Cement production is one of the dirtiest industrial processes on the planet. It produces nearly 9% of global carbon emissions. This increases every year with the extraordinary demands for building materials in China and India. But it is set to become much greener: cements and concretes of the future will sequester vast amounts of carbon dioxide (CO2) and utilise huge volumes of industrial wastes in the form of additives.
Cement (and the concretes made with it) are about to become carbon negative – absorbing more carbon that they produce. It will happen by mimicking nature – in this case, the process through which marine organisms build shells.
It is not widely appreciated that the most substantial process of carbon sequestration on the planet is accomplished by myriad marine organisms making their exoskeletons, or shells. Shells are produced biologically from calcium and magnesium ions in sea water and carbon dioxide from the air, as it is absorbed by sea water. When the organisms die, their shells disintegrate and form carbonate sediments, such as limestone, which are permanent, safe carbon sinks.
We can emulate this natural process by producing cement, concrete and other composite construction materials that are “shell-like”. They contain synthetic calcium and magnesium carbonate, and are produced at temperatures far below those employed in conventional kilns.
The calcium and magnesium have to be sourced industrially (and there are various promising routes, quite apart from mining the stuff). The carbon comes from the air – from our releases via combustion of fossil fuels and ordinary cement production. This is biomimicry in action – or what the Australian geoscientist John Harrison calls geomimicry – emulating geological processes such as weathering.
Almost all cement used today is Portland Cement (PC), a convenient and cheap material that reacts with water to bind aggregates like gravel and sand. PC was patented in 1824, and has become by far the dominant technology, ousting traditional rival construction materials.
Now China and India are gearing up for a huge industrialisation and infrastructure building effort of world-historical scale. China and India between them in the next year will use 40 times the amount of cement used in the United States.
This is surely the time to rethink the dominant technology, with its excessive dependence on fossil fuels, high temperatures and resulting carbon emissions.
There are several green alternatives to Portland cement, based in different ways on biomimicry. The most straightforward alternative is to bypass the use of limestone altogether. The other important point is to utilize magnesium in cements to give them carbon absorption characteristics.
Harrison advocates a process of carbonation of magnesium ions found in seawater, brine or other waste streams, to produce a product that uses the carbonates as aggregate and a cement to bind them that absorbs carbon dioxide as it sets. This technology eliminates the burning of limestone (calcining), a potent source of CO2 emissions, and has the potential to sequester huge amounts of CO2.
These “eco-cements” can be produced at much lower temperatures. This means manufacturers can use renewable sources of energy (such as solar furnaces), again eliminating carbon emissions associated with the traditional use of fossil fuels. Eco-cements absorb CO2 as they set, making them carbon-negative if the CO2 released during manufacture is used to make synthetic carbonate aggregate.
Magnesium cements can have greater compressive and tensile strength, greater capacity to “breathe” and to bond to cellulosic (woody) materials. They can be used to build lighter structures with better insulating properties.
Another promising approach is catalytic flash calcination technology, being developed by the Australian company Calix. This separates the calcination step in cement production from the process of producing clinker. It allows the carbon dioxide otherwise emitted to be trapped, and perhaps utilised by some subsequent industrial process.
Calcination is the oldest industrial process that we have, dating back to the development of the first fertiliser (lime produced by heating limestone was found to improve soil fertility). Developing a green version of calcination in cement production has a beautiful connection back to the very origins of our industrial civilization.
The problem is that no cement company has to date exhibited any interest in moving off the dominant Portland technology, with its cost-minimising business model. And the alternatives have not yet been able to prove themselves in commercial-scale operations. This is what has to change if India and China are to move along a different industrial trajectory.
The standard approach to carbon capture and storage involves pumping carbon dioxide through lengthy pipelines to be disposed of down mineshafts and geological reservoirs – a risky, uncertain and extremely expensive option.
