
Overview
Background
Yongjun Peng is a Professor at School of Chemical Engineering, The University of Queensland. He obtained his PhD under the supervision of Profs Stephen Grano, John Ralston and Daniel Fornasiero from the Ian Wark Research Institute of the University of South Australia in 2002. This study was part of a large international project, AMIRA P260C regarding grinding and flotation chemistry in fine particle flotation with application of complementary solution and surface analytical techniques. He studied the galvanic interactions between grinding media and base metal sulphide minerals, mineral oxidation and dissolution, the activation of iron sulphide minerals, and surface contamination in improving mineral flotation. He was the 1st researcher developing the well-known Magotteaux Mill which allows the control of chemical reactions during grinding. His research work also guides the industry to use high chromium media in primary grinding mills and inert grinding media in regrinding mills to minimize the negative effect of galvanic interactions.
From 2002 to 2006, Yongjun Peng worked at the COREM Research Centre in Canada which is supported by the Canadian government and eleven international member mining companies. During his time there, he developed technologies for member mining companies to improve base metal, gold and niobium flotation. He was awarded an expert certificate for five years in Canada by the Quebec government, and also awarded NSERC (Natural Sciences and Engineering Research Council of Canada)-Industry Research Fellowship. From 2006 to 2009, Yongjun Peng worked at BHP Billiton Perth Technology Centre in Australia as a Senior Metallurgist/Engineer responsible for fine nickel flotation in saline water, gold and uranium processing. He won a major BHP Billiton internal prize in 2008.
Yongjun Peng’s current research at the University of Queensland focuses on froth flotation and the underlying solution chemistry, colloid/surface chemistry and electrochemistry. In addition to solving problems for individual companies, the underlying theme is the particle interaction taking place during the processing of low quality and complex energy and mineral resources with low quality water to address key challenges that face the resource industry today. His research is supported by the Australia Research Council, the Australian Coal Industry’s Research Program (ACARP) and the resource industry. In 2022, he was awarded the ACARP Research Excellent Award recognising research and leadership excellence through long term commitment and impact.
New technologies developed
Depressing hydrophobic gangue minerals in the flotation of sulphide ores. Traditional prefloat to float and remove hydrophobic gangue minerals also floats and removes sulphide minerals due to the collectorless flotation of sulphide minerals upon surface oxidation. This technology introduces a prefloat cleaner stage where sulphide minerals recovered to the prefloat concentrate are depressed and separated from other hydrophobic gangue minerals at a low pulp potential using innovative reducing agents which do not affect the natural floatability of sulphide minerals. The prefloat cleaner tailings are then fed back to the main sulphide flotation circuit. Traditional reducing agents applied in prefloat require high consumptions and also interfere with the downstream flotation. Flotation tests using chalcopyrite and organic carbon show that the new approach can reduce the loss of chalcopyrite in the prefloat by over 40% without affecting the rejection of naturally hydrophobic gangue. This technology is commercialized by ALS.
GoldRecover. This technology improves the gold flotation recovery from comminution circuit and flotation circuit in gold processing operations using innovative chemicals to remove iron contamination from gold surfaces. Iron contamination prevents the adsorption of collectors on mineral surfaces. Based on a copper-gold ore, this technology achieved a gold recovery up to 30% and a copper recovery up to 12% higher than the base line. Based on a pyrite-gold ore, this technology achieved a gold recovery up to 10% higher than the base line. This technology is commercialized by Kinetic Group Worldwide.
Counteracting the adverse effect of cyanide in flotation. Cyanide added to depress gangue minerals or existing in process water can depress the flotation of sulphide and precious minerals. Cyanide can also complex with metal ions and form metal cyanide which can depress or activate mineral flotation depending on the pulp chemistry. The new technology involves the modification of pulp chemistry to make metal cyanide activate sulphide and precious minerals in flotation. This technology has been applied in the sponsor’s flotation plant to improve gold and silver recoveries since 2012.
Regrinding-flotation pre-treatment prior to CIL leaching. This technology has been applied in the sponsor’s plant to improve copper and gold recoveries while reducing cyanide consumption since 2012.
New sulphidisation to improve the flotation of oxidized minerals. Traditional sulphidisation suffers from drawbacks such as low efficiency, low pulp potential with a high reagent consumption and difficulty to sulphidise some minerals. The new sulphidisation we developed from the ARC Linkage Project LP160100619 supported by Newmont and Newcrest is conducted at higher pulp potential. Based on a stockpile copper ore, the new sulphidisation improves the copper recovery from 76% (base line) to 93% with even higher copper grade. Based on a stockpile pyritic ore containing gold, the new sulphidisation improves the recovery of total S from 48% (base line) to 68% and the recovery of sulphide S from 84% (base line) to 92%.
