746
C. Zschiesche and I. Bauer
Fig. 7 Lining of a kettle station with openings for maintenance and the burner equipment
accelerates the period time during cooling, e.g. immediately after antimony removal
(T > 600 °C).
The step of Zn-removal and Bi-removal takes a relevant portion of the total processing time. Facing the current development of growing complexity in bullion composition, this process step could be de-coupled by the implementation (2018) of a
new kettle K7 (Fig. 8).
This new kettle which has also a volume of 200 t is now fully dedicated for the Biremoval step and received the crude lead after Zn-removal. During the Zn-removal,
the lead level is decreasing which is mitigated with the addition of crude lead bullions
to this new kettle to manage the bath levels and keep the initial Bi-content before
refining on the desired level. All in all, this had a quite positive effect on the Bi
concentration Bi-product which is an PbBi alloy.
Fig. 8 Implementation of a new kettle to de-couple Zn-removal and Bi-removal stage