ROTARY FURNACE FOR HEAT TREATMENT OF ALUMINIUM FLUORIDE Russian patent published in 1995 - IPC

FIELD: rotary furnaces. SUBSTANCE: rotary furnace has housing, metal shell arranged inside housing and secured to it and heat- insulating layer in circular space formed by furnace housing and metal shell; furnace is also provided with devices for delivery and discharge of materials and discharge of flue gases. Metal shell is made in form of plain sections inter- connected by means of corrugated sections at ratio of length of plain section to length of corrugated section equal to (3-12):1; used as heat-insulating layer is powder-like material at heat conductivity factor not exceeding 0.4 W/m°C at block coefficient of circular space equal to 0.85 to 0.98. Furnace housing is provided with hatches for loading the heat-insulating material and safety valves for discharging the gas-phase components separated from heat-insulating powder. Furnace may be additionally provided with heat exchanger mounted in unloading portion of housing. EFFECT: production of aluminium fluoride of high quality; increased service life of furnace due to compensation for thermal expansion and enhanced reliability of heat insulation. 2 cl, 2 dwg