Development of a Continuous Process Chain for Selective Recovery and Purification of Rare Metals

Solar cells, liquid crystal displays (LCDs) and light-emitting diodes (LEDs) have become more and more important in recent decades. Crucial components of such electronic devices include rare metals (e.g., indium and gallium), which are only available in limited quantities. In order to meet their rising demand in the coming years, recycling processes, especially those that enable selective recovery of the individual components, are steadily gaining in importance. One conceivable method is particle-loaded solvent extraction followed by mechanical processing. Therefore, we first investigated the possibility of recovering individual particle fractions from a multicomponent mixture on the basis of the surface properties. Both UV–Vis spectroscopy and small-angle X-ray scattering (WAXS) were used for evaluation. The conducted experiments showed, among other things, that the indium oxide content increased from 50% to 99% in a binary system and from 33% to 94% in a ternary compound. In addition, the purification of the separated particles was examined in detail. Using UV–Vis spectrometry, it was found that permeation washing of filter cakes is suitable for removing impurities and retrieving most of the solvent used. Based on the results of the conducted laboratory tests, we finally developed a concept for the continuous and selective recovery of rare metals

Development of a prototype dynamic flowsheet simulation of mixed domestic waste treatment processes

Die vorliegende Arbeit befasst sich mit der Erschaffung und exemplarischen Anwendung eines Prototyps zur Modellierung und dynamischen Fließschemasimulation von Abfallbehandlungsverfahren. Zur Eingrenzung des Betrachtungsrahmens wird einführend der Wissensstand zum Stoffsystem „Gemischte Siedlungsabfälle“ zusammengetragen. Neben den jährlich in Deutschland anfallenden Mengen und erzielten Verwertungsquoten werden dabei schwerpunkthaft stoffliche und granulometrische Zusammensetzungen und weitere für die Aufbereitung relevante Merkmale von Haushaltsabfällen herausgearbeitet. Anhand eines Überblicks über gegenwärtig verbreitete Aufbereitungsverfahren und dabei eingesetzte Prozesse wird der erforderliche Umfang an mechanischen Prozessmodellen eingegrenzt. Der anschließend vorgestellte Fließschemasimulator stellt das Ergebnis einer vertikalen Prototypentwicklung dar. Die jeweiligen Realisationsstufen umfassen die Definition eines Stoffstromobjektes und dessen Ablage in einem Datenbankformat, die Formulierung von Prozessmodellen verschiedener Abbildungstiefe sowie der Entwurf einer grafischen Oberfläche zur Parametereingabe und Ergebnisvisualisierung. Anhand verschiedener Einsatzszenarien wird abschließend die Anwendbarkeit des Prototyps demonstriert.The present work deals with the creation and exemplary application of a prototype dynamic flowsheet simulation system for modelling waste treatment processes. The scope of consideration is established by an introductory summarization of the current knowledge concerning the material system „mixed domestic wastes“. Germany’s annual waste quantities and recovery rates are presented along with selected material and granulometric compositions of municipal wastes, as well as further properties relevant to treatment processes. The scope of modelling is then narrowed based on an overview of today’s commonly used treatment processes and techniques. The subsequently described flow sheet simulator represents the product of a vertical prototyping process, whose realization stages include the definition of a material flow representation and its database storage, the formulation of process models with varying levels of modelling depth, and the draft of a graphical user interface for parametrization and display of simulation results Finally, the applicability of the prototype is demonstrated by means of several usage scenarios

Development of a Continuous Process Chain for Selective Recovery and Purification of Rare Metals

Solar cells, liquid crystal displays (LCDs) and light-emitting diodes (LEDs) have become more and more important in recent decades. Crucial components of such electronic devices include rare metals (e.g., indium and gallium), which are only available in limited quantities. In order to meet their rising demand in the coming years, recycling processes, especially those that enable selective recovery of the individual components, are steadily gaining in importance. One conceivable method is particle-loaded solvent extraction followed by mechanical processing. Therefore, we first investigated the possibility of recovering individual particle fractions from a multicomponent mixture on the basis of the surface properties. Both UV–Vis spectroscopy and small-angle X-ray scattering (WAXS) were used for evaluation. The conducted experiments showed, among other things, that the indium oxide content increased from 50% to 99% in a binary system and from 33% to 94% in a ternary compound. In addition, the purification of the separated particles was examined in detail. Using UV–Vis spectrometry, it was found that permeation washing of filter cakes is suitable for removing impurities and retrieving most of the solvent used. Based on the results of the conducted laboratory tests, we finally developed a concept for the continuous and selective recovery of rare metals