Theory

To increase the productivity of a copper tankhouse the current efficiency and/or current density needs to be increased. According to physical and chemical laws, the only way to increase the current density in a way that ensures that the electro deposition is still pure and the copper sheets are smooth and of a high quality, is to minimize the diffusion boundary layer.

Electrolyte Flow in a Conventional Electrorefining Cell

The electrolyte enters the cell at the bottom of the front and leaves it at the upper opposite end. One major disadvantage of this conventional arrangement of inlet and outlet is that the fresh electrolyte, and hence also the additives like inhibitors, is not inserted directly at the cathodes, where it is needed, and a part of it also leaves the cell by bypassing the electrodes on the sides.

As described above, increasing the current efficiency and/or density in a reasonable way, i.e. so that a high cathode quality is ensured, can only be achieved by decreasing the diffusion boundary layer in front of the electrodes.

Electrolyte Flow in a Cell using the METTOP-BRX-Technology

The METTOP-BRX-Technology enables a parallel electrolyte flow between the electrodes in order to minimize the diffusion boundary layer. Special designed nozzles govern the fresh electrolyte in an upwards natural electrolyte flow in front of the cathode.

Therefore, the fresh electrolyte an also the additives enters directly at the cathode, where it is needed, and the bypass-flow, which occurs in conventional cell design is minimized. Additionally, the parallel electrolyte flow results in a more homogeneous distribution of concentrations and temperature in the cell. Due to the optimized nozzle design and positioning, the settlement of the anode slime is not influenced by using the METTOP-BRX-Technology, and hence neither the cathode quality decreased.