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Description
Life cycle assessment (LCA) is increasingly identified as the proper tool/framework for performing cradle to grave analysis of a product, technology, or supply chain. LCA proceeds by comparing the materials and energy needed for materials extraction, benefaction, and end-of-life management, in addition to the actual lifetime of the product. This type of analysis is commonly used to evaluate forms of renewable energy to ensure that we don't harm the environment in the name of saving it. For instance, LCA for photovoltaic (PV) technologies can be used to evaluate the environmental impacts. CdTe thin film solar cells rely on cadmium and tellurium metals which are produced as by-products in the refining of zinc and copper ore, respectively. In order to understand the environmental burdens of tellurium, it is useful to explore the extraction and refining process of copper. Copper can be refined using either a hydrometallurgical or pyrometallurgical process. I conducted a comparison of these two methods to determine the environmental impacts, the chemical reactions which take place, the energy requirements, and the extraction costs of each. I then looked into the extraction of tellurium from anode slime produced in the pyrometallurgical process and determined the energy requirements. I connected this to the production of CdTe and the power produced from a CdTe module, and analyzed the production cost of CdTe modules under increasing tellurium prices. It was concluded that tellurium production will be limited by increasing hydrometallurgical extraction of copper. Additionally, tellurium scarcity will not provide a physical constraint to CdTe commercial expansion; however it could affect the price reduction goals.
ContributorsMacIsaac, Kirsten Breanne (Author) / Seager, Thomas (Thesis director) / Fraser, Matthew (Committee member) / Wender, Ben (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2013-05
Description
Mangura Mine in Zimbabwe has been operating under a traditional copper mining method for the past few decades. This mining method is referred to as the pyrometallurgical process. The process involves copper ore extraction, crushing, milling, floatation, concentrating and smelting. With the low copper grades reported at the mine, this multi-stage process is not highly effective to extract this metal. The energy, labor and other expenses incurred in pollution control, have been high. The mine is downsizing every year and it is expected to close in the foreseeable time horizon, even though they still have copper reserves at their property. This project was aimed at providing an effective approach to the future of extracting low grade copper through using a hydrometallurgical extraction process. The hydrometallurgical method is a multi-stage process involving the leaching of copper ore, solvent extraction and electrowinning. The economic viability of implementing a hydrometallurgical process for extracting copper was evaluated. The paper demonstrated the feasibility of the hydrometallurgical process in extracting low grade copper at the mine. A detailed extraction process was developed with the goal of recovering 2.9 million metric tons of copper per year with 99.9 wt.% minimum purity. The return on investment was estimated to be more than 200%. All the findings indicated that implementing a hydrometallurgical process should be the future of Mhangura Mine.
ContributorsMtemeri, Lincoln (Author) / Raupp, Gregory (Thesis director) / Taylor, David (Committee member) / Chemical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05