[skywhopper]

Lots of questionable assumptions in this article, but I wanted to call this particular calculation out because it's so blatant:

    5 MAF/year of 6% salinity brine contains more than 10 million tonnes
    of magnesium, comparable to current global production, not to mention
    other light metals. At spot prices around $5000/T, a mature brine
    extraction industry could net >$50b/year

"Net" means after expenses, so this calculation is assuming that extracting 100% of the magnesium from the brine would have zero cost, not to mention that it also assumes that doubling the world supply of magnesium would have zero impact on its price.