In conversation with Ronald Woods, eminent flotation chemist



Ron and Elspeth, Phoenix 2016

Although his reputation greatly preceded him, I first met Professor Ronald (Ron) Woods in 1999, when he participated in Minerals Engineering ’99 in Falmouth. Our paths crossed again at Precious Metals ’07 in Brisbane, and three months later at Flotation ’07 in Cape Town, where he was accompanied by his wife Elspeth. 

We have kept in touch professionally ever since, and he is a trusted reviewer for Minerals Engineering, but my last meeting with Ron and Elspeth was at this year’s SME Annual Meeting in Phoenix, where Ron was awarded the SME’s coveted and highly prestigious Antoine M. Gaudin Award, for his outstanding contributions to advancing the chemistry of flotation of sulfide minerals and precious metals. In 2005 he was honoured by the SME/AusIMM as a Living Legend at the Centenary of Flotation Symposium in Brisbane, Australia. 

Ron receiving the Antoine M. Gaudin Award from Dr. Robert Seitz,
chair of the Gaudin Award Committee

During our brief meeting in Phoenix, I asked Ron if he would like to be interviewed for MEI's In Conversations series, and I was very pleased when he readily agreed. One of the first things I learned was that, like me, Ron was born in Lancashire in the north of England, he in St. Helens, and me 38 miles away in Ashton-u-Lyne. When I was born, Ron was just beginning his secondary education at Prescot Grammar School. The 2nd World War had recently finished, the barrage balloons had been removed, and the bomb sites were under repair. 

Ron was born on 3rd November 1934, and realised his future lay in the sciences when he attended Grammar School. His first employment was as a chemist by the North Western Gas Board in St Helens. 

During this period, he attended St Helens Technical College and obtained a London University external B.Sc. with honours in 1956 in Chemistry, Physics and Mathematics. The Gas Board then financed a year at Liverpool College of Technology which led to him being awarded a Graduate of the Royal Institute of Chemistry in 1957. The College offered him a Research Assistant position in 1958 to carry out research for a London University external M.Sc., and he received this degree in 1960 for a thesis entitled "An Oscilloscopic Study of Various Phenomena at the Dropping Mercury Electrode".

Elspeth and Ron met while hiking the hills and dales of England and Wales with the Liverpool Ramblers Association and related groups. They were married at the Church of Our Lady and St Nicholas in Liverpool on 10th August, 1960 before travelling to Minnesota in the USA, where he had accepted a Research Fellowship in the Analytical Department of the University of Minnesota with Professor I.M. Kolthoff to study induced reactions.

Wedding day, 1960

Ron with Prof. 'Piet' Kolthoff in 1963

His research in Minnesota was submitted to London University and he was awarded a Ph.D. in 1964 for a thesis entitled Arsenic(IV) as an Intermediate in the Induced Oxidation of Arsenic(III) by Free Radicals. 

I wondered how a Lancastrian lad became one of Australia’s most respected scientists. In 1964, Ron applied for a Research Fellowship at the University of Melbourne, Australia and was successful. He continued his studies on induced reactions and 3 publications resulted. In 1966, he moved to the CSIRO Division of Mineral Chemistry in Port Melbourne to work with Dr David F.A Koch to research the electrocatalysis of the oxidation of acetate for the Paper Industry. In 1968, he began research on the chemisorption properties of noble metals and their alloys at CSIRO and this work, carried out with Dr. Tom Biegler and Dr. David A.J. Rand, led to 27 journal publications. Ron reviewed this field in 1976 in a Chapter in Bard’s Electroanalytical Chemistry Series, entitled Chemisorption at Electrodes: Hydrogen and Oxygen at Noble Metals and their Alloys. 

Ron’s work on mineral flotation began in 1971 when Broken Hill silver-lead-zinc mines had problems in achieving good metal recoveries after introducing cemented fill. CSIRO was approached to further elucidate the flotation process to avoid similar problems in the future. A solution to the robust disagreements between the flotation doyens in the mid-20th century had been suggested by Salamy and Nixon. Those two authors proposed a mixed potential mechanism for the interaction between mineral and collector involving anodic oxidation of the collector coupled with cathodic reduction of oxygen. This process involves electrons passing through the conductivity bands of the mineral. It implies that one can look at the individual anodic and cathodic reactions using electrochemical techniques. Ron’s initial studies pursued this concept and the results were presented at the A.M. Gaudin Memorial Symposium organised by the SME in 1976. 

