Orbite Aluminae Message Board

To: E. Charters who wrote (324)	12/7/2011 10:21:03 AM
From: Whaspe	of 5043

The dissolution of metal oxides proceeds by a more complex set of reactions then what the stoichiometry of the final summed reaction tells us. Putting aluminum ions into solution does not depend on the stoichiometry solely. However, you are correct, to precipitate the aluminum you will need to reach a three to one stoichiometry between aluminum and chloride ions. This is why the Orbite process breaks this up into stages, first putting the metal ions into solution, then separating the aluminum ions from everything else (which is sent off to the acid regeneration plant for recovery of acid and purified metal oxides). The aluminum is precipitated by reaction with hydrochloric gas and is then calcinated to produce alumina, which also allows for recovery of the hydrochloric gas.