 | TOD Local Open Thread: What's your town doing about high gas prices? | The Oil Drum | Future Scenarios: Mapping the Cultural Implications of Peak Oil and Climate Change |  |
70 comments on Biomimicry and Ocean Generated Energy: Are Humans Smarter Than Sea Sponges?
Comments can no longer be added to this story.
User login
Contact
- anz at theoildrum dot com
License
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
Archives
GAIA Host Collective
The following item (last week) was the best news I've heard on low-greenhouse cement production for a long time... Maybe it's "obtainium" at last...
http://www.abc.net.au/catalyst/stories/2244816.htm
At this point in time 'green' cement seems to be dependent on fossils fuels. Like liver extract for vegans it doesn't help to look at the ingredients. Fly ash comes from coal fired power stations and the slag appears to come from iron furnaces fired by coke. If the slag contains much silica it will be a lot of work to grind into powder. Therefore when coal burning and steel making nosedive they could take 'green' cement with them.
Although its a bit of spin to label it "green" I think you are missing the point.
At least we can use the waste product of coal fired power to make cement AND therefore not have to burn any more coal to produce the clinker!
It interests me that you discount this because the slag, a concentrated by product, needs to be ground, but in other posts you advocate the grinding of vast quantities of ore and rock to extract uranium, currently a diesel intensive process.
Before you try the acid leach escape clause... where DOES all that acid come from?
If using fly ash and slag as a substitute for concrete is bad... then I guess using sulfuric acid derived from sour oil must also be bad... not to mention nitric acid derived from oxidising ammonia which used natural gas as the energy source for its synthesis... or hydrochloric acid produced by electrolysis of salt.
It's not much but its a step in the right direction. Use our waste streams to produce other materials where we can before mining more material with consequently greater energy use.
I didn't say it was bad just not 'green' in the sense of being indefinitely renewable. The rationale for indirect CO2 in uranium mining is the large net savings. I haven't yet seen such an estimate for 'green' cement but it might assume business as usual for the coal and steel industries. Both those industries are likely to peak within a generation.