GLASS-CERAMIC MATERIALS OBTAINED BY RECYCLING GEOTHITE 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 comb ination with raw materials, for producing glass-ceramic (GC) materials with good commercial properties. Four batch compositions were prepare d, with an Fe2O3 content ranging from 15 to 25 weight The mixtures wer e melted at 1400-1450-degrees-C and quenched to obtain the glass (G). The nucleation and crystallization temperatures and the activation ene rgy of the crystallization process were determined by differential the rmal analysis (DTA). The G samples were nucleated at 650-700-degrees-C for times ranging from 1 to 4 h and crystallized at 800-900-degrees-C for 1 to 4 h. X-ray diffraction and fluorescence analysis were perfor med on the G and GC samples and the crystalline phases characterized. The ratio G/GC phases was determined as a function of the thermal trea tment temperature and time. The chemical, thermal and mechanical prope rties of the G and GC were evaluated.