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| Science & Technology |
| Making Cement from CO2 and Seawater |
| 2008-08-11 |
| The turbines at Moss Landing power plant on the California coast burn through natural gas to pump out more than 1,000 megawatts of electric power. The 700-degree Fahrenheit (370-degree Celsius) fumes left over contain at least 30,000 parts per million of carbon dioxide (CO2)—the primary greenhouse gas responsible for global warming—along with other pollutants. Today, this flue gas wafts up and out of the power plant's enormous smokestacks, but by simply bubbling it through the nearby seawater, a new California-based company called Calera says it can use more than 90 percent of that CO2 to make something useful: cement. It's a twist that could make a polluting substance into a way to reduce greenhouse gases. Cement, which is mostly commonly composed of calcium silicates, requires heating limestone and other ingredients to 2,640 degrees F (1,450 degrees C) by burning fossil fuels and is the third largest source of greenhouse gas pollution in the U.S., according to the U.S. Environmental Protection Agency. Making one ton of cement results in the emission of roughly one ton of CO2—and in some cases much more. While Calera's process of making calcium carbonate cement wouldn't eliminate all CO2 emissions, it would reverse that equation. "For every ton of cement we make, we are sequestering half a ton of CO2," says crystallographer Brent Constantz, founder of Calera. "We probably have the best carbon capture and storage technique there is by a long shot." |
| Posted by:Bobby |
| #13 On a not-necessarily-unrelated note, a old theory about the construx of Guam's ancient Latte Stones was that these may had been made from primitive but potent form of concrete [frame + silica + seawater/water + heat]. Although this theory has been mostly discounted over the decades by local academic scholars, espec vee ground-based Chisel/Shaping- and Heat Pits, the issue of how Guam's ancient Chamorros dev and contructed their Latte Stones remains under intense debate. IFF ANCIENT EGYPTIANS [new Pyramid Theory] AND INDIGENS INDIAN CULTURES, ETC. CAN DO IT, i.e. DEV "CONCRETE" WIDOUT OUTSIDE HELP OR INFLUENCE, WHY NOT PACIFIC ISLANDERS!? Lest we fergit, GIZA PYRAMID DEV THEORY > DID ANCIENT EGYPTIANS GET THEIR PYRAMID KNOWLEDGE FROM INTERACTION/TRADE WID ANCIENT INDIAN CULTURES??? |
| Posted by: JosephMendiola 2008-08-11 23:33 |
| #12 (CO2)--the primary greenhouse gas responsible for global warming Water vapor is the #1 "greenhouse gas," and CO2 doesn't cause "global warming," it is a lagging indicator. But thanks for playing "Repeat the lies often enough and somebody just might believe them!" |
| Posted by: skh.pcola 2008-08-11 16:53 |
| #11 I recently read about some Indian fellow that came up with cement that absorbs Co2 in the air. I guess until it's saturated, who knows. Some Belgian town was gonna use it on roads as a test. Imagine modified Concrete, a Roman invention, being used to clean up the environment. How odd is that? |
| Posted by: rjschwarz 2008-08-11 12:24 |
| #10 Al Gore wouldn't approve the planting of trees -- until he can get a cut of the take (see 'Carbon Credits'...) either by taxing the planting of trees or taxing the absorption of CO2. Same for the Democrats. |
| Posted by: CrazyFool 2008-08-11 12:05 |
| #9 TW, Some trees (because of their roots) are excellent at sequestering CO2. However, trees also absorb solar radiation much less than most bare ground. The math works out (or at least the current consensus says) that a rule-of-thumb is that trees planted between about 25 degrees of the equator have a net cooling effect on the planet, trees between 25 and 35 are a wash and poleward of 35, trees heat the planet (of course there are exceptions to this). |
| Posted by: mhw 2008-08-11 12:04 |
| #8 I suspect we would get more benefit from planting Al Gore. Less hot air generated and reduction of his carbon footprint. |
| Posted by: tipover 2008-08-11 11:59 |
| #7 Can't we just plant more trees to absorb the CO2? |
| Posted by: trailing wife 2008-08-11 11:34 |
| #6 Cement is funny stuff. As it hardens, it forms long molecular chains that make it hard, but brittle. The formation of these chains can be prevented by adding a relatively small amount of sugar (sucrose) to the mix. A fact used by the CIA to ruin enemy concrete edifices. They look fine until the first rain, but the cement is water soluble. So somebody just dumps 10 pounds of table sugar into the concrete mixer when nobody is looking. Who guards a concrete mixer? Conversely, cement can be made extraordinarily strong by adding carbon nanotube fiber. A blow from a 10 pound sledge hammer might scuff it, but little more. This is the future for combat military buildings. The biggest practical problem faced by concrete is erosion, because of heat, cold, wind, water and ice, acids and bases, and physical stresses. The most resilient coating to protect concrete are silica glasses. However much is still unknown about why glass behaves the way it does. The pursuit of concrete glazes and silica coatings and paints has been going on for centuries. (I noted an interesting innovation used in colonial Hawaii, where through a forgotten process, beach sand was mixed with a durable paint to protect a plantation house. The paint and house are still in good condition after over 100 years in very erosive conditions.) The other major problem is mortar. The purpose of mortar is to provide as level as possible a surface for cement, as it is particularly susceptible to stresses other than compression. But mortar erodes very quickly compared to cement, in most circumstances, and nobody has ever figured out how to make a very durable mortar. Again, carbon nanotubes may help, but the underlying matrix might be inherently weak. |
| Posted by: Anonymoose 2008-08-11 11:27 |
| #5 Where do the silicates come from? Ah, I know. From killing billions of sea creatures. I'll let PETA know. |
| Posted by: phil_b 2008-08-11 10:52 |
| #4 There are a lot of coal fired plants reasonably near the ocean so this technology could be ramped up fairly quickly. A big concern is the properties of the cement product produced. While there are some applications which do not bear a substantial load, most cement is used in concrete elements that have to withstand serious compressive force. One of the problems in using fly ash in cement has been getting a cement product that cures quickly and has good strength. |
| Posted by: mhw 2008-08-11 10:49 |
| #3 This would be very nifty if human caused "climate change" was anything other than utter fiction. The first faulty premise is that CO2 is a pollutant. It isn't. It is a vital nutrient for 3/4 of the life on this planet. The 2nd faulty premise is that mankind's contribution of less than 1/3 of 1% of the CO2 has any real effect on anything at all. |
| Posted by: DLR 2008-08-11 10:40 |
| #2 This isn't going to be feasible in too many places. You make cement near where you use it, it's just too expensive to transport. |
| Posted by: Silentbrick 2008-08-11 10:38 |
| #1 Interesting. |
| Posted by: john frum 2008-08-11 10:07 |