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2011-Sustainable Industrial Processing Summit
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| Editors: | Florian K |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2012 |
| Pages: | 754 pages |
| ISBN: | 978-0-9879917-3-7 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Microwave Assisted Recovery Of Platinum
Monika Willert-Porada1;1UNIVERSITY OF BAYREUTH, Bayreuth, Germany;
Type of Paper: Regular
Id Paper: 294
Topic: 12
Abstract:
Microwave Assisted Recovery of PlatinumT. Gerdes, M. Willert-PoradaUniversität Bayreuth, Lehrstuhl für WerkstoffverarbeitungPlatinum metals are important industrially applied catalysts. Currently, exhaust gas catalysts account for approx. 10 % total Pt use, however, based on expected demand soon probably 20 % of the total consumption of platinum group metals will be allocated to exhaust gas catalysis in automotive applications. Materials used in cars have to be recycled. Currently the recycling rate of platinum is very high. Consequently, the primary Pt-production equals the secondary production. In view of the rising volume of secondary Pt-production the economy of Pt-recycling gains importance.Primary as well as secondary processing of Pt consists of numerous dissolution and precipitation processes with their individual efficiency governing the overall economy of the process. In particular, only Pt of exceptional purity is capable of catalytic activity or superior refractory metal properties. Consequently, unique oxidation and reduction steps have to be applied in order to insure enrichment and purity of the refractory metal.The entrapment of impurities upon subsequent repetition of dissolution and precipitation steps is an issue in current state of the art Pt-purification and recycling processes. The aim to use microwave heating upon purification processes is to enhance dissolution and precipitation of Pt metal without retention of impurities, by selective overheating of the leaching agent. Microwave heating enables pulsed application of energy, thus accelerating dissolution of Pt-sponge and its precipitation while limiting sintering of the Pt-sponge accompanied by impurities entrapment. A significant reduction of processing time can be achieved by utilisation of microwave assisted processing conditions.In the paper a comparison of conventional and microwave assisted process is presented. The influence of MW-power control (power level, pulse length, local plasma ignition) on the platinum sponge morphology and details of the re-dissolving process of platinum sponge in a chlorine saturated hydrochloric acid upon microwave heating are discussed