Question

What is bayers method?

Answer 1

1. Purification of bauxite by Baeyer's process:-

In the Baeyer's process, the bauxite ore is heated with concentrated NaOH solution under pressure (Aluminum is purified by leaching method). The alumina dissolves as sodium meta aluminate. The other materials present in the ore are left as insoluble part. This solution is filtered in ore are left as insoluble part. This solution is filtered off. From the solution Al(OH)3 is precipitated by adding freshly prepared Al(OH)3 to the cold dilute solution and agitating.


Al2O3 + 2NaOH -------> 2NaAlO2 + H2O
NaAlO2 + 2H2O -------> NaOH + Al(OH)3


The precipitated Al(OH)3 is dried and ignited to get pure alumina.
2Al(OH)3 --------> Al2O3 + 3H2O