METHOD OF ROASTING GRANULAR MATERIAL Russian patent published in 1994 - IPC

FIELD: manufacture of constructional materials. SUBSTANCE: this process of roasting granular material prescribes dual-step heat treatment. First step is heating material in bed. It is followed by sintering material in rotary furnace. About 70 to 90 % of fuel are burnt up prior to introducing material into bed and about 20 to 50 % of resulting combustion products are admixed with off-gases outflowing from heating zone and then introduced into bed for drying material which is caked in rotary furnace by flame-burning of other portion of fuel (from 10 to 30 %) to avoid formation of cakes and conglomerates. EFFECT: more effective drying and higher reliability. 1 dwg, 3 tbl