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Title: Mineral processing using deep eutectic solvents
Authors: Al-Bassam, Ahmed Z. Mohamed Hussein
Supervisors: Abbott, Andy
Jenkin, Gawen
Award date: 20-Aug-2018
Presented at: University of Leicester
Abstract: Processing sulfur containing minerals is one of the biggest sources of acute anthropogenic pollution particularly in the form of acid mine drainage. Sulfur-based minerals are generally roasted to convert them to the oxide, producing SO2 or leached in acid producing H2S. This study attempts to show an innovative method for processing sulfide-based minerals using a deep eutectic solvent (DES), Ethaline, which is a mixture of choline chloride and ethylene glycol. It is shown that pyrite can be solubilised by both electrochemical oxidation and reduction in a DES. A novel method is demonstrated to investigate the redox properties of minerals using a paste made from the mineral powder in a DES. The first bulk electrochemical dissolution of pyrite is shown without the formation of H2S or SO2. The solubilised species are investigated using cyclic voltammetry UV-vis spectroscopy and EXAFS. In all cases for the iron minerals studied, it was found that the electrochemistry of the counter ion and not the metal, controlled the ease of dissolution. It is also shown that the soluble species, including elements such as arsenic, can be recovered electrochemically which could potentially decrease acid mine drainage. The electrochemical properties of other iron–sulfur and iron–arsenic minerals are also presented and compared to those of pyrite. The final part of this study uses different cell designs in an endeavour to optimise the space-time-yield of the electrochemically assisted digestion of jarosite. It was found that the electrochemical digestion of material was up to 20 faster than the chemical dissolution. It was, however found that formation of insoluble precipitates, particularly of lead and zinc sulfates affected the performance of the separator membranes and this could decrease the yield of digested metal. The presence of high concentrations of iron salts led to passivating films on the zinc surface during cementation.
Type: Thesis
Level: Doctoral
Qualification: PhD
Rights: Copyright © the author. All rights reserved.
Appears in Collections:Leicester Theses
Theses, Dept. of Chemistry

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