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CN-121974397-A - Method for preparing vanadium trioxide from ammonium polyvanadate based on precalcination decomposition

CN121974397ACN 121974397 ACN121974397 ACN 121974397ACN-121974397-A

Abstract

The invention discloses a method for preparing vanadium trioxide based on ammonium polyvanadate and vanadium trioxide, which comprises the following steps of S1, pre-calcining and decomposing ammonium polyvanadate, wherein the ammonium polyvanadate is uniformly paved in a calcining kiln, calcining is carried out in an oxidizing atmosphere or an inert atmosphere at 400-650 ℃ to obtain powdery vanadium pentoxide, S2, the powdery vanadium pentoxide is collected and sent into a reducing kiln, the reduction reaction is carried out in the reducing atmosphere at 600-800 ℃, the solid-gas reaction state is kept in the reduction process all the time to obtain vanadium trioxide powder, and S3, the post-treatment is carried out, and the reduced vanadium trioxide powder is subjected to cooling screen to obtain a final product. According to the invention, through introducing a pre-calcination decomposition procedure, APV is converted into powdery V 2 O 5 , and the powdery V 2 O 5 enters a reduction kiln and is quickly reduced into low-valence vanadium oxide with high melting point, so that the possibility of ring formation of the reduction kiln is eliminated at the source, and the reduction reaction efficiency and the product purity are synchronously improved.

Inventors

  • YE LU
  • DU GUANGCHAO
  • SHEN BIAO
  • HUANG YUN

Assignees

  • 攀钢集团攀枝花钢铁研究院有限公司

Dates

Publication Date
20260505
Application Date
20251231

Claims (10)

  1. 1. A method for preparing vanadium trioxide based on precalcined decomposed ammonium polyvanadate, characterized by comprising the following steps: s1, pre-calcining and decomposing, namely calcining ammonium polyvanadate in an oxidizing atmosphere or an inert atmosphere at 400-650 ℃ to obtain powdery vanadium pentoxide; s2, reducing, namely carrying out reduction reaction on the powdery vanadium pentoxide in a reducing atmosphere at 600-800 ℃ to obtain vanadium trioxide powder; And S3, post-treatment, namely, carrying out post-treatment on the vanadium trioxide powder to obtain a final product.
  2. 2. The method for preparing vanadium trioxide based on pre-calcined decomposed ammonium polyvanadate according to claim 1, characterized in that in step S1, the temperature range of calcination is 450-550 ℃.
  3. 3. The method for preparing vanadium trioxide based on pre-calcined decomposed ammonium polyvanadate of claim 1, wherein in step S2, the reaction temperature of the reduction reaction is 650-750 ℃.
  4. 4. The method for preparing vanadium trioxide based on precalcined decomposed ammonium polyvanadate according to claim 1, characterized in that the oxidizing atmosphere is air or oxygen-enriched air.
  5. 5. The method for preparing vanadium trioxide based on precalcined decomposed ammonium polyvanadate according to claim 1, characterized in that the inert atmosphere is nitrogen or argon.
  6. 6. The method for preparing vanadium trioxide based on pre-calcined decomposed ammonium polyvanadate according to claim 1, characterized in that the calcination time ranges from 0.5 to 3 hours.
  7. 7. The method for preparing vanadium trioxide based on precalcined decomposed ammonium polyvanadate according to claim 1, characterized in that the calcination is carried out in a pusher kiln and/or a rotary kiln and/or a shuttle kiln.
  8. 8. The method for preparing vanadium trioxide based on precalcined decomposed ammonium polyvanadate according to claim 1, characterized in that the reducing atmosphere is composed of one or more of hydrogen, carbon monoxide, gas or ammonia decomposing gas.
  9. 9. The method for preparing vanadium trioxide based on precalcined decomposed ammonium polyvanadate of claim 1, wherein the material residence time of the reduction reaction is 1-3 hours.
  10. 10. The method for preparing vanadium trioxide based on precalcined decomposed ammonium polyvanadate according to claim 1, characterized in that the post-treatment comprises cooling and/or sieving.

