The Glassy Matrix in Tank Blocks

JSGT 1944 V28 T119-T132

Specimens cut from refractory blocks employed in the walls of glass tank furnaces have been subjected to a small tensile stress of 500 grams per sq.cm. at 1350° for long periods. Differences in the rate of creep were observed. Some specimens extended rapidly and failed in a few hours; others much more slowly and had not failed after 300 hours. It is suggested that differences in the nature of the glassy matrix accounts for the different behaviour of these specimens; and the conclusion is drawn that the face of a tank block exposed to molten glass consists of crystals set in a matrix which must be a viscous glass rather than a solid at the temperatures of tank furnace operation. In general, blocks possessing the more viscous matrix were more resistant to corrosion by molten glass than those which failed in a few hours under this high-temperature creep test. The effect of an addition of substances to sillimanite–clay mixtures to produce denser tank blocks and to promote crystallisation of mullite has been investigated from the point of view of resistance to "creep" at high temperatures and to corrosion by molten glass. It is suggested that a more resistant block will be produced rather by firing it to higher temperatures than by adding fluxing materials with the object of achieving a similar macroscopic texture at lower temperatures.

J. H. Partridge & K. Seal