In 1977, Ron was invited by the Universidad de Concepcion to be plenary speaker at the Avances en Flotacion Symposium in Concepcion. He presented a talk entitled, Mixed Potential Mechanisms in Metallurgical Systems. He was also invited to tour mines and processing plants in Chile. He has attended a number of conferences in South America since that time. He has also participated in a number of international conferences in other parts of the world.

With the Chilean conference organisers, Profs. Jaime Alvarez and Sergio Castro in Concepcion

Ron’s research on sulfide minerals has, to date, produced 173 research and review papers in journals and advanced texts. Sir Ian W. Wark, one of the doyens of early research on flotation mechanisms, was a consultant to both CSIRO Minerals Divisions from 1971 until his death in 1985. Sir Ian often invited CSIRO scientists to a sandwich lunch in his office on a one-to-one basis and Ron found these events most interesting and rewarding. Sir Ian was honoured in 1983 by the AusIMM with a Symposium on “Principles of Flotation”. Ron contributed to this Symposium and, in a subsequent letter Sir Ian described Ron as “a man of talent of the next generation of scientists”.  

Ron with Prof. George W. Poling, of the University of British Columbia,
in Canada at the Wark Symposium in 1983

Voltammetry allows flotation recovery and surface collector coverage to be related to potential displayed by minerals in the flotation pulp. Ron’s studies confirmed that collector/mineral interaction follows a mixed potential mechanism, in which an anodic oxidation process involving the collector is coupled with the cathodic reduction of oxygen on the mineral surface. Ron and his colleagues also applied a number of complementary experimental techniques to enhance electrochemical studies. These include contact angle and flotation recovery as a function of potential, UV/Vis spectroscopy, infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and ToF-SIMS. These studies involved close collaboration with Dr. Alan N. Buckley of CSIRO and now Professor at the University of New South Wales, which have continued for more than thirty years. Ron provided the electrochemistry and Alan the electron spectroscopy. Of particular importance is their demonstration that collectors can chemisorb at potentials below those predicted from thermodynamics due to the higher reactivity of the species exposed on mineral surfaces. Another important result is the confirmation that flotation recovery can reach a maximum value when only a sub-monolayer is present on the mineral surface. 

Ron and Alan Buckley (right) with Dr. Paul E. Richardson of the US Bureau of Mines
in Avondale for a workshop organised by the Bureau in 1986, on
Flotation-Related Surface Chemistry of Sulfide Minerals

The application of Eh measurements in practical flotation plants to optimize recovery is now commonplace. Continuous control of Eh has proved much more difficult and this a question still to be answered.

Ron receiving the Stokes
Medal from Prof. Robin
Stokes in 1989

Ron was invited to contribute to the Arbiter Symposium in 1986 and, with Elspeth, stayed at Arbiter’s ranch adjacent to Saguaro National Park - Nat Arbiter signed the flyleaf of the Symposium Volume with the comment “with appreciation for your splendid work on electrochemistry of sulfide mineral flotation”. Ron was awarded the Stokes Medal by the Electrochemistry Division of the Royal Australian Chemical Institute (EDRACI) in 1989 for his work on sulfide mineral flotation. He is a Fellow of the Australian Institute of Mining and Metallurgy and a Life Member of Sigma Xi.

Ron advanced within the CSIRO research scientist grade structure to reach the top of the research oriented level of Chief Research Scientist 2. He also undertook a number of management roles culminating in 1990 with the position of Research Manager of the Metal Production Section. He was also involved in both research and management roles in a Government sponsored project on the development of better storage batteries. His research in that area led to 9 journal papers and a book, Batteries for Electric Vehicles, co-authored with Dr David A.J. Rand of CSIRO Minerals and Dr Ron M. Dell of the Atomic Energy Research Establishment, Harwell, UK. 

During his employment at CSIRO, Ron was involved in various educational activities, e.g., presenting an advanced course on Electroanalytical Chemistry at the University of Western Australia (1976), co-supervision of research for higher degrees at Ballarat College of Advanced Education (1976-1977) and Chairing the Multidisciplinary Degree Course Advisory Committee at Ballarat (1977-1990). He also acted as Chairman of EDRACI and was a member of the Advisory Boards of the Journal of Applied Electrochemistry and the International Journal of Mineral Processing. He was the joint organiser of eight Symposia on the Electrochemistry of Mineral and Metal Processing presented at The Electrochemical Society Meetings and joint editor of the resulting Proceedings Volumes.

