Re choice of minerals, it must really depend on what is locally available so as to minimise transport costs and emissions - and particularly to include readily available stocks of mine waste, for example from nickel mines, diamond mines. Mine wastes are great as there's lots of them, there is no need to cause fresh environmental damage, infrastructure - roads, railways, ports etc - is generally in place to shift them, and often they are already milled to some extent, reducing grinding overheads (both $ and C). Choices typically include olivine / serpentine / peridotite / granite / volcanic ash.
BTW someone previously said there was loads of Ca silicate. For some reasons there is mainly Mg silicate with not much Ca silicate. Doubtless the result of some twist of ocean chemistry which I have not yet elucidated. Also to pick up on another discussion, the reaction we want now is not silicate to carbonate, but silicate to bicarbonate, which typically ends up in the oceanic reservoir - like that you get double the CO2 sequestration. This is the natural result of dispersal and weathering in the aequeous phase. On this basis a tonne of olivine gives you a little over a tonne of CO2 sequestration. Oliver. On Sep 26, 4:45 am, [email protected] wrote: > Oliver, Greg etal -- 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.
