| 摘要 |
PURPOSE:To prepare high-purity beta-MnO2 at low cost stably, by treating electrolytic MnO2 or chemical synthesized MnO2 at high temperature, heat-treating it with nitric acid. CONSTITUTION:gamma-MnO2 such as electrolytic MnO2, chemically synthesized MnO2, etc. as a raw material is heated at 420-650 deg.C. In this heat treatment, beta-MnO2 is formed by phase transition of gamma-MnO2, Mn2O3 is produced simultaneously by thermal decomposition, and a mixture of both of the compounds is obtained. >=0.4Ml of 13 normal HNO3 based on 1g mixture of beta-MnO2 and Mn2O3, namely >=0.52g equivalent HNO3 is added to the mixture, and heated at 170-500 deg.C, so that high-purity beta-MnO2 containing no Mn2O3 is prepared stably from the inexpensive raw material. |
