The present invention relates, generally, to a method and apparatus for
electrowinning metals, and more particularly to a method and apparatus
for copper electrowinning using the ferrous/ferric anode reaction and a
flow-through anode, such as, for example, a dimensionally stable carbon,
carbon composite, metal-graphite, or stainless steel anode. In general,
the use of a flow-through anode--coupled with an effective electrolyte
circulation system--enables the efficient and cost-effective operation of
a copper electrowinning system employing the ferrous/ferric anode
reaction at a total cell voltage of less than about 1.5 V and at current
densities of greater than about 26 Amps per square foot (about 280 A/m2),
and reduces acid mist generation. Furthermore, the use of such a system
permits the use of low ferrous iron concentrations and optimized
electrolyte flow rates as compared to prior art systems while producing
high quality, commercially saleable product (i.e., LME Grade A copper
cathode or equivalent), which is advantageous.