De-aerating froth products (patented technologies). Persistent froth in flotation concentrates presents operational challenges in downstream processing such as pumping in sumps and dewatering in filters and thickeners. In sumps where flotation concentrates are pumped to the dewatering process, the liquid level sensors often fail to detect the persistent froth which may lead to flooding of the processing area or even the entire plant. In dewatering to separate the solids in the concentrate from water, persistent froth significantly reduces both thickening and filtration efficiencies. The accumulated persistent froth floating on top of thickeners can also limit the capacity of the plant. Two types of physical froth de-aerators have been developed, one based on physical forces and another based on pressure changes. The de-aerator using physical forces is suitable for destabilising froth in sumps and filters, while the de-aerator using pressure changes is suitable for destabilising froth in thickeners. These technologies are commercialized by DADI (AUSTRALIA) Engineering Company.
Rapid measurement of coal oxidation (patented technology). This technology can be used in the plant to determine the degree of coal oxidation in natural environments within 5 minutes. The solvens used are environmentally friendly. Based on the degree of coal oxidation, a ratio of non-polar collector to polar collector can be determined to maximise the coal flotation while minimizing reagent consumptions. At one coal preparation plant this technology demonstrates an improvement of 5%-26% increase in the recovery of coal (based on applying optimised ratios of oily and polar collectors for the measured degree of coal oxidation).This technology is commercialized by interchem.
Apparatus and method for emulsifying oily collectors for use in flotation (patented technology). Oily collectors are widely used in the flotation of various commodities. Due to their low solubility in water, a large amount of oily collectors has to be used with a long conditioning time. A number of studies has demonstrated that chemical emulsifiers can significantly improve the efficiency of oily collectors by reducing their droplets. However, the application of chemical emulsifiers in flotation plants is limited due to their strong frothing abilities which can cause various problems. We have developed apparatus to physically emulsify oily collectors to droplets with a size ranging from 12.2 µm to 0.7 µm and found that the flotation performance increases with the decrease of droplet size until an optimal droplet size. Droplets smaller than the optimal size is not beneficial to flotation. The apparatus has a low equipment cost and low maintenance. Based on the test work on five different coal samples from 3 Australian coal preparation plants, the emulsified diesel could increase the yield by 2.5 to 15.3% at the same product ash content while reducing the diesel consumption by 97,412 L to 304,941 L per annum. This technology is commercialized by DADI (AUSTRALIA) Engineering Company.
Availability
- Professor Yongjun Peng is:
- Available for supervision
Fields of research
Qualifications
- Doctor of Philosophy, University of South Australia
Research interests
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Particle and Reagent Interactions in Low Quality and Saline Water
This work not only identifies the different particle interactions in saline water, but also addresses the different behaviour of flotation reagents (collector, frother, polymeric dispersant and flocculant) in saline water. Novel reagents have been developed to be used in saline water to mitigate slime coating, gangue entrapment and overly stable froth. Yongjun Peng is also working on cyanide chemistry and the interaction of free cyanide and WAD cyanide in recycle water with base metal sulphide and precious minerals. New technologies have been developed to counter the depression of cyanide species in process water on the flotation of pyritic gold. Cyanide speciation is also manipulated to enhance the depression or activation. In addition, his group discovers that the low dissolved oxygen content and the low electrochemical potential in saline water promote copper activation on pyrite, leading to a low grade of copper flotation concentrates. Based on this finding, a radical chain reaction involving the redox cycling of Cu(I/II) induced by sulphite has been developed to de-activate copper activation in saline water.
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Ultra-fine Particle Flotation
Yongjun Peng has been working on oxidation and dissolution of fine sulphide minerals and how these alter surface characteristics and affinity to other gangue minerals and colloids governing the bubble-particle attachment efficiency. He has also worked on strategies to control the oxidation of fine particles and their interactions with other gangue minerals and colloids in improving ultra-fine particle flotation. He has developed a simple chemical process to clean the surface contamination to improve copper and gold flotation. Presently, he starts a new research program to improve fine particle flotation by engineering the surface properties, and develops simple tools to measure surface oxidation in plants.
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Gangue Chemistry
This work explores slime coating of fine gangue minerals, the entrainment of normal gangue minerals through the water films of gas bubbles and the entrapment of anisotropic gangue minerals through network structures in flotation. Yongjun Peng’s research addresses how slimes coat mineral surfaces and how anisotropic minerals form network structures under flotation context and then affect pulp rheology and subsequent mineral flotation and gangue entrapment. He also works on strategies to mitigate slime coating and reduce particle entrainment and entrapment by modifying particle interactions and network structures through polymers and inorganic salts. Simple tools have been developed to characterize clay minerals.