Description

Method for preparing vanadium trioxide from ammonium polyvanadate based on precalcination decomposition Technical Field The invention relates to the technical field of vanadium fine chemical engineering and metallurgy, in particular to a method for preparing vanadium trioxide from ammonium polyvanadate based on precalcination decomposition. Background Vanadium trioxide (V 2O3) is a key intermediate product in the vanadium industry chain, and its quality directly affects the performance of downstream ferrovanadium, vanadium nitride and vanadium battery electrolytes. The main production route in industry is to take Ammonium Polyvanadate (APV) as a raw material, and introduce reducing gas (such as H 2) into a rotary kiln to perform one-step reduction. The chemical reaction of the process is complex and mainly comprises the decomposition of APV and the reduction of V 2O5: Decomposition stage 2NH 4V3O8→ 3V2O5+ 2NH3+ H2 O Stage of reduction V 2O5+ 2H2→ V2O3+ 2H2 O V2O5＋2CO=V2O3＋2CO2↑ 2V2O5＋CH4=2V2O3＋2H2O↑＋CO2↑ However, this conventional one-step reduction process has inherent, difficult to overcome drawbacks: (1) The reduction kiln is severely circled, and the decomposition reaction of APV and the melting of V 2O5 almost simultaneously occur in the heating process. V 2O5 has a melting point of about 690℃and the decomposition temperature interval of APV overlaps with this. The result is that the material melts into a liquid phase in the kiln before complete reduction. The molten V 2O5 has very strong viscosity and can be firmly adhered to the refractory lining of the rotary kiln, so that increasingly thickened 'loops' are formed. The problem of looping forces frequent interruptions of production for the clearing operation, greatly compromising the equipment utilization and production continuity, and presenting high maintenance costs and safety risks. (2) The reduction efficiency is low and the product grade is poor, and the V 2O5 in a molten state can wrap unreacted APV particles to form a compact shell layer so as to seriously prevent the diffusion of reducing gas into the particles. This "self-protecting" effect results in incomplete reduction reactions, requiring higher temperatures or longer residence times, and increased energy consumption. Unreduced V 2O5 or partially reduced VO 2 are often mixed in the final product, making it difficult to stabilize the purity (grade) of V 2O3 beyond 98.5%, limiting its application in high value fields. (3) The operation window is narrow, in order to avoid severe looping, the lower kiln head temperature is often forced to be adopted in actual operation, which in turn exacerbates the problem of incomplete reduction and forms vicious circle. In view of the above problems, the prior art has focused on the optimization of the reduction section itself. For example, the Chinese patent with the application publication number of CN102557134A provides a fluidization reactor suitable for producing high-purity vanadium trioxide and a production method, but the flow is long and the production cost is high, and the Chinese patent with the application publication number of CN101880059A provides a method for producing vanadium trioxide by adopting a fluidized bed reactor, so that the latent heat of tail gas at the outlet of the fluidized bed reactor and the sensible heat of high-temperature flue gas are fully utilized, the energy consumption in the production process is reduced, the economy is improved, and the problem of long flow still exists. In view of this, improvements should be made over the prior art. Disclosure of Invention According to the invention, through introducing a pre-calcination decomposition procedure, APV is converted into powdery V 2O5, and the powdery V 2O5 enters a reduction kiln and is quickly reduced into low-valence vanadium oxide with high melting point, so that the possibility of ring formation of the reduction kiln is eliminated at the source, and the reduction reaction efficiency and the product purity are synchronously improved. According to one aspect of the present invention, a method for preparing vanadium trioxide based on ammonium polyvanadate is presented, comprising the steps of: S1, pre-calcining and decomposing, namely uniformly paving ammonium polyvanadate in a calcining kiln, and calcining at 400-650 ℃ in an oxidizing atmosphere or an inert atmosphere to obtain powdery vanadium pentoxide; S2, reducing, namely collecting the powdery vanadium pentoxide, sending the powdery vanadium pentoxide into a reduction kiln, and carrying out reduction reaction in a reducing atmosphere at 600-800 ℃ to obtain vanadium trioxide powder, wherein the reduction process always maintains a solid-gas reaction state; and S3, post-treatment, namely obtaining a final product after the reduced vanadium trioxide powder is subjected to cooling screen. According to one embodiment of the present invention, in step S1, the calcination temperature ranges from 450 ℃ to 550 ℃. Acc