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Review of the 2016 Gilchrist Thomas Prestige Lecture delivered by Professor Derek Fray

Newport & District Materials Society
13 May 2016

The biennial Sidney Gilchrist Thomas Prestige Lecture brought the curtain down on the Society's 2015-2016 lecture programme.  Held in Cardiff University's impressive new building in Maindy Road that houses the School of Optometry and Visual Sciences, the evening was chaired by Programme Organiser Tony Jones who began proceedings by inviting the audience to observe a brief silence in memory of the late David Barradell.  David, who passed away in March, had been a Committee member for over a decade during which time he organised the Society's Annual Guest Dinner each year with his usual quiet efficiency.  David also made his presence felt in the Golf tournament  which he won for three successive years, beginning in 2008.  He'll be missed in many ways!

Tony Jones then gave the background to the Sidney Gilchrist Thomas Prestige Lecture.  Although he is rarely remembered today, Sidney Gilchrist Thomas (1850-85), working with his cousin Percy Gilchrist at Blaenavon Ironworks in the late 19th century, made a groundbreaking contribution to steelmaking technology that continues to influence modern practice.  Put simply, Thomas successfully removed phosphorus from liquid iron in a Bessemer converter, a challenge which had eluded the best efforts of numerous luminaries of the time including Sir Henry Bessemer himself.  Thomas' announcement of his achievement initially met with scepticism, but he was ultimately proved to be right and the Thomas process (sometimes misleadingly called the basic Bessemer)  was in use for 90 years whilst the principle upon which phosphorus removal is based endures to this day in other processes.  In 1960, the Newport & District Materials Society was instrumental in having a memorial to Sidney Gilchrist Thomas erected at Blaenavon.   It is now at the Blaenavon ironworks.

To acknowledge the importance of Sidney Gilchrist Thomas the man, the lecture which bears his name is intended to demonstrate the relevance of his approach to industrial challenges in the21st century.  It was therefore fitting that Professor Derek Fray from Cambridge University had been invited to be the 2016 lecturer, since his breakthrough research into the extraction of titanium to some extent parallels the work of Sidney Gilchrist Thomas.  Professor Fray's lecture was entitled "Examples of Synergy Leading to Innovations in Materials Science" and a brief summary of the key points appears below.

Professor Fray began by describing the extraction of titanium by the Kroll process which originated in pre-WW2 years.  Essentially it is a pyrometallurgical process.  Rutile (TiO2) is reduced with carbon in a fluidised bed and the Ti released is then combined with chlorine to yield titanium tetrachloride (TiCl4), which is refined by distillation before purified titanium is produced by displacing it from combination with chlorine by magnesium.

TiO2 + 2C +2Cl2 = Ti + 2CO + TiCl4

2Mg + TiCl4  = 2MgCl2 + Ti

The titanium at this stage is a spongy product that requires re-melting so that overall the Kroll process is time-consuming and very expensive.  Whilst researching in the field of electrolysis in the 1990s, however, Professor Fray and two colleagues developed a different process that is known as the FFC Cambridge process (Fray, D. J.; Chen, G. Z.; Farthing, T. W. (2000). "Direct electrochemical reduction of titanium dioxide to titanium in molten calcium chloride". Nature 407 (6802): 361–4.)   In the interest of accuracy readers are referred to this publication since your reporter is not confident that his notes made on the night are a sufficient guide.  Suffice it to say that electro-deoxidation of metal oxides such as TiO2 in a calcium chloride electrolyte can be achieved in 12-15 hours compared to the 21 days of the Kroll process.  Other metals such a zirconium, chromium, niobium and niobium-titanium alloys can also be produced in a similar way.  The opportunities for innovation don't stop there.  Titanium-tantalum alloys, photobaric silicon i.e., silicon with a needle-like surface structure giving the product a black appearance due to the lack of reflected light are additional possibilities. Black silicon is especially interesting since it should be an improvement on a conventional photovoltaic cell which takes five years to generate more energy that its production consumed.

The audience was left with the impression that Professor Fray and his team had struck upon a fertile seam of ideas, but that bringing them to fruition was hindered by the scepticism of funding agencies and the complexities of protecting intellectual property.  In this, there were echoes of the Sidney Gilchrist Thomas story.  Even so, electrolysis pointed the way to further advances in lithium-tin batteries, in the production of carbon nanotubes and even to the addition of hydrogen to graphite to produce graphene.  Somewhere along the line producing diamonds at 1 atmosphere pressure was also touched upon, but at this stage your reporter had lost the thread of the argument.  Photoionisation detection (PID) sensor technology is another area of development.  In this case readers are advised to look at for enlightenment.

Professor Fray's final section dealt with medical applications of electrolysis and specifically with the idea that since oxygen is required for wound healing then concentrating the supply of oxygen in the area of a wound ought to accelerate recovery.  This had led to the development of devices which are currently arousing great interest in the NHS.  Again further details of these Natrox devicescan be obtained by visiting

In his conclusion, Professor Fray expressed his strong belief in the potential for basic science research to generate innovative ideas, although he was not sanguine about funding bodies sharing this viewpoint.  Nevertheless, if new process can be shown to be viable then in his experience venture capital can be attracted.

In the ensuing question and answer session Professor Fray expanded on some of his ideas and the audience went home reassured that materials research leading to the emergence of new processes is not yet dead in the United Kingdom.  The 2016 Sidney Gilchrist Thomas Prestige Lecture was a fitting conclusion to the lecture programme for the year and Professor was warmly thanked.

Robert Walker