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Economic performance assessment of control in direct copper electrowinning operations
Roos, V. 2025. Economic performance assessment of control in direct copper electrowinning operations. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/fbb37390-f61b-44c7-a8db-e3478830b36b
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614136844681216 |
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| access_status_str | Open Access |
| author | Roos, Vincent |
| author2 | Tadie, Margreth |
| author_browse | Roos, Vincent Tadie, Margreth |
| author_facet | Tadie, Margreth Roos, Vincent |
| author_sort | Roos, Vincent |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Roos, V. 2025. Economic performance assessment of control in direct copper electrowinning operations. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/fbb37390-f61b-44c7-a8db-e3478830b36b |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132458 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:47:15.075Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132458 Economic performance assessment of control in direct copper electrowinning operations Roos, Vincent Tadie, Margreth Auret, Lidia Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Copper -- Electrometallurgy Composition operators Metallurgical plants -- Economic aspects Hydrometallurgy UCTD Roos, V. 2025. Economic performance assessment of control in direct copper electrowinning operations. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/fbb37390-f61b-44c7-a8db-e3478830b36b Thesis (MSc)--Stellenbosch University, 2025. ENGLISH ABSTRACT: Copper electrowinning (EW) is an industrial process used to refine high purity copper cathodes from electrolytes. Controlling this process is challenging due to the slow response times from large liquid hold-ups in cells and tanks, as well as the offline nature of electrolyte composition analysis. Operators typically determine control setpoints manually, which can lead to suboptimal performance (Bergh, Jämsä-Jounela & Hodouin, 2001). Simulations of zinc electrowinning process control (Barton & Scott, 1994; Mahon, 2016) suggest that controlling electrolyte composition is feasible and economically beneficial. However, advancements in copper electrowinning control have been limited by a scarcity of dynamic models (Bergh & Yianatos, 2001). Recent models (Aminian, Bazin, Hodouin & Jacob, 2000; Tucker, 2019; Grobbelaar, 2023) aim to enable research in this area and support the development of model-based control strategies. This thesis expands on the work by Grobbelaar (2023) by combining the dynamic, semi-empirical model of an electrowinning cell with a dynamic model for a generic, industrial scale direct EW circuit to enable process control simulation in MATLAB Simulink (2022). The model includes a series of pumps, piping and tanks whose dynamics are described using first-principle mass balances, as done by Aminian et al. (2000). The circuit was assumed to form part of a larger leaching-electrowinning (LX-EW) operation, where the EW circuit aimed to maximise the production of copper cathodes whilst maintaining a minimum copper concentration in the cell’s electrolyte, required for promoting the formation of a high-quality product. The EW circuit was required to supply leaching acid at a flow rate and sulphuric acid concentration specified by the leaching plant. A baseline level-only control strategy was simulated, alongside two feedback and one model-based strategy. The strategies, in increasing order of sophistication, were named: fixed-increment control, automatic feedback control and model predictive control. The strategies were then compared for their effectiveness in maximising the circuit’s operating profit. Profit was generated through the sale of copper cathodes and costs were incurred through the consumption of electrical power and fresh sulphuric acid. Control actions also incurred costs associated with equipment wear. Furthermore, operating costs were incurred for a shortage in sulphuric acid in the leaching acid product stream. Simulations introduced disturbances in the concentrations of the fresh electrolyte copper, sulfuric acid, ferric, and ferrous ions, as well as in circuit current losses. Variations in leaching acid flow rate and concentration demands were also simulated as disturbances. A one-sided Wilcoxon signed-rank test compared operating profits across 30 simulations with unique disturbances, yielding p-values well below the Bonferroni corrected significance level. This result indicates significant profit gains with more advanced control strategies. The scientific contribution of this work lies in advancing the limited literature on copper electrowinning process control. Additionally, the developed model of the generic electrowinning circuit provides a versatile platform for gaining process insight, training plant personnel and for enabling further research into different control strategies. Design parameters are readily configurable which enables adaption to site-specific conditions, making this work valuable to both academia and the metal processing industry. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2025-06-09T08:53:48Z 2025-06-09T08:53:48Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132458 en Stellenbosch University 270 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Copper -- Electrometallurgy Composition operators Metallurgical plants -- Economic aspects Hydrometallurgy UCTD Roos, Vincent Economic performance assessment of control in direct copper electrowinning operations |
| title | Economic performance assessment of control in direct copper electrowinning operations |
| title_full | Economic performance assessment of control in direct copper electrowinning operations |
| title_fullStr | Economic performance assessment of control in direct copper electrowinning operations |
| title_full_unstemmed | Economic performance assessment of control in direct copper electrowinning operations |
| title_short | Economic performance assessment of control in direct copper electrowinning operations |
| title_sort | economic performance assessment of control in direct copper electrowinning operations |
| topic | Copper -- Electrometallurgy Composition operators Metallurgical plants -- Economic aspects Hydrometallurgy UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132458 |
| work_keys_str_mv | AT roosvincent economicperformanceassessmentofcontrolindirectcopperelectrowinningoperations |