Richards Bay zircon.
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Date
1992
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Abstract
Zircon from the zircon concentrate of Richards Bay Minerals was investigated with a view
to understanding the morphology and provenance. The obsevations were applied to the reduction of
uranium, thorium and other trace elements in the heavy mineral placer deposits. It is evident from
differences in morphology, optical characteristics, cathodoluminescence, inclusion types and trace
element analyses that the zircon is derived from numerous parent rocks. Rare earth element
modelling reveals several possible parent rocks including rhyolites, granites, syenites, pegmatites and
carbonatites.
Fission track U mapping of individual zircons indicated an enrichment of U in the rims and
grain terminations. The U maps were used to devise and test several methods, including abrasion and
partial dissolution, to reduce the combined U and Th concentration from 450-563ppm to below
400ppm. The effect of magnetic cleaning, density separation and size classification of the zircon
concentrate on the U +Th concentration was found to be negligible. Air abrasion and HF acid
dissolution successfully reduced the U +Th concentrations to between 332 and 383ppm.
The contribution of trace elements from inclusions, surface pit fillings and coatings, and
foreign minerals within the zircon concentrate were evaluated by by scanning electron microscope
identification.
Description
Thesis (M.Sc.)-University of Natal, Durban, 1992.
Keywords
Zircon--Kwazulu Natal--Richards Bay., Richards Bay Minerals., Placer deposits--Kwazulu Natal--Richards Bay., Theses--Geology., Electron probe microanalysis.