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A comment on Is carbon capture a viable solution?. Parent comment

Re:Is carbon capture a viable solution? by philipkglass on Tuesday November 24, 2020 @01:04PM (#25201077)
The reaction between carbon dioxide and alkaline earth silicates is thermodynamically spontaneous in the presence of water, but kinetically hindered. It's a reaction with slow diffusion of reactants through the product layer, limited by surface area. So crush rocks rich in alkaline earth silicates and distribute them in near-shore environments. It's an artificially accelerated version of the geological carbon cycle. It still requires vast-in-absolute-terms amounts of energy to crush billions of tons of rock, but it's not running uphill against thermodynamics.

Olivine:

Mg2SiO4 + 2CO2 → 2MgCO3 + SiO2: ΔH -89 kJ mol/CO2

Serpentine:

Mg3Si2O5(OH)4 + 3 CO2 → 3MgCO3 + 2SiO2 + 2H2O: ΔH -64 kJ mol/CO2

Wollastonite:

CaSiO3 + CO2 → CaCO3 + SiO2: ΔH -90 kJ mol/CO2

https://www.ipcc.ch/site/assets/uploads/2018/03/srccs_chapte... (Section 7.2.2 "Chemistry of mineral carbonation")

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Re:Is carbon capture a viable solution? by CyanBird on Tuesday November 24, 2020 @01:42PM (#25201501)
We already have catalytic convertors on cars, can we add co2 capture to them as well? Add a little box with powdered olivine and some extra chemical bits to capture a higher % of co2 than absolute 0?

Catalytic convertors already use finely coated incredibly expensive platinum to break down complex molecules, and it is certainly easier to capture co2 near the source than when dissipated in the atmosphere

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Re:Is carbon capture a viable solution? by dodobirdlord on Tuesday November 24, 2020 @01:55PM (#25201651)
No. The reaction happens in water, it’s fairly slow, the mixture needs to be agitated, and it would require similar quantities of silicates to the among of hydrocarbons being burned. Better to ignore capture at the source and instead prioritize mass-capture in places that are energy efficient. Shallow coastal areas near major deposits.
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Re:Is carbon capture a viable solution? by sunstone on Tuesday November 24, 2020 @06:18PM (#25204175)
A couple of H-bombs in the Himalayas might do the trick quite quickly.
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