Aluminum production method
- Charles M. Hall, Paul Héroult
- Patented independently 1886
- Electrolysis of alumina (Al<sub>2</sub>O<sub>3</sub>) in cryolite (Na<sub>3</sub>AlF<sub>6</sub>)
$
\ce{2Al2O3_{(diss)} + 3 C_{(s)} -> 4Al_{(l)} + 3CO2_{(g)}}
$
# Difficulties addressed
- Aluminum likes to react with oxygen
$
\ce{2Al + \frac{3}{2}O2 -> Al2O3}
$
- difficult to reduce
- Al reacts with water:
- water electrolysis infeasible
- Al<sub>2</sub>O<sub>3</sub> insoluble by most solvents
- only cryolite (Na<sub>3</sub>AlF<sub>6</sub>) dissolves Al<sub>2</sub>O<sub>3</sub> in molten state