By weathering minerals, a lot off CO2 is captured.
This can easely explained: a chemical reaction between a alkaline mineral and an acid (CO2). The end state has got a lower energy (this is the reason why the reaction proceeds in nature by itself)
This reaction takes place at the surface of the grain and proceeeds very slowly.
A solid rock takes millions of years to weather. The CO2 capture in one year is very limited.
The amount of CO2 depends on the kind of mineral and the kind of reaction.
The most common minerals, with can be used to capture CO2 are:
The reaction speed depends on:
- Kind of mineral
- Size of the grain ( contact surface)
- CO2 concentration
- Acid grade
- Ability of ion exchange
- Bacteria and fungi
- Plant Roots (they excrete organic acids to facilitate the
weathering. Their aim is to obtain nutrients from the minerals.
There are more then hundred publications about the weathering of minerals and CO2 capture.
Nevertheless, It is still not clear how fast the reaction is..
According to the publications, the speed is 10 to 100 µm yearly.
In The Netherlands, Prof. D.R. Schuiling has done a lot off research at the weathering of minerals for the capture of CO2.
Please see the subject.
The weathering and CO2 capture is the most beneficial in tropical circumstances.
Innovation Concepts is starting up a project in Tanzania.
The essence is to capture CO2 and simultaniously increase the food production. This project is the CO2 for food program.