| Abstract: | The principal mineralogical constituents of fusion-cast magnesite chrome refractories were identified as periclase solid solution, intergranular spinel and forsterite solid solution. Their amount and composition, their crystal size and some of the optical properties are determined and their empirical formulae have been predicated. The characteristics of each type of microstructure observed as well as the conditions of its formation are discussed. Such brick after service in copper flash smelters may be distinguished into slag zone, reaction zone and unaltered zone. It is due to the thin reaction zone and absence of a transition zone that no penetration of low melting phase has substantially occurred. From the results of chemical analysis and petrological observation of various zones, it may be concluded that the main attack comes from the ferrous silicates and iron oxide in the slag which corrode the periclase and spinel in the brick, and that the periclase is more easily eroded than intergranular spinel. The basic requirements for the microstructure of the brick for service in copper flash smelter are discussed and measures for control of the microstructure have been suggested. |
