Ineta Rozenštrauha

Glassceramics obtained from industrial waste

Abstract Large areas of Latvia are contaminated with industrial waste: metallurgical slag, fly-ash, etching refuse, peat, and coal ash as well as glass waste which often contain dangerous substances. From the environmental point of view this waste should be neutralised. As this waste also contains valuable chemical compounds, it can be considered as a raw material for the generation of new materials. One method of utilisation is to produce recycled materials — street plates, decorative tiles, or floor tiles. Dense sintered glassceramics with a water uptake of 0.34–3.23 wt.%, a final density of 2.93–3.05 g/cm 3 , and a bending strength of 80–96 MPa have been created from industrial waste. The mast chemically durable glassceramics contained clay additions. Thus, the material containing only waste had a durability (mass loss) of 3.02% in 0.1 N HCl, while the composition containing 30% clay addition had a durability of 0.2% in 0.1 N HCl.

Characterization of glass-ceramics microstructure, chemical composition and mechanical properties

Given paper presents the results of industrial waste recycling - steel cooling refuse, etching refuse and alumina containing waste. In order to characterize the microstructure and chemical composition of a glass-ceramic material obtained from Latvian industrial waste, the scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analyses were used. In the glass-ceramic material various crystalline phases such as quartz, hematite, anorthite, spinels etc. were identified. The crystalline phases contain a higher amount of metallic elements (e.g. Al, Cr, Fe, Ni and Zn and most probably also other heavy metals) than the residual glassy phase. Relations between microstructure, chemical composition and mechanical properties were established.

Use of Industrial Waste and Raw Materials in Iron Sorption

This work focuses on pellets made by Latvian industrial waste (waste cullet glass, sewage sludge, metallurgical slag and alumina scrap metal processing waste and raw mineral materials (limeless clay) to gain high porosity and water sorptiom. Iron sorption using ceramic pellets is explored more detailed. Physical-chemical properties and microstructure were researched to obtain a deeper understanding of how these qualities affect water purification from iron compounds. Three pellets with different properties were made in this paper : B5, A5 and E1. Composition B5 indicates highest iron sorption rate at sintering temperature 1100 °C and shows considerable iron reduction in a solution after one week.