Sunday, 19 December 2010

Season's Greeting from MEI



On behalf of the Wills family at MEI we wish you all a Happy Christmas and best wishes for 2011.

Thanks to all of you who have sent greetings by card, email, Facebook and LinkedIn. We appreciate your kind thoughts.

Thursday, 16 December 2010

News of people you may know

Below are snippets of news from my LinkedIn contacts:

Wendy Zheng is Technical support for sales at Shandong Huamin Steel Ball Joint-Stock Co., China
Jess Kinal is Manager Metallurgy - Implementation at Magotteaux, Australia
Josh Rubenstein is now Senior Metallurgist at Minto Explorations Ltd, Canada
Yves Mwabila is Senior Process Engineer at Gekko Systems, South Africa
Erik Hulthén is Researcher at Chalmers University of Technology, Sweden
Anna Kaksonen is Research Team Leader at CSIRO, Australia
Snezana Bajic is now a PhD- Research High Degree Candidate at The University of Queensland, Australia
Persio Rosario is Principal Project Metallurgist at Aura Minerals Inc., Canada
Quintin Buthelezi is metallurgist at Gold Fields Exploration, Inc., South Africa
Greg O'Connor is Metallurgist at Fortescue Metals Group, Australia
Magnus Evertsson is now Senior Process Crushing Specialist, Founder and partner at Roctim AB, Sweden
Bryn Harris is President at Neomet Technologies Inc., Canada

For more comprehensive news of People, visit People News on MEI Online.

For regular updates of news from the world of mineral processing and its people, submit your email address in the box in the right-hand column.

Monday, 13 December 2010

Geopolymerisation and the pyramids

One of the themes of May’s SRCR ’11 conference is “Developments in geopolymers as alternatives to conventional cements”. Geopolymer is a term covering a class of synthetic aluminosilicate materials with potential use in a number of areas, essentially as a replacement for Portland cement and for advanced high-tech composites, ceramic applications or as a form of cast stone.

Minerals Engineering has published a number of papers on geopolymerisation over the years, and, far from being a mundane subject, it is a field of great scientific potential, with some fascinating implications, which bring together two of my interests, science and history.

I am fairly sure that the first paper on this topic published in Minerals Engineering was co-authored by my two old friends Jannie van Deventer and Leon Lorenzen, who were then at the University of Stellenbosch, but are now pursuing successful careers in Australia.

The paper, by Jannie, Leon and J.G.S. Van Jaarveld, entitled “The potential use of geopolymeric materials to immobilise toxic metals: Part I. Theory and applications” is an excellent review of the science of geolpolymeric materials, but what hit me between the eyes when I read it all those years ago was a couple of paragraphs describing the ideas of Davidovits, who postulated that the pyramids of Egypt were not built by the means previously thought, but were cast in place and allowed to set, creating an artificial zeolite rock. His ideas were published in a book (The Pyramids; An Enigma Solved, Hippocrene Books, Inc, New York, 1988). Unfortunately I did not follow this up, as at the time I thought it was just another crackpot idea, such as von Daniken’s 1968 book Chariot of the Gods, which proposed that the pyramids were built by aliens, or the later, and more believable, Fingerprints of the Gods by Graham Hancock, which proposed the building by a long-gone ancient civilisation, but which was also deeply flawed, being based on very selective “research”. I was then unaware that Joseph Davidovits was a respected materials scientist, who first applied the name geopolymer to these materials in the 1970s.

Barbara and me at Giza in 1995
Having visited the pyramids at Giza a couple of times, I am fascinated by not only their sheer size but also the precision in construction, by what was essentially a civilisation only just emerging from the stone age. There have been many hypotheses about the construction techniques, which seem to have developed over time, later pyramids not being built in the same way as earlier ones. Most of the construction hypotheses are based on the idea that huge stones were carved with copper chisels from stone quarries, and these blocks were then dragged and lifted into position. Disagreements chiefly concern the methods used to move and place the stones.

