Method for high-efficiency preparation of high-purity sodium metavanadate

The invention belongs to the field of metallurgy and particularly relates to a preparation method of sodium metavanadate. The invention aims at providing a method for high-efficiency preparation of high-purity sodium metavanadate. The method comprises the following steps: (a) adding sulfuric acid and ammonium sulfate into a vanadium-extracting leaching solution; (b) adjusting pH value of the solution to 4-6, and filtering to obtain sodium ammonium vanadate solid; (c) adding the sodium ammonium vanadate solid into a sodium hydroxide solution, deaminizing, and adjusting pH value of the solution to 8-8.5 to obtain sodium metavanadate solution; and (d) carrying out spraying and flash evaporation on the sodium metavanadate solution to obtain sodium metavanadate solid. The preparation method provided by the invention has the advantages that the high-purity sodium metavanadate can be prepared, the crystallization efficiency and the yield of sodium metavanadate are obviously improved, the purity of sodium metavanadat