Gasification of coal combustion ash for its reuse as adsorbent

Beneficiation through gasification of coal combustion ash coming from an industrial power plant aimed at its reuse as adsorbent is dealt with. The raw ash was gasified in a tubular reactor at 850 °C for times ranging from 10 to 60 min, using either steam or CO2 as gasifying agent. The relationships among parent ash properties, gasification treatments and properties of the gasified ash deserve investigation. Therefore, ash characteristics (such as carbon content, porosimetric, diffractometric, chemical and granulometric properties) were correspondingly determined. In the light of a critical analysis of the obtained results, gasification conditions able to make the parent ash a potentially better adsorbent material were defined, with a particular emphasis on similarities and differences between steam and CO2 gasification. Preliminary results concerning cadmium adsorption onto gasified materials were also reported.