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Preparation of battery‐grade manganese dioxide through disproportionation of partially oxidised hydrous manganese oxide in dilute sulphuric acid
Author(s) -
Kanungo S. B.
Publication year - 1991
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280500110
Subject(s) - manganese , chemistry , disproportionation , inorganic chemistry , manganese oxide , hydroxide , leaching (pedology) , electrochemistry , calcination , oxide , alkaline battery , slurry , pyrolusite , catalysis , electrolyte , materials science , electrode , environmental science , organic chemistry , soil science , composite material , soil water , biochemistry
Abstract Manganese hydroxide was precipitated from MnSO 4 and NH 4 OH at controlled pH, partially oxidised by aeration and finally calcined at 573–623 K to yield manganese oxide with oxidation state between +3 and +4. When the calcined oxide was leached in dilute sulphuric acid, MnO 2 of high electrochemical activity was obtained. In order to improve the bulk or packing density of the product various oxidants were added during the aerial oxidation of the Mn(OH) 2 slurry and also during the leaching in dilute H 2 SO 4 . It was observed that the best results were obtained when active MnO 2 was added during the aerial oxidation of Mn(OH) 2 slurry.