wastes often contain some germanium. Lead blast furnace slag is then exposed to reducing conditions in a process known as slag fuming, to volatilise its zinc content which is subsequently re-oxidised to zinc oxide fume. Finally the fume is acid leached to produce electrolyte for zinc electrowinning. The amount of germanium in the electrolyte is dependent on the distribution of germanium among the various phases in the blast furnace and the slag fumer. Figure 1 shows the general flowsheet for zinc recovery during lead smelting.It is clearly important to understand how germanium distributes between the various phases during these processing stages so that it can, as far as practical, be directed away from streams which send it towards zinc electrowinning. There have been investigations into the distribution of minor elements such as arsenic, 7,8 gold, 9 silver, 7,8,10 copper, 7,8,10,11 zinc, 7,8,10 antimony, 7,8,11 bismuth, 7,8 cobalt, 10 tin, 7,8 and even the very minor metal indium, 11 between lead and either iron silicate slag or calcium ferrite slag during lead smelting. However, no information on germanium distribution in lead-zinc smelting could be found.Distribution data can be used to determine important thermodynamic parameters such as activity coefficients for germanium and its oxide in metals and slags. It is then possible to use computational thermodynamics to predict the effects of changing processing conditions on the distribution of germanium between phases and to propose strategies to minimise the proportion of germanium moving towards the zinc electrolyte.The work discussed in the present paper focuses on germanium distribution during lead blast furnace smelting. The data derived are also applicable to the modelling of germanium behaviour in the new direct lead smelting methods, such as the QSL and Kivcet processes. 12,13 EXPERIMENTAL Slag was prepared by mixing finely ground silica tubing, calcium carbonate, iron (III) oxide (Aldrich Chemicals, +99·9% purity) and iron powder (Javac Chemicals, +99·5% purity) in the required proportions. The raw materials were mixed and ground in a ring mill, then heated to 1300ºC in an alumina crucible under nitrogen for 4 h. The crucible was removed from the furnace to air cool and, after breaking the crucible and separating the slag from the crucible material, the slag was finely ground and mixed thoroughly. The slag used for most experiments was found to contain 9·8 wt-%SiO 2 , 18·1 wt-%CaO, 49·5 wt-% FeO and 9·7 wt-%Al 2 O 3 . The lead used was refined lead metal (99·99% purity) from Pasminco Port Pirie smelter.The experimental apparatus is shown in Fig. 2 and is similar to that used by Louey et al. 14 for determining the distribution of tin between slag and copper matte.Germanium is present as a minor element in most mined lead-zinc concentrates, and during subsequent processing part of it is carried in electrolyte to zinc electrowinning. Germanium is well known to reduce drastically the current efficiency of zinc deposition and to cause a multitude of pinho...