A mould and a method for the casting of metals and refractory compositions for use therein

摘要

A mould for metal casting contains a bonded refractory heat-insulating composition comprising hollow alumina- and silica-containing microspheres and a binder, in which the microspheres have an alumina content of at least 40% by weight, and the quantity of alumina present in the composition expressed as a percentage of the total alumina plus silica is less than 55% by weight. The mould may be an ingot mould and the bonded refractory heat-insulating composition may be in the form of a sleeve or boards located in the top of the mould or in the head box thereto. The mould may be a sand mould and the bonded refractory heat-insulating composition may be in the form of a sleeve or boards located in a feeder cavity or in the form of a board or pad located so as to constitute a metal casting surface where it is desired to promote directional solidification in the cast metal. The bonded refractory heat-insulating composition may also be in the form of a breaker core.