[trustmeimdrunk]

I hate to be the bearer of bad news, as I am happy to see this issue making headlines, but this sounds like something out of Mike Judge's Idiocracy universe.

It's probably a really bad idea to spread rock dust on arable land. The mixture will probably retard the natural soil microbiota, and at worst render land unusable.

Just try adding a bunch of concrete dust to your basil plant in the window sill, see what happens. Most likely this will be the source, as concrete waste is a huge issue in most population centers. Natural microbiota, the life in soils, are our best bet at sequestering our overabundance of atmospheric ghg, because we literally have to do nothing. Just leave it the fuck alone. Most land is not past the point of no return, and most land is not being used to grow essential food crops. Our actual food is grown on a very small part of farms worldwide and has lots of room to intensify while reducing energy and chemical inputs.

Rebuilding and growing bogs, marshes, and wetlands should be our top priority if we want our great-grandchildren to enjoy the world outside of a cave or a bubble.

[ggm]

you know, if you showed us you are a soil agronomist, and cited something we might agree. Or, we might look at the other people commenting some of them who do cite references, who say this isn't retarding natural soil microbiota and isn't going to the at-worst case, making land unusable.

your example of "try this at home" is not actually good. concrete dust before hydration is completely different to the dust made post hydration, or fly ash, or surplus rock dust from mining. The properties of the pre-build and post-build chemical reactivity of concrete (its an exothermic reaction) need to be borne in mind.

That said, aggressive de-carbonisation of industry and agriculture, biochar, wetland remediation, re-forestation are probably vital, and urgent.

[jaclaz]

Maybe you are confusing (or I am not understanding) concrete dust with cement dust.

Concrete dust should be the result of demolition of concrete (already hydrated when it was cement to form the concrete, i.e. post exothermic reaction).

But, allegedly, the concrete surfaces (not reduced to dust) exposed in the Biosphere2 was sequestering both CO2 and oxigen, and - at least in that case - the "solution" was a supplement of oxygen, so maybe the concrete (not cement) dust uses both CO2 and oxigen while basalt only or mainly uses CO2?

Also, whether it is basalt or concrete dust, wouldn't this treatment alter the pH of the soil? (at least here historically where there is an excessively acid soil it is often corrected with additives like calcium carbonate or similar).

[kolinko]

concrete is not basalt - different chemistry.