Anionic activation in the flotation of chromite from a low-grade ore

CIM Bulletin, Vol. 83, No. 938, 1990

P.R.A. Andrews, Industrial Minerals Section, Mineral Processing Laboratory, CANMET-EMR

Batch flotation testwork demonstrated that a low-grade chromite ore from Bird River, Manitoba, was best floated at pH 2 using Armac C (coco amine acetate) collector and sulphuric acid as pH modifier. A grind of 100% minus 150 fj,m was necessary for liberation, and flotation selectivity was greatly enhanced by prior desliming. A concentrate analyzing 24.2% Cr2O3 with a recovery of 90.2% was obtained, after three cleaning stages, from ore grading 6.05% Cr2O3. Total rougher collector concentration was 500 g/t and cleaner collector concentration 380 g/t. Similar grade and recovery were obtained during the pilot-plant evaluation, when a concentrate analyzing 22.3% Cr2O3 with a recovery of 93% (based on deslimed feed) was obtained for a total collector addition of 630 g/t. Selective flotation in a region of positive surface charge implies anionic activation, and a possible flotation mechanism is suggested.
Mots Clés: Mineral processing, Chromite, Flotation, Industrial minerals.