Fundamentals of the flotation behaviour of palladium bismuth tellurides

Show simple item record

dc.contributor.advisor Pistorius, Petrus Christiaan en
dc.contributor.postgraduate Vermaak, M.K.G. (Matthys Karel Gerhardus)
dc.date.accessioned 2013-09-07T14:04:00Z
dc.date.available 2005-10-13 en
dc.date.available 2013-09-07T14:04:00Z
dc.date.created 2005-05-08 en
dc.date.issued 2006-10-13 en
dc.date.submitted 2005-10-13 en
dc.description Thesis (PhD (Metallurgical Engineering))--University of Pretoria, 2006. en
dc.description.abstract Previous mineralogical investigations (QemSCAN) performed on all effluent flotation streams of Mimosa mine (Zimbabwe) indicated the presence of appreciable amounts of platinum group minerals (PGMs), which are not recovered. Most, generally in excess of 70%, of the liberated PGMs in these streams belonged to the Pt-Pd-Bi-Te class in all the samples investigated. In the first part of this work, electrochemical investigations, electrochemically-controlled contact angle measurements and Raman spectroscopy have been employed to investigate the interaction of ethyl xanthate with Pd-Bi-Te and PtAs2. Impedance measurements showed lower capacitance values in solutions containing KEX indicating the formation of a continuous surface layer. Anodic and cathodic polarization diagrams show the mixed potential to be higher than the reversible potential of the xanthate-dixanthogen equilibrium reaction, hence the formation of dixanthogen on the surface is possible. Electrochemically controlled in situ Raman spectroscopy has confirmed the co-presence of xanthate with dixanthogen indicating that xanthate retains its molecular integrity when it adsorbs on the surface of the Pd-Bi-Te. The result of this investigation has shown dixanthogen to be present on both the minerals (PtAs2 and Pd-Bi-Te) when the surfaces are anodically polarized. Chemisorbed xanthate could be identified within 120 seconds yielding a hydrophobic surface as indicated by electrochemically-controlled contact angle measurements. Maximum contact angles of 63o were measured in the case Pd-Bi-Te. As a result the mineral surface is expected to be hydrophobic and a lack of collector interaction with the mineral is not the reason for low PGM recoveries experienced. Secondly, the flotation recovery of synthetically prepared Pd-Bi-Te was compared with that of chalcopyrite (a typical fast-floating mineral) and pyrrhotite (a typical slow-floating mineral), with microflotation tests. These indicated Pd-Bi-Te to be a fast-floater with flotation rates exceeding that of chalcopyrite. Predicted flotation rate constants (from the Ralston model) were significantly lower for small particles (with diameters similar to those lost to the effluent streams) compared with those of particle with intermediate sizes. This supports the suggestion that losses to effluent streams are caused by particle size effects. en
dc.description.availability unrestricted en
dc.description.department Materials Science and Metallurgical Engineering en
dc.identifier.citation Vermaak, M 2005, Fundamentals of the flotation behaviour of palladium bismuth tellurides, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/28676 > en
dc.identifier.upetdurl http://upetd.up.ac.za/thesis/available/etd-10132005-105623/ en
dc.identifier.uri http://hdl.handle.net/2263/28676
dc.language.iso en
dc.publisher University of Pretoria en_ZA
dc.rights © 2005, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. en
dc.subject Great dyke and pd-bearing bismutho-tellurides en
dc.subject Precious metal ores en
dc.subject Pgm en
dc.subject Platinum flotation en
dc.subject Flotation kinetics en
dc.subject Microflotation en
dc.subject Particle size en
dc.subject Ore mineralogy en
dc.subject Froth flotation en
dc.subject UCTD en_US
dc.title Fundamentals of the flotation behaviour of palladium bismuth tellurides en
dc.type Thesis en


Files in this item

This item appears in the following Collection(s)

Show simple item record