Black Sand Placers I Project off Mozambique. Oremicroscopic Investigations on Magnetic Separation Products Schwermineralseifen 1 VOR Mocambique. Erzmikroskopische Untersuchungen an Magnetischen Aufbereitungsprodukten.

摘要

Numerous products of magnetic separations of heavy mineral sands were investigated by means of ore microscopy, chemical analyses, and electron microprobe analyses. In addition to the identification of the mineral association the chromium contents were investigated as a significant feature. The results can be summarized as follows: all ferromagnetic products are composed mainly of titaniferrous-magnetite with high tenors of chromium. The ilmenite concentrates contain 44.7 to 46.7% TiO2 and 0.09 to 0.11% Cr2O3. Chromium is present in the form of chromite and chromspinelle grains and as an isomorphous constituent of hematite exsolution lamellae. Furthermore, higher chromium contents are found within exsolutions of rutile. Ilmenite without exsolutions of hematite contains practically no chromium. (Author)