Abstract: An erosion resistant refractory mortar composition is described which is suitable for bonding a zirconia insert in an alumina graphite plate of a sliding gate valve. The refractory mortar is made from a mix consisting of, in weight percent, about 50%-85% zirconia; about 15%-50% alumina; up to 5% chromium oxide; up to 6% phosphoric acid plus an effective amount of a binder. Sufficient water is added to provide proper plasticity to the mix.

Abstract: A corrosion and erosion resistant, high strength refractory composition suitable for use as a slide gate valve plate or insert for such plates. The mix for the composition comprises in weight per cent about 87-90 high purity, partially stabilized zirconia; 4-5 silicon metal; 3-12 alumina, 3-5 graphite and 4-7 carbonaceous binder. The mix is pressed to a desired shape and fired in a reducing atmosphere at a temperature in excess of 1000.degree. C. to produce a carbon bonded shape. High purity magnesia and high purity yttria, partially stabilized zirconia materials are employed in the mix to obtain superior hot strength properties.