Mineralogical and process controls on the oxidative acid-leaching of radioactive phases in Elliot Lake, Ontario, uranium ores: II – Brannerite and allied titaniferous assemblages

CIM Bulletin, Vol. 89, No. 1001, 1996

Roy O. Ifill, Department of Mining, Metallurgical and Petroleum Engineering, University of Alberta, Edmonton, Alberta, W. Charles Cooper, Department of Metals and Materials Engineering, The University of British Columbia, Vancouver, British Columbia, and Alan H. Clark, Department of Geological Sciences, Queen’s University, Kingston, Ontario

In representative, run-of-mine samples from the Panel and New Quirke mines of the Elliot Lake uranium district, Ontario, brannerite, a metamict uranous titanate, occurs in microscopic grain-aggregates which display wide variations, both in textural habit and in the relative proportions of brannerite, titania polymorphs and/or “uraniferous titania”. As is widely documented, much of the brannerite occurs as trellis-like arrays of laths and needles pseudomorphing rutile or anatase. In some cases, the laths and needles are cemented by coffinite. Brannerite, with an average composition of (U0.629 Th0.039Ca0.20 ) (Ti2.199 Fe0.13 )O69 contains =3 wt% Th and is distinctly Ti-rich relative to the ideal composition, UTi2O6 . Much of the Si reporting consistently in electron microprobe analyses (between 1 wt% and 5 wt%) is tentatively attributed to contamination by the quartz-sericite matrix, and a minor proportion is attributed to the presence of coffinite intergrowths. “Uraniferous titania” (average partial composition by weight: 10.8% U, 0.3% Th, 32.9% Ti) is considered to represent an intermediate stage in the conversion of titania to brannerite.

Keywords: Brannerite, Coffinite, Elliot Lake, Leaching, Metallurgy, Mineralogical controls, Oxidative leaching, Process controls, Titaniarich phases, Uranium ores.