Development of an industrially applicable electrostatic solvent extraction column for process metallurgy

The Challenge

Solvent extraction (SX) is the only commercial separation technique for complete separation of chemically similar metals such as nickel and cobalt, or rare earth elements (REE). Current SX technologies are inefficient in terms of mass transfer and energy consumption, making industrial separation by this approach often prohibitively expensive.

Key Findings

The electrostatic solvent extraction (ESX) technique evaluated through Zela’s work allows operation with much smaller droplets than conventional SX technologies. This promotes efficient separation, but excessively small droplets can also lead to the formation of environmentally harmful emulsions.
Droplet size distribution can be controlled through varying the geometry, strength, and frequency of the electrostatic field applied.
Optimum ESX performance is delivered by parallel-plate electrodes with alternating current (AC) fields operated at high voltage and low frequency. This configuration supports high mass-transfer rates, but also allows rapid phase disengagement to retard the formation of emulsions.

Benefits to WA

Zela’s research advances practical understanding of ESX, paving the way toward more energy-efficient hydrometallurgical separation and purification of a range of critical and strategic resources. Improved metal purification technology would deliver an advantage to Western Australia’s mining and refining sectors, supporting the delivery of additional value from the State’s significant endowment in nickel, REE and other strategic metals.