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Calera and Novacem use concrete to capture CO2

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February 1, 2010

Novacem Chairman Stuart Evans and Chief Scientist Nikolaos Vlasopoulous, with samples of t...

Novacem Chairman Stuart Evans and Chief Scientist Nikolaos Vlasopoulous, with samples of their CO2-absorbing concrete

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Concrete seems pretty inoffensive. It just looks like mud, and appears to do nothing except sit there and harden. The fact is, though, concrete is the world's third-largest source of man-made carbon dioxide. Its production process accounts for at least 5% of the CO2 our species pumps into the atmosphere annually. Apparently, however, it doesn't have to be that way. Two companies are now using different technologies that not only make concrete carbon-neutral, they actually make it carbon-negative.

Calera's CMAP process

Calera is a California-based company that converts the carbon in industrial flue emissions (i.e: smoke stack output) into components of concrete and asphalt. The process is called Carbonate Mineralization by Aqueous Precipitation, or CMAP, and involves running flue gases through pH-adjusted seawater or alkaline brine water. The chemical qualities of the water convert the CO2 to calcium and/or magnesium carbonate, which is then precipitated from the water and dried, using the heat already being released from the flue. These solidified minerals can be used as cement or aggregate, two of the three ingredients in concrete (the third being water). The process is said to remove 70-90% of CO2 from the gases, and every ton of the resultant building materials contains up to half a ton of captured carbon.

Other benefits

CMAP has a couple of other aces up its sleeve. It has been shown to capture 95-98% of sulfur dioxide in flue gases, and neutralizes other pollutants such as mercury, trace metals, nitrogen and ammonia. Combined with a desalination plant, it could also produce low-cost drinking water - the seawater would already be getting pumped in, and would already have its calcium and magnesium removed, making the desalination process cheaper and easier. In another scenario, Calera's process could use the leftover brine slurry from a desalination plant to extract CO2 from flue gas. This set-up would result in cleaner post-slurry wastewater than would be possible with a stand-alone desalination plant. It is also hoped that revenue generated by desalination, along with concrete sales, would help make CMAP cost-effective.

Calera's process is currently being used in a pilot project at the Moss Landing power plant in California. Similar technologies are being pursued by companies such as America's Carbon Sciences and Canada's Carbon Sense.

Novacem's CO2-absorbing cement

Over in London, Novacem is claiming carbon-capture figures similar to Calera's, but by taking a different approach. It uses magnesium silicate as its product's base, as opposed to the limestone that is used in traditional Portland cement. Through a low-heat, low-carbon process, that silicate is converted to magnesium oxide, which is then made into cement. As that cement hardens within a concrete mixture, it actually absorbs and stores atmospheric CO2. Novacem claims that for every ton of its cement that is used, approximately three-quarters of a ton of carbon dioxide is captured. Production costs are said to be comparable to Portland cement, and it's recyclable, to boot.

As is the case with Calera, Novacem is not alone in its field. Other companies developing similar products include Australia's TecEco and Calix, and the Dutch C-Fix. Gizmag has also previously looked at a "green" concrete being developed by Louisiana Tech University.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
8 Comments

If we have lost a major percentage of our atmosphere to coal and other fuel burning since the beginning of the industrial revolution and we know that a human needs 17% oxygen content to be cognizant and I believe we are at 19% prox if I recall correctly, then why do we wish to disrupt the natural cycle of allowing the plants to process the oxygen from the COsub2 by COsub2 sequestration. There are other geopl;ymers taht completely eliminate the problem at lower overall energy costs. These men are in my opinion well meaning eco-criminals.

In a nutshell we need more processable oxygen not less by shutting down the photosynthesis cycle.

RICHDUNN
2nd February, 2010 @ 06:22 am PST

Hey Nikolaos, Why call it CALERA?

edubasaez
2nd February, 2010 @ 08:40 am PST

Rich, Try googling, "Global Warming."

BigCat
11th February, 2010 @ 07:57 pm PST

BigCat, whenever I Google Global Warming mainly I find links to faked science, falsified and manipulated data, investigations of nearly everyone involved, and the massive amounts of money that caused them to do it.

Todd Dunning
13th February, 2010 @ 03:34 pm PST

Todd Dunning

Correct me if I'm wrong, but do you by that statement indicate that global warming is a fake topic, and no actually phenomenon we need to worry about? I hope not.

