Abstract: Slag sand and slag wool are formed by a method wherein molten slag is poured at a temperature above 1300.degree. C. in a thin flowing stream onto a vaned drum rotating at a peripheral speed of at least 25 m/sec. This drum, which may have forwardly directed nozzles for mixing the falling slag stream with a cooling medium such as water, breaks the slag up into droplets and projects these droplets through the air so they cool and form filaments and granules. The granules are collected separately from the filaments so that the installation simultaneously produces slag sand and slag wool.

Abstract: Molten metallurgical slags are expanded by contact with water in a liquid or vapor state by passing the molten slag along a prefoaming or expanding trough by delivering the slag to this trough via an intermediate trough which is shiftable along the prefoaming trough in order to vary the location at which the slag contacts the prefoaming trough and the expanding-agent film thereon in accordance with physical characteristics of the molten slag, especially its temperature and viscosity. From the pre-expanding or prefoaming trough, the partially expanded slag may be subjected to expansion by conventional means, e.g. a rotating drum which disperses the slag particles through the air so that they can be collected in a completely expanded, dry and solidified state.

Abstract: Slag sand is produced by first mixing a stream of molten slag with a quantity of between 0.5 m.sup.3 and 0.7 m.sup.3 of water per ton of slag to chill the slag while leaving it above the pyroplasticity threshold. Thereafter water at a rate of between 0.3 m.sup.3 and 0.4 m.sup.3 is added to the slag to stiffen the stream and this stiffened stream is fed to a drum rotating at a rate between 600 rpm and 1000 rpm to break it up into fine granules which are collected on a foraminous belt.

Abstract: Molten metallurgical slags are expanded by contact with water in a liquid or vapor state by passing the molten slag along a prefoaming or expanding trough by delivering the slag to this trough via an intermediate trough which is shiftable along the prefoaming trough in order to vary the location at which the slag contacts the prefoaming trough and the expanding-agent film thereon in accordance with physical characteristics of the molten slag, especially its temperature and viscosity. From the pre-expanding or prefoaming trough, the partially expanded slag may be subjected to expansion by conventional means, e.g. a rotating drum which disperses the slag particles through the air so that they can be collected in a completely expanded, dry and solidified state.

Abstract: Expanded slag, especially blast-furnace slag of Thomas melts is made by passing the slag along a trough in which water is fed into a layer of the molten slag. The slag is then permitted to cascade downwardly along an inclined surface which is wetted with water and finally is dispersed by a rotating disintegration drum and curtain of finely divided water. The expanded slag has a lower density, a more complete expansion characteristic and a greater uniformity than conventionally produced expanded slags.