Method of manufacturing structural insulation

Claim 1

IN MANUFACTURING MOLDED STRUCTURAL ARTICLES HAVING A HYDROUS CALCIUM SILICATE BOND, THE STEPS COMPRISING, FORMING A DILUTE AQUEOUS SLURRY MIXTURE INCLUDING ASBESTOS FIBERS, SODIUM SILICATE AND WATER, AGITATING THE RESULTING MIXTURE TO EFFECT DISTRIBUTION OF THE SODIUM SILICATE OVER THE SURFACES OF THE FIBERS, INCORPORATING IN THE RESULTING SLURRY SUBSTANTIALLY REACTIVE PROPORTIONS OF HYDRATED LIME AND FINELY DIVIDED SILICA, THE AMOUNT OF SODIUM SILICATE IN SAID SLURRY APPROXIMATELY 1-10% DRY WEIGHT OF REACTIVE SILICATE EQUIVALENT BASED ON THE DRY WEIGHT OF THE ARTICLE, PARTIALLY DEWATERING AND SHAPING THE MIXTURE UNDER PRESSURE TO FORM A GREEN PREFORM, REMOVING THE PREFORM TO A CURING ZONE AND SUBJECTING IT TO DIRECT STEAM CURE UNDER PRESSURE, AND FINALLY DRYING THE THUS CURED ARTICLE.