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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Investigations into the segregation of heaps of particulate materials with particular reference to the effects of particle size

Salter, Guy Francis January 1999 (has links)
No description available.
2

The Material Separation Process for Recycling End-of-life Li-ion Batteries

Li, Liurui 27 October 2020 (has links)
End-of-life lithium-ion batteries retired from portable electronics, electric vehicles (EVs), and power grids need to be properly recycled to save rare earth metals and avoid any hazardous threats to the environment. The recycling process of a Lithium-ion Battery Cell/Module includes storage, transportation, deactivation, disassembly, and material recovery. This study focused on the disassembly step and proposed a systematic method to recover cathode active coating, which is considered the most valuable component of a LIB, from end-of-life LIB pouch cells. A semi-destructive disassembly sequence is developed according to the internal structure of the LIB cell. A fully automated disassembly line aiming at extracting cathode electrodes is designed, modeled, prototyped, and demonstrated based on the disassembly sequence. In order to further obtain the coating material, the extracted cathode electrodes are treated with the organic solvent method and the relationship between process parameters and cathode coating separation yield is numerically studied with the help of Design of Experiment (DOE). Regression models are then fitted from the DOE result to predict the cathode coating separation yield according to combinations of the process parameters. The single cell material separation methodology developed in this study plays an important role in the industrial application of the direct recycling method that may dominate the battery recycling market due to its environmental friendly technology and high recovery rate regardless of element type in the short future. / Doctor of Philosophy / The bursting demand of lithium-ion batteries from portable electronics, electric vehicles, and power grids in the past few years not only facilitate the booming of the lithium-ion battery market, but also put forward serious global concerns: Where should these batteries go at their end-of life and how should they be treated in a safe and harmless manner. As a metal enriched "city mine", end-of-life LIBs are expected to be properly stored, transported, deactivated, disassembled, and recovered with sufficient safety precautions to prevent fire, explosion or any hazardous emissions. This study focuses on the disassembly procedure and emphasized automated battery disassembly techniques and the improving of material separation efficiency. A disassembly sequence of the pouch cell is scheduled and optimized for the first time. To realize the scheduled sequence, a fully automated pouch cell disassembly system is designed to achieve semi-destructive disassembly of z-folded pouch cells. Fixtures, transporters and end-effectors were prototyped and assembled into the modularized disassembly line which extracts cathode electrodes as final product. Cathode electrodes as the most valuable component in a LIB then need to go through multiple chemical-mechanical treatments to future separate cathode coating and Al current collector. This study utilized DOEs to optimize the operating parameters of the material separation process for Lithium cobalt oxide (LCO) coating and Lithium iron phosphate (LFP) coating. Regression models are successfully established for yield prediction with certain levels of control factors.
3

Recycling Waste Solar Panels (c-Si & CdTe) in Sweden

Nekouaslazadeh, Alireza January 2021 (has links)
Solar energy industries are one of the fastest-growing industries in the global energy market. Between 2018 and 2019, installed capacity in Sweden increased by 70%. This is due to a combination of declining PV module and inverter costs, as well as  increased conversion to fossil-free energy production to mitigate greenhouse gas emissions. In fact, solar PVs have a 25-year life span, and soon many deployed PVs would soon reach their end of life (EoL), it is, therefore, important to organize for the EoL of PVs in order to recover precious resources and recycle PV modules in a sustainable manner. Currently, less than 10% of global solar cell waste is recycled, due to the lack of incentives for recycling in most countries. In the European Union, used-up modules are governed by the WEEE (Waste Electrical and Electronic Equipment) Directive, which requires the collection of 85% of solar cell waste, with at least 80% of the waste being prepared for reuse or recycling. Solar cell waste has not amounted to significant volumes in Sweden, due to the lack of no known systems for recycling. Used-up modules are currently collected and managed as electronic waste in one of two approved collection systems in Sweden. The aim of this thesis is to analyze and assess methods of recycling waste solar panels in Sweden and is it economically viable to set up a solar waste recycling center before it reaches the right amount of waste. Moreover, the main focus is on the analysis and comparison of the environmental impacts of various recycling methods for crystalline silicon (c-Si) and cadmium telluride (CdTe) panels. To recycle solar panel waste, the elements of these panels must be assessed from both an economic point of view as well as environmental impacts. Today, the most common PV panels in the global market and also Sweden are c-Si and CdTe types. The results showed except for the pyrolysis method, the environmental impacts of both c-Si and CdTe PV panels from the thermal-based recycling methods, are lower than chemical methods. Furthermore, the extraction of Al, Si, and glass from c-Si and the extraction of glass from CdTe has a less environmental impact than the current techniques used in the recycling of PV panels. Finally, in this study, we revealed which materials can be prioritized for maximum economic and environmental advantages from recycling. In c-Si modules, these are Ag, Al, Si, and glass and in CdTe modules, these are Te, Cu, and glass. Currently, investing in a new solar module recycling center in Sweden is not economically viable. Because the possibility of such an investment requires economic and political incentives. Given that by 2042 the volume of Swedish solar waste will not reach the minimum level of profitability to build a new specialized center for the recycling of solar modules, the best decision is to modify the existing plants in Sweden to recover expensive and vital materials.

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