Of course you are right about there being a lot of bullshit arguments and fake "research". All sides of this topic is guilty of making such shit. Any topic of great interest, as this one obviously is, real or not, will have a lot of bullshit attached. This must be seen as part of the general "noise". Every human must filter which influences they want to pay attention to, and how to evaluate them. Most of everyday noise is filtered away with no further thought.

In the case of global warming, the topic is so big and complex, and the effects are so vague, seen from everyday life, that the normal way of filtering info intuitively will not work well. One needs to see it all intentionally from a bit of distance. Look at the big things and the longer perspectives. Worrying about polar beers is good, I do, but that's just noise in this context. Forget the mass of statements and look at the stuff all agree on. The stuff even "anti-global-warming-fear-ists" say are facts.

Given what I've just said, mentioning where I think you should look, would just make me too participate in the creation of petty noise and mere opinions. My point is: If you look with an interest and a critical eye, you will very easily find highly convincing or incontradictible evidence: The effect on the global climate only from human culture is huge, beyond anything ever observed from volcanos and so on. How this will affect the Earth, nobody knows.

Some believe it will be no big problem, or they say the problem will take time to evolve, so we can fix it... I cannot contradict them, as they may be correct. But I'd feel more comfortable if we just accepted that we don't really know, and it does look bad. Since it's kinda important, shouldn't we be a bit conservative and assume it may be as bad as it looks? Of course I won't live to see too much effect of anything humanity may decide on this, but still...?

No actual researcher or even slightly knowledgeable authority disagree on the fact that human culture has actually changed the climate notably and is changing it more, and at a faster rate than ever recorded in the history of this planet.

Please do not let all the bullshit, both ways, in the media and elsewhere, cloud the real issue...

Stein

Stein
14th February, 2010 @ 12:10 am PST

Stein you show excellent concern for the planet, as we all do. I agree it is a very important topic. I can understand the rage of the believers; that we skeptics are so cavalier in the way we pooh-pooh such an important issue.

I don't wish to change your mind on this issue. You shouldn't listen to me or anybody else, because we all have our biases of course.

You say "Since it's kinda important, shouldn't we be a bit conservative and assume it may be as bad as it looks?" - a level-headed response indeed. It's the responsible reaction by sensible people concerned about a threat.

As you know, creating a fear and selling the solution is the time-honored technique to sell just about everything, from gingko boloba to castor oil. What are you being sold? The largest new tax in human history; a surcharge of 15% on almost everything that requires energy to produce. You'll just have to trust it will solve all the planet's 'problems'.

I should stop right here because I'll just get going. I appreciate your concern for the planet, and hope it only increases.

Todd Dunning
14th February, 2010 @ 01:14 pm PST

Despite the CC, GW, AGW, ACC or whatever acronym you like to use today...

People talk about Acidification of the Ocean due to CO_2 (forgetting that a warming ocean boils off CO_2 not dissolves it. I'm not real sure if the quantities of calcium and magnesium which will be extracted out of seawater are significant in a global way, BUT...

Did anyone here learn in Chemistry that Calcium is an acid Buffer, so this bright idea, is to remove the buffer from the seawater to remove the CO_2 from the air which would cause the acidification... It is Ok, because there is plenty more calcium in the world to dissolve into the "acid ocean", the Barrier Reef for one, every other coral reef for 2, and of course there are thousands of miles of subterranean Limestone and Dolomite ridges, not to forget the Limestone Cliffs that some people like to live on top of, no biggie, just that these structures could collapse in order to remove CO_2 from the Flue emissions....

This company things that it can get in on a cash cow... It may be a good idea, as burning the limestone for cement manufacture releases probably more like 20% of Human originated CO_2 (Dwarfed by all those volcano-s burping away, need to tax Italy (Mt Etna), and Iceland (Several active volcanos) for all their emmisions Nice.

MD
6th October, 2011 @ 09:27 am PDT

The Argus plant in Trona, California operates a coal burning powerhouse for process CO2. They are carbonating Searles Lake brine containing Sodium Sulfate to get Sodium Carbonate as an intermediary for producing Sodium Oxide (Soda Ash). This has been operating since 1979. The ready market for Soda Ash in the glass bottle industry, and the saturated brine deposit made the economics work out at the time. Sea water might be a good deal more difficult. Kerr McGee was the owner back in the day.

Bob Woolery
6th October, 2011 @ 09:46 am PDT
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