Many hydrometallurgical processes produce large amounts of
acid waste. This is illustrated by the copper S/X-E/W process
which produces a bleed from the electrolysis tank house in the
form of a concentrated sulphuric acid stream. Currently, the
bleed stream is necessary to remove impurities such as iron that
decreases the efficiency of the electrowinning process. However,
this comes at a high financial cost owing to large quantities of
make-up sulphuric acid required. A process has thus been
developed with Zeneca Specialties (UK), ICI Australia and
Gunpowder Copper Co at the University of Melbourne for the
recovery of sulphuric acid from copper tank house bleed liquor.
The recovery process uses the method of solvent extraction.
Solvent extraction has the advantage of being a well-established
technology in the mining industry and will reduce the
environmental impact of the S/X-E/W process, as all additional
chemicals can be completely recycled. A simplified diagram of
the process is shown in Figure 1. Tank House