Manufacture of shaped refractory objects

A method of manufacturing shaped high quality refractory objects suitable for use with molten steel, said method comprising the steps of mixing refractory grains with a liquid binding system to form a slurry, said binding system consisting essentially of water, polyammonium phosphate and grains of a reactive magnesium compound, said compound selected from the group consisting of calcined magnesia and calcined magnesite, which react to form a solid magnesium phosphate, incorporating reactive alumina into the slurry in an amount sufficient to ensure the formation of a spinel bond during firing, setting said slurry into a shape at a setting temperature, drying and progressively heating the set shape through temperatures ranging from 250.degree. C. to 350.degree. C. to form phosphate bonds, and thereafter firing the shape at a temperature over 1400.degree. C. to form spinel bonds, the formation of the spinel bonds occurring prior to a substantial weakening of the phosphate bonds during said firing, thereby maintaining the strength of the objects during firing.