Fluidized bed electrowinning of copper

Abstract

A fluidized bed electrowinning system and method includes a fluidized bed reaction vessel in which a fluidized bed of conductive particles serves as the cathode for the electrowinning reaction, the anodes being in the form of hollow tubes of electrochemically active material inserted into the fluidized bed and separated therefrom by a membrane. The catholyte and anolyte are separately supplied from an electrolyte supply tank, the catholyte being pumped through the conductive particles to form the fluidized bed and the anolyte being supplied to individual anodes, and are commingled at the top of the reaction vessel before return to the supply tank. Removal of particles from the tank occurs through a part in the side of the tank, the removed particles normally being recycled through a selector valve back into the tank to maintain continuous operation. Periodically, the selector valve is operated to divert particles removed from the reaction vessel to a particle storage tank for subsequent size separation, with smaller particles being returned to the output product. Recycling of the particles during normal operation is facilitated by a recycle pump and eductor located outside the output port, the recycle solution also being commingled with the catholyte and anolyte at the top of the tank before return to the electrolyte supply tank. The electrolyte is refreshed by a separate leaching circuit responsive to monitoring of electrolyte supply in the tank.