Bio-sourced reagents for the flotation of minerals in the mining industry

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Mining companies are forced to exploit ore bodies that are more complex and of lower grade, while complying with increasingly challenging environmental regulations. Many of those companies use froth flotation to concentrate mineral ores. In this process, often toxic chemicals are added to specifically alter mineral surface properties (mainly hydrophobicity). With increasing regulatory restrictions (for instance, Ontario contemplates the ban of xanthates), the industry could face a dead end with no alternative reagents that are sufficiently efficient, low cost or environment friendly. It has been previously shown that peptides could selectively bind mineral surfaces. This project therefore aims at the development of alternative flotation bio-reagents, based on i) large-scale screening of peptides libraries; ii) peptide mathematical modeling and in-silico optimization integrating hydrophobic/hydrophilic functions into selective sequences identified in (i), in order to favor mineral flotation; iii) constructing an expression system that will present the bio-reagents in the most effective way as well as maximize yield; iv) modeling and optimizing a bioprocess to produce the best bio-reagents selected/designed in (i/ii) at its maximum productivity. These molecules will be developed for the specific processes of gold, silver, copper, zinc and nickel sulfides flotation. Special emphasis will be put on the analysis and minimization of bio-reagent production costs in order for it to be a competitive alternative to the presently used, toxic reagents. These new bio-reagents will be relatively easy to treat in mine effluents and will therefore greatly reduce environmental impact of mineral flotation processes. At the end of this project, new bio-collectors with improved efficiency, smaller environment footprint and competitive costs will be available for industrial and commercial development by the mining industry.