This study is based on several coal and fly ash samples which were collected from three Bulgarian and Greek thermoelectric power plants. The separation procedures, extraction of humic acids from lignite and infrared spectroscopy (FTIR) were applied on the samples. The present investigation indicates that char has a leading role for the partial capture and retention behaviour of mercury in fly ashes. The main proportion of mercury in low rank coal is closely connected with organic compounds of humic acids. In the humic acids mercury most probably is bounded to the organic matter in the form of complex organometallic compounds and less probably, as methylmercury. It can be supposed that during thermal treatment mercury in fly ash is bounded in appropriate form to aromatic structures rich in oxygen containing groups.
Key words: organic compounds, mercury, coal, fly ash
Topic: GEOLOGY