Patent ID: 6500395
Filing Date: 2002-12-31
Classification: C22B,Y02P

Abstract:
A method for the treatment of air pollution control (APC) residues comprising:a) alkaline washing the residues at least one time, said washing including mixing a liquid with the residues to produce a solution, said solution being maintained at a pH not lower than 11.5, to generate alkaline washed residues; b) separating the alkaline washed residues from the liquid portion of the solution produced in a) to generate separated alkaline washed residues; c) acid washing the separated alkaline washed residues at least one time, said washing including mixing a liquid with the separated alkaline washed residues to produce a solution, said solution being maintained at a pH between 2 and 4.5, to generate acid washed residues; d) separating the acid washed residues from the liquid portion of the solution produced in c) to obtain residues that are substantially devoid of metal components.