By contrast, sequestering carbon in a cement that absorbs it as it cures (eliminating up to 3 billion tonnes of carbon dioxide emissions while producing the green cement) is a straightforward process. It pays for itself via the cement produced. It is a classic instance of industrial ecology at work.
There is clearly enormous scope for carbon sequestration via industrial ecology solutions rather than the simplistic “bury it and it will disappear” approach to carbon capture and storage. The production of carbon-negative cement and building materials is one of the most attractive and forceful of these industrial ecological initiatives, because it addresses the problem directly and can be scaled to the required dimensions.
Co-locating facilities that produce oil, power, cement and other industrial materials, and linking them so waste is converted into feedstock and new carbon-negative products result, is one of the most exciting aspects of industrial evolution. Australian technology can play an important role in this essential transition.
The author wishes to acknowledge extensive and rewarding discussions held with John Harrison, Principal of TecEco, and Dr Mark Sceats of Calix.
David Collett
IT Application Developer at Web Generation
Nice article. Thanks!
Zvyozdochka
logged in via Twitter
Great explanation John, thank you.
I recall being howled down on Brave New Climate by the usual suspects for suggesting much of the foundations of solar thermal plant could be made with these materials. Ho-hum.
Tom Keen
BSc
That's interesting, because the idea of using the magnesium silicate variety of cement has been promoted on Brave New Climate before (e.g., see: http://bravenewclimate.com/2011/02/24/advanced-nuclear-power-systems-to-mitigate-climate-change/ ).
Dale Bloom
Analyst
This would be an excellent building material for the future, but cement is only one material used in buildings, and buildings also require energy to build.
The real challenge is to reduce the necessity to build new buildings, and so conserve resources.
In the case of China, much of its real estate boom has been speculative, and the result is a large number of vacant apartment buildings and housing complexes that may never have anyone in them.
Glenn Tamblyn
Mechanical Engineer, Director
Dale
Yes,Cement is only one component but in termsofenergy required,nothing comes close to it.Next closest are probably things like making steel. But steel is usually used sparingly in construction where as concrete is used as a bulk material.
If buildings used thing like steel for strength in tension situations, and concrete for situations where we need strength in compression but we used more sustainable, lower energy materials for basic infill uses we might cut concrete use substantially.
Concrete has grown so much as a building material because it is fairly cheap, and is simple and quick to use. But it's carbon price isn't factored into that.
Geoff Russell
Computer Programmer, Author
Glenn: "nothing comes close to it" ... beef beats it easy, see page vi and vii in
http://www.energyrating.com.au/library/pubs/2003-endusereport-volume1.pdf
This figure of 51.7 kg-co2eq/kg for beef is a carcase figure. The emissions per kg eaten are, of course, much higher.
Jonathan Maddox
Software Engineer
Glenn wrote that the energy requirements of cement manufacture were very high ... which isn't true, but not because the CO2 emissions of beef are higher.
Geoff, I think you may be conflating greenhouse emissions with energy inputs. The two are interrelated, but there are greenhouse-emissions-free energy sources, and greenhouse gas sources which have nothing to do with energy.
The greenhouse emissions of cement manufacture are high because of *both* the emissions from burning fossil fuels (although energy requirements are lower per tonne of material produced than the input energy required for metallurgical processes) *and* the CO2 resulting from thermal calcination of limestone.
The greenhouse emissions from beef production are high because cattle emit methane, which is a high global-warming-potential gas, and have (almost) nothing to do with energy requirements.
Geoff Russell
Computer Programmer, Author
Jonathan: Sure. I was a little sloppy but the climate doesn't care whether the radiative forcings are from CO2 or CH4 or albedo so while plenty of people are concerned about aluminium or cement production, they are quite happy to BBQ a slab of beef without a thought.
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Craig Minns
Self-employed
I like this idea. Carbon is an invaluable asset in our industrial society, not a waste product and it's always seemed stupid to me to want to spend lots of money and effort to bury it rather than use it.
