Aurubis to examine anode sludge recycling

Germany – The German Federal Ministry of Environment has approved a Euro 328 000 grant to Europe’s leading copper producer Aurubis for a pilot project at its plant in Hamburg.

This will cover the further development of a new treatment concept for anode sludge – a by-product of the copper electrolysis process containing precious metals such as silver and gold.

To achieve a residual moisture of less than 3%, the sludge is dried in a one-step process using a heated, evacuated, membrane filter press rather than the existing energy-intensive, three-stage process. The drying stage is aided by integrated heating plates driven by 120 degC process steam; the saturated air is sucked through a vacuum and condensing system such that subsequent gas scrubbing is not required.

The membrane filter press technology is part of an overall concept for the treatment of anode mud with the aim of optimising the use of energy, the recovery of resources and the reduction of emissions.