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Regrinding Chemistry
Yongjun Peng’s research addresses regrinding chemistry to identify how particle breakage mechanisms in tumbling mills and stirred mills affect pulp and surface chemistry and the redistribution of surface oxidation species, activation species and flotation reagents in improving mineral flotation and separation. He have developed a new regrinding-flotation process to improve copper and gold recoveries prior to CIL while reducing reagent consumption in flotation and cyanidation. Presently, his research focuses on mitigation of negative effects of pulp chemistry after fine regrinding on the adsorption of collectors on value minerals and the activation on gangue minerals.
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Green Flotation Chemistry
The research aims to overcome the drawbacks of natural products when applied in industry, i.e., low solubility and low selectivity, by designing modified macromolecules and understanding the role of their structure features in mineral flotation. His group has successfully modified lignosulphonates and wheat starches to produce macromolecules which vary in molecular weight distribution and functional group content. The group discovered that a chelating type bond centred on mineral surfaces determines the adsorption of modified polymers and the conformation of supramolecular and molecular structures of the polymers are more influential than functional groups for depressing minerals. At the same time, his group had an initiative to develop a new type of green collector for gold flotation based on Eucalyptus oils extracted from Eucalyptus to replace toxic collectors used in gold flotation. The group found that the collecting power of Eucalyptus oils is correlated to the percentage of non-polar and weakly polar constituents which possess strong selectivity for free gold.
Works
Search Professor Yongjun Peng’s works on UQ eSpace
2011
Conference Publication
Mechanisms for the improved flotation of ultrfine pentlandite and its separation from serpentine in saline water
Peng, Yongjun and Bradshaw, Dee J. (2011). Mechanisms for the improved flotation of ultrfine pentlandite and its separation from serpentine in saline water. Flotation '11, Cape Town, South Africa, 14-17 November 2011.
2010
Journal Article
Effect of iron contamination from grinding media on the flotation of sulphide minerals of different particle size
Peng, Yongjun and Grano, Stephen (2010). Effect of iron contamination from grinding media on the flotation of sulphide minerals of different particle size. International Journal of Mineral Processing, 97 (1-4), 1-6. doi: 10.1016/j.minpro.2010.07.003
2010
Journal Article
Reducing quartz gangue entrainment in sulphide ore flotation by high molecular weight polyethylene oxide
Gong, J., Peng, Y., Bouajila, A., Ourriban, M., Yeung, A. and Liu, Q. (2010). Reducing quartz gangue entrainment in sulphide ore flotation by high molecular weight polyethylene oxide. International Journal of Mineral Processing, 97 (1-4), 45-51. doi: 10.1016/j.minpro.2010.07.009
2010
Journal Article
Inferring the distribution of iron oxidation species on mineral surfaces during grinding of base metal sulphides
Peng, Yongjun and Grano, Stephen (2010). Inferring the distribution of iron oxidation species on mineral surfaces during grinding of base metal sulphides. Electrochimica Acta, 55 (19), 5470-5477. doi: 10.1016/j.electacta.2010.04.097
2010
Journal Article
Dissolution of fine and intermediate sized galena particles and their interactions with iron hydroxide colloids
Peng, Y.J. and Grano, S. (2010). Dissolution of fine and intermediate sized galena particles and their interactions with iron hydroxide colloids. Journal of Colloid and Interface Science, 347 (1), 127-131. doi: 10.1016/j.jcis.2010.03.027
2010
Journal Article
Effect of grinding media on the activation of pyrite flotation
Peng, Yongjun and Grano, Stephen (2010). Effect of grinding media on the activation of pyrite flotation. Minerals Engineering, 23 (8), 600-605. doi: 10.1016/j.mineng.2010.02.003
2010
Conference Publication
Understanding the roles of polyethylene oxide and xanthate in reducing quartz gangue entrainment in sulfide ore flotation
Ourriban, Mohamed, Liu, Weikang, Liu, Qi, Gong, Jihua, Peng, Yongjun and Bouajila, Ahmed (2010). Understanding the roles of polyethylene oxide and xanthate in reducing quartz gangue entrainment in sulfide ore flotation. 49th Annual Conference of Metallurgists (COM 2010), Vancouver, BC, Canada, 3-6 October 2010. Montréal, QC, Canada: Canadian Institute of Mining, Metallurgy and Petroleum.
