[floxy]

>how you would sequester the gaseous CO2 other than "put it underground."

I wonder if there is a reason you couldn't just sequester the powder. Probably too expensive? Or not volume efficient?

>to leak out eventually due to plate techtonics

This might seem shortsighted, but I'm OK pushing the problem out by 50 million years or so.

[BizarroLand]

Since the powder is reusable, it likely wouldn't make sense to sequester it with the CO2 either materially or financially.

[entropicdrifter]

This. The powder is more efficiently used as a way to move the CO2 around than as a means to keep it sequestered.

[Woodi]

Still, tree produce oxygen from that CO_2. And do not need energy from grid for that :)

Threating CO_2 like radioactive waste, putting it underground etc - that what I call not self-sustained :>