Thermal insulating material, composition and process for making the same

Claim 1

A THERMAL INSULATING MATERIAL, HAVING THE PROPERTY OF FORMING CERAMIC BONDS AS ITS TEMPERATURE IS ELEVATED FROM AMBIENT TEMPERATURE TO ABOUT 1700*F., CONSISTING ESSENTIALLY OF FROM ABOUT 4% TO ABOUT 35% OF AN ALUMINUM SILICATE CLAY OF THE NON-SWELLING TYPE SELECTED FROM THE GROUP CONSISTING OF KAOLINITE, HALLOYSITE, ILLITE AND ATTAPULGITE, FROM ABOUT 4% TO ABOUT 25% ON A DRY WEIGHT BASIS OF A WATER-SOLUBLE ALKALI METAL SILICATE SELECTED FROM THE GROUP CONSISTING OF POTASSIUM SILICATE AND SODIUM SILICATE HAVING A RATIO OF ALKALI TO SILICATE FROM ABOUT 1 TO 1.6 AND TO ABOUT 1 TO 3.75. FROM ABOUT 0.3% TO ABOUT 3% OF A FOAMING AGENT INERT TO THE ALKALI METAL SILICATE, AND FROM ABOUT 40% TO ABOUT 90% OF AN EXPANDED SILICEOUS INORGANIC AGGREGATE SELECTED FROM THE GROUP CONSISTING OF EXPANDED PERLITE, EXPANDED CLAY, CELLULAR GLASS, AN EXPANDED SLAG, EXPANDED VERMICULITE, CELLULAR DIATOMITE AND CELLULAR PUMICE, SAID SILICEOUS MATERIAL EACH CONTRIBUTING TO THE FORMATION OF SAID CERAMIC BONDS OF GLASS-LIKE TYPE AND THE ALUMINA CONTENT OF SAID CLAY PRODUCING SAID CERAMIC BONDS OF INCREASED STRENGTH AT ELEVATED TEMPERATURES.