Abstract Impregnated refractory structures, such as, for example, bricks which have increased resistance to the destructive action of molten glass are disclosed. The structures are produced by an impregnation and densification process in which conventional, prefabricated, solid, porous, refractory structures are first treated with a solution of a polysilicon compound which is thermally decomposable to silica, and the solution-treated structure is then heat treated, to cause a deposition of amorphous silica in the brick pores. Because of the silica deposition and pore impregnation, a densification and decrease in porosity is effected which greatly decreased molten glass penetration and internal destruction of the silica impregnated refractory structure. The use of these impregnated structures also produce a glass with substantially fewer seeds. A particularly suitable polysilicon compound which may be employed is a hydrolyzed and condensed ethyl silicate.
The improvement of claim 1 wherein X is an OR group with R being an alkyl of one to eight carbon atoms.
Claim 2
Dependent Claim
17 words
The improvement of claim 2 wherein said polysilicon compound is a hydrolyzed and condensed ethyl silicate polymer.
Claim 3
Dependent Claim
252 words
In a method which comprises positioning a plurality of solid, porous, structurally-stable silica refractory bricks having a porosity of about 8 to about 20 percent and a density of about 1.7 to 2 grams per cubic centimeter in a glass melting furnace at a molten glass contacting location therein and heating said furnace to its normal operating temperature to melt glass, the improvement which comprises increasing the resistance of said refractory bricks to the corrosive and errosive action of molten glass by introducing into the pores of said bricks throughout their entire thickness a substantially gel-free solution consisting essentially of a hydrolyzed and condensed compound of the formula SiX4 wherein X is a halide or an OR group in which R is an alkyl or aryl group of less than about 8 carbon atoms, said introduction being prior to positioning said bricks in said melting furnace, and further wherein said hydrolyzed and condensed compound is heated during said heating of said furnace to its normal operating temperature as follows: heating to a temperature of about 300*C to about 375*C within a period of time not to exceed about one day, maintaining a temperature of about 300*C to 375*C for at least about 3 hours and heating to at least about 500*C and holding this temperature for a sufficient time to effect a decomposition of said compound to silica and thereby deposit silica into the pores of said bricks substantially throughout its entire thickness and increase the porosity in density of said bricks.
Claim 4
Dependent Claim
11 words
The improvement of claim 4 wherein said compound is ethyl silicate.