Loy Yang brown coal from Australia with ion-exchanged iron or nickel was carbonized up to 1000°C to study the influences of the exchanged cations on the char structure. The iron- and nickel-exchanged coals carbonized at 1000°C were converted to amorphous carbon. On the other hand, the Ca-Fe- and Ca-Ni- co-exchanged coals carbonized at 1000°C were converted to turbostratic carbon (interlayer spacing of C (002) is about 3.43 Å and crystallite size along c-axis is 40-70 Å). Ratio of turbostratic carbon to total carbon increased from about 25 to 65 % with increasing nickel loading. Mechanism of the formation of the turbostratic carbon was discussed in terms of aggregation behaviors of loaded metal species and C1 gas evolution profiles.
