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This Lab-Made Mineral Just Became a Key Candidate For Reducing CO2 in The Atmosphere
Scientists just worked out a way of rapidly producing a mineral capable of storing carbon dioxide (CO2) - giving us a potentially exciting option for dealing with our increasingly overcooked planet. Magnesite, which is a type of magnesium carbonate, forms when magnesium combines with carbonic acid - CO2 dissolved in water. If we can produce this mineral at a massive scale, it could safely store large amounts of carbon dioxide we simply don't need in our planet's atmosphere.
[...] Being able to make the mineral in the lab could be a major step forward in terms of how effective carbon sequestration might eventually be. "Using microspheres means that we were able to speed up magnesite formation by orders of magnitude," says [Ian] Power. "This process takes place at room temperature, meaning that magnesite production is extremely energy efficient."
[...] With a tonne of naturally-occurring magnesite able to capture around half a tonne of CO2, we're going to need a lot of magnesite, and somewhere to put it all as well. As with other carbon capture processes, it's not yet clear whether this will successfully scale up as much as it needs to. That said, these new discoveries mean lab-made magnesite could one day be helpful – it puts the mineral on the table as an option for further investigation.
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(Score: 3, Insightful) by c0lo on Monday August 20 2018, @10:58AM (2 children)
And the precursor that combines with CO2 is... what exactly?
If the answer is magnesium or magnesium hydroxide, I'll have to tell you the majority of those two substances are obtained from magnesite [wikipedia.org]. With a process that not only releases the CO2 already sequestered, but very likely produces extra amount of CO2 by burning coal.
I can easily take calcined lime to "sequester" CO2 as calcium carbonate... except that the calcined lime is obtained by heating calcium carbonate until it gives away the C02.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 3, Informative) by takyon on Monday August 20 2018, @11:21AM
Everything I wrote was a summary of the research. See reply made to fraxinus above for some ideas about the chemistry.
There is also another source of magnesium compounds I didn't mention.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1, Informative) by Anonymous Coward on Monday August 20 2018, @10:25PM
Extracting magnesium from magnesite appears to be very energy intensive. I guess that's because magnesium is so reactive. China produces the lion's share of the world's magnesium using the Pidgeon process (which extracts magnesium from magnesite), and that process requires about 100 kWh / kg of magnesium [uow.edu.au]. If you used diesel to power this you'd need to burn about 8kg of diesel [wikipedia.org] fuel to release the 100kWh to obtain about 1kg of magnesium (assuming you can use 100% of the energy from burning diesel). Burning 8kg of diesel fuel emits about 18kg of carbon dioxide [eia.gov], plus the half kg of CO₂ from the magnesite, let's say 20kg of CO₂ emissions per kg of magnesium produced by this process.
Unfortunately I don't have a figure for the total energy required to extract magnesium from water. That would avoid the problem of releasing already-sequestered carbon from the materials, at least, but I expect the energy requirement is probably on a similar scale.