Potentially toxic elements in fly ash dependently of applied technology of hard coal combustion.

Coal combustion is one of the most significant anthropogenic sources of thallium in the environment. This study presents the results of determination of thallium and some toxic elements (Pb, Cd, As, Ni, Zn, and Cu) concentration in fly ash produced in the coal combustion in conventional furnaces (pulverized coal furnace and grate furnace), in a fluidized-bed furnace with circulation bed, and in a home furnace. The high content of thallium was determined in ash produced in the grate furnace (on average 10.7 mg/kg) and fluidized-bed furnace with circulation bed (6.6 mg/kg). The average content of Tl in the fly ash of the pulverized coal furnace and in the home furnace is 1.7 and 2.4 mg/kg, respectively. There was a strong relationship between the occurrence of Tl and As, Cd, Pb, Cu, and Zn in ash from grate and pulverized coal furnace.