Abstract: Disclosed is a one-package inorganic binder composition comprising a powdery mixture of a powdery alkali metal silicate having a water solubility or water dispersibility, an alkali metal borate soluble in an alkaline aqueous solution and silicon polyphosphate.

Abstract: Disclosed is an unfired refractory composition comprising a refractory aggregate and a binder for the refractory aggregate, in which the binder comprises a water-soluble or water-dispersible siliceous binder in an amount of 1 to 20% by weight based on the refractory aggregate, a carbonizable organic binder in an amount of 2 to 15% by weight based on the refractory aggregate and a phosphate type hardening agent in an amount of 0.5 to 20% by weight based on the refractory aggregate.This refractory composition is moldable and hardenable at normal temperatures, and has an excellent mechanical strength not only at relatively low temperatures below about 500.degree. C. and high aggregate-firing temperatures but also intermediate temperatures between these low and high temperatures.

Abstract: Water glass composition comprising a water-soluble or water-dispersible silicate binder and an inorganic phosphate curing agent, wherein said inorganic phosphate curing agent is composed of an inorganic solid fine powder comprising as the main ingredient a silicon polyphosphate or its metal salt and said curing agent has an initial dissolution amount (B) of up to 200 mg and an average hydrolysis rate constant (A) of at least 0.2, said initial dissolution amount (B) and average hydrolysis rate constant (A) being defined by the following formula:Y = AX + Bwherein X stands for the lapse of time (minutes) of up to 120 minutes after 1 g of the curing agent has been added to 100 ml of a 4N sodium hydroxide aqueous solution, and Y stands for the integrated amount (mg/100 ml) of phosphoric acid dissolved out of the curing agent into said aqueous solution during the time X.