Reduction Kinetics Of Slags Produced From Recycling Of Lead Batteries

The extent and the rate of reduction of slags produced from the smelting of recycled lead batteries were investigated under laboratory conditions using graphite as reductant. Simultaneous reduction of PbO, Fe2O3, Sb2O3 and As2O3 occurred at temperatures of 1180 and 1200°C, with Sb and As reporting to the metal phase while the PbO content of the slag was above 2 wt%. Fuming of As from the metal occurred at lower concentrations of lead in the slag. Discard slags with low levels of As, Pb and Sb were produced. Arsenic levels were reduced to less than accurately measurable by ICP analysis, and Sb levels in the final slags were in the range of 0.1 to 0.2 wt%. The kinetic data obtained were analysed and compared with other measurements on lead oxide containing slags. The results showing a dependence of the reduction rate on the oxidation state and the basicity are consistent with other studies on well characterised industrial and. synthetic lead slags. These results indicate that when carbonaceous reductants are used, the rate of interfacial reactions play an important role in enabling the production of environmentally acceptable discard slags.