Methods for controlling iron via magnetite formation in hydrometallurgical processes

Abstract

A method of controlling iron in a hydrometallurgical process is disclosed. The method may comprise the steps of: leaching () a feed slurry (); forming a pregnant leach solution (); removing a first leach residue () from the pregnant leach solution (); and sending a portion () of the pregnant leach solution () and/or raffinate () produced therefrom, to an iron removal process (). According to some preferred embodiments, the iron removal process () may comprise the steps of: sequentially processing the pregnant leach solution () and/or raffinate () produced therefrom in a first reactor (R) a second reactor (R), and a third reactor (R); maintaining a pH level of the first reactor (R) above 4, by virtue of the addition of a first base; maintaining a pH level of the second (R) and/or third (R) reactors above 8.5, by virtue of a second base; and forming solids () comprising magnetite (). The method may further comprise the steps of performing a solid liquid separation step () after the iron removal process (); and performing a magnetic separation step () to remove magnetite () from said solids comprising magnetite (), without limitation. A system for performing the method is also disclosed.