In a method of forming a shaped body, a mixture is formed comprising a particulate silica-rich material, water and a potassium base or basic salt, wherein the total solids content of the mixture is from about 20 to about 90 weight percent. The mixture is extruded into extrudates and the extrudates are dried and heated to a temperature of from about 300° C. to about 800° C. to form the shaped body.