Carbon Foams from Different Coals

摘要

Carbon foams were obtained from several bituminous coals with different plasticity and volatile matter content by a two-stage thermal process. The first stage, a controlled carbonization treatment under pressure at 450-500 ℃, is responsible for the final textural properties of the foam. In the second stage, the carbonization product was baked at 1100 ℃. The foams produced display a macroporous texture with fluidity, volatile matter content, and maceral composition of the precursor coals, having an influence on the apparent density and the pore size of the resultant porous products. Coals with low fluidity, volatile matter content, and liptinite content give rise to foams with lower pore size and lower apparent density. In the case of high fluidity coals, their foams display an increase of flexural strength with the increasing relative density. In general, the carbon foams obtained in this study display good electrical properties (electrical resistivity comparable to that of commercial foams).