Refractory compositions and method

Abstract

Refractory compositions based upon alumina or aluminum silicate chemically bound by aluminum phosphate have a shelf life of three months to more than one year where the composition includes both liquid aluminum phosphate and phosphoric acid to form a portion of the aluminum phosphate binder in situ. In accordance with another embodiment of the present invention, increased strength is achieved by including alumina, and an aluminum silicate bearing material, such as clay, in the refractory composition to form the in situ aluminum phosphate bond from the reaction of phosphoric acid and aluminum silicate. The aluminum phosphate should be provided in the composition in an amount of about 5% to about 70% by weight of the bone dry composition and the phosphoric acid should be included in an amount in the range of about 1% to about 10% based on the weight of the bone dry composition to provide the surprisingly new and unexpected shelf life to the refractory composition. The aluminum phosphate and phosphoric acid together are particularly useful in a refractory ramming mix composition containing a heat insulator such as perlite, vermiculite, diatomaceous earth, expanded clay, flourspar, or an additive which is intended to be burned out to leave a void space at the intended use of the refractory, such as wood, flour, sawdust and the like.

Dependencies are inferred from the claim text.