Abstract: A cementitious formulation which is self-setting when mixed with water, and which can be cast into monolithic refractory components capable of resisting molten metal and repeated thermal shocks, has three main components: high purity magnesia (at least 94% by weight being MgO); high purity alumina (at least 98% by weight Al.sub.2 O.sub.3) and high alumina cement (preferably 75% Al.sub.2 O.sub.3) by weight, or greater). The magnesia may be 60 to 95% by weight of the three components and the alumina amounts to at least 1% by weight of the three components. Castings produced from the formulation can survive repeated flame testing even after exposure to firing at elevated temperature: known, conventionally pressed and similarly fired magnesia refractories may not survive a single flame test.

Abstract: A sliding gate valve slide plate in a can has an integral collector nozzle and is formed as two conjoined refractory concrete mouldings with a cup or trough shaped metal foil lying in the joint therebetween. The foil is oxidisable in service to form a bond between the concretes. The concretes may be of different formulations, and the moulding with which molten metal makes contact is preferably the more resistant to the rigorous environment presented by flowing molten metal.The slide plate is cast in two steps using the shaped foil and the can as respective lost mould members which coact with a planar polished surface to produce a cast slide plate needing effectively no finish grinding before installation in a valve.

Abstract: Method for making a refractory valve is disclosed. The sliding gate valve slide plate in a can has an integral collector nozzle and is formed as two conjoined refractory concrete mouldings with a cup or trough shaped metal foil lying in the joint therebetween. The foil is oxidisable in service to form a bond between the concretes. The concretes may be of different formulations, and the moulding with which molten metal makes contact is preferably the more resistant to the rigorous environment presented by flowing molten metal.The slide plate is cast in two steps using the shaped foil and the can as respective lost mould members which coact with a planar polished surface to produce a cast slide plate needing effectively no finish grinding before installation in a valve.