Australian University Unveils New Carbon-Trapping Bricks

FirephoxRising writes "A research pilot plant in Newcastle will trial world-first technology that turns carbon emissions into bricks and pavers for the construction industry. More efficient and stable than storing gas in the ground, the new method will sequester carbon and can work anywhere, unlike geo-sequestration which is site specific."

Comments

Bringing coal to Newcastle!

[Anonymous Coward]

From TFA: "capture carbon dioxide emissions and turn them into rock." We all know what rock is made from carbon...

So they're bringing coal to Newcastle -- specifically, artificial coal bricks and pavers!

Turning CO2 into carbonates?

[Immerman]

A good question, though I'm less cynical about the presumed answer. They did say something like they were recreating the Earth's natural processes, so probably something like calcium carbonate (CaCO3), the stuff that egg and seashells are made of.

Can anybody say how various carbonates compares energetically to oil and CO2? My chemistry is pretty rusty. Since the final cycle would be oil -> CO2 -> carbonate the maximum net energy would be that from a hypothetical fossil fuel -> carbonate transition, which would tell us how energetically feasible this is with the right catalysts. If it's an endothermic reaction this is a complete non-starter except as part of some hypothetical future atmosphere-scrubber (and I do really hope we have the tech ready if it comes to that).

If the reaction is exothermic though then there's hope, especially if it's a significant portion of the (presumably larger) oil -> CO2 energetic gap. If we could complete the fossil fuel -> brick transition while generating even half as much power as currently then this could be a real game-changer. Every coal- or oil-fired power plant could have it's adjacent brick factory and become carbon neutral. We could stay on fossil fuels for centuries without aggravating the global climate, even as oil and gas run out - we have truly massive coal reserves to fall back on. Of course we'd need to really shift the attention back to general environmental protection again, and get serious about that, otherwise the search for fuel could get *really* ugly. Coal mining isn't exactly environmentally friendly

Re:Turning CO2 into carbonates?

[ceoyoyo]

It's been a while since I did chemistry, but calcium carbonate can be made from calcium oxide and carbon dioxide in the presence of water. I think that's more or less how it's done in sea creatures. So you've got:

CaO + H2O + CO2 --> CaCO3 + H2O

I believe the reaction takes place spontaneously when you dissolve calcium oxide and CO2 in water. To check, add up the standard enthalpy of formation for both sides. The water cancels, of course, leaving:

635 kJ/mol + 393.5 kJ/mol --> 1207 kJmol

Right is more negative than the left so the reaction is exothermic. Calcium carbonate is basically limestone or marble, so a nice building material, mixed with other stuff to stabilize it against acid rain. Leaving the question of where you get the CaO.

Having done all that work, I found this: http://www.globalccsinstitute.com/publications/novel-co2-capture-taskforce-report/online/54351.

Looks like the reactions are all exothermic, but you have to come up with the minerals, which means mining a ton and a bit of rock for every ton of coal you burn. But you get building materials out of the bargain too.

Re:Turning CO2 into carbonates?

[Anonymous Coward]

A bit of digging finds that they are reacting Olivine (Magnesium silicate) with CO2 giving Magnesium Carbonate.

This reaction has been studied for years as a sequestration reaction for CO2 but traditionally it needs high pressure and moderate temperature to get reasonable
conversion of the Olivine. The team at Newcastle Uni have come up with a method to produce Magnesium Carbonate (Dolomite) at much more modest reaction conditions.

Re:Seems like overkill

[aardvarkjoe]

I bet you could get a lot of investors on board with a plan to use solar power to convert atmospheric CO2 into building materials. Just don't tell them that the super-secret device that does so is called a "tree."