process for the manufacture of refractory material and castings, able to withstand large variations in temperature

摘要

Refractory masses comprising on an oxide basis 50-80% of alumina, 15-49.5% of silica and 0.5-6% of lithium oxide are produced by mixing finely ground alumina with lithium silicates and/or lithium aluminium silicates, the particle size of the mixture not exceeding 0.2 mm., granulating to form a homogeneous mass with the aid of a liquid, e.g. mineral oil, sulphite lye and/or water, pressing into moulds and firing at 1300-1450 DEG C. The alumina used may be calcined alumina, calcined iron-poor bauxite, corundum, natural or synthetic sillimanite or mullite clay or mixtures thereof. The lithium is added in the form of natural or synthetic eucryptite, spodumene, petalite, lithium aluminium silicate from a previous firing, or mixtures thereof. The fired product may be comminuted and employed as a component of subsequent batches.