2001 Volume 80 Issue 10 Pages 953-962
Properties and liquefaction activities of Ni containing Soroako limonite ores, deposited in the upper layers of nickel mine, Sulawesi Island in Indonesia, were examined by comparing with those of Yandi Yellow limonite in Australia. It was found that Soroako limonite consisted of mainly a -FeOOH and Al (OH) 3, containing 1.0-2.0wt‰ of Ni, Cr, Si and a small amount of Mg and Co on the dry basis. Results of the wet pulverization test with a process solvent by using an agitated mill showed that Soroako limonite could be easily pulverized to sub-micron particle size as well as Yandi Yellow. The finely pulverized Soroako limonite catalyst exhibited a high liquefaction activity in the liquefaction of Indonesian Banko coal, compared to Yandi Yellow catalyst. It appeared that Soroako limonite could be transformed into smaller crystallite size of pyrrhotites (Fe1-XS) by the addition of elemental sulfur, leading to high catalytic activity. The agglomeration or crystal growth of pyrrotites may be suppressed by Al-O-Fe strong interaction between FeOOH and Al (OH) 3. Results of TEM-EDX analysis indicated that Ni could be coexisted with Fe and S in the used catalyst. It suggested that Ni could be located near the Fel_xS structure, leading to the promotion effect on the liquefaction activity. Soroako limonite can be used advantageously in a commercial plant as a cata-lyst raw material for the liquefaction of brown coal in Indonesia.
