What is the least expensive of all metals?
Aluminium is the most abundant metallic element in the crust but
its intensive reduction process sets its cost at $1/lb. along with
zinc, lead, and cadmium. The next abundant metal is iron; its
enthalpy of reduction is much milder and its (pig iron's) cost is
set by the coal feedstock to 25¢/lb. Sixth and seventh cheapest are
manganese and magnesium at $1.35/lb. Eighth cheapest is calcium at
$1.60/lb. Seventh cheapest is copper at $3.50/lb. Nineth and tenth
cheapest are antimony and chromium at $5.60/lb. Eleventh cheapest
is tin at $9/lb. Twelfth, thirteenth, and fourteenth cheapest are
nickel, bismuth, and titanium at $10/lb. Fifteenth and sixteenth
cheapest are cobalt and tungsten at $15/lb.