Chemical durability of glasses obtained by vitrification of industrial wastes

The Vitrification of zinc-hydrometallurgy wastes, electric are furnace dust (EAFD), drainage mud, and granite mud was shown to immobilize the hazardou s components in these wastes. Batch compositions were prepared by mixing th e wastes with glass-cullet and sand to force the final glass composition in to the glass forming region of the SiO2-Fe2O3-(CaO, MgO) system. The vitrif ication was carried out in the 1400-1450 degreesC temperature range followe d by quenching in water or on stainless steel mold. The United States (US) Environmental Protection Agency (EPA) toxic characterization leaching proce dure (TCLP) test was used as a standard method for evaluating the leachabil ity of the elements in the glasses and glass-ceramics samples made with dif ferent percentages of wastes. The results for EAFD grasses highlighted that the chemical stability is influenced by the glass structure formed, which, in turn, depends on the Si/O ratio in the glass. The chemical durability o f jarosite glasses and glass-ceramics was evaluated by 24 h contact in NaOH , HCl and Na2CO3, at 95 degreesC. Jarosite glass-ceramics containing pyroxe ne (J40) are more durable than the parent glass in HCl. Jarosite glass-cera mics containing magnetite type spinels (J50) have a durability similar to t he parent glass and even lower in HCl because the magnetite is soluble in H Cl. (C) 2000 Elsevier Science Ltd. All rights reserved.