Migration and volatilization features of arsenic in combustion processes for six coal samples selected from three different ranks were studied in a horizontal tube furnace at various temperature ranges. The mass change of arsenic in the combustion process was tracked and analyzed using the instruments and theoretical method of thermal analysis (TG/DTG) and coal analysis for these selected coal samples. The curves of arsenic mass loss and its rate were obtained by fitting these experimental results. The occurrence form of arsenic in the coals and corresponding ashes was determined by using a sequential chemical leaching method. The experimental results show that arsenic volatility and the releasing proportion increase with temperature

and the proportions varied from 30% to 67% at 1100℃. The mass loss rate of arsenic varies for different temperature regions

and a peak value of arsenic loss rate is observed at 800—900℃

mainly due to decomposition/oxidation of arsenic in sulfide form. Furthermore

lignite shows the highest mass loss ratio and rate of arsenic under the same temperature

followed by bituminous coals and anthracite. With temperature increases

organic arsenic volatiles easily into gas phase

and the interaction between acid-soluble and residual arsenic makes them migrate mainly into gas phase

and only a small part is transferred to its exchangeable form.