Density Differences' Effect on Phase Transition Kinetics.

In this theoretical study, we investigate the impact of density differences between the growing new phase and the parent phase on the overall transformation degree. By extending Kolmogorov's formalism, we derive an expression for the overall volume transformation degree, which becomes relevant when density differences are not negligible. We demonstrate that the volume and mass transformation degrees differ in the presence of density differences and provide an expression for the mass transformation degree.

Thermal Properties of Geopolymer Based on Fayalite Waste from Copper Production and Metakaolin.

In the present study, thermal properties of geopolymer paste, based on fayalite waste from copper producing plants and metakaolin, were analyzed. The used activator solution was a mixture of sodium water glass, potassium hydroxide and water with the following molar ratio: SiO/MO = 1.08, HO/MO = 15.

Sintered Glass-Ceramics, Self-Glazed Materials and Foams from Metallurgical Waste Slag.

The materials used for the synthesis of parent glass are 70% wt. metallurgical slag and 30% wt. industrial quartz sand.

Toxicological analysis of ceramic building materials - Tiles and glasses - Obtained from post-treated bottom ashes.

In Italy, the production of bottom ash from waste incineration was estimated as 1.6 million tons/year, corresponding to 30% of the total input waste. The bottom ash is mainly formed by SiO, AlO, CaO, NaO and low amount of heavy metals, therefore it cannot be considered a 'non-hazardous' waste.

New fired bricks based on municipal solid waste incinerator bottom ash.

The main objective of this work was to study the sintering process and technological properties of new fired bricks based on high amount of post-treated municipal solid waste incinerator bottom ash and refractory clay. In addition, the effect of the minor addition of flux (NaCO) or reinforce (corundum) was also highlighted. Several methods were used to study the effect of compositions variations on the sintering process, structure and the mechanical characteristics of the test briquettes.

Glass-ceramic frits from fly ash in terracotta production.

Preliminary results of an investigation into the possible use of glass-ceramic frits from fly ash and glass cullet in terracotta (stoneware) tile manufacture are reported. Two new ceramics were studied and compared with a plant composition, containing 45 wt.% sodium feldspar.

Vitrification of copper flotation waste.

The vitrification of an hazardous iron-rich waste (W), arising from slag flotation of copper production, was studied. Two glasses, containing 30wt% W were melted for 30min at 1400 degrees C. The first batch, labeled WSZ, was obtained by mixing W, blast furnace slag (S) and zeolite tuff (Z), whereas the second, labeled WG, was prepared by mixing W, glass cullet (G), sand and limestone.

Sintered glass ceramic composites from vitrified municipal solid waste bottom ashes.

A glass ceramic composite was obtained by sinter-crystallisation of vitrified municipal solid waste bottom ashes with the addition of various percentages of alumina waste. The sintering was investigated by differential dilatometry and the crystallisation of the glass particles by differential thermal analysis. The crystalline phases produced by the thermal treatment were identified by X-ray diffraction analysis.

Vitrification of electric arc furnace dusts.

Electric arc furnace baghouse dust (EAFD), a waste by-product of the steelmaking process, contains the elements that are volatilized from the charge during the melting (Cr, Pb, Zn, Cu and Cd). The results of leaching tests show that the concentration of these elements exceeds the regulatory limits. Consequently, EAFD cannot be disposed of in ordinary landfill sites without stabilization of the heavy metals.

Chemical durability of glasses obtained by vitrification of industrial wastes.

The vitrification of zinc-hydrometallurgy wastes, electric arc furnace dust (EAFD), drainage mud, and granite mud was shown to immobilize the hazardous components in these wastes. Batch compositions were prepared by mixing the wastes with glass-cullet and sand to force the final glass composition into the glass forming region of the SiO2-Fe2O3-(CaO, MgO) system. The vitrification was carried out in the 1400-1450 degrees C temperature range followed by quenching in water or on stainless steel mold.