VOLATILITY OF TRACE ELEMETS IN HUAINAN AND GUIZHOU COALS DURING HIGH TEMPERATURE PYROLYSIS

摘要

Volatility of several trace elements (Se, As, Cd, Ga, Pb, Zn, Ba, Cr, Be, Ni, Sr and Hf) in Huainan and Guizhou coals during high temperature pyrolysis was studied. The pyrolysis experiments were carried out in box resistance reactor and rapid pyrolysis device at 950～1400 ℃. The contents of trace elements in coal and char were analyzed by Inductively Coupled Plasmas - Mass Spectrometry (ICP-MS) and the volatility of trace elements were calculated. The results show that the volatile elements (Pb, As, Cd, Ga and Se) are inclined to release from raw coal and enrich in volatile phase, while the non-volatile elements (Sr and Hf) are more likely to enrich in char. The volatility of some volatile and semi-volatile trace elements increase obviously with increasing the pyrolysis temperature; for non-volatile trace elements the effects are relatively smaller. But the change is relatively less in rapid pyrolysis. The trace element volatility in slow and rapid pyrolysis is similar to each other and the trace elements are more volatile with slow heating rate.