This is a process for the production of Alumina
, which was patented by Karl Josef Bayer in Austria
in 1888. It involves the digestion of crushed Bauxite
in sodium Hydroxide
solution at high temperatures (~240 o
Most of the Alumina will dissolve, leaving a "red mud", which is removed by filtration.
The remaining product is then decomposed by reversing the reaction, by cooling and adding the trihydrate, Al2O3.3H2O.
2NaAlO2 + 2H2O -> 2NaOH + Al2O3.3H2O
This is then heated to drive off the water of crystallization, which produces Alumina.