RAW MEAL FOR FIRE-PROTECTIVE HEAT-INSULATION BOARDS AND METHOD OF MANUFACTURE THEREOF Russian patent published in 1999 - IPC

FIELD: manufacture of building materials. SUBSTANCE: raw meal contains 30-40% of vesicular vermiculite, 30-60% of liquid glass, and 10-30% of finely ground dolomite with grain composition, according to riddlings on sieves No 05K and 01K, 3 and 40- 70 wt %, respectively. In addition, sodium alkyl siliconate and dust fractions from vermiculite burning may also be used in quantities (above 100%) 2-3 and 2-6%, respectively. Dosed amounts of vesicular vermiculite, liquid glass, and additive are intermixed to form raw meal, which is then compacted, heated, and dried. According to invention, all components, prior to be dosed, are warmed to 40-70 C and compaction is accomplished with compression ratio 2-3 in non-heated press-mold or on conveyor belt for 0.5-30 min. Damp board is dried in at least two steps. In one of the steps, drying is effected by simultaneously blowing round the upper and lower sides of board perpendicularly with two directed jets of air heated to 140-200 C. In the other step, board is warmed up by microwave radiation. Fire resistance of resultant boards is 1.5 to 2.5 h. EFFECT: enhanced process efficiency and reduced power consumption. 12 cl, 3 tbl, 7 ex