| 摘要 |
PURPOSE:To obtain extremely high purity Mo or W powder, by bringing aq. soln. obtd. by decomposing material powder of Mo or W with H2O2 water and strong acid, into contact with cation exchange resin, heating and condensing the obtd. aq. soln. to solid material and hydrogen reducing it. CONSTITUTION:Mo or W powder contg. a much quantity of impurity controlled usually to 0.1-100mum grain size especially 1-30mum is decomposed by H2O2 water adjusted to 5-35wt% especially 20-35wt% concn. and strong acid. Acid concn. thereat regulated to <=0.4N especially 0.05-0.2 N, and decomposition is carried out while cooling to <=60 deg.C. Next aq. soln. obtd. in above described process is brought into contact with cation exchange resin, impurity existing as cation is adsorbed to cation exchange resin and removed. Next, solid material obtd. by heating, condensing above described aq. soln. after ion exchanging treatment at 100-300 deg.C usually is heated and reduced at 800-1,000 deg.C in H2 atmosphere by ordinary method to obtain extremely high purity Mo or W powder having ppb order impurity content.
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