Process Design for Efficient Metal Extraction from Concentrates

Traditional ore processing is generally carried out using either hydrometallurgy (high cost, low volume, reasonable selectivity) or pyrometallurgy (lower cost, high volume, low selectivity). Both methods require a large energy input and produce large volumes of waste e.g. slags or waste water. This project will seek to use a new type of solvent process which will be more selective, use less energy, and be more environmentally compatible.

Electrocatalytic and electrolytic methods can be used to solubilize metals and metallic compounds from complex matrices. Ionic liquids can also increase the selectivity and efficiency of metal extraction and winning. The main issue is that this approach necessitates a new approach to reactor design. The majority of processes use batch style tanks or heap leaching to extract metals from their ores.

The project will address a diverse group of ore minerals commonly encountered in important hydrothermal deposit types such as epithermal gold and porphyry copper (including the world-class Lepanto deposit of one of our partners). These minerals, and the chemical elements they host, pose both challenges and opportunities for mineral processing operations.

This project will explore the electrochemistry of common sulfosalt minerals in ionic liquids to assess the potential for new environmentally-benign approaches to processing. It will suit a student, either with a degree in mineral processing/applied geology/geochemistry/mineralogy who is keen to develop skills in chemistry, or with a degree in chemistry who is keen to apply their skills in the mineral processing industry.

You will need to design new ionic liquids to selectively extract specific metals from a concentrate and selectively precipitate the base metals enabling efficient recovery of the more strategic elements. The challenge will be to control material flow to optimise both mineral dissolution and metal recovery while using the minimum volume of solvent. You will also carry out techno-economic analysis during the design stage to ensure that it is viable on a practical scale. The Green metrics of the process will be calculated to support the objectives of improving sustainability and decreasing environmental impact.

You will characterise the structure and chemistry of sulphosalt samples, assessing their reactivity in deep eutectic solvents and their reaction products using optical profiling, cyclic voltammetry, UV-vis spectroscopy and electrochemical quartz crystal microbalance. These data will be correlated with the mineralogical information to derive general rules about the behaviour of these minerals. These will then be used to design bulk tests on concentrate samples to assess the efficacy of dissolution and methods of recovery of the components from solution. There will be the opportunity to investigate routes to produce end-products as well as means of safe disposal of waste products (such as converting arsenic to scorodite). Based on results, a pilot scale test will be carried out to demonstrate the possible industrial application of your work. One aim will be to focus on a non-cyanide based method for extracting gold from ores which is an important issue in artisanal mining.

Prof Abbott developed deep eutectic solvents and their application to metal processing. He has worked on scale-up and chemical engineering aspects of reactor design through numerous EU and Innovate UK projects. He is a partner on a Marie Curie Training network on ionometallurgy. Prof Jenkin has over 25 years’ experience in mineralogy and geochemistry and their application to mineral deposits He has pioneered mineral processing with Prof Abbott over the past 5 years.

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-CHEM2-ABBO in the funding section.
• Complete an online project selection form Apply for CENTA2-CHEM2-ABBO