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Title: Cross-current leaching of indium from end-of-life LCD panels

Graphical abstract: Display Omitted - Highlights: • End-of-life LCD panels represent a source of indium. • Several experimental conditions for indium leaching have been assessed. • Indium is completely extracted with 2 M sulfuric acid at 80 °C for 10 min. • Cross-current leaching improves indium extraction and operating costs are lowered. • Benefits to the environment come from reduction of CO{sub 2} emissions and reagents use. - Abstract: Indium is a critical element mainly produced as a by-product of zinc mining, and it is largely used in the production process of liquid crystal display (LCD) panels. End-of-life LCDs represent a possible source of indium in the field of urban mining. In the present paper, we apply, for the first time, cross-current leaching to mobilize indium from end-of-life LCD panels. We carried out a series of treatments to leach indium. The best leaching conditions for indium were 2 M sulfuric acid at 80 °C for 10 min, which allowed us to completely mobilize indium. Taking into account the low content of indium in end-of-life LCDs, of about 100 ppm, a single step of leaching is not cost-effective. We tested 6 steps of cross-current leaching: in the first step indium leachingmore » was complete, whereas in the second step it was in the range of 85–90%, and with 6 steps it was about 50–55%. Indium concentration in the leachate was about 35 mg/L after the first step of leaching, almost 2-fold at the second step and about 3-fold at the fifth step. Then, we hypothesized to scale up the process of cross-current leaching up to 10 steps, followed by cementation with zinc to recover indium. In this simulation, the process of indium recovery was advantageous from an economic and environmental point of view. Indeed, cross-current leaching allowed to concentrate indium, save reagents, and reduce the emission of CO{sub 2} (with 10 steps we assessed that the emission of about 90 kg CO{sub 2}-Eq. could be avoided) thanks to the recovery of indium. This new strategy represents a useful approach for secondary production of indium from waste LCD panels.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [1]
  1. Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona (Italy)
  2. Institute of Environmental Geology and Geoengineering IGAG, National Research Council, Via Salaria km 29300, 00015 Montelibretti, Rome (Italy)
  3. Department of Industrial Engineering, Information and Economy, University of L’Aquila, Via Giovanni Gronchi 18, 67100, Zona industriale di Pile, L’Aquila (Italy)
  4. ISL Kopacek KG, Beckmanngasse 51, 1140 Wien (Austria)
Publication Date:
OSTI Identifier:
22472536
Resource Type:
Journal Article
Resource Relation:
Journal Name: Waste Management; Journal Volume: 42; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ABUNDANCE; CARBON DIOXIDE; ENVIRONMENTAL PROTECTION; INDIUM; LEACHING; LIQUID CRYSTALS; MATERIALS RECOVERY; OPERATING COST; SOLID WASTES; SULFURIC ACID; ZINC