Method for making foam glass from diatomaceous earth and fly ash

Abstract

A method of making foam glass by impregnating diatomaceous earth, fly ash or mixtures thereof, and insoluble modifiers, if any, with at least one water soluble glass former in an amount expressed as its oxide of about 2.5 to 20 weight percent of the impregnated diatomaceous earth, fly ash or mixtures thereof; at least one water soluble flux in an amount expressed as its oxide of about 8 to 20 weight percent of the impregnated diatomaceous earth, fly ash or mixtures thereof; and at least one gas generator. The diatomaceous earth, fly ash or mixtures thereof is impregnated by mixing diatomaceous earth, fly ash or mixtures thereof and an impregnating solution comprising at least one water soluble glass former in an amount expressed as its oxide of about 3 to 14 weight percent; at least one water soluble flux in an amount expressed as its oxide of about 10 to 20 weight percent; at least one gas generator, and water in an amount of about 50 to 80 weight percent. Excess impregnating solution is removed and the impregnated diatomaceous earth, fly ash or mixtures thereof is heated to a sufficient temperature, generally about 720.degree. to 1000.degree. C., to cause foaming of the impregnated diatomaceous earth, fly ash or mixtures thereof. The foamed diatomaceous earth, fly ash or mixtures thereof is cooled and a foam glass body is thus formed.