(5) collecting the gas generated in the steps (1), (2) and (4) to obtain mixed gas, firstly introducing the mixed gas into a spraying tank, dissolving and spraying with ferrous sulfate aqueous solution, cooling the sprayed gas to 0 ℃ for liquefaction, and discharging the cooled and liquefied gas.

The concentration of ferrous sulfate in the ferrous sulfate aqueous solution is 30 g/L.

Researches show that graphene has very good heat conduction performance, trace graphene is added into solid powder, so that the material is heated uniformly, and the affinity of the graphene helps to form a nano-pore structure; and (4) improving the activity of the reaction of the material at the lower roasting temperature and the shorter roasting time in the step (4), forming a stable structure, obtaining a target product and improving the purity of the vanadium trioxide. Moreover, the addition of graphene is superior to the addition of graphite, probably because of the special structure inside graphene, which graphite does not have such structure and performance.

In the step (1), the heating and dissolving temperature of the crude ammonium metavanadate in water is 100 ℃, and the weight ratio of the crude ammonium metavanadate to the water is 1: 3.

Further, in the step (2), the mass concentration of ammonium chloride in the aqueous solution of diluted ammonium chloride is 1%.

Further, in the step (2), ammonia water is added to the sodium metavanadate solution obtained in the step (1) until no precipitate is generated.

In the low-valence vanadium oxide obtained by the method, the purity of vanadium trioxide is 99.8%. Gases such as ammonia are not detected in the discharged gas.

Example 3

The method for treating tail gas generated in the preparation of low-valence vanadium from ammonium metavanadate comprises the following steps:

(1) heating and dissolving the crude ammonium metavanadate in water, adjusting the pH value to 8 by using a sodium hydroxide solution after dissolving, and filtering to obtain a sodium metavanadate solution; a small amount of ammonia gas is generated after the sodium hydroxide is added, and the generated small amount of ammonia gas is collected;

in the step (1), some soluble impurities or impurities which can be dissolved in the alkali solution sodium hydroxide solution are removed, and the purity of the sodium metavanadate solution is improved.

(2) Adding ammonia water into the sodium metavanadate solution obtained in the step (1) to obtain ammonium metavanadate precipitate; dehydrating the ammonium metavanadate precipitate, washing with water of a dilute ammonium chloride aqueous solution, dehydrating after washing with water, and roasting to obtain vanadium pentoxide; ammonia gas, ammonium chloride gas, hydrogen chloride gas and the like can be generated in the operation and reaction processes, and the gases are collected;

in the step (2), the purity of the ammonium metavanadate precipitate is further improved, and the purity of vanadium pentoxide can be improved and the content of impurities in the vanadium pentoxide can be reduced through water washing.

(3) And (3) uniformly mixing the vanadium pentoxide obtained in the step (2), carbon powder and graphene according to a molar ratio of 2: 1: 0.008 to obtain a mixture.

(4) Firing the mixture obtained in the step (3) for 5 hours at 550 ℃ under the protection of argon inert gas to obtain vanadium trioxide; a mixed gas of carbon dioxide and inert gas is generated in the step;

(5) collecting the gas generated in the steps (1), (2) and (4) to obtain mixed gas, firstly introducing the mixed gas into a spraying tank, dissolving and spraying with ferrous sulfate aqueous solution, cooling the sprayed gas to 2 ℃ for liquefaction, and discharging the cooled and liquefied gas.

In the step (5), the concentration of the ferrous sulfate in the ferrous sulfate aqueous solution is 20 g/L.

Researches show that graphene has very good heat conduction performance, trace graphene is added into solid powder, so that the material is heated uniformly, and the affinity of the graphene helps to form a nano-pore structure; and (4) improving the activity of the reaction of the material at the lower roasting temperature and the shorter roasting time in the step (4), forming a stable structure, obtaining a target product and improving the purity of the vanadium trioxide. Moreover, the addition of graphene is superior to the addition of graphite, probably because of the special structure inside graphene, which graphite does not have such structure and performance.

In the step (1), the heating and dissolving temperature of the crude ammonium metavanadate in water is 95 ℃, and the weight ratio of the crude ammonium metavanadate to the water is 1: 3.5.

In the step (2), the mass concentration of ammonium chloride in the dilute ammonium chloride aqueous solution is 2%.

In the step (2), ammonia water is added into the sodium metavanadate solution obtained in the step (1) until no precipitate is generated.

In the low-valence vanadium oxide obtained by the method, the purity of vanadium trioxide is 99.9%. Gases such as ammonia are not detected in the discharged gas.

Comparative example 1

The operation and parameters of this comparative example were the same as those of example 1, except that graphite was used instead of graphene in step (4).

In the step (4) of the comparative example, vanadium trioxide can not be obtained by low-temperature roasting. But the roasting temperature in the step (4) is increased to more than 1200 ℃, and when the roasting is carried out for 3 hours, vanadium trioxide can be obtained, and the purity of the vanadium trioxide in the obtained low-valence vanadium oxide is 99.0%.

Comparative example 2

The operation and parameters of the comparative example are the same as those of example 1 except that the addition amount of the graphene in the step (4) is the ratio of vanadium pentoxide to carbon powder to graphene according to the molar ratio of 2: 1: 0.001.

In the low-valence vanadium oxide obtained in this example, the purity of vanadium trioxide is 99.0%. Probably because the addition amount of graphene is not sufficient, the reaction purity is not high.

Comparative example 3

The operation and parameters of the comparative example are the same as those of example 1 except that the addition amount of the graphene in the step (4) is the ratio of vanadium pentoxide to carbon powder to graphene according to the molar ratio of 2: 1: 0.03.

In the low-valence vanadium oxide obtained in this embodiment, the purity of vanadium trioxide is 99.0%, and impurities of graphene exist. Probably because the addition amount of graphene is too much, the reaction is not complete, and the purity of the final product is influenced.

Comparative example 5

The operation and parameters of this comparative example were the same as those of example 1 except that the concentration of the aqueous solution of ferrous sulfate in step (5) was 2 g/L. A small amount of ammonia-containing gas was detected in the discharged gas.

Comparative example 6

The operation and parameters of this comparative example were the same as those of example 1 except that the concentration of the aqueous solution of ferrous sulfate in step (5) was 40 g/L. A small amount of ammonia-containing gas was detected in the discharged gas.