Glass ceramics from pulp and paper waste ash.

摘要

Pulp and paper industries face tremendous problems in eliminating waste, which is in the form of sludge, wood, and reject material. Although incineration is seen as the most effective solution, this unfortunately leaves large quantities of residues such as fly ash and bottom ash. The ashes are alumino-silicate materials, which are excellent candidates for producing both glasses and glass ceramic materials.;In the present work, samples of pulp and paper incinerator residues were collected and the initial characteristics (moisture content, loss on ignition, particle size and size distribution, chemical composition) were analyzed. The major oxides were found to fall within the SiO2-Al2O 3-CaO (CAS) system. Moreover, nucleating agents such as TiO2, Fe2O3, Cr2O3 and P2O 5 were also present in the glass. Through thermal analysis (TGA and DTA) optimum heating schedules were selected for producing glass ceramic materials. It was found that the optimum devitrification temperature for fly ash was 1200°C and the final product contained anorthite with/without albite. Hardness values exceeded that of the parent glass and thus the material should be useful in glass ceramic applications.