Method for preventing scabbing in ammonium metavanadate crystallization process

Abstract

The invention provides a method for preventing scabbing in an ammonium metavanadate crystallization process. The method includes steps: 1) preparing ammonium metavanadate mother liquor, naturally cooling and crystallization, and taking an obtained solid phase as seed crystal and a liquid phase as circulating liquid; adding the circulating liquid into a crystallizer, stirring, adding the seed crystal into the crystallizer, starting low-temperature thermostatic reaction bath, and controlling the temperature of the circulating liquid in the crystallizer to be constant all the time; 2) preparing ammonium metavanadate mother liquor identical to ammonium metavanadate mother liquor prepared at the step 1) in concentration, keeping warm in constant-temperature water bath, and adopting a flow pump to slowly add the ammonium metavanadate mother liquor into the crystallizer; 3) allowing an upper discharging port of the crystallizer to discharge intermittently to guarantee constant concentration of the circulating liquid. By addition of the seed crystal and reduction of the supersaturation degree of the mother liquor, scabbing of walls is effectively prevented, heat transferring is benefited, descaling time is saved, production efficiency is improved, and the process is simple in operation and beneficial to industrial production.

Description

technical field [0001] The invention belongs to the technical field of vanadium chemical metallurgy and relates to a method for preventing scabbing during the crystallization process of ammonium metavanadate. Background technique [0002] Crystallization is an important chemical process and one of the main means of substance purification. Many chemical and pharmaceutical products and intermediate products appear in the form of crystals, and crystallization is often the best and most economical way to produce them on a large scale. [0003] During the crystallization process of ammonium metavanadate, some crystalline fine particles will adhere to the heat transfer interface (the inner wall of the cooling crystallizer or the inner wall of the pipe) to form scars, and the amount of scars accounts for about 8-12% of the total crystallization amount. Ammonium vanadate scarring has the following disadvantages: (1) process heat transfer coefficient decreases, cooling energy consum...

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Problems solved by technology

[0006] Although the above two methods can effectively avoid scarring, the purchase of new equipment requires a large amount of money, which increases production costs

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