Building units and method of producing the same

Claim 1

THE METHOD OF PRODUCING A CERAMIC BUILDING UNIT HAVING HIGH STRENGTH TO WEIGHT CHARACTERISTICS COMPRISING THE STEPS OF ADMIXING SWELLING BENTONITE, A PRE-FIRED, FINELY DIVIDED, VESICULAR VOLCANIC MATERIAL AND A PARTICULATE CERAMIC AGGREGATE IN THE PRESENCE OF SUFFICIENT WATER TO PRODUCE A TACKY MASS, SAID AGGREGATE BEING SELECTED FROM THE GROUP CONSISTING OF PRE-FIRED AND BLOATED CLAYS, SHALES, SLAGS AND VOLCANIC ROCKS, SAID AGGREGATE BEING SELECTED FROM FUSION POINT THAN THE BENTONITE AND SAID MATERIAL, SAID BENTONITE CONSTITUTING FROM APPROXIMATELY 1/2 TO ABOUT 5 PERCENT BY WEIGHT OF THE TOTAL DRY ADMIXTURE, THE VOLCANIC MATERIAL CONSTITUTING FROM APPROXIMATELY 2 TO ABOUT 10 PERCENT BY WEIGHT OF THE TOTAL DRY ADMIXTURE AND THE AGGREGATE CONSTITUING SUBSTANTIALLY THE REMAINING PORTION OF SAID ADMIXTURE; FORMING THE TACKY ADMIXTURES INTO A BUILDING UNIT; AND FIRING THE UNIT AT A TEMPERATURE SUFFICIENT TO SINTER ONLY THE BENTONITE AND MATERIAL TO THEREBY EFFECT PERMANENT BONDING OF THE PARTICLES OF AGGREGATE.