PROCESS

摘要

PROBLEM TO BE SOLVED: To produce a vanadyl/vanadous sulfate solution or its crystal used as an electrolyte for a vanadium redox battery. SOLUTION: The vanadyl/vanadous sulfate crystal is prepared from the vanadyl/vanadous sulfate solution and then water is added to the crystal and the vanadyl/vanadous sulfate solution is again prepared. The process comprises the steps; 1) a step to supply a starting substance as the vanadyl/vanadous sulfate solution having a specific chemical composition, 2) a step to obtain the crystal by heating the solution and 3) a step to obtain a clear solution having practically same chemical composition as the starting substance by dissolving the crystal again adding a specific volume of deionized water with continuous agitation, if necessary with heat.