In 1983, Professor Roe-Hoan Yoon of Virginia Polytechnic Institute and State University invited Ron to present an advanced course on Electrochemical Technology in his Department during the Fall Quarter. This activity led to annual short visits to Virginia up to 1995 to carry out flotation research with Professor Yoon and his team on subjects of complementary interest. These endeavours resulted in 12 joint publications.



With Prof. Roe-Hoan Yoon at Virginia Tech in 1983

London University, 1994

Ron was awarded a D.Sc. (Eng) by London University in 1994 for his work in the field of Application of electrochemistry to mineral processing and energy storage.

In 1995, he left CSIRO and continued his research career at a number of Universities in Australia and the USA. This allowed him to continue his collaboration with Professor Alan Buckley of the University of New South Wales (UNSW) on the combined application of electrochemical techniques and electron spectroscopy to understanding flotation collector/mineral interaction, which commenced when they were both at CSIRO.

In 1995, Ron spent the Fall Quarter in the Department of Metallurgical Engineering of the University of Utah where he presented an Advanced Course on Electrochemical Technology and collaborated on research topics with Professors Milton E. Wadsworth and Jan D. Miller. A joint paper with Wadsworth was published in Nickel-Cobalt 97. In the last half of 1995, Ron worked with Professor Ian M. Ritchie at the University of Western Australia working with Ritchie’s research students and completing a review paper on the metal/solution interface in which electrochemical reactions were compared with those at the metal/gas interface.

He also collaborated with Dr Matthew I. Jeffrey on gold metallurgy and other subjects related to the minerals industry when Matthew was at Monash University and at CSIRO in Perth. They are co-authors of 10 publications. They applied the electrochemical quartz crystal microbalance to measure the adsorption of xanthate on surfaces and to monitor changes in wettability. Matthew joined Newmont Mining in Denver in 2011 and is now Director of Mineral Technology. 

With Matthew Jeffrey in Phoenix, 2016

With Greg Hope on the occasion of Ron's 80th
birthday. Ron is wearing the Ronaldo
football shirt acquired at the Brazil-Australia
Workshop organised by Greg in Rio

In 1996, Ron was invited by Professor Gregory. A. Hope of Griffith University in Queensland to work with his group that was focussing on the application of Raman and related spectroscopies, together with electrochemical techniques, to elucidate processes of importance to the minerals industry. They worked together on the interaction of flotation collectors with metal and sulfide mineral surfaces. Ron has a position of Adjunct Professor in the School of Natural Sciences at Griffith University and his collaboration with Professor Hope is continuing. It has resulted in 54 publications to date. The Griffith team collaborates with Professor Buckley of the UNSW on areas of joint interest.

I asked Ron what were his plans for the future? He told me he is continuing his involvement with sulfide mineral flotation as a consultant to the Australian Minerals Industry and as part of the joint Griffith/UNSW team working on projects sponsored by this Industry. He said the team are presently looking at the interaction of combinations of collectors with sulfide minerals. He noted that Cytec is marketing collector blends in its Flotation Matrix 100 approach. Also, Clariant is marketing collector mixtures in its Hostaflot range and these were promoted strongly at the Phoenix SME meeting.

I also asked him what are the areas of flotation that he feels should be most actively pursued? He pointed out that economic ore bodies were becoming lower grade and more complex, so there will always be need for research to enhance recovery and grade as no alternatives to flotation for ore treatment are on the horizon. I also asked him if we have sufficient talent in the minerals industry to attack these problems? His answer was “Yes!” He said a number of Australian Universities were active in flotation research and CSIRO was continuing work relating flotation recovery of copper/arsenic minerals to electrode potential in order to identify improved arsenic rejection. I asked him if too much research emphasis was being placed on reagents rather than the fundamental electrochemistry? He pointed out that reagents are the key to flotation so there can never be too much work directed towards determining how they interact with minerals. He said the problem in Australia did not lie with lack of talent, but with inadequate funding for mineral flotation research. 

Finally, I asked Ron if he and Elspeth have any plans for retirement? He said he is not employed by anyone, so “retirement” doesn’t appear to be an option. On behalf of MEI I wish him and Elspeth all the very best wishes for the future.

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