Hydrometals –
Crud Treatment / Clay Treatment

Separators and decanters from GEA Westfalia Separator ensure better efficiency for the liquid extraction of base metals.

Metals such as copper, uranium, cobalt, nickel and zinc are extremely important commodities. Liquid extraction with acid has become established as the standard method for recovering such metals. However, the formation of crud in the settling tanks is a problem; crud is an emulsion layer comprising aqueous and organic components, air and solids. Because the emulsion is stable under normal conditions of gravity and has a considerably negative impact on the effectiveness of the extraction process, it has to be continuously removed from the recovery process, or must be prevented from occurring.

One possibility is to remove the crud in the extraction stage from the process. For this purpose, GEA Westfalia Separator has developed special 3-phase decanters designed for the tough requirements of the product. In an initial stage, these decanters separate the emulsion which has previously been drawn off from the tank into solids, aqueous phase and solvent. Water and solids are disposed of. The organic phase, however, is enriched with activated clay and is then passed through a 2-phase decanter. In this way, it is possible to recover the solvent with such high quality that it can be recycled back to the extraction stage without a negative impact on the efficiency of the process.