Monday, 12 January 2015

Is the end of the world of mineral processing nigh?

Here's some food for thought for the new year:

An article in the December issue of Materials World may have passed many people by, but it discussed a topic which would be of profound significance to the world, and, closer to home, to the minerals industry.  Eoin Redahan asked "How close are we to a nuclear fusion reactor?", a carbon-free process that produces four times more power than nuclear fission, with no waste disposal problems, and a fuel, isotopes of hydrogen, which is abundant.

Despite billions of dollars having been thrown at it, fusion’s imposing challenge has not yet been met. For atoms to fuse, a huge amount of energy must be generated. As such, materials must be developed that can withstand hundred of millions of degrees. To create fusion energy, light atomic nuclei are fused within high-pressure, high-temperature plasma, which is contained by a magnetic field. As yet, scientists haven’t refined this magnetic confinement efficiently enough to reach a break-even point – where the energy output equals the energy input.

As discussed in the article, billions of euros have already been spent on just one facility, the International Thermonuclear Experimental Reactor (ITER) in the south of France. The aim of the ITER project, which is funded by the EU, India, Japan, China, Russia, South Korea and the USA, is to prove that nuclear fusion is commercially viable.  However, the goal of having its deuterium-tritium facility operational by 2027 is looking increasingly optimistic, but encouraging noises are being made about several smaller projects. According to researchers at Sandia Laboratories in Albuquerque, USA, their huge electric pulse generator is progressing in its pursuit of the fusion dream. In September 2014, the team reported significant by-products of fusion reactions in one of its experiments. Sandia’s approach involves putting fusion fuel inside a tiny metal can and passing a pulse of 19 million amps through it from top to bottom for 100 nanoseconds. The powerful magnetic field created crushes the can inwards at a speed of 70km/second. At the same time, the researchers pre-heat the deuterium fuel with a laser pulse and apply a steady magnetic field, which holds the fusion fuel in place.  The team reports that it has produced significantly more fusion neutrons than previous methods, though there is still a long way to go – 100 times more neutrons will have to be produced to achieve break-even point.

Lockheed Martin is a major American global aerospace, defence, security and advanced technology company, which caused a stir recently with claims that its compact fusion reactor, which will fit "on the back of a truck" and produce a 100 MW output, enough to power a town of 80, 000 people, will be developed and deployed within 10 years. The company claims that the key to the success of its reactor concept lies in a magnetic bottle that withstands 150 million-degree temperatures while offering 90% size reduction over previous concepts.  Lockheed Martin's plan is to "build and test a compact fusion reactor in less than a year with a prototype to follow within five years, operational reactors being available in 10 years time.

Lockheed Martin reactor: neutrons released from plasma (purple)
transfer heat through reactor walls to power turbines
There is obviously a lot of skeptism about these claims, but there is little doubt that the intent is there, and it could be a fair bet that sometime this century nuclear fusion will become a reality, If it does it will change civilisation as we know it, and will certainly have a profound effect on our industry.

Ironically in the same issue of Materials World I authored a short article where I put a case (as I have done many times before) for froth flotation being the most important technological development since the discovery of smelting. But what would be the future for flotation if nuclear fusion became a practical proposition? Would its use be confined just to the production of industrial minerals? Would there be any need to comminute and concentrate metallic ores, and concentrate them prior to smelting? Maybe the metal mines of the future might crush the mined ores to make them easier to handle, and then transport them to huge on-site or custom smelters where the ore would be direct smelted, the energy being supplied by the smelter's on-site fusion reactor? The advantages of pyrometallurgy are of course that reactions are much faster at high temperatures than they are in slurries or aqueous solutions, and mineral characteristics are lost in melts, making the reactions controllable by known universal thermodynamic and kinetic laws. Separation by differential melt solubility or volatilisation permits recoveries that are impossible by mineral processing methods.

It would be a strange new world, little comminution, no concentration, no need for process mineralogy and expensive automated scanning electron microscopes, and more seriously no further editions of Wills' Mineral Processing Technology!  And probably quite a dreary one- what would be the technological challenges once complex ores are no longer complex and when we are all pyrometallurgists?

So what do you think? Is this likely to happen in this century?  My bet is that it will, although within 10 years might be optimistic.  Never underestimate the ingenuity of man; if great minds get together to solve a problem there is a fair chance that they know that the problem can eventually be solved.

There are great parallels with the Large Hadron Collider at CERN. Particle physicists have their various theories of the origin of matter, much of it hinging on the quest for the Higgs boson, but to find proof protons must be collided at near light speeds to basically see what happens. The science behind the LHC experiment is therefore fairly simple, but the engineering problems are immense, but were overcome despite much opposition. Questions were asked about the possible benefits to humanity, and I like the answer of one of the project leaders who said that when radio waves were discovered they were not called radio waves, as there were no radios!

