This appears to be one of many ideas to mineralise CO2 using Mg silicate rock using an industrial reaction process. The question has to be, is this necessary or cost effective when there is a low tech, low cost alternative - to distribute the rock powder on farm / pasture / forest soils and in intertidal zones? And then let nature take its course. Depending on the rock composition, this can also help remineralise depleted soils, much as volcanic ash so often does, and raise fertility. The main argument used in favour of the industrial approach is that the natural weathering takes place very slowly, but this is incorrect. Biological processes, as noted by Lovelock in 1981 (http://www.jameslovelock.org/page29.html) accelerate the chemistry of weathering, as also does agitation / abrasion from wave action.
Oliver Tickell On Sep 23, 9:18 pm, "Rau, Greg" <[email protected]> wrote: > Speaking of mineral carbonation, check > out:http://onlinelibrary.wiley.com/doi/10.1111/j.1530-9290.2011.00368.x/a... > ;jsessionid=15DD453CB61D6B1B218D916F13507A2E.d01t01 > > -Greg > > On 9/23/11 4:40 AM, "Oliver Tickell" <[email protected]> wrote: > > > > > > > > > Monbiot's real mistake here is to swallow the conclusion of the Royal > > Society report on the subject, whole and undigested, without critical > > scrutiny or attention to other sources of information - in particular > > as regards the weathering of magnesium silicate (not enough Ca > > silicate to bother with): > > > Monbiot reports: "Dumping lime or calcium or magnesium silicates into > > the sea, where they react with carbon dioxide. Fairly safe. Effective. > > Expensive. Has > > the advantage of potentially reversing ocean acidification, but the > > amount of quarrying required to produce enough ground-up rock is > > likely to be prohibitive. " > > > A) where does he get the idea that it's about dumping it in the sea? > > It is about spreading the rock powder on land, and in intertidal > > zones. > > B) So it's "fairly safe". Why only "fairly"? This is just to > > accelerate a natural process that is going on all the time anyway. > > C) "Expensive" - how much? People who have done the sums > > conservatively estimate $10-15 per tCO2. Making it one of the cheapest > > options around. > > D) It will only "potentially" reverse ocean acidification. Well, > > insofar as the science of chemistry "potentially" applies. He seems to > > be implying that maybe chemistry is "potentially" all wrong. George, > > tell us more! > > D) The amount of quarry is "likely to be prohibitive" - is it? Has he > > done the sums? Has he asked anyone who has done the sums? Or is this > > just his uniformed guess? For a start there are Gt of already mined > > rock that can be used, in mine tailings around the world. From then > > on, roughly 1t of rock sequesters 1t of CO2. So you need to mine an > > amount of rock comparable to the amount of fossil fuel we are burning. > > If it's not "prohibitive" to mine the coal, why's it "prohibitive" to > > mine the rock? > > > Oliver Tickell. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
