| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for preparing a tetravalent vanadium compound wherein the highly pure tetravalent vanadium compound is obtained in a high yield from combustion ash of fossil fuel through few purification steps. SOLUTION: The preparation process comprises a step (a) wherein pH of a suspension containing the combustion ash of the fossil fuel is adjusted to≤3 and insoluble residues are removed through filtration, a step (b) wherein the solution is brought into contact with an oxidizing agent to convert vanadium ions within the solution into pentavalent vanadium ions, a step (c) wherein the pentavalent vanadium ions are adsorbed by an anion-exchange resin, a step (d) wherein aqueous ammonia solution is brought into contact with the anion-exchange resin to obtain an aqueous ammonia solution having the pentavalent vanadium ions and a step (e) wherein a reducing agent is added to precipitate vanadium oxyhydroxide hydrate. COPYRIGHT: (C)2004,JPO
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