‘It is no use saying we are doing our best You have to succeed in doing something necessary’ Winston Churchill
It is difficult to resist the temptation to do what most of the commentators do at the beginning of a New Year. This is to review the past year with the satisfaction of saying ‘I told you so’, and then to pontificate on New Year’s resolutions aimed at avoiding the sins of the past causing disasters in the future. There was a temptation to discuss aluminium plants in relation to Escom’s capacity to produce power. Fortunately this was overcome by the publication of this suite of papers from the Heavy Minerals Conference (now a regular feature on our programme), which made it irresistible to reminisce on the unpredictable path of scientific and technological advancement.
After my introduction to the mining and metallurgical industry after graduation, by way of work on uranium extraction, my second major assignment in the metallurgical field was to embark on a worldwide study on the future prospects of the ‘wonder metals’ that had come to the fore after the war years, metals that were going to revolutionize aerospace, nuclear energy and superalloys for ultra high temperature use in gas turbines. These wonder metals were going to launch a new era in metallurgy, materials science and engineering.
My ‘sponsors’, my first industrial employers, had interests in a large number of these almost unheard of metals. Very interestingly, a significant proportion of these metals occur in the heavy minerals present in beach sands. It was an assignment more akin to an educational programme with a steep learning curve since most of the metals on the list were, to a novice chemical engineering graduate, little more than strange names in obscure corners of the Periodic Table. Titanium was the top of the list as the new wonder metal, the successor to aluminium, the ultralight structural metal of the 19th century. Then came beryllium, the lightest of the structural metals, which was predicted to play a key role in the nuclear power industry, because of its low neutron absorption and superior high temperature corrosion properties.
Similar properties were evident in zirconium and niobium, which had to be separated from their sister metals hafnium and tantalum, respectively, with almost identical chemical and physical properties but with high neutron absorption coefficients. The most intriguing suite of metals was the fifteen so-called rare earth metals, chemically known as the Lanthanides but with beautifully erotic names like, lutetium, ytterbium, didymium, praseodymium, and europium. These were almost invariably associated with thorium, the only naturally occurring fissile metal other than uranium. Thorium was predicted to have a big future as the basis of the breeder nuclear reactor as it produced as much fuel as it consumed. It was a voyage of discovery in terms of the new extraction techniques of solvent extraction fused salt, chlorination and fluorination metallurgy.
High temperature electron beam vacuum melting for fabrication of metals was the order of the day. Every physical metallurgical laboratory worth its salt had active programmes on the alloys, physical properties and fabrication techniques. A large amount of excellent sophisticated forefront work was accomplished. A bright future was predicted for them especially for titanium, which many claimed would be the next commodity metal. In Southern Africa, there were many known deposits of most of these metals. Indeed, at that time we had become one of the largest exporters of monazite, the predominant source of thorium and rare earth elements. Previously, the major use of thorium was to make gas mantles from the thorium oxide, and cigarette lighter flints from a cerium alloy known as ‘Misch-metal’. With the exception of beryllium, niobium and tantalum, the new metals were all to be found in beach sands with ilmenite being the main source of titanium metal.
A new plant for recovery of the heavy minerals in the beach sands at Umgababa had been commissioned. A rare mineral, baddeleyite (almost pure zirconium oxide), had been identified in the ores at Phalaborwa and was shown to be recoverable in substantial quantities. Baddeleyite was, coincidently, a key material in the nuclear submarines developed by the United States. Urano-thorianite was also located in the Phalaborwa orebody in commercially recoverable quantities. South Africa was poised to become a major player in the nuclear industry and other areas in which these exotic wonder metals were used. Then the bubble burst. Possibly one of the major puncturing events occurred with the calamitous crashes of the first commercial jet powered, airliners the De Havilland Comet. Key components had been made of titanium metal and certain of these failed due to metal fatigue.
Whether this was correct or not, suspicion was cast on the new aerospace metal. In any event, the cost of production of most of the wonder metals was exceptionally high and the more conventional alloys were commercially more cost-competitive. There were also some nasty health hazards associated with some of the metals. Beryllium in micro quantities could cause Berylliosis, a killer disease. There were radiation hazards associated with monazite and other thorium-bearing minerals to the extent that shipping companies refused to handle bulk material. The beach sand operations at Umgababa were abandoned due to marine pollution problems. Thus the wonder metals never reached the status of commodities but remained as specialist products and, in many cases, curiosities. What I find fascinating is that among the best forecasters at the time when the titanium metal bubble burst, nobody predicted the phenomenal demand for the vast beach sands deposits prevalent along our north-eastern and west coast.
The demand arose as a result of the ‘whiter than white’ titanium dioxide replacing the lead based material in the pigment market. This made the beach sands one of the biggest success stories in our mineral processing history. It took the Canadians to show us the way to exploit this bonanza. Of the fifteen ‘lanthanides’ only one hit the big commercial jackpot, and this was one of the rarest rare earths, Europium, which became a unique and essential compound to provide the red phosphors in all television tubes. Europium oxide sold at prices that made gold and platinum comparable to scrap metal. One of the richest and largest resources was located as an impurity in the foskorite being mined at Phalaborwa.
Sadly we missed the boat on this one, because the Chinese had collared the world market before we woke up to its potential. Nuclear grade zirconium metal was produced in small quantities at the National Institute for Metallurgy in the 1970s as a precursor to fuel element production at Pelindaba. But this never realized any significant scale. Thus almost all the unique baddeleyite went into glazes for beautiful decorative ceramic tiles made overseas. There is no profound moral to this Journal Comment other than to observe that it is a brave forecaster who claims reliably to predict the future outcomes arising from the inexorable march of science and technology. I remain convinced that the payback from R&D at the forefront of new developments is best predicted from statistical probability rather than any brilliant farsighted scientific or business acumen. R.E. Robinson January 2008
- Written by R.E. Robinson
- Hits: 9874