Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants
Includes abstract.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Centre for Bioprocess Engineering Research
2014
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613335153803264 |
|---|---|
| access_status_str | Open Access |
| author | Kriek, R J |
| author2 | Gaylard, Peter |
| author_browse | Gaylard, Peter Kriek, R J |
| author_facet | Gaylard, Peter Kriek, R J |
| author_sort | Kriek, R J |
| collection | Thesis |
| description | Includes abstract. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/5611 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:34:28.941Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Centre for Bioprocess Engineering Research |
| publisherStr | Centre for Bioprocess Engineering Research |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/5611 Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants Kriek, R J Gaylard, Peter Nicol, Mike Nikoloski, Aleks leaching platinum palladium rhodium PGM (Platinum Group Metal) catalytic converter/autocatalyst thermodynamics electrochemistry Includes abstract. Includes bibliographical references (leaves 74-79). Historically the platinum group metals (PGMs) have been, and are still being dissolved by means of rather aggressive methods, e.g. aqua regia. Limited research has been conducted into the dissolution of the PGMs using different oxidizing agents. The dissolution of gold on the other hand has been afforded extensive research, and numerous papers and review articles have been published on the subject. The last number of years has seen the biggest application by volume of the PGMs as part of autocatalysts towards the degradation of harmful motor vehicle exhaust gases. This has subsequently sparked research into the recovery of specifically platinum, palladium, and rhodium from spent autocatalysts. Currently pyrometallurgical recovery of PGMs is being employed predominantly. A hydrometallurgical process on the other hand is, based on current technology, still a rather aggressive process that makes for high maintenance costs and an unpleasant environment. Gold has traditionally been dissolved by making use of cyanide, which is still the major route for gold dissolution. Due to environmental concerns lixiviants such as thiosulphate (S2O3 2-), thiourea (H2NCSNH2), and thiocyanate (SCN-) are gaining acceptance due to them being more environmentally friendly and giving good recoveries. These ‘softer’ alternatives have however not been tested on the PGMs. It is therefore the aim of this study to obtain an improved understanding of the leaching of the PGMs using lixiviants less aggressive than aqua-regia. These lixiviants include (i) SCN-, (ii) S2O3 2-, (iii) H2NCSNH2, and (iv) AlCl3/HCl. A thermodynamic study highlighted the fact that thermodynamic data for platinum-, palladium- and rhodium complexes are basically non-existent. To therefore obtain a clearer thermodynamic understanding of the leaching of the platinum group metals by means of these alternative lixiviants, future detailed speciation and thermodynamic investigations need to be conducted. An exploratory electrochemical investigation focusing on open circuit potentials and potentiodynamic scans, showed AlCl3 / HCl / NaOCl to be a good candidate for the leaching of the platinum group metals followed by SCN- / Fe3+ and CS(NH2)2 / Fe3+. Actual leach results, employing virgin autocatalysts as sample material, again highlighted the potential of AlCl3 / HCl / NaOCl as being a good lixiviant system. The surprise package, however, has been SCN- / Fe3+ that rendered very good results for Pd and Pt. 2014-07-31T11:40:34Z 2014-07-31T11:40:34Z 2008 Master Thesis Masters MSc http://hdl.handle.net/11427/5611 eng application/pdf Centre for Bioprocess Engineering Research Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | leaching platinum palladium rhodium PGM (Platinum Group Metal) catalytic converter/autocatalyst thermodynamics electrochemistry Kriek, R J Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants |
| thesis_degree_str | Master's |
| title | Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants |
| title_full | Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants |
| title_fullStr | Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants |
| title_full_unstemmed | Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants |
| title_short | Leaching of selected PGMs : a thermodynamic and electrochemical study employing less aggressive lixiviants |
| title_sort | leaching of selected pgms a thermodynamic and electrochemical study employing less aggressive lixiviants |
| topic | leaching platinum palladium rhodium PGM (Platinum Group Metal) catalytic converter/autocatalyst thermodynamics electrochemistry |
| url | http://hdl.handle.net/11427/5611 |
| work_keys_str_mv | AT kriekrj leachingofselectedpgmsathermodynamicandelectrochemicalstudyemployinglessaggressivelixiviants |