Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier (2017-2018 à 2020-2021).

Most refractory gold ores need to be treated to destroy the encapsulating sulfide minerals to release the gold forx000D
cyanidation recovery. Pressure leaching or bioleaching (oxidation) are typically used to destroy the sulfidex000D
minerals, followed by cyanide leaching. The presence of carbonate minerals in the refractory gold ore, thex000D
generation of partial oxidation product such as elemental sulfur during pressure leaching and bioleaching, arex000D
detrimental to the gold recovery process due to wasteful acid and cyanide consumption. We propose to removex000D
these carbonate minerals and elemental sulfur by reverse flotation. For that purpose, appropriate flotationx000D
depressants for gold are required, which are not currently available.x000D
In refractory gold ores the gold is typically associated with arsenopyrite. Often it is required that thex000D
arsenopyrite be concentrated to enrich the gold grade for subsequent processing. This usually entails thex000D
selective separation of arsenopyrite from pyrite. Current practice is to use strong oxidation reagents to depressx000D
arsenopyrite while floating away pyrite. Again suitable gold depressants are required if the ore contains nativex000D
gold nuggets.x000D
In the proposed research we will utilize the phenomena of self-assembling of thiol reagents on gold surface tox000D
guide the development of gold flotation depressants. Microflotation and batch flotation as well as atomic forcex000D
microscopic (AFM) force and induction measurements will be performed on gold powders, refractory goldx000D
ores, and silicon wafers sputtered with gold. The flotation and force/induction time will be correlated so thatx000D
the AFM will be the primary tool to assess the effect of reagents on gold. The research will not only developx000D
suitable gold depressants but also suitable evaluation techniques to assess the flotation behaviors of hard-to-getx000D
or expensive high purity minerals and precious metal powders.