Not clear how silicates relate to air capture - CO2 must be significantly concentrated for the reaction to happen, e.g. via costly amine capture from power plants. Even then the kinetics are slow unless additional T, P, or chemistry is applied. House et al (2007)does offer an indirect electrochemical "weathering" of silicates for air capture, but at a severe energy penalty. "Carbonation" of carbonates: CO2 + H2O + CaCO3 ---> Ca++ + 2HCO3- also requires elevated CO2, but straight flue gas will work and the kinetics here are much more favorable. There is an electrochemical version of this for air capture, but again at a significant energy price tag. Are you suggesting that these are our first tier abiotic air capture technologies?
-Greg >not quite sure what you meant by comment "If there is anyone left on >this ----- >but this "peridotite" idea is of great interest. It was also mentioned in a >thread a few months ago.There's lots in Iran > >removing CO2 from the atmosphere is the "B" of the Pachauri letter and of >the possible ways of doing this I would bet on this one. > >The chemistry is > >iron/magnesium/calcium silicate(solid) + CO2 (gas) ---> iron/mag/cal >Carbonate(solid -chalk) + SiO2 (solid-sand) > >and its exothermic! If we can get it going it doesnt need energy. The >silicates -peridotite- are magma when it comes to the surface volcanicly. > >We letter signatories believe that A,B and C are not alternatives. All are >necessary to solve the problem so we are very interested. > >regards > >John G > > >----- Original Message ----- >From: "David Schnare" <dwschn...@gmail.com> >To: "geoengineering" <geoengineering@googlegroups.com> >Sent: Tuesday, March 10, 2009 4:08 PM >Subject: [geo] Mineral sequestration of CO2 > > >> >> If there is anyone left on this group that is actually looking for >> politcally acceptable solutions to excessive atmospheric CO2, you may >> be interested in this report, out recently on locations where mineral >> sequestration resources are available in the U.S. >> >> http:// pubs.usgs.gov/ds/414/downloads/DS414_text_508.pdf >> >> >> > >> > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
