Effect Of Ball Milling Time On Pcdd/Fs Formation

Model fly ash was subjected to grinding without any additive, at 300 rpm in a planetary ball mill to investigate effect of milling time on formation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) during de-novo tests. Results showed that PCDD/Fs decreased > 98 % after 1 h milling but at 2, 4 and 8 h milling, the total amount of dioxins raised again with maximum value at 4 h (1766.81 ng g(-1)). The I-TEQ concentrations decreased from original sample > 99 % after 1 h milling. Formation of high chlorinated PCDDs and PCDFs at prolonged milling suggests de-novo formation as a result of copper, present in fly ash.