METHOD FOR MANUFACTURE OF CERAMICS Russian patent published in 1995 - IPC

FIELD: manufacture of ceramics. SUBSTANCE: method for manufacture of ceramic includes combined grinding of clay shale and perlite, or obsidian, or broken glass to particle dimensions of 50-600 mcm, mixing with adding of quicklime, moistening with 5-10% aqueous solution of sodium hydroxide to obtain mixture containing, mas.%: clay shale 60-80; perlite, or obsidian, or broken glass 5-20; quicklime 5-10; sodium hydroxide 5-10. Mixture is used for molding billets, their drying and firing by heating up to maximum temperature of 750-800 C at the rate of 200-300 C/h with subsequent holding for 1-3 h. Billets are produced by semidry molding at specific pressure of 15-20 MPa and dried up to moisture content of less than 1%. Ceramics characteristics:water absorption 2.1-10%: frost resistance 25-50 cycles; compression strength 22-45 MPa; bending strength 2-4 MPa; color: from yellow to red-brown. EFFECT: higher efficiency. 3 cl, 4 tbl