There are quite a few groups working on polymerisation and other methods for utilising this resource and I wish them all the best.
Mark Amey
logged in via Facebook
fascinating that we can emulate our marine cousins to produce our own shells, using less energy, and releasing less carbon at the same time. I hope this sort of technology becomes commonplace, and that we don't have to pay a premium price for the 'eco-option'.
Felix MacNeill
Environmental Manager
Mark, if we added to our emulation of our marine cousins the ability to design buildings as sensible as that achieved by termites we'd be beginning to actually look a bit less like the dumbest smart animal on the planet.
Add in the use of modern timber laminates in place of a fair bit of structural steel and we're really getting somewhere!
John Harrison
logged in via LinkedIn
The aim Mark is to make synthetic carbonate concretes cheaper than the current offering. Given the simplicity of TecEco Gaia Engineering this should not be too difficult.
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Adrian Palmer
Consultant
We investigated the use of Eco-Cement for a major project. The issue came down to a lack of experience of the engineers in using a different material. Despite no cost disadvantage, given the timelines, no-one was prepared to spend the time designing for the different - even improved - properties. So we then tried to get the eco-cement used for non-structural purposes such as roads. The thought of interfering with a standard procurement method, two supply chains and storage on site, with insufficient economic incentive, was enough to kill the proposal. The fact that PC can be imported from non carbon taxed countries, on non carbon taxed ships, indicates a failure of current policy settings.
aligatorhardt
logged in via Twitter
A process with potential for big improvements is often not accomplished by markets, due to established practices and income streams. It may be up to government and university sponsorship to develop engineering details for these materials. Hopefully that will occur.
John Harrison
logged in via LinkedIn
Although I have no record of previous conversations with Adrian the barriers are indeed formidable but the potential profits to be made correspondingly huge. We have progressed a long way in the last few years. Early in our genesis the high cost of reactive magnesia as well as industry conservatism and prescription based standards were a major barrier to implementation.
We have now substantially overcome these barriers. Gaia Engineering (www.gaiaengineering.com) can provide cheap magnesia and even the worst of our earlier detractors have now figured out that Portland cement (PC) is a catalyst for the carbonation of reactive magnesia (rMgO) and that it can be combined other hydraulic cements such as PC in any proportion.
Adrian is right. There is a failure of current policy settings. We think government, after doing the appropriate due diligence, should mandate the use of synthetic carbonate in building and construction.
Chris Pittock
logged in via Twitter
John, thank you for an enlivening update on cement and concrete options emerging from R&D. It'd be a valuable addition to u deist and what the projected cost of the concrete products might be, and the quantum of CO2 storage potential in these new products. Within the limits of current knowledge and what efficiencies of scale might apply, this would add further depth to your stated claim of being the cheapest form of sequestration.
Chris Pittock
logged in via Twitter
Apologies for the auto-correction horrors above!
John Harrison
logged in via LinkedIn
Hello Chris
To answer your questions briefly.
Cost is important. Making a profit is however a better. The N-Mg process within TecEco Gaia Engineering should produce reactive MgO cheaper than cement is currently produced and make a profit.
The total sequestration possible for TecEco Gaia Engineering using 2011 figures is some 22 - 23 billion tonnes. This is because synthetic carbonate aggregate does not have to be used with our Eco-Cements. roughly a third of all aggregate is carbonate…
Read moreGeoff Russell
Computer Programmer, Author
The word "promising" always worries me in articles like this. There is a constant stream of new promising technologies that will roll back radiative forcing, but we have had all the technologies required for at least 50 years. If we lack the will using well known technologies, what makes anybody think that new technologies will generate this will as they arrive?
Martin Green predicted solar would replace coal in 10 to 15 years:
http://www.abc.net.au/catalyst/stories/3228140.htm
... and that…
Read moreJohn Harrison
logged in via LinkedIn
Geoff
I cannot speak for Calix but you totally misunderstand what the TecEco technology is all about. Burn these words into your memory for a moment. "The technology paradigm defines what is or is not a resource" They define a truism about resources in the supply chain. The challenge that our Gaia Engineering technology paradigm addresses is the profitability of the solution.
