| abstract |
The invention is intended to establish means for stably producing manganese oxide high in tap density, suitable for use as a raw material for producing a positive plate material of a lithium secondary cell at high production yield and with high work efficiency. The means comprise the steps of employing a rotary kiln as a roasting furnace when producing manganese oxide by roasting of manganese carbonate, starting the roasting by supplying the manganese carbonate through a material charging port of the rotary kiln while filling up the roasting furnace with a low oxidizing atmosphere, (for example, in the atmosphere with oxygen concentration not more than 15%) and continuing the roasting of material for roasting while blowing an oxygen-containing gas (for example, a gas with oxygen concentration not less than 15%) onto the material for roasting, placed at a position inside the roasting furnace, away at a distance from the material charging port. Atmospheric temperature inside the roasting furnace is preferably kept in a range of 400 to 600° C. |