Basic refractory brick

Claim 1

A REFRACTORY BIRCK, UNFIRED AND SUITABLE FOR USE WITHOUT KILN FIRING, CONSISTING ESSENTIALLY OF REFRACTOTY MATERIAL MADE UP OF A MIXTURE OF COARSER MAGNESIA PARTICLES, COARSER CHROME ORE PARTICLES AND FINER MAGNESIA PARTICLES, UNNATURALLY LOW IN PARTICLES OF INTERMEDIATE SIZE, THE COARSER PARTICLES BEING OF A SIZE SO THAT MORE THAN 90 PERCENT OF THE COARSER PARTICLES BY WEIGHT REST ON A 28 MESH SCREEN, MORE THAN 80 PERCENT OF THE COARSER PARTICLES BY WEIGHT REST ON A 14 MESH SCREEN, AND MORE THAN 35 PERCENT OF THE COARSER PARTICLES BY WEIGHT REST ON AN 8 MESH SCREEN, THE COARSER PARTICLES MAKING UP 65 TO 90 PERCENT BY WEIGHT OF THE REFRACTORY MATERAIL, 10 TO 50 PERCENT BY WEIGHT OF THE REFRACTORY MATERIAL BEING COARSER CHROME ORE PARTICLES, THE FINER PARTICLES BEING SMALLER THAN 48 MESH, MAKING UP 10 TO 35 PERCENT BY WEIGHT OF THE REFRACTORY MATERIAL, AND SUBSTANTIALLY FREE FROM CHROME ORE, AND INCLUDING AS BOND BASED ON THE WEIGHT OF REFRACTORY MATERIAL A BONDING SUBSTANCE WHICH IS ACTIVE AFTER DRYING OF THE CLASS CONSISTING OF FROM 0.5 TO 5 PERCENT OF SULFURIC ACID, MAGNESIUM SULPHATE, CHROMIC ACID, HYDROCHLORIC ACID, MAGNESIUM CHLORIDE, SODIUM CHROMATE, SODIUM DICHROMATE, SODIUM SILICATE, SULPHITE PAPER WASTE, CARBOHYDRATE, PITCH TAR AND TALL OIL.