Prof Mathews may disagree but Gaia engineering is a perfect industrial ecology that uses only waste and produces none…
Read moreJonathan Maddox
Software Engineer
I find the article rather dissatisfying.
Flash calcination is just another way of making portland cement and carbon dioxide is still a waste product to get rid of -- the only advantage is that the CO2 is cleaner.
The other process mentioned, "a process of carbonation of magnesium ions found in seawater, brine or other waste streams, to produce a product that uses the carbonates as aggregate and a cement to bind them that absorbs carbon dioxide as it sets", is described in no clearer terms than this. What does it mean, exactly, in terms of industrial process?
I'm guessing it refers to the same technology as this page : http://www.greensols.com.au/Technology.php
But that too, I find unclear. A concept is promoted but not described in any detail.
John Harrison
logged in via LinkedIn
How do you do Jonathon.
By dissatisfying I assume you are a technologist of sorts and not enough detail was provided to satisfy you.
If you want the full heads up on the TecEco technologies there are a number of talking presentations I have loaded to the Gaia Engineering downloads area. Go to http://www.gaiaengineering.com/movies.php
If you are a YouTube fan have a look at http://youtu.be/XvAVfxPk67A and http://youtu.be/ISDXKzwat10.
If you are satisfied please make an intelligent positive…
Read moreAlex Cannara
logged in via LinkedIn
Very good, and a Carbon tax would assist the economics of implementation.
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John Mathews
Professor of Strategic Management at Macquarie Graduate School of Management
To Zvyozdochka, Adrian, Craig – thanks for the endorsements. As you say Adrian, the barriers to the uptake of alternatives to PC are formidable, but the stakes are so high, and the potential for gains for the atmosphere if China and India can be brought onto a new trajectory, that these topics are worth pursuing. Craig, you are quite right to point to the ‘waste’ involved in pumping carbon dioxide down into holes as in the standard version of CCS (yet to be commercially demonstrated in Australia…
Read moreJonathan Maddox
Software Engineer
Thanks for the pointers, John. I found Christopher Cuff's patent application here, which does indeed give some interesting detail, patent-lawyer-ese notwithstanding : http://www.faqs.org/patents/app/20090214408
The interesting words are "nucleating agent" and "ion exchange medium". The long list of potential nucleating agents includes the slightly disconcerting "purified bovine carbonic anhydrase" and "purified human carbonic anhydrase" -- the list puts one in mind of the determined inventor of the incandescent light globe trying everything from copper wire to a red hair from the beard of an Irishman, before hitting on a tungsten filament. Yet if the pretty pictures of crystals on the Greensols website are indicative (and they may be more decorative), the process may already be quite successful in the lab at least.
Ian L. McQueen
Retired
Why are our comments being deleted? This blog is no better than Real Climate or any of the other warmist sites that will brook no voice opposing their view.
IanM
Alex Cannara
logged in via LinkedIn
"Warmists"? What does that convey, intellectually, factually, Ian?
;]
Tom Keen
BSc
Thanks for an excellent article, Professor Mathews. I really do hope that the potential of these carbon-sequestering varieties of cement is realised.
Just one question: do you know if there are any engineering concerns with these varieties of cement? E.g., from swelling or increased weight due to the absorbed CO2?
Cheers
John Harrison
logged in via LinkedIn
As the inventor of Eco-Cement (See www,tececo.com) and synthetic carbonate concrete (See www.gaiaengineering.com) the answer is no in a word but the devil is in the detail.
There are two critical considerations:
Particle packing (See http://www.tececo.com/technical.particle_packing.php
Low temperature calcination (see http://www.tececo.com/technical.reactive_magnesia.php)
Scott Phillips
logged in via Facebook
Brief disclosure: I used to work for TecEco.