2008
Conference Publication
The effect of polyethylene oxide (PEO) on reducing the mechanical entrainment of fine quartz gangue during sulphide ore flotation
Gong, J., Yeung, A., Liu, Q., Bouajila, A., Ourriban, M., Jang, H. and Peng, Y. (2008). The effect of polyethylene oxide (PEO) on reducing the mechanical entrainment of fine quartz gangue during sulphide ore flotation. XXIV International Mineral Processing Congress (IMPC 2008), Beijing, China, 24-28 September 2008. Beijing, China: Science Press.
2006
Journal Article
Exploiting the dual functions of polymer depressants in fine particle flotation
Liu, Q, Wannas, D and Peng, Y (2006). Exploiting the dual functions of polymer depressants in fine particle flotation. International Journal of Mineral Processing, 80 (2-4), 244-254. doi: 10.1016/j.minpro.2006.05.004
2006
Conference Publication
Reduction of fine quartz entrainment in sulfide flotation by polymer depressants
Girard, J., Jang, H., Liu, Q., Ourriban, M., Pelletier, P. and Peng, Y. (2006). Reduction of fine quartz entrainment in sulfide flotation by polymer depressants. XXIII International Mineral Processing Congress (IMPC 2006), Istanbul, Turkey, 3-8 September 2006. Istanbul, Turkey: Promed Advertising.
2006
Conference Publication
Roles of metal oxidation species in the flotation of fine sulfide minerals
Ourriban, M. and Peng, Y. (2006). Roles of metal oxidation species in the flotation of fine sulfide minerals. COM2006 Sixth UBC-McGill-University of Alberta Biennial Symposium on Interfacial Phenomena in Fine Particle Technology, Montréal, Canada, 1-4 October 2006. Montréal, Canada: Canadian Institute of Mining, Metallurgy and Petroleum.
2006
Conference Publication
Some approaches in improved fine particle flotation and separation
Cotnoir, D., Liu, Q., Ourriban, M. and Peng, Y. (2006). Some approaches in improved fine particle flotation and separation. 38th Canadian Mineral Processors Operators Conference, Ottawa, Canada, 17-19 January 2006.
2005
Conference Publication
Some solutions to the problems in fine particle flotation
Cotnoir, D., Liu, Q., Ourriban, M., Peng, P. and Richard, D. (2005). Some solutions to the problems in fine particle flotation. Centenary of Flotation Symposium, Brisbane, QLD, Australia, 6-9 June 2005. Carlton, VIC, Australia: Australasian Institute of Mining and Metallurgy.
2005
Conference Publication
Reduction of mechanical entrainment by polymer depressants
Liu, Q., Peng, Y. and Wannas, D (2005). Reduction of mechanical entrainment by polymer depressants. Centenary of Flotation Symposium, Brisbane Australia, 6-9 June 2005. Victoria, Australia: Australasian Institute of Mining and Metallurgy.
2003
Journal Article
Control of grinding conditions in the flotation of galena and its separation from pyrite
Peng, YJ, Grano, S, Fornasiero, D and Ralston, J (2003). Control of grinding conditions in the flotation of galena and its separation from pyrite. International Journal of Mineral Processing, 70 (1-4), 67-82. doi: 10.1016/S0301-7516(02)00153-9
2003
Journal Article
Control of grinding conditions in the flotation of chalcopyrite and its separation from pyrite
Peng, YJ, Grano, S, Fornasiero, D and Ralston, J (2003). Control of grinding conditions in the flotation of chalcopyrite and its separation from pyrite. International Journal of Mineral Processing, 69 (1-4), 87-100. doi: 10.1016/S0301-7516(02)00119-9
2002
Journal Article
Towards prediction of oxidation during grinding I. Galena flotation
Peng, Y, Grano, S, Ralston, J and Fornasiero, D (2002). Towards prediction of oxidation during grinding I. Galena flotation. Minerals Engineering, 15 (7), 493-498. doi: 10.1016/S0892-6875(02)00062-6
1999
Journal Article
The development of a composite collector for the flotation of rutile
Liu, Qi and Peng, Yongjun (1999). The development of a composite collector for the flotation of rutile. Minerals Engineering, 12 (12), 1419-1430.
