Abstract: A system for treating a barren solution typically containing a heavy metal such as copper, and complexed cyanide, from a precious metal mill, is treated in a first electrochemical cell to remove the heavy metal and free the cyanide whereafter the treated solution can be returned to the precious metal mill as leaching solution; the barren solution flows through a porous cathode in which the heavy metal is electrochemically deposited, and against an inert anode; the deposited heavy metal is recovered in a sheet form by employing the heavy metal loaded cathode as an anode in a second electrochemical cell, the heavy metal entering solution and being deposited on a cathode sheet typically of stainless steel or titanium from which a deposited sheet of the heavy metal is readily peeled; the porous cathode free of heavy metal can be reused in the first cell.