Nickel constitutes the major impurity encountered during copper electrorefining (Cu ER) operations. Continuous nickel build-up in the electrolyte is controlled by withdrawing a fraction of solution from the tankhouse and separate nickel as crude NiSO4.2H2O via Evaporative Crystallisation . The energy required to evaporate water is high, increasing thus the operation costs; moreover, the product thus obtained is of poor quality in terms of purity and crystal size. / As part of an ongoing research project launched at McGill University, the Solvent Displacement Crystallisation (SDC) technique is investigated as an attractive alternative to the conventional method. SDC involves the addition of low-boiling point, watermiscible organic solvents (MOs) to aqueous solutions to cause salt precipitation based on the "salting out" effect. The crystals are separated by filtration whereas the solvent is subsequently recovered for reuse by low-temperature distillation. / The present work describes the successful application of SDC method to the precipitation of NiSO4.6H2O from Cu ER spent electrolytes. Tests have been performed on synthetic and industrial electrolytes (courtesy of Canadian Copper Refineries), using Isopropanol as precipitant. By maintaining a low supersaturation (i.e. controlled addition of the solvent to the electrolyte) and heterogeneous crystallisation conditions (use of seed/product recycling), crystal growth is favoured while impurity uptake/contamination is minimised.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.30262 |
| Date | January 1999 |
| Creators | Moldoveanu, Georgiana A. |
| Contributors | Demopoulos, George P. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Mining and Metallurgical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001746011, proquestno: MQ64238, Theses scanned by UMI/ProQuest. |
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