Abstract
METALLURGICAL PROCESS FOR THE RECOVERY OF BISMUTH FROM THE NICO DEPOSIT
Alex Mezei1, Robin Goad1, Mike Johnson2, Crispinne Patino3, Mike Pimentel3 , MD Mezbahul Islam3
1Fortune Minerals Limited
617 Wellington Street
London, Ontario, Canada
amezei@fortuneminerals.com & rgoad@fortuneminerals.com,
2SGS Canada Inc.
185 Concession Street
Lakefield, Ontario K0L 2H0
3XPS Industry Relevant Solutions,
A Glencore Company
Falconbridge, ON, P0M 1S0
Crispinne.Patino@xps.ca, Mike.Pimentel@xps.ca, Mezbahul.Islam@xps.ca
ABSTRACT
Fortune Minerals Limited is developing the vertically integrated NICO cobalt-gold-bismuth-copper critical minerals project in Canada. The project is comprised of an open pit and underground mine plus concentrator in the Northwest Territories and a dedicated hydrometallurgical facility in Lamont county, Alberta where concentrates from the mine, and other feed sources, will be processed to bismuth ingots, gold doré, cobalt sulphate and copper cement.
The NICO project, is at the definitive feasibility study stage after extensive resource delineation and engineering work that included metallurgical studies and piloting to develop process flowsheets specifically designed to maximize the recoveries for each of the four payable metals into value-added products.
Historically, the NICO deposit was primarily a cobalt-gold asset, but it is also the largest deposit of bismuth in the world with 12% of global reserves. This paper describes the recovery of bismuth from its concentrate produced from the ore using bulk and selective flotation, followed by hydrometallurgical and a pyrometallurgical processing to 99.99% (4N) bismuth ingots. The relevant testing was performed at SGS and XPS, respectively with Worley responsible for leading the Feasibility Study engineering.
Bismuth concentrate, averaging 40-45% bismuth and 400 - 500 g/t gold is subjected to hydrochloric acid oxidative leaching using regenerated ferric chloride lixiviant, followed by thickening, filtration and washing. The well-washed filter cake containing most of the recoverable gold is blended with auriferous cobalt concentrate and subjected to pressure oxidation to recover the gold, cobalt and copper. The combined bismuth pregnant leach and wash solution is subjected to bismuth cementation using iron powder. The cementation barren solution is directed to ferric regeneration with chlorine. Free acidity and chloride levels are adjusted using sulphuric acid and sodium chloride, respectively.
The bismuth cement containing about 90% bismuth is subjected to reductive smelting using charcoal and sodium carbonate flux. The crude ingot containing about 95-98% bismuth is subjected to multiple stages of refining to produce the high purity bismuth ingots.
Keywords
Keywords: NICO Project, Bismuth, Hydrochloric acid oxidative leaching, Ferric chloride lixiviant, Bismuth cementation, Iron powder, Reductive smelting, Refining, 4N Bi.