Hard setting refractory composition

Abstract

Novel compositions are disclosed for the manufacture of gunning mixes and strong castable products for use as monolithic refractory and construction materials which may contain no lime bearing cements. Bonding is based on the setting reaction of fumed silica with an alkali metal silicate preferably a particulate sodium or potassium silicate that slowly dissolves in water such as an anhydrous sodium silicate of SiO.sub.2 :Na.sub.2 O molar ratio of 1:1 to 4:1; or an anhydrated potassium silicate having an SiO.sub.2 :K.sub.2 O molar ratio of 3:1, or a hydrated sodium silicate having an SiO.sub.2 :Na.sub.2 O molar ratio of 3:1. Setting and mechanical characteristics allow this class of castable and gun mixes to be placed more rapidly into service since the time required for curing is much less. Although initial set strengths are not as high as those of conventional castables, very high strengths can be made to occur shortly after setting by heating. The addition of sodium hexametaphosphate was found to be highly beneficial to working and handling characteristics.

Dependencies are inferred from the claim text.