Profile
Michael Cox was born in 1933 in Dartford Kent and following the family move to Warwickshire was educated at Solihull School. Leaving school in 1950 he joined the Australian National University, Department of Medicinal Chemistry which at this time was sited in London. On the University’s move to Canberra he attended University College London gaining a BSc in Chemistry in 1955, followed by MSc and PhD degrees in inorganic coordination chemistry. After a brief spell in industry Michael joined the Hatfield College of Technology in 1962 which at that time this was predominately a teaching establishment but later, when granted permission to award degrees under the Council of National Academic Awards (CNAA), opportunities to conduct research became available. CNAA Research Degrees required that all research should have industrial relevance and support with the appointment of an industrial supervisor a requirement which influenced his selection of future research projects. In 1969 the opportunity for a sabbatical was taken at Warren Spring Laboratory (WSL) working with Dr Douglas Flett in solvent extraction. This led to several projects in the fields of synergistic extraction, liquid-liquid interfacial studies and kinetics of metal extraction. Using his expertise in synthetic organic chemistry gained at the ANU a number of pure analogues of commercially available extraction reagents were synthesised and used for fundamental studies on the physical and inorganic chemistry of extraction. During this time a number of visitors were attracted to Hatfield including three Spanish students who completed their PhD studies in Spain working on projects started at Hatfield under his supervision. Funding was later received from the European Commission for two collaborative projects involving solvent extraction. The first under the Brite-Euram scheme involved the extraction of nickel from Greek laterite ores in collaboration with the National Technical University in Athens and University of Minho in Portugal in which Hatfield was responsible for developing the solvent extraction circuit. The second, an INCO-Copernicus project, involved the development of research expertise in solvent extraction and ion exchange in Eastern Europe involving Hatfield and the Polytechnic University of Catalonia (Spain) and two Eastern European research institutes, Institute for Non-Ferrous and Rare Metals (IMNR, Romania) and Institute for Non-Ferrous Metals (IMN, Poland) and also including local industries in these countries. The two solvent extraction projects were concerned with removal of impurities from copper tank-house liquors (IMNR) and the treatment of waste-water from the lead/zinc industry (IMNG) with both the lead scientists in the research institutes awarded PhDs as a result of their work in these projects. In recognition of his studies in the field of solvent extraction of metals in 1992 Professor Cox was awarded the Kurnakov Memorial Medal of the Russian Academy of Sciences for his work.
Recurring concern over the hydrometallurgical circuit and its requirement for large quantities of aqueous and organic solutions with accompanying environmental problems led to the study of alternative process to separate and recover metals. The first to be investigated was supported liquid membranes where the ability to develop and economically use selective extractants led to projects to treat dilute feed solutions such as arise from effluents. Bulk liquid membranes do not often feature commercially because of slow overall kinetics; however a contactor designed by Russian colleagues at the Mendeleev University of Technology was successfully demonstrated to a number of UK industries. Another invention to recover metals direct from ores stemmed from the studies of analysis of metallic elements by gas chromatography of volatile metal chelates. The observation that some complexes could be reduced to the metal by the hydrogen carrier gas provided the basis for a process to recover metals direct from ores, similar to the Mond nickel process. The system was successfully developed with support from WSL and the British Technology Group and was patented as the SERVO process (Selective Extraction and Recovery using Volatile Organics). A special acidic chelating reagent was required to provide selectivity over iron and the process was successfully demonstrated for recovery of elemental copper and nickel direct from lateritic ores and also waste materials.
Another major environmental concern in the hydrometallurgical circuit is solid/liquid separation following leaching which generates large amounts of tailings a potential environment hazard over many years. To address this hazard and reduce the overall costs a project using extractants to adsorb metal ions onto impregnated clays was developed. The ultimate aim was to suspend pelleted clays in the leach and selectively adsorb desired metals; subsequently the pellets would be collected and the metals recovered by leaching and the pellets recycled. Although adsorption and recovery operations were successful, the pellets proved unstable to the cycle of swelling and contraction during metal uptake and recovery and finally lack of financial support and the closure of the Chemistry Department meant that work on this promising process ceased.
Also during this time a number of projects on resin ion exchange addressing an important local environmental problem of nitrate pollution and accompanying operational difficulties were successfully completed. In 2011 a special issue of the journal Solvent Extraction and Ion Exchange: ‘Recent Developments in Solvent Extraction and Ion Exchange’ was published as a tribute to Michael’s career.
In addition to his research activities Professor Cox made significant contributions to the world-wide promotion of solvent extraction. From 1969 he was an officer of the Solvent Extraction Group (currently Separation Science and Technology Group) of the Society of Chemical Industry (SCI). In these positions he organised many international meetings including ISEC93 for which he was Secretary. For this and other activities for the Society he was awarded the SCI Lampitt medal in 2003. He was a member of the ICSE from 1993 and secretary from 1996-2002. Since resigning from the ICSE he formed the International Committee for Ion Exchange (ICIX) in 2004 and is currently secretary. ICIX was formed to perform a similar role to ICSE and has successful organised the coordination of the two major series of international ion exchange meetings in Japan and UK.
His professional interest in teaching led to invitations to contribute to several books on solvent extraction including chapters in: Handbook of Solvent Extraction; Science and Practice of Liquid-Liquid Extraction, Kirk-Othmer Encyclopaedia of Chemical Technology. He also edited a number of books including Solvent Extraction Principles and Practice 2nd edition, with Jan Rydberg, Claude Musikas and Greg Choppin and proceedings of several ISEC and IEX conferences.