Entity

Time filter

Source Type

Eindhoven, Netherlands

Sun Z.H.I.,Technical University of Delft | Xiao Y.,Tata Steel | Sietsma J.,Technical University of Delft | Agterhuis H.,Van Gansewinkel Groep BV | Yang Y.,Technical University of Delft
Waste Management | Year: 2016

Recovery of valuable metals from electronic waste has been highlighted by the EU directives. The difficulties for recycling are induced by the high complexity of such waste. In this research, copper could be selectively recovered using an ammonia-based process, from industrially processed information and communication technology (ICT) waste with high complexity. A detailed understanding on the role of ammonium salt was focused during both stages of leaching copper into a solution and the subsequent step for copper recovery from the solution. By comparing the reactivity of the leaching solution with different ammonium salts, their physiochemical behaviour as well as the leaching efficiency could be identified. The copper recovery rate could reach 95% with ammonium carbonate as the leaching salt. In the stage of copper recovery from the solution, electrodeposition was introduced without an additional solvent extraction step and the electrochemical behaviour of the solution was figured out. With a careful control of the electrodeposition conditions, the current efficiency could be improved to be 80-90% depending on the ammonia salts and high purity copper (99.9. wt.%). This research provides basis for improving the recyclability and efficiency of copper recovery from such electronic waste and the whole process design for copper recycling. © 2016 Elsevier Ltd. Source


Sun Z.,Technical University of Delft | Xiao Y.,Tata Steel | Agterhuis H.,Van Gansewinkel Groep BV | Sietsma J.,Technical University of Delft | Yang Y.,Technical University of Delft
Journal of Cleaner Production | Year: 2016

Urban mining has attracted increasing attention as a research topic, owing to the high growth rate, environmental issues, and market potential of waste generated in urban areas. Metal recovery from such waste has become increasingly important especially in accordance with the concept of metal criticality. This study develops a model by evaluating various types of urban waste in order to understand the criticality of these waste streams and determine their potential for metal recovery. Two factors, i.e. the resource index and technology index, are defined and assessed through a systematic review of data from the literature and industry. High values of the resource index indicate that the waste is important to the European Union (EU) economy and hence has significant potential for recycling as a resource. Furthermore, a high technology index indicates that the waste can be processed for metal recovery with less technology investment than that required for a waste that has a low technology index. However, a high environmental impact for the recovery of metals, indicates that processing of the waste is difficult and potentially has high impact on the environment. A case study of 11 waste streams from a local recycling company is performed, by using the correlation of these two indices. The results of the evaluation suggest that the information and communication technology (ICT) scrap and the rare-earth elements (REEs) containing end-of-life (EOL) products exhibit significant potential for metals recovery. The technical aspects governing the recovery of valuable metals from these two resources are further analysed and potential processing routes (flowsheets) can be suggested. Combined with both physical separation and metallurgical processing, the proposed evaluation methodology and the processing routes for targeted critical metals, are expected to contribute to the development of competitive recycling technologies. © 2015 Elsevier Ltd. All rights reserved. Source


Sun Z.,Technical University of Delft | Xiao Y.,Tata Steel | Sietsma J.,Technical University of Delft | Agterhuis H.,Van Gansewinkel Groep BV | Yang Y.,Technical University of Delft
Environmental Science and Technology | Year: 2015

In recent years, recovery of metals from electronic waste within the European Union has become increasingly important due to potential supply risk of strategic raw material and environmental concerns. Electronic waste, especially a mixture of end-of-life electronic products from a variety of sources, is of inherently high complexity in composition, phase, and physiochemical properties. In this research, a closed-loop hydrometallurgical process was developed to recover valuable metals, i.e., copper and precious metals, from an industrially processed information and communication technology waste. A two-stage leaching design of this process was adopted in order to selectively extract copper and enrich precious metals. It was found that the recovery efficiency and extraction selectivity of copper both reached more than 95% by using ammonia-based leaching solutions. A new electrodeposition process has been proven feasible with 90% current efficiency during copper recovery, and the copper purity can reach 99.8 wt %. The residue from the first-stage leaching was screened into coarse and fine fractions. The coarse fraction was returned to be releached for further copper recovery. The fine fraction was treated in the second-stage leaching using sulfuric acid to further concentrate precious metals, which could achieve a 100% increase in their concentrations in the residue with negligible loss into the leaching solution. By a combination of different leaching steps and proper physical separation of light materials, this process can achieve closed-loop recycling of the waste with significant efficiency. (Graph Presented). © 2015 American Chemical Society. Source


Sun Z.H.I.,Technical University of Delft | Xiao Y.,Tata Steel | Sietsma J.,Technical University of Delft | Agterhuis H.,Van Gansewinkel Groep BV | And 2 more authors.
Hydrometallurgy | Year: 2015

Electronic waste treatment within EU has focused on valuable metal recycling and has been defined by the EU directives. The difficulties for recycling are induced by the high complexity of such waste. In this research, a hydrometallurgical process was developed to recycle copper from industrially processed information and communication technology (ICT) waste. By using air as the oxidant and ammonia-ammonium carbonate leaching solution, copper could be extracted with high recovery - more than 90%, and high extraction selectivity - around 98%. In order to understand the copper extraction process and the reaction mechanisms, the effects of a range of parameters during copper leaching were comprehensively investigated, including ammonia concentration, leaching temperature, ammonium carbonate concentration, the liquid-to-solid ratio, air flow rate and mechanical stirring rate. The controlling step for the leaching kinetics was identified and the effects of different parameters were investigated. This research is potentially beneficial for further optimisation of the copper leaching process and the whole process design for copper recycling after incorporating with solvent purification and electrowinning of the copper-rich solution. © 2014 Elsevier B.V. All rights reserved. Source


Sun Z.H.I.,Technical University of Delft | Xiao Y.,Tata Steel | Sietsma J.,Technical University of Delft | Agterhuis H.,Van Gansewinkel Groep BV | And 2 more authors.
Waste Management | Year: 2015

Recycling of valuable metals from electronic waste, especially complex mixtures of end-of-life information and communication technology (ICT) products, is of great difficulty due to their complexity and heterogeneity. One of the important reasons is the lack of comprehensive characterisation on such materials, i.e. accurate compositions, physical/chemical properties. In the present research, we focus on developing methodologies for the characterisation of metals in an industrially processed ICT waste. The morphology, particle size distribution, compositional distribution, occurrence, liberation as well as the thermo-chemical properties of the ICT waste were investigated with various characterisation techniques, including X-ray Fluorescence Spectrometry (XRF), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) with energy dispersed spectroscopy (EDS). Due to the high heterogeneity of the material, special sample preparation procedures were introduced to minimise the discrepancies during compositional analyses. As a result, a clearer overview of the ICT waste has been reached. This research provides better understanding of the extractability of each metal and improves the awareness of potential obstacles for extraction. It will lead to smarter decisions during further development of a clean and effective recovery process. © 2014 Elsevier Ltd. Source

Discover hidden collaborations