GB1113014A - Refractory compositions - Google Patents

Abstract

A binder for conventional particulate metal oxide refractory materials and coal dust and saw dust comprises 100 parts by weight sodium or potassium silicate and 10 to 60 parts by weight calcium silicate. The molecular ratios should be: silica to alkali metal oxide, from 1.5 to 1 to 3.85 to 1; silica to calcium oxide, from 1 to 1 to 6 to 1, and preferred ranges are given. Preferred calcium silicates are synthetic hydrated types, and should be of a particle size to pass through a 100 B.S. sieve. The binder should form 1.05 to 30 parts by weight per 100 parts by weight of refractory, and a watersoluble carbohydrate, e.g. dextrose, glucose, cane or beet sugar, in a weight ratio not exceeding 3:10 of the alkali metal silicate, may be included. Surface active agents, and known metal and silicide exothermic materials in amounts up to 30% by weight of the calcium silicate may be incorporated. Specific examples are described. The binder may be used in making foundry cores and moulds, e.g. with molochite or chelford silica sand.ALSO:A binder for conventional particulate metal oxide refractory materials and coal dust and sawdust comprises 100 parts by weight sodium or potassium silicate and 10 to 60 parts by weight calcium silicate. The molecular ratios should be: silica to alkali metal oxide, from 1.5 to 1 to 3.85 to 1; silica to calcium oxide, from 1 to 1 to 6 to 1, and preferred ranges are given. Preferred calcium silicates are synthetic hydrated types, and should be of a particle size to pass through a 100 B.S. sieve. The binder should form 1.05 to 30 parts by weight per 100 parts by weight of refractory, and a water-soluble carbohydrate, e.g. dextrose, glucose, cane or beet sugar, in a weight ratio not exceeding 3:10 of the alkali metal silicate, may be included. Surface active agents, and known metal and silicide exothermic materials in amounts up to 30% by weight of the calcium silicate may be incorporated. Specific examples are described.