[pitspotter2]

And while we're in the Sahara Desert with abundant sunshine, sand and carbon dioxide, let's build a silicon carbide brick factory. Sunlight to provide electrical power and, via focussed mirrors, heat. Sand to supply the silicon. Carbon from carbon dioxide to be extracted from the air at $100 per tonne (well, eventually).

Silicon carbide bricks, emerging gloriously from their tungsten moulds, would possess supreme corrosion resistance and almost double the crushing strength of engineering bricks. High thermal conductivity should reduce cracking and spalling, further increasing lifetime. A short railway journey to the nearest port and water desalination plant whence they can be distributed throughout the world.

We'll beat the Romans! Our public buildings will last for millennia!

[ncmncm]

It will take a very long time to beat the Romans, and more than twice that long to beat the Egyptians.

Corundum bricks would suffice. The Egyptians knew a way to cut corundum like butter; the method apparently was lost before the pyramids were built.

Solar panels have proven quite a lot cheaper than mirror-concentrated solar heat as a source of electrical power. Concentrated solar has not really been tried as a source of direct industrial heat, where it might yet excel. But choosing the bit of Sahara to site in has proven harder than expected. To make building materials economically useful, the site needs immediate sea access. Pisco, Peru might be a better choice, although Nouakchott, Mauritania is well sited. Broome, Australia might do.

[pitspotter2]

Corundum vs carborundum. It's a conundrum!