The concentration of bauxite varies greatly depending on the location in which it is found. In some places, it can be up to 60-70% aluminium oxide, whereas in others it can be as low as 30-40%.
The bauxite added NaOH solution step is a process used to extract aluminium from bauxite ore. In this process, NaOH (sodium hydroxide) is added to the bauxite ore, which then reacts with the aluminium in the bauxite ore to form aluminium hydroxide. The aluminium hydroxide is then filtered out and the remaining solution is heated, which causes the aluminium hydroxide to crystallize and precipitate out of the solution. The aluminium hydroxide is then collected and processed further to produce aluminium metal.
The reaction formula for this process is as follows:
Al2O3 + 2NaOH → 2NaAl(OH)4