Understanding and mitigating the environmental impacts of metal ore processing wastes produced using “green” solvents
Dr GRT Jenkin
Dr M Whelan
No more applications being accepted
Funded PhD Project (European/UK Students Only)
Conventional mineral extraction from mined ores (e.g. for metals) is often an energy-intensive process, requiring either smelting or leaching at elevated temperature, or the use of large quantities of strong acids or bases that are energy intensive to produce. Furthermore, some treatments, most notably cyanidation hydrometallurgy, have poor public perception (e.g. residual cyanide trapped in mine tailings as well as being a poison to wildlife can also facilitate the release of toxic metals, such as mercury). Deep eutectic solvents (DES), such as Ethaline (choline chloride + ethylene glycol; Jenkin et al., 2016), provide a “greener” alternative for the extraction of metals from ores with less energy, lower costs and (in principle) fewer environmental impacts.They can also help with the co-extraction of rare e-tech elements such as tellurium (used in solar photovoltaic cells). However, the actual environmental risks associated with waste products from mineral processing using DES have not yet been quantified. In this project, the impacts of DES-processed ore waste (tailings) on soil function and on the leaching of potentially toxic components to ground and surface waters will be assessed using a combination of manipulative field and lab experiments and numerical modelling.
The project will examine the degradation of the organic solvent in the tailings, the mobility of residual metals, the toxicity of residual solvent, its breakdown products, and dissolved metal load to soil function and the potential for ground and surface water pollution. Given the potential surge in DES applications in the minerals processing industry in the near future, the project is likely to have significant and immediate impact and could be used to define industrial best practice.
Laboratory experiments will be conducted to determine the effects of fine-grained particulate tailings composed of waste metalliferous minerals containing residual organic solvent and its breakdown products, the oxidising agent (e.g. iodine) and dissolved metals, on key soil functions (e.g. nitrification, respiration). The leaching potential of hazardous components will be determined using mesocosm and leaching column experiments, supported by numerical modelling. Scenarios such as oxygen-limited tailings ponds, oxygenated stacked tailings, and a catastrophic spillage will be simulated. The dynamics of solute transport and transformation in soils, groundwater and rivers will also be explored using state-of-the-art solute transport and reaction models.
Professor Gawen Jenkin, Dr Mick Whelan and Dr Dan Smith will supervise this project. The group have interests in ore mineralogy and extraction and in understanding the fate and transport of environmental contaminants in terrestrial and aquatic systems. The Leicester team have excellent links with industry and have a large well-funded group including NERC projects TeaSe (Tellurium and Selenium Cycling and Supply) and FAMOS (From Arc Magmas to Ores).
Entry requirements Applicants are required to hold/or expect to obtain a UK Bachelor Degree 2:1 or better in a relevant subject. The University of Leicester English language requirements apply where applicable.
How to apply Please refer to the CENTA Studentship application information on our website for details of how to apply.
As part of the application process you will need to:
• Complete a CENTA Funding form – to be uploaded to your PhD application
• Complete and submit your PhD application online. Indicate project CENTA2-GGE5-JENK in the funding section.
• Complete an online project selection form Apply for CENTA2-GGE5-JENK
This studentship is one of a number of fully funded studentships available to the best UK and EU candidates available as part of the NERC DTP CENTA consortium. The award will provide tuition fees as the UK/EU rate and a stipend at the RCUK rates for a period of 3.5 years.
For more details of the CENTA consortium please see the CENTA website: www.centa.org.uk.
Applicants must meet requirements for both academic qualifications and residential eligibility: http://www.nerc.ac.uk/skills/postgrad/