Thermal Oxidation of Indium, Germanium, and Tin from Lead-Bearing Alloys Generated in Zinc Refinement

Abstract

According to European regulations, indium and germanium are critical metals. Therefore, their recovery is a crucial issue. The present study was focused on the pyrometallurgical treatment of polymetallic PbSnIn and PbSnCuGeIn generated at the Miasteczko Zinc Smelter in order to recover In and Ge. The paper presents the production process of these alloys, as well as their characteristics. The materials were subjected to thermal processing in a laboratory-scale refining kettle fired with natural gas and air. Two different methods for the processing of the individual alloys are described. Two series (one for each material) consisting of five tests were performed in order to determine the optimal metal recovery parameters. The described pyrometallurgical process resulted in the production of an indium-enriched semi-product (In—1.15%) and a Ge⁻In-enriched product (Ge—11.1%, In—3.0%). Direct indium recovery rates were approximately 83% and >99%, respectively.

Keywords

• polymetallic alloys
• thermal oxidation
• New Jersey process
• pyrometallurgy