Davidovits claimed that the blocks of the pyramid are not carved stone, but mostly a form of limestone concrete and that they were "cast", as with modern concrete. According to this hypothesis, soft limestone with a high kaolinite content was quarried in the wadi on the south of the Giza Plateau. The limestone was then dissolved in large, Nile-fed pools until it became a watery slurry. Lime (found in the ash of cooking fires) and natron (also used by the Egyptians in mummification) was mixed in. The pools were then left to evaporate, leaving behind a moist, clay-like mixture. This wet "concrete" would be carried to the construction site where it would be packed into reusable wooden moulds and in a few days would undergo a chemical reaction similar to the "setting" of concrete. New blocks, he suggests, could be cast in place, on top of and pressed against the old blocks. 

In 1979, at the second International Congress of Egyptologists, Grenoble, France, Davidovits suggested that the pyramid blocks were cast as concrete, instead of carved. Such a theory was greatly disruptive to the orthodox theory and his research was fiercely opposed by some experts (geologists and Egyptologists).

My interest in this has been reawakened by a fairly recent peer-reviewed paper being drawn to my attention (M. W. Barsoum, A. Ganguly, G. Hug (2006). Microstructural Evidence of Reconstituted Limestone Blocks in the Great Pyramids of Egypt. Journal of the American Ceramic Society 89 (12), 3788–3796). The findings of Michel Barsoum and his colleagues at Drexel University, USA support Davidovits' hypothesis. They claim to have found particles and air cavities in pyramid limestone that do not occur in natural limestone. After extensive scanning electron microscope observations and other testing, they finally began to draw some conclusions about the pyramids. They found that the tiniest structures within the inner and outer casing stones were indeed consistent with a reconstituted limestone. The cement binding the limestone aggregate was either silicon dioxide or a calcium and magnesium-rich silicate mineral.

The stones also had a high water content, which is unusual for the normally dry, natural limestone found on the Giza plateau, and the cementing phases, in both the inner and outer casing stones, were amorphous, their atoms not being arranged in a regular and periodic array. Sedimentary rocks such as limestone are seldom, if ever, amorphous.

More startlingly, Barsoum and another of his graduate students, Aaron Sakulich, recently discovered the presence of silicon dioxide nanoscale spheres (with diameters only billionths of a meter across) in one of the samples. This discovery further confirms that these blocks are not natural limestone.

Egyptologists are consistently confronted by unanswered questions: How is it possible that some of the blocks are so perfectly matched that not even a human hair can be inserted between them? Why, despite the existence of millions of tons of stone, carved presumably with copper chisels, has not one copper chisel ever been found on the Giza Plateau? At the end of their most recent paper reporting these findings, the researchers reflect that it is “ironic, sublime and truly humbling” that this 4,500-year-old limestone is so true to the original that it has misled generations of Egyptologists and geologists and, “because the ancient Egyptians were the original-albeit unknowing-nanotechnologists.”

To counter this, Dipayan Jana, a petrographer, made a presentation to the ICMA (International Cement Microscopy Association) in 2007 and gave a paper in which he discusses Davidovits' and Barsoum's work and concludes "we are far from accepting even as a remote possibility of a “manmade” origin of pyramid stones."

So there is still much controversy, but what a fascinating subject this is. I would like to know what other researchers in the field of geopolymerisation have to add to this, and hopefully talking to a few of them at the conference in May.

Friday, 10 December 2010

Famous visitors to the CSM Pilot Plant

Gaynor Yorath's photos of the CSM student pilot plant run (4th December) has reminded me of the many illustrious visitors that I had the privilege of showing round this wonderful facility. Unfortunately only a few photos were taken, and these are shown below.

I would love to hear from anyone who has memories of their visit to CSM, particularly if photos are available.
1986 with the late Gilles Barbery,
H. Oberndorfer and Nick Miles

1986 with Jim Finch, Derek Ottley, Jim Watson
and Wally Kopp
Reagents '91 Delegates
1980 with H.M. Queen Elizabeth II
75% of the future MEI team in 1981
Barbara, me and Jon

Tuesday, 7 December 2010

Monday, 6 December 2010

Final calls for abstracts for Computational Modelling and Physical Separation '11

Delegates at Physical Separation '09
Beautiful Falmouth is the venue for next year's Computational Modelling '11 and Physical Separation '11 conferences, running back to back in June.

Those wishing to present papers should submit short abstracts no later than the end of this month.  As with all MEI Conferences, papers will be considered for special issues of Minerals Engineering.

