GB697653A - Method of making refractory masses - Google Patents

Abstract

Basic refractory granules containing a reactive alkali earth oxide present in a proportion of at least 6 per cent by weight in excess of that required to form the orthosilicate of said oxide with all the silica present are bonded together by forming a mixture of the granules and ingredients of a non-refractory silicate which also contains said oxide, the mixture containing no more silica than will combine with said oxide to form the orthosilicate, and the total surface area of all non-volatiles in the mixture being not more than 2.4 times the total surface area of the free and combined silica, heating the mixture to form and melt the non-refractory silicate in situ and so coat the granules, and further heating to convert the non-refractory silicate, by reaction with the excess oxide, into a refractory silicate and thus bond the granules. The ingredients for the non-refractory silicate may be pelletized to give the required surface area. The non-refractory silicate forms 6-30 per cent by weight of the granules. The granules may comprise either lime, \sB magnesia but no alumina or magnesia \sB alumina, but no lime. The ingredients for the non-refractory silicate contain at least 42 per cent of p silica which is equivalent to the surface area of the total mixture being not more than 2.4 times the surface area of the free and combined silica. A table giving the relative area per unit weight is furnished whereby the relative proportions of the reacting materials can be calculated. Ingredients specified include raw and hard burned dolomite, quartzite, lime, magnesia, alumina, bonding clay, certain slags asbestos waste and sodium silicate as a bond. Specifications 668,187 and 679,273 are referred to.