A potential solution to the sand crisis - FINITE

Actually 'melted down' to be reused? A different resource I read said, [t]he recycling process is a secret but talking over email,  Oza described the gist: “We use a non-toxic solution that allows the material to enter a more liquid state that can be recast or reapplied” in new Finite-based constructions.

That reads to me a lot more like either dissolving or de-polymerizing rather than 'melting'.

The actual information about Infinite comes at 4:30 in the above video: the reasoning, the general method of binding the desert sand, their testing, the project's future.

Sadly they are very tight-lipped about the method of binding the desert sand together. I'm really curious about it.

More reading about Finite...

• The Next Great Building Material? It Could be Sand from Deserts
• Finite's website

CarbonCure Technologies - Simply better concrete.

When the claim is that spectacular...

CarbonCure works with existing concrete factories to simply add CO2 without changing the concrete recipe or machines. CO2 is collected from smokestacks of large polluters like coal power or cement plants and brought to the concrete factory for recycling. Our proprietary technology injects the CO2 gas into the concrete where it is converted into more stone within the concrete...

The best part is that it costs about the same and it keeps the same good looks and durability that you're used to with regular concrete.

It's green concrete without the trade-offs.

...I find myself skeptical as to just how we get benefits without any downsides at all.

Ok, I don't get it. My understanding is that cement is produced by heating calcium carbonate to decompose it into calcium oxide and carbon dioxide. Why, then, can we just add the carbon dioxide back into the concrete to produce calcium carbonate later in the process? And if that's the case, why did we both to take the carbon dioxide out of the calcium carbonate in the first place?

I'm confused.



How does the CO2 get trapped?

According to a CNN article,

CarbonCure's system takes captured CO2 and injects it into concrete as it's being mixed. Once the concrete hardens, that carbon is sequestered forever. Even if the building is torn down, the carbon stays put. That's because it reacts with the concrete and becomes a mineral.

...

"The best thing about it is the mineral itself improves the compressive strength of the concrete," Christie Gamble, the director of sustainability at CarbonCure, told CNNMoney."

Again with the extraordinary claims. I'm going to need a little more detail.

From the CarbonCure website...

The technology may be used to increase the compressive strength performance of a concrete mix. The strength improvement can then be leveraged in the optimization of the mix design for a specific end goal[.] (source)

...

Once injected into the wet concrete mix, the CO2 reacts with calcium ions from cement to form a nano-sized calcium carbonate mineral that becomes permanently embedded in the concrete. (source)

I hope that this technology is as perfect as is suggested, but I'm not holding my breath.