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Browsing by Author "Petersen, Jochen"

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Ammonia leaching as a pre-treatment for the processing of oxidised PGM ores

Author: Musonda, Kabwe Julianna Date: 2015 The exploitation of near-surface deposits has resulted in the need to adjust current conventional mineral processing technologies for the treatment of low grade oxidised PGM ores. The exposure of the ore to the atmosphere leads to the formation ... Read more
Ammonium hexachlororuthenate precipitation

Author: De Klerk, Frederick Jacobus Date: 2011 Ammonium hexachlororuthenate (ACR) is a salt precipitated during a substitution reaction between ammonium and ruthenate dissolved in a strong hydrochloric acid medium. This precipitation reaction is used within the platinum industry as a means ... Read more
The anodic dissolution of covellite in acidic, chloride solutions

Author: Basson, Petrus Date: 2010 An electrochemical study was conducted on a stationary, synthetically produced, covellite electrode in acidic, chloride solutions at ambient conditions to investigate the dissolution behaviour of the mineral over a surface potential range ... Read more
Application of HPGR and X-Ray CT to investigate the potential of Witwatersrand gold ore for heap leaching : a process mineralogy approach

Author: Nwaila, Glen Date: 2014 Auriferous conglomerates of the Archaean Witwatersrand Basin in South Africa host one of the largest known gold resources and rate as the worldâ€™s most outstanding example of a fossil megaplacer deposit. For the past 40 years, Witwatersrand ... Read more
Assessment of a Shredding Technology of Waste Printed Circuit Boards in preparation for Ammonia-based Copper leaching

Author: Prestele, Marc Patrick Date: 2020 The electronic waste (e-waste) stream grows at a global annual rate of 3-5%, with an expected 50 Mt to be discarded worldwide in 2020 alone. These large amounts of e-waste pose considerable environmental and health problems while also presenting ... Read more
Assessment of the potential carbon footprint of engineered processes for the mineral carbonation of PGM tailings

Author: Ncongwane, Mpendulo S Date: 2016 Mineral carbonation is a carbon sequestration technology that entails the reaction of CO2 with oxides or silicates of magnesium, calcium or iron to produce stable carbonate compounds. Magnesium-rich tailings from the platinum industry in South ... Read more
Base metal heap and tank leaching of a platreef flotation concentrate using ammoniacal solutions

Author: Muzawazi, Caroline Date: 2013 The technical feasibility of the ammonia leaching process of a Platreef flotation concentrate was investigated in different reactor settings i.e. shake flasks, columns and batch stirred tank reactors, respectively. The process investigated ... Read more
Biooxidation kinetics of Leptospirillum Ferriphilum attached to a defined solid substrate

Author: Duku, Porogo Date: 2011 Bioleaching can be categorized as being either stirred tank type (i.e. bio-oxidation) or irrigation type (i.e. heap/dump bioleaching) yet studies investigating the kinetics of bioleaching systems mostly use empirical data determined from ... Read more
Characterisation of the effect of alteration on the PPM platinum ore and evaluation of selected strategies to improve metallurgical performance

Author: Ramonotsi, Mpho Date: 2011 The aim of this study is in two parts; the first part focuses on mineralogical quantification of the extent of weathering at PPM by profiling the flotation behaviour and host rock density with spatial depth. Read more
Competitive Bioleaching of Pyrite and Chalcopyrite

Author: Petersen, Jochen ; Dixon, David G Date: 2006 An experimental study was conducted to investigate the heap bioleaching of a copper-gold concentrate using the Geocoat™ technique. Small-scale columns were operated at selected temperatures using bacterial consortia suited to these temperatures. ... Read more
Conventional and electrochemical bioleaching of chalcopyrite concentrates by moderately thermophilic bacteria at high pulp density

Author: Ahmadi, Ali ; Schaffi, Mahine ; Petersen, Jochen ; Schippers, Axel ; Ranjbar, Mohammad Date: 2011 Conventional and electrochemical bioleaching were investigated to extract copper from Sarcheshmeh chalcopyrite concentrate at high pulp densities. Experiments were conducted in the presence and absence of a mixed culture of moderately ... Read more
The development of an online amperometric technique to measure free and WAD cyanide in gold plant leach liquors and effluent streams

Author: Van der Merwe, Wendy A M Date: 2012 In 2004, Mintek recognised the gold mining industry‘s need for an online free and WAD cyanide measurement device and went about extending the existing free cyanide analyser,the Cynoprobe to include WAD cyanide measurement. The WAD cyanide ... Read more
The effect of carbon dioxide on the growth and activity of leptospirillum ferriphilum

Author: Naik, Linus Date: 2010 Microbial oxidation rates catalysed by the acidophilic micro-organisms mediating mesophilic and thermophilic bioleaching of mineral sulphides have been well characterised under conditions typical of active tank leaching processes in the mineral ... Read more
The effect of dissolved cations on microbial ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture

Author: Ojumu, Tunde V ; Petersen, Jochen ; Hansford, Geoffrey S Date: 2008 In heap bioleaching the dissolution of gangue minerals from igneous ore materials can lead to the build-up of considerable concentrations of Mg and Al sulphates in the recycled leach solution. This may interfere with microbial ferrous iron ... Read more
Effect of HPGR on platinum bearing ores and the flotation response as compared to the conventional ball mill

Author: Solomon, Nomonde Date: 2011 This thesis focuses on the application of the high pressure grinding rolls (HPGR) on platinum bearing ores Merensky, UG2 and Platreef. Conventional tumbling mills such as the ball mill that are typically applied on these ore types are highly ... Read more
Effect of scale of operation on heap leaching performance

Author: Van Staden, Petrus Johannes Date: 2019 The extent to which differences in bulk density and in irrigation geometry contribute towards the differences observed in leaching performance between laboratory-scale columns versus commercial-scale heaps was investigated. Furthermore, the ... Read more
The effects of solution conditions on the kinetics of microbial ferrous-iron oxidation by Leptospirillum ferriphilum in continuous culture

Author: Ojumu, Tunde Victor Date: 2008 The objective of this work was to investigate the effects of a wide range of solution conditions,namely: temperature, pH, dissolved Al and Mg, and the effect of total iron concentration on the kinetics of microbial ferrous-iron oxidation by ... Read more
An electrochemical reduction process for the recovery of copper powder from a refinery effluent stream

Author: Bezuidenhout, Chandon Date: 2014 In recent years a significant amount of research has gone into the development of a feed pretreatment process for the concentrate refined at Anglo American Platinum's Precious Metals Refiners (PMR). Such a process has the potential to ... Read more
Electrorefining of base metal refinery residue copper alloy for platinum group metal recovery

Author: Kruyswijk, Lizelle Date: 2009 Secondary leach concentrate (SLC) is an important bleed stream for minor elements from Anglo Platinum’s Base Metal Refinery (BMR) which produces copper nickel and cobalt sulphate. It contains mainly sulphur, iron jarosites, unleached base ... Read more
Evaluating the effect of alternative neutralising agent and seeding on the zinc recovery through the Zincor iron removal circuit

Author: Taggart, Diane Date: 2016 Zincor's average zinc recovery was 90.29 % (for the period of 1 January 2009 to 30 September 2011), which was well below the industry standard of 96 %. Due to limitations in Zincor's iron removal technology, the maximum achievable recovery ... Read more

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