Similarly the science behind nuclear fusion is simple- smashing hydrogen atoms together to produce helium and lots of energy. The engineering problems are, however, truly formidable, but the fact that billions of dollars are being spent on the quest for controlled nuclear fusion suggests that these might eventually be overcome.

12 comments:

  1. If it is economically feasible, possibly. Though I would expect some pre-concentration would really help keeping energy costs down, hence there'll be a (reduced) need for mineral processing whatever happens.

    That said, on the scale of things I think there are far more realistic factors that threaten mineral processing as a profession. Think for instance the implementation of non-metallic alternatives for metals if prices go up too much or availability is too constrained (as has happened with REEs in some instances). Similarly, I wouldn't be surprised if carbon fibres affect demand for (structural) steel at some point in the future, or carbon nano-tubes reducing the demand for copper. The latter would have a roll-on effect on gold, whilst reduced demand for iron would affect coal demand and mining of metals used as steel additives.

    Unfortunately these are also factors mineral processing engineers have little control over, other than making sure we keep recovering metals at reasonable costs so the alternatives are not economically feasible.

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  2. Mineral Processing will always have a place in the production of metals. Given that todays ores are lower grade than those mined in past decades/centuries, there will be a need to reject the non-metallic portion of an ore. Now there may be less requirement to separate different minerals like lead from zinc from copper. Fusion reactors generate energy but no one would want to waste that energy smelting silicates just to get the metallics from low-grade ores.

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  3. Barry,
    This is really exciting;it shows that the barriers between the disciplines are breaking fast so that the next generation of Mineral Engns work on more challenging areas; however, the basics of ore mineralogy, mineral characteristics,would still be the basics.

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  4. Everything we use to build our civilization is either grown or mined. As long as there is civilization there will be a need for mining and mineral processing. The methods will be as foreign to us as our current methods would be to a person from the time of J.C. Future generations will continue to refine our methods and create new ones. When nuclear fusion becomes a reality and energy costs plummet, our mineral processing costs will also decrease, so don't rush to the conclusion that everything will go to direct smelting. On a cautionary note: we do not know what the unintended consequences of fusion will be. Will we eventually run short of hydrogen?

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  5. Dave Middleditch15 January 2015 at 20:33

    By the time this happens I will be retired and "sailing" around the world on my nuclear fusion powered yacht - Paid for by a long and successful career in Mineral Processing...

    One can only dream!

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  6. The point is that mineral processing, no matter how cheap it might become with 'limitless' energy, is basically a very inefficient process, with high value losses to tailings. We need it at present, however, because of energy costs- it is necessary to concentrate before smelting, which is a very high consumer of energy. So if energy does ever become limitless in the near or far future, why concentrate?

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  7. "Is the end of the world of mineral processing nigh?" I will take the counterpoint and say, that with cheap energy. especially fusion, the world of mineral processing will expand.

    Let's start with the first case, direct smelting of ores, and start with copper. Since a current high grade copper ore is less than 3% copper, a direct smelt would need a furnace that would have a slag of 97+% of the feed. That is a lot of slag to handle. Even current trends where a 30% copper feed is handled, slag disosal, and stack gas cleanup are big issues.

    Even for iron, the slag disposal would be considerable.

    But on the other hand, with cheap energy, comminution becomes a lot more practicle, and perhaps it would push the cutoff grade even lower requireng fewer mines but with much higher recoveries (even a 0.5% increase is big at the mine and mill).

    Mike Albrecht, USA

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  8. Slag can hold more than 0.5% Cu, If slag is about 99% of the product and ore is less than 0.5% Cu, then you will have trouble getting a good recovery.
    Adam

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  9. Hello Barry,
    Thank you for ppproviding us with interesting ideas. I support Mike's comments and add this one.
    You suggested a reduction in comminution, yet you write about moving all the ore around. If you are going to move t, you need to do milling.
    I would like to see money being spent on reducing the incedibly high cost of milling, not so much to say P80 = 100 micron, but to say 1 micron?

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  10. Another point, the Lockheed announcement seems to have been met with more than skepticism, but rather complete disbelief:

    http://www.theguardian.com/environment/2014/oct/16/has-lockheed-martin-really-made-a-breakthrough-on-nuclear-fusion

    One quoted from a scientist: "Cowley says it is unlikely fusion will become part of the world’s power generation before 2050 and Lockheed’s announcement does little to change his mind. “I can’t see any results. I mean what have they achieved? It’s all promise,"

    In any case, in Lockheed they talk about 20 years minimum for it to reach the civil sector, according to the same news piece, so a long way even for them.

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  11. Could this new design bring nuclear fusion reactors closer to reality?

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