국내무연탄과 수입유연탄을 대상으로 molten caustic leaching(MCL)방법으로 처리한 후 유기구조의 변화를 고찰하였다. 원소분석과 IR, NMR을 이용한 작용기분석, microphotometer를 이용한 반사율 측정 및 마세랄 분석을 수행하였다. 분석결과 처리탄은 H/C가 감소하고 방향족 탄화수소 중위에 결합되어 있는 반응성이 강한 지방족 탄화수소 group들이 감소하였으며 vitrinite 반사율이 증가하였다. 이러한 변화는 탄화가 진행된 것과 같은 경향이다. 그러나 마세랄 group의 표면관측결과 유기물질들의 표면이 심하게 훼손되었으며 따라서 탄화 진행과 함께 증가되어야 하는 방향성은 오히려 감소하였다. 처리탄의 연소온도가 낮아지고 연소반응성이 증가하는 등의 변화는 유기 group들의 붕괴와 같은 화학적 변화에 기인한다기 보다는 처리과정에서 생긴 유기 group표면의 흠집 등과 같은 물리적 원인에 기인하는 것으로 판단되었다.

Domestic anthracite and imported bituminous coals were treated according to the molten caustic leaching procedures and changes in their organic structures were investigated. The investigation was conducted through ultimate analysis, functional group analysis using IR/NMR, and vitrinite reflectance measurements and marceral analysis with microphotometer. The results of analyses showed that the H/C ratio and the highly reactive aliphatic hydrocarbon groups linked with aromatic hydrocarbons decreased and the vitrinite reflectance increased with treatment. These are changes observed when carbonization occurs. However, the results of the observation of maceral surface showed that the surface of the organic groups was severely damaged and the anisotropy, which should increase with carbonization, decreased. The decrease in the combustion temperature and the increase in combustion reactivity were attributed to the physical changes on the surface of organic groups rather than to the chemical changes such as break down in the organic groups.

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