A certain customer approached us with a sample that had a 48% Cr2O3 grade from alluvial ore.
Peacocke & Simpson developed the flowsheet, process and much of the equipment for the module, which was supplied as a turnkey plant complete with water and power reticulation, tailings handling, etc.
Ore feed to the plant comprises predominantly eluvial soils with a high clay content, and containing between 10 and 20% Cr2O3. Complete dissemination of the clay is required in order to liberate the chromite grains, which lie mostly in the particle range 50-250 microns. Minor ore sources also include competent chromite-hosting rock and a highly “sugary” ore, where loosely-bound chromite grains adhere to the ore matrix.
The plant incorporates an RG200 autogenous drum rubble scrubber with a capacity of up to 15 tonnes per hour, designed and developed by Peacocke & Simpson. The tumbling action of the scrubber liberates chromite from the eluvial clays and topsoil, and fractures the sugar ore to liberate adhering chromite grains. Fine slurry product from the scrubber is treated in rougher-cleaner mode via spiral concentrators.
Washed coarse rejects from the scrubber, at +50mm, are hand-sorted for chromite, while mid-size product (-50+4mm) is conveyed to a Peacocke and Simpson Hi-Y Jig.
Early tests during plant commissioning, which is presently underway, indicated chromite grades in final concentrates of up to 48% Cr2O3, and up to 2.2 Cr/Fe ratio.
Peacocke & Simpson, together with APT (www.aptprocessing.com) enabled the customer to go: