Deep eutectic solvents for the leaching of technology metals from oxide minerals

Lime dosing in a high-density sludge (LD-HDS) process is amongst the most widely applied acid mine drainage (AMD) treatment process worldwide. An intrinsic issue of the LD-HDS process is the formation of an ecotoxic metal(loid) bearing ochre waste product. Such waste is a major liability and requires long-term management to prevent major environmental and/or human health impact. In the UK alone approximately 4500 tonnes of ochre (dry) are produced per year, most of which are disposed in landfill. Landfill disposal costs for ochre are between £79-129 per tonne at 50% solids (Sapsford et al., 2015). Similar situations exist in countries around the world. This lack of technology is therefore a major environmental issue and barrier stopping mining operations from gaining a social licence to operate worldwide. This PhD project will aim to develop novel techniques utilising "green" solvents to extract specific metals/metalloids from LD-HDS ochres to produce metals and industrial materials of economic value. LD-HDS is underexplored and to date is limited to few preliminary studies (e.g. Crane & Stewart, 2020). A number of industrial partners (First Quantum Minerals, Veolia, and the Coal Authority) have stated a demand for new research in this important area. This PhD enables me to build on this preliminary research and combine this with my background in ascorbic acid research to open up a new area in chemical engineering.