A silica-polyamine based extraction material removes selected transition metal
ions from solution in the presence of iron ions. The silica-polyamine base is a
reaction product of a polyamine and a covalently anchored trifunctional hydrocarbylsilyl
that yields non-crosslinked amino groups to which pyridine function group is attached.
The extraction material is particularly useful in selectively removing copper from
low concentration, low pH leach solutions separating copper from ferric iron or
chloride ions. The product is a durable, high capacity extraction material that
selectively captures copper at high flow rates and releases that copper into highly
concentrated solutions.