Experience in operating the girilambone copper SX-EW plant in changing chemical environments

The copper SX-EW plant operated by the Girilambone Copper Company (GCC) has suffered a number of severe process upsets immediately following commissioning. The organic reagent was degraded by the action of manganese entrained from the leach solution. The reagent chemistry was restored by the large scale use of treatment by an activated clay. A further problem was identified as the reduction in SX performance by the generation of silica gels in the organic reagent. A novel mechanism has been proposed for the generation of these gels. Application of the mechanism has allowed the identification of alternate operating conditions to prevent their formation. These altered conditions have resulted in further equipment developments to treat the symptoms generated. A new design of loaded organic coalescer has removed the increased entrainment of aqueous resulting from operation of the upstream extraction stage in organic continuity. A new medium has been developed for installation in the settlers, to minimise the total entrainments reporting to the subsequent stages of the SX plant. Application of these techniques has been shown to be generally appropriate by use in other operations suffering poor SX performance.