Ash morphology and metals distribution during combustion of de-inking sludge.

摘要

Sludge combustion experiments were performed using a computer-controlled thermogravimeteric system. Microscopy and spectometry techniques were used to determine ash morphologies and structures, metals distribution inside ash particles and leachability of toxic metals from ash. Parameters examined included temperature, residence time, heating rate and cooling rate.; The combustion process consisted of four stages: initial burning, transition, sintering and melting. It was found that temperature has the greatest effect on ash morphologies and metals distribution in the ash particle. It was observed that light metals predominated in the surface layers of the ash particle while heavy metals were mostly partitioned in the core area. As the temperature increased, leaching of heavy metals from ash decreased significantly. At temperatures above 1200{dollar}spcirc{dollar}C, no toxic metals were leached out. Such ash particles could be safely disposed of and reused.