Monday, 5 June 2017

Developments in the Processing of the "Hi-Tech" metals

The Minor Metals classification includes metals which have no obvious practical use, or those which do have a potential practical use but cannot be economically extracted.  A good example is nickel, which in the early 20th century was regarded as a minor metal, until it was discovered that nickel and chromium, when alloyed with mild steel (itself an alloy of iron and 0.2% carbon), could produce an alloy steel with good mechanical properties, but which would not corrode. These stainless steels, of which 18/8 (18% Cr, 8% Ni) is the most well known, rapidly changed nickel's status from minor metal to steel making metal, allowing it to be mined at high tonnages.
In the late 19th century aluminium was more precious than gold, and classified as a minor metal, although it was well known that it had potential as a light, strong metal which would not corrode, due to its passive oxide layer. No one of sound mind would have predicted that aluminium would one day be a cheap metal in global use for common household utensils, the invention of the Bayer and Hall-Héroult processes allowing the economic mass processing of bauxite ores.
When I was at University studying metallurgy in the 1960s, the rare earth elements were classed as minor metals- who had even heard of neodymium, now essential in the production of powerful rare earth permanent magnets, used in wind turbines and many other applications (see also posting of 11 February 2013)? 
Lithium was essentially a curiosity, the third element in the Periodic Table, and the lightest metal. Now, of course it is in high demand for light, powerful batteries, and the increasing prevalence of electric cars will increase the demand for this once minor metal.
The rare earths and lithium are primary mined, but some of the once minor metals, such as gallium, germanium and indium, which are essential for our modern way of life, are by-products of base metal mining.
The importance of all these 'Hi-Tech' metals cannot be overestimated and MEI is pleased to announce our first international conference on the mineral processing and extraction of the hi-tech metals (Hi-Tech Metals '18) in Cape Town in November of next year. The conference will immediately follow Process Mineralogy '18 at the Vineyard Hotel.
Towards a circular economy is the theme of another MEI Conference next year, Sustainable Minerals 18. How well do the hi-tech metals fit into the circular economy? Not very well at all unfortunately. Take indium, for instance, now critical to our modern lifestyle, the most important ingredient, as an indium-tin oxide,  in the production of ubiquitous touch screens. Indium is produced in small amounts from the mining of Zn ores, and the sheer number of smart phones, tablets etc. produced each year requires around 700 tonnes per year of indium. Recent estimates however, suggest that total reserves are around 16, 000 tones, so it is a very finite resource.
So is recycling the answer, the aim of the circular economy? Unfortunately not at present- a smart phone for instance contains around half of the elements of the Periodic Table, and indium contributes around 0.02 g, so recovery by recycling of indium, and all the other metals in the phone, many of which are locked together as alloys, is unfortunately not practical as the moment, yet another reason why research into mineral processing and extractive metallurgy is so critical to modern life.


  1. Very important and vital topic,Barry. The elements mentioned are rare.precious/trace and are of strategic importance. In India we are giving importance for R&D to find technically feasible and economically viable processes to recover them. Many times, some of them are in the dumps of over burden of mines because no attempt was made earlier to recover them.A holistic approach which includes the huge volumes of material involved to recover these small volumes of values/environmental aspects have to be also considered.
    May be a good marriage of physical,chemical and bio techniques will give a lead.
    I hope many researchers would share their experiences on this.

  2. Barry, Recycling of 'High Tech' metals including the rare earths is going to be of utmost importance in future ! I wish you success in your venture.
    Arun Dongrey, M/S Dongrey & Associates, India

  3. Dear Barry

    Great that you are advancing this! It dovetails very well with your Sustainable Minerals '18 conference series which is pushing the circular economy paradigm.

    The work we recently did for Fairphone
    links simulation using HSC Sim 9 (a minerals and metallurgical processing simulation tool) to product design to understand how well high Tech metals can be recovered from complex products. This is rather challenging as the results show and I would think this will be one of the foci of this new conference.

    Obviously the primary recovery of these High Tech metals will remain important as present products dissipate to an extent High Tech elements partially due to product complexity.

    So once again, great that you are pushing so strongly the sustainability and circular economy issues! High Tech elements lie at the very fabric of the renewable energy and other sustainability enabling infrastructure and technologies.

    Kind regards, Markus.

    1. Many thanks Markus. We are excited about this new conference and are confident that it will be a great success. If all goes well in Cape Town next year we will certainly consider linking with the Sustainable Minerals conferences, for which you play a very important part

  4. Prof.T.Subbaiah6 June 2017 at 17:06

    Dear Dr Barry,
    Very important subject for the conference.You can add Tellurium also into the list.Energy critical elements research is one of the topic to be included.


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