Oxides
These comprise alumina, magnesia, thoria, beryllia and zirconia. Other oxides that are utilized sparingly due to high cost comprise hafnia, ceria and yttria. Variety of shapes in oxide refractories can be acquired by process of slip casting. This is a process whether fine particles of oxides are mixed in temporary organic binders as like: starch, wax, latex or polyvinyl alcohol. The mixture is after that moulded in desired shape such is created in plaster of Paris mould. After the mould has dried adequately so that this can be handled it is fired at a temperature of about 1800oC. At such temperature the suitable particles sinter rapidly, facilitating the solid surface reaction among fine particles. The resulting material is self bonded refractory of coherent structure that refractoriness approaches such of the material itself.