Whatever one's belief about the effects of CO2 on the mean global temperature we should treat the excessive CO2 in our atmosphere as problematic from a stewardship point of view. It simply isn't a good idea to mess with the chemical composition of something as crucial to our survival as our atmosphere. Until it's proved to be a good idea, we should keep CO2 within its historical range. Promoting the idea that excess CO2 in the atmosphere isn't a…
Read moreAlex Cannara
logged in via LinkedIn
I'll add to Scott's remarks that ~40% of asll human-generated Csions are now in the seas, acidifying them (reducing their pH) to values close to what repvents the base of most sea food chains from forming their skeletal materials from oceanic carbonate.
This is the primartyy natural sink for CO2, sequestering it in lomestone on seabeds, when these organisms die.
Oceanic pH is now so low that deformities are obseved in fiheries now, particularly Nordic regions of the Atlantic.
The fact that ~20% of all human food protein comes from the sea should alert us to the imminent danger. This is a danger to over 1 billion people, withing years, not deacades.
The natural carbon cycle can handle ~200 million tons of C per year. We now deliver ~30 times that via combustion, each yera.
Climate change & sea rise are peaniuts compared to ocean acidification.
darryl siemer
retired "consulting scientist" Idaho
I have lots of "technical" issues with this article because neither it nor the websites to which we are directed to do a good (or balanced) job of comparing this sort of eco cement with alternatives. For example, one of the "unique" (implied) advantages of this stuff is that it's supposed to harden by sucking CO2 out of the environment (usually air) & thereby form a stable hydrated magnesium carbonate binder mineral. While this sounds great, it also means that the rate at which such minerals…
Read moreJohn Mathews
Professor of Strategic Management at Macquarie Graduate School of Management
Darryl
Nice to have you join the conversation. From my quick Google and YouTube searches, you are presumably the Darryl Siemer who is making contributions on the disposal and recycling of nuclear waste. Well, cement (and even more so) concrete are crying out for recycling solutions -- and I began to address them in the article. Much of the world's technical literature on carbon sequestration looks at the issue in terms of mineralization of carbon dioxide streams -- a topic you would be familiar…
Read moreAlex Cannara
logged in via LinkedIn
Just an FYI John, Darryl & I know one another and are very much concerned with the promotion of molten-salt nuclear reactors, partly because they can consume most of what we now call nuclear waste in the form of 'spent' fuel (which is not actually "spent").
In the US, we have about enough old fuel removed from our reactors to run them for many decades more, if the fuel is properly processed, as the French have long done. That resource can run molten-=salt reactors even longer, because of their superior efficiency.
As for making some form of concrete which might include radioactive waste, we did that decades ago in Nevada & Utah, where some houses were built with cinder block incorporating Uranium mine tailings, etc. Didn't work out well.
;]
Eddy Wajon
logged in via LinkedIn
I have been working with John Harrison trying to get a trial of pervious concrete pavement using Ecocement in a road project funded by Main Roads Western Australia. Unfortunately, though we designed and costed a trial, the cost was seen as excessive (for the engineering, not the materials) and the benefits and longevity of a pervious road pavement were not considered to be sufficiently acceptable to warrant a trial (though this could be disputed).
I have actually undertaken a 50-year, whole-of-life Sustainability comparison of pervious concrete road pavement with standard deeplift asphalt road pavement and found that pervious concrete road pavement is much more sustainable than deeplift asphalt road pavement on cost, carbon dioxide emissions and water consumption. I would love to publish the results of this study somewhere.
Craig Minns
Self-employed
Having had some experience dealing with MRWA in the past, I have to say they tend to the conservative although what is regarded as conservative over there is quite different from a great deal of the practice over here. The soils are also very different. We don't get any Pindan over here, or much calcarous sediment and they have a lot more lateritic clay soils than we do, as well as very salty water. I recall on one job the best bore we had varied between 188,000 ppm and about 210,000. We carted a…
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