Computational Modelling '11 is sponsored by the UK company DEM Solutions. The previous two Computational Modelling conferences were held in Cape Town, and the previous Physical Separation conference was in Falmouth in 2009.

Saturday, 4 December 2010

Memories of the CSM pilot plant

With Jim Turner and Nick Wilshaw
Today was the Camborne School of Mines (CSM) Association Christmas lunch in Redruth, attended by many old boys and staff. Sadly there were only 3 mineral processors present, myself, my old colleague Jim Turner, and 1980 old boy Nick Wilshaw, now an independent consultant. We naturally talked about old times, and in particular the unique student 'pilot plant run', which Jim and I initiated in 1979. Nick was in the first group of students who spent a week on shifts operating the plant, treating ore from the nearby South Crofty tin mine, under conditions simulating real mine continuous conditions. Unfortunately this was just one of the good things which was lost when CSM was assimilated into Exeter University in the mid 1990s.

Coincidentally, little over a week ago I had coffee at the Mount Nelson Hotel in Cape Town with Gaynor Yorath, a senior researcher at the University of Cape Town. Gaynor graduated from CSM in 1985, and she brought photographs to show me of her time at Camborne, and in particular of the valuable week that she had spent on the pilot plant operation.

Among the young faces in the photos, some may be familiar to attendees at recent MEI conferences and IMPCs.


The CSM Pilot Plant
Gaynor with fellow members of her shift crew
Steve Downard, Paul Morgan, Paul Benjamin,
Andy Mitchell, Jim Turner and Ray Manser
The late Dr. Vic Phillips in the shift foreman's office

Thursday, 2 December 2010

Richard Williams will present 3rd keynote at SRCR '11

I was very pleased this week when my old friend and colleague Richard Williams agreed to present a keynote lecture at next May's Sustainability through Resource Conservation & Recycling '11 conference in Falmouth, sponsored by Outotec.

Richard is Professor of Mineral and Process Engineering at the University of Leeds. He is also currently Pro-Vice-Chancellor for International Partnerships.

He was formerly a Senior Lecturer in Chemical Engineering at UMIST, Manchester (as was) and The Royal Academy of Engineering Professor at the University of Exeter (Camborne School of Mines).

He has been at the University of Leeds since January 1999 and is a founder of the Institute of Particle Science and Engineering (IPSE) – with some 130 researchers working on measurement, modelling and manufacture of particles and colloidal products. His research interests are in particle separation, colloid aggregation and precision emulsification and he has worked on the development and specification of tomographic techniques since 1988.

Apart from being a superb speaker, the title of his keynote: Rethinking Separation Methods and Sustainable Uses of Fine Minerals is one to wet the appetite.

A very fine international programme is developing, and will be published next month. Richard joins two other distinguished keynote speakers, Prof. Jan Cilliers of Imperial College, UK, and Dr. Terry Norgate, of Australia's CSIRO.

Anyone wishing to present a paper should submit an abstract as soon as possible.

News of people you may know

Below are snippets of news from my LinkedIn contacts:

Jonas Addai-Mensah is Associate Director at University of South Australia
Eliab Roman is Chief Metallurgist at Northgate Minerals Corp-Kerness Mine, Canada
Stephen Grano is Executive Director for Mineral and Energy Resources at University of Adelaide, Australia
Bill Skinner is Research Professor at Ian Wark Research Institute, Australia
Chris Kelaart is Division Manager Bruker AXS at Bruker Biosciences, Australia
C. Raghu Kumar is Head of Minerals and Ferro Alloys Technology at Tata Steel, India
Folohan Adekola is Head of the Analytical and Environmental Chemistry Unit at the University of Ilorin, Nigeria
Vanessa Torres is Vice President Group Planning at BHP Billiton, Australia
Michael Willis is Area Manager-Mine at SNC Lavalin, Canada
Nigel Ricketts is Manager Strategy and Development at AMEC MinProc, Australia
Jide Olurin is Chief Metallurgist at Teck Resources Duck Pond Operations, Canada
Alex Jankovic is General Manager - Technology and Innovation at Metso Process Technology Group, Australia

For regular updates of news from the world of mineral processing and its people, submit your email address in the box in the right-hand column.