Glass-ceramic materials obtained by recycling goethite industrial wastes

The aim of this work (supported by the European Communities under the contract MA2R-CT90-0007) is the recycling of goethite wastes, in combination with raw materials, for producing glass-ceramic (GC) materials with good commercial properties. Four batch compositions were prepared, with an Fe sub 2 O sub 3 content ranging from 15-25 wt.%. The mixtures were melted at 1400-1450 deg C and quenched to obtain the glass (G). The nucleation and crystallization temperatures and the activation energy of the crystallization process were determined by differential thermal analysis (DTA). The G samples were nucleated at 650-700 deg C for times ranging from 1-4 h and crystallized at 800-900 deg C for 1-4 h. X-ray diffraction and fluorescence analysis were performed on the G and GC samples and the crystalline phases characterized. The ratio G/GC phases was determined as a function of the thermal treatment temperature and time. The chemical, thermal and mechanical properties of the G and GC were evaluated.