| 摘要 |
512,179. Batteries. LECLANCHE SOC. ANON. June 17, 1938, No. 18107. Convention date, June 23, 1937. Drawings to Specification. [Class 53] [Also in Group III] In the production of a depolarizer, pyrolusite is roasted, for example at from 600 to 700‹C. for half an hour, in the presence of carbon to reduce the main body to a mixture of lower oxides, cooled suddenly to obtain a large superficial area and treated with at least one acid to decompose the Mn 2O3 and to dissolve the MnO so formed and originally present, the residue being separated from the solution which also contains the impurities. The reduction is preferably carried out until the product corresponds to the formula Mn 2O3 while the acid may be 10 per cent. sulphuric acid. If much silica or silicates are present hydrofluoric acid may be used with the sulphuric acid to remove them. A further washing with acidulated water may be given, the final product having less than 5 per cent. of MnO. The ratio of the specific gravity of the final product to the untreated material is said to be 0.69:1 and an example of its use with 25 per cent. of graphite is given. |
