ラテライト型スカンジウム含有鉱床

抄録

This study evaluates the potential of scandium resources in lateritic bauxite deposits and lateritic Ni-Co deposits derived from mafic parent rocks. Mafic rocks generally contain more Sc than felsic rocks because Sc replaces iron and manganese in pyroxene and amphibole. Pyroxenite and hornblendite are most enriched in Sc whereas peridotite is poor in Sc. Chemical weathering causes rocks to be enriched in Sc, which behaves as an immobile element, because mobile elements are leached from the rocks. Scandium contents of bauxite depend on those of parent rocks and they are estimated to be ~40 ppm in Indochina Peninsula. Red mud, Fe-rich residue in the process of refinery of bauxite, contains high concentration of Sc. Scandium-bearing lateritic Ni-Co deposits contain higher grades of Sc ores than bauxite and recently have been explored in Australia. As Sc contents of the laterite is controlled by those of parent rocks, pyroxenite-derived laterite may form high-grade Sc deposits (>100 ppm). However, Ni and Co grades tend to decrease in the high-grade deposits in Australia. Large amounts of resources and developed techniques in Sc recovery as a by-product indicate that bauxite deposits and lateritic Ni-Co deposits are prospective Sc resources in the near future.