RESEARCH ON INDIUM AND GERMANIUM DISTRIBUTIONS BETWEEN LEAD BULLION AND SLAG AT SELECTED PROCESS CONDITIONS

摘要

The recovery of indium and germanium during lead metal extraction processes has the potentialto add value to existing pyrometallurgical operations. Few experimental data are available that describe thepartitioning of these species between major phases at the industrial process conditions. In addition, thebulk chemical analysis techniques used in previous studies have limited accuracy since the solid phasesand their proportions in slag are not identified. A novel methodology was developed for the hightemperature equilibration and quenching technique where the composition of the quenched liquid slagphase was analysed by Electron Probe X-Ray microanalysis (EPMA) and the metallic lead phase byInductively Coupled Plasma (1CP). The improved methodology developed in the present study providesthe opportunity to resolve differences between the data presented in the literature, and accurate descriptionof the systems. Results of the study show that at the selected experimental conditions, indium ispredominantly present in the slag as In~(3+), and germanium as Ge~(4+). Germanium partitions preferentially tothe slag phase between PO_2 of 10~(-8) to 10~(-12) arm. Indium partitions preferentially to the metal under low PO_2and to the slag at high PO_2. Additions of copper, arsenic or antimony at levels below 5 wt% in the leadmetal phase do not affect the partitions of indium or germanium. Increasing the temperature from 1150 °Cto 1300 °C increases the partition of indium. At the experimental temperatures in the range of 1200 °C to1150 °C no significant change in the partition ratio of germanium was observed.