Abstract: A refractory brick without a metal casing and having built-in expansion at the hot face is formed by having at least one side face divided into two sections, the section adjacent the cold face being of normal configuration, but the section adjacent the hot face being inclined at a greater angle to the opposed side face, whereby expansion allowance is provided at the hot face, the section adjacent the hot face also having at least one raised portion, preferably adjacent the hot face, the height of the raised portion being such that its surface lies substantially in the plane extended of the lower, cold face section. By this construction, a brick is provided with built-in expansion allowance at the hot face, substantial bearing surface at the cold face to prevent loosening of the refractory structure in use, and means to prevent inadvertent closing of the hot face thermal expansion allowance during placement of the brick in a kiln or furnace.

Abstract: Repair of furnace structures, particularly hot furnace structures, can be achieved by gunning with less dusting and rebound and higher cohesiveness, adherence, and strength in the gunned refractory when the refractory comprises an admixture of aluminosilica aggregate, plastic clay, graphite and, as binder, a liquid sodium silicate solution.