exchemist
Veteran Member
This article in Nature:
https://www.nature.com/articles/s41586-020-2448-9.epdf?sharing_token=lu7fAF3SYEA3-3cqr4bW1NRgN0jAjWel9jnR3ZoTv0OtB5LS5Y5Cwumoumb5Vs9pGQp7NWqtO_367vUmB4Gw5d1jrtY1Q_fxsg9CqaP7u_roOx47rRI35TgOlouSUMFkWDAwBhqKIiHcHdlpCXCw7u7xFUnOVehztmJFe0_XsbW7Fhs4q-ual8XY248j3f-wBPIPsr85yaM7LPsBpj8TlAAp0lgkjnl_N_D5WhFjCb8=&tracking_referrer=www.theguardian.com
proposes a man-made adaptation of the geological Carbon-Silicate Cycle* as a way of sequestering significant amounts of CO2 from the atmosphere.
It seems that basalt from mining operations, or the slag from iron smelting, are good sources of Mg and Ca based silicate material. These react with water and CO2 to form carbonate minerals (initially bicarbonates), using the general reaction scheme :
MSiO3 + H2O +2CO2 -> M(HCO3)2 + SiO2.
(M = Mg or Ca)
Apparently, this "weathering" reaction proceeds fairly rapidly, especially in warmer climates. (I had no idea.)
The authors calculate that spreading silicate rock dust on fields around the world could lock up significant quantities of CO2 from the air, and would improve the soil in the process, as it reduces the acidification that can occur in intensive farming.
Looks like rather a good win-win. One would need to be careful to avoid accidental heavy metal pollution from some sources of silicate, but this should not be insurmountable.
*https://en.wikipedia.org/wiki/Carbonate–silicate_cycle
https://www.nature.com/articles/s41586-020-2448-9.epdf?sharing_token=lu7fAF3SYEA3-3cqr4bW1NRgN0jAjWel9jnR3ZoTv0OtB5LS5Y5Cwumoumb5Vs9pGQp7NWqtO_367vUmB4Gw5d1jrtY1Q_fxsg9CqaP7u_roOx47rRI35TgOlouSUMFkWDAwBhqKIiHcHdlpCXCw7u7xFUnOVehztmJFe0_XsbW7Fhs4q-ual8XY248j3f-wBPIPsr85yaM7LPsBpj8TlAAp0lgkjnl_N_D5WhFjCb8=&tracking_referrer=www.theguardian.com
proposes a man-made adaptation of the geological Carbon-Silicate Cycle* as a way of sequestering significant amounts of CO2 from the atmosphere.
It seems that basalt from mining operations, or the slag from iron smelting, are good sources of Mg and Ca based silicate material. These react with water and CO2 to form carbonate minerals (initially bicarbonates), using the general reaction scheme :
MSiO3 + H2O +2CO2 -> M(HCO3)2 + SiO2.
(M = Mg or Ca)
Apparently, this "weathering" reaction proceeds fairly rapidly, especially in warmer climates. (I had no idea.)
The authors calculate that spreading silicate rock dust on fields around the world could lock up significant quantities of CO2 from the air, and would improve the soil in the process, as it reduces the acidification that can occur in intensive farming.
Looks like rather a good win-win. One would need to be careful to avoid accidental heavy metal pollution from some sources of silicate, but this should not be insurmountable.
*https://en.wikipedia.org/wiki/Carbonate–silicate_cycle
There are plenty of successful precedents for that as well. But certainly one needs to pilot all such ideas, with careful monitoring for unintended consequences.
