System and method for purifying and producing high-purity vanadium pentoxide powder

Abstract

The invention discloses a system and method for purifying and producing high-purity vanadium pentoxide powder, belonging to the fields of chemical engineering and materials. According to the invention, fluidizing low-temperature chlorination is used for converting industrial-grade vanadium pentoxide into vanadium oxytrichloride; through heat exchange between fluidization gas and chlorination flue gas, chlorination gas is preheated; a proper amount of air is added to allow a part of coke powder to combust, thus providing a balanced supply of heat during the process of chlorination, improving chlorination efficiency, and ensuring good selectivity of low-temperature chlorination; and the vanadium oxytrichloride is subjected to fluidized-vapor-phase ammoniation after distillation and purification and further to fluidized calcination to produce a high-purity vanadium pentoxide product. The system and method have the advantages that raw materials are good in adaptability, only a small amount of ammonia-nitrogen wastewater is discharged, low energy consumption in production and low cost in operation are realized, product quality is stable, etc.; and the system and method are applicable to large-scale industrial production of high-purity vanadium pentoxide having a purity of 4N or higher and have good economic benefits and social benefits.

Description

technical field [0001] The invention belongs to the fields of chemical industry and materials, and in particular relates to a system and method for purifying and preparing high-purity vanadium pentoxide powder. Background technique [0002] Vanadium pentoxide is one of the important industrial vanadium products, widely used in the production of alloy additives such as ferrovanadium and vanadium nitride, as well as catalysts, colorants, cemented carbide additives and other fields. With the continuous development of new energy technologies, the demand for high-purity vanadium pentoxide (purity above 3N5) is increasingly strong in the battery industry, including all-vanadium redox flow batteries (VRB) with good large-scale energy storage performance and vanadium for electric vehicles Acid-based lithium-ion batteries, etc. However, the existing industrial technology can usually only prepare vanadium pentoxide with a purity of 2N5 (that is, the product specified in HGT 3485-2003...

AI Technical Summary

Problems solved by technology

This patent has the following deficiencies: (1) Similar to the aforementioned Iowa State University research, this patent actually only provides the principle process of chlorination and lacks specific operable solutions. For example, the chlorination method includes boiling chlorine chlorination, including molten salt chlorination, and molten salt chlorination and boiling chlorination are completely different chlorination methods; for another example, it is proposed to use "rotary kiln, fluidized furnace, fluidized furnace, shaft furnace, "Multi-hearth furnace" and other reactors actually cover almost all commonly used mainstream reactors in the field of metallurgical industry, but different reactors have very different requirements for raw materials. The shaft furnace can only handle "coarse" particles larger than 8mm. "Fine particles" require pelletizing and pre-sintering treatment, and boiling chlorination is generally suitable for processing fine particles, so for a specific vanadium raw material, it cannot be directly applied to rotary kilns, fluidized furnaces, fluidized fluidized furnaces, shaft furnaces, multi- Hearth furnace and other reactors; besides, "fluidized furnace" and "fluidized fluidized furnace" are essentially the same, but they are called differently; it can be seen that because the operation methods and conditions of these reactors are very different, only the principle process is given. (2) vanadium oxychloride is passed into ultrapure aqueous solution and hydrolyzed, because vanadium pentoxide is very easy to dissolve in hydrochloric acid solution, the precipitation recovery rate of vanadium is too low; When HCl concentration is greater than 6.0mol / L In the hydrochloric acid solution, when vanadium pentoxide dissolves, it will be reduced to VOCl 2 , and release chlorine gas at the same time, which will further reduce the precipitation recovery rate of vanadium; the precipitation and washing process will inevitably produce a large amount of vanadium-containing hydrochloric acid solution, which is difficult to effectively realize comprehensive treatment

[0007] In addition, for large-scale industrial applications, the existing vanadium raw material chlorination technology still has the following two problems: (1) The chlorination and roasting of vanadium raw materials is a strong exothermic process, and the heat generated by the chlorination reaction can not only meet the needs of solid and gas In addition to the preheating of the reaction material, it is still necessary to remove it through furnace wall heat dissipation to stabilize the chlorination temperature. Therefore, solids and gases usually enter the reactor at a state close to room temperature, and can only participate in the reaction after being preheated by the heat generated by the chlorination reaction. The local reaction efficiency of the chlorination reactor is too low; (2) due to the need to remove the heat generated by the chlorination reaction through a large amount of heat dissipation to maintain the operating temperature, the operating conditions and environmental climate changes are likely to cause fluctuations in the chlorination temperature, resulting in chlorination selection Reduced performance and efficiency, it is necessary to adopt a reasonable heat balance supply and temperature control method

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