Caking property of hypercoal prepared from Ordos lignite

The hypercoal was extracted from Ordos lignite by different solvents and high temperatures (300-400 ℃ ). The structural changes of hypercoal and the influence factors of its caking property was investigated by means of FT-IR,and TG analysis. The caking components were separated by classified extraction at room temperature from hyper- coal to analyze the origin and property of caking components. The results show that:Hypercoal has high caking index by high temperature extraction despite its raw coal without caking ability. Hypercoal has high volatiles by relatively low temperature and polar solvent,these compounds are not conducive to the formation of plastic mass because of its in- tense volatilization before coal pyrolysis,in contrast,high extraction temperature and nonpolar solvent are beneficial for reducing oxygen containing functional groups and maintaining the active hydrogen content,so the caking indexes of hy- percoal are 89. 6 and 98. 2 when using NMP and washing oil as solutions at 300 ℃ and 380 ℃ ,respectively. Asphalt- ene and preasphaltene are caking components in hypercoal with moderate molecular weight,they have many aliphatic hydrocarbons and polycyclic aromatic hydrocarbons,which determine the caking property of hypercoal.