Study on preparation of VOSO4 by chemical synthesis of sodium metavanadate
Vanadium sulfate(VOSO4)electrolyte is the active material and energy carrier of electro-chemical reaction in vanadium battery,and its quality directly affects the performance of vanadium bat-tery such as energy efficiency,energy density and service life.In this paper,VOSO4 was synthesized from sodium metavanadate(NaVO3)and sodium sulfite(Na2SO3)by reduction,precipitation,acid dis-solution and crystallization.The effects of various factors on vanadium recovery were investigated,and the intermediate products VO(OH)2 and VOSO4 were characterized.The results show that vanadium(Ⅴ)can be reduced to vanadium(Ⅳ)by adding sodium sulfite into the leaching solution of sodium metavanadate with a mass ratio of m(V)∶m(S)of 1∶0.5 and keeping it at 70 ℃ for 60 min in a solution with pH 2.5.When pH value was adjusted to 7.0 and the reaction temperature was 20 ℃ for 10 min,the blue solution could be converted into VO(OH)2 intermediate product,achieving a highest vanadium re-covery of 98.51％.The diameter of VO(OH)2 spherical structure was 50～200 nm.Blue VOSO4 solution can be obtained by dissolving VO(OH)2 with sulfuric acid.After drying and crystallizing,VOSO4 crys-tal with an average diameter of 5 μm was obtained,and the quality of the product met the second grade standard of national standard.This study provides a preliminary experimental basis for in-situ prepara-tion of VOSO4 from sodium leaching solution of vanadium slag.
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