Fördelning av gallium, germanium, indium och tenn mellan bly och slagg

摘要

This work examines the distribution of the trace elements gallium, germanium, indium and tin at lead smelting conditions. First part of the work is a literature overview and the latter part is an experimental part where a laboratory work on the distribution of the trace elements between lead and slag is presented. The work is concentrating on modern direct smelting technologies, because these are the promising technologies for the future.The experimental work was performed at 1150 °C (1423 K). The aim of the work is to research how the elements distribute when the oxygen partial pressure is changed. Oxygen partial pressures used in the experiments (10-7-10-12 atm) are around the same values that are used in industrial processes. The experimental method employed consists of three main stages: equilibration at high temperature, fast quenching and EPMA-analyses. The EPMA-analyses were implemented by the Geological survey of Finland (GTK). A pseudo-wollastonite crucible was used to hold the lead and slag. The conclusions were that gallium dissolves in the slag, germanium has the oxidation state Ge2+ during reducing conditions and Ge+ during oxidating conditions, indium has the oxidation state In2+ and tin has the oxidation state close to Sn2+. The distribution coefficients were 0.01-0.8 for gallium, 0.1-8 for germanium, 0.003-11 for indium and 0.002-4 for tin. The concentrations were close to the detection limits but it was possible to make conclusions from the results.