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Comment by program_whiz | Hacker News Reader

Interesting comment on article: Isn't this better stated as "some areas of the world are running out of sand"? The Sahara is 9.2E12 meters squared and one estimate puts the average depth of sand at 150m, giving 1.38E15 m^3 of sand. The earth's land area is 5.1E14 m^2, meaning the sand in the Sahara alone is enough to cover earth's land area in 2.7m (9ft) of sand

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Sand =! Industrial usable Sand. Not all kind of "Sand" is suited for the industry(today). Most desert/dune sand is to fine grained and has a smooth surface, so that it is unusable to create strong material. There are some projects/studies already that use "desert sand + X" to create "strong" material.

http://www.resourcepanel.org/reports/global-material-flows-a...

https://na.unep.net/geas/archive/pdfs/GEAS_Mar2014_Sand_Mini...

https://www.hindawi.com/journals/amse/2016/2158706/

http://maxwellsci.com/print/rjees/v4-1071-1078.pdf

> Sand =! Industrial usable Sand. Not all kind of "Sand" is suited for the industry(today). Most desert/dune sand is to fine grained and has a smooth surface

That's why you mine it to the East, closer to where it erodes, rather than to the West, where it is fine enough to be considered dust.

Sand is not just sand. It's not a fungible thing. Different kinds of sand have different mineral compositions, different sizes and shapes for the grains, different consistencies, etc. The sand used to make an iPhone screen is different from the sand used to peel paint, but both are highly specific.

It's not just sand that's running out. It's specific kinds of sand, or sand that is readily available (because sand is expensive and annoying to transport).

Sahara sand is not suitable for construction or island building because it is too spherical, desirable sand is jagged because it clumps together better.

Seems like an opportunity to use sun and sand to construct 3D-printing oases in the middle of nowhere.

https://www.youtube.com/watch?v=ptUj8JRAYu8

Wonder why this isn't working out as the "new construction technique" hit success that it seems, with a little optimisation, it could be?

> Wonder why this isn't working out as the "new construction technique" hit success that it seems, with a little optimisation, it could be?

Well, it's incredibly dangerous to set up an array of solar concentrating fresnel lenses and/or mirrors anywhere near human beings. Concentrating radiation on things which are becoming more and more shiny and/or refractive as you go can go very wrong, as you start having to manage the caustics of even the cloudy glass you end up making.

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