Funding
Current funding
Past funding
Supervision
Availability
- Professor Yongjun Peng is:
- Available for supervision
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Available projects
Supervision history
Current supervision
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Doctor Philosophy
The Flotation Behaviour of Minerals in the Reflux Flotation Cell
Principal Advisor
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Doctor Philosophy
Understanding the stability of micro-nanobubbles induced by flocculants
Principal Advisor
Other advisors: Dr Liang Cao
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Doctor Philosophy
The Flotation Behaviour of Minerals in the Reflux Flotation Cell
Principal Advisor
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Doctor Philosophy
1197 - Jiarui Chen - Flotation of minerals in Reflux Flotation Cell
Principal Advisor
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Doctor Philosophy
Depressing pyrite in copper flotation in the presence of a high concentration of pyrite
Principal Advisor
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Doctor Philosophy
The effect of saline water on chalcopyrite flotation behaviours.
Principal Advisor
Other advisors: Dr Liang Cao
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Doctor Philosophy
Modifying the interfacial properties of coal, mineral and bitumen froths
Principal Advisor
Other advisors: Dr Liang Cao
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Doctor Philosophy
Selective Surface Oxidation in Differential Particle Separation
Principal Advisor
Other advisors: Professor Mingxing Zhang
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Doctor Philosophy
Depressing pyrrhotite in copper-gold flotation
Principal Advisor
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Doctor Philosophy
The deportment and surface properties of pyrrhotite superstructures in copper-gold flotation
Principal Advisor
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Doctor Philosophy
The effect of saline water on chalcopyrite flotation behaviour
Principal Advisor
Other advisors: Dr Liang Cao
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Doctor Philosophy
Interactions of inorganic components in process water with gold
Associate Advisor
Other advisors: Associate Professor James Vaughan
Completed supervision
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2025
Doctor Philosophy
The Flotation Behaviour of Minerals in the Reflux Flotation Cell
Principal Advisor
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2024
Doctor Philosophy
Depressing pyrite in copper flotation in the presence of a high concentration of pyrite
Principal Advisor
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2024
Master Philosophy
The Effect of Inorganic Species on Gold Flotation
Principal Advisor
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2022
Doctor Philosophy
The flotation of oxidised pyrite activated by lead ions in the absence and presence of cyanide species
Principal Advisor
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2021
Doctor Philosophy
The Interactions of Radioactive Lead with Copper Sulphide Minerals and the Consequences for its Recovery in Flotation
Principal Advisor
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2021
Doctor Philosophy
Improving the flotation of oxidised copper sulphide minerals
Principal Advisor
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2021
Doctor Philosophy
The emulsification of diesel and the hydrophobization of coal surfaces by frother surfactants
Principal Advisor
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2021
Master Philosophy
Diesel emulsification for coal flotation in saline water
Principal Advisor
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2020
Doctor Philosophy
Effects of particle interactions in coal froth on dewatering efficiency of fine coal flotation products
Principal Advisor
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2018
Doctor Philosophy
Slime Coating Mitigation on Mineral Surfaces in Froth Flotation by Saline Water
Principal Advisor
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2018
Doctor Philosophy
Improvement of oxidized coal flotation in fresh water and saline water
Principal Advisor
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2018
Doctor Philosophy
The galvanic interaction between gold and pyrite and its effect on the surface properties and dissolution of pyrite
Principal Advisor
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2017
Doctor Philosophy
Depression of Pyrite Flotation by Lignosulfonate Biopolymers
Principal Advisor
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2017
Doctor Philosophy
Entrainment of Fine Particles in Froth Flotation
Principal Advisor
Other advisors: Associate Professor Kym Runge
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2016
Doctor Philosophy
Mitigating the deleterious effect of clay minerals on copper flotation
Principal Advisor
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2016
Doctor Philosophy
The Effect of Polymers on the Treatment of Clay Minerals in Coal Flotation Using Saline Water
Principal Advisor
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2016
Doctor Philosophy
Interactions of clay minerals and their effects on copper-gold flotation
Principal Advisor
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2016
Doctor Philosophy
The effect of free cyanide and weak acid dissociable cyanide on minerals flotation
Principal Advisor
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2015
Doctor Philosophy
The Effect of Regrinding Chemistry and Particle Breakage Mechanisms on Subsequent Cleaner Flotation
Principal Advisor
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2014
Master Philosophy
Development of a regrind-flotation pre-treatment methodology for the carbon-in-leach circuit of a copper-gold processing plant
Principal Advisor
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2014
Master Philosophy
Production of a Low Arsenic Copper Concentrate from a VMS Ore
Principal Advisor
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2014
Doctor Philosophy
The Behaviour of Clay Minerals in Coal Flotation Using Saline Water
Principal Advisor
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2014
Master Philosophy
The Interaction of Clay Dispersants and Grinding Chemistry in Copper-Gold Flotation
Principal Advisor
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2014
Master Philosophy
Understanding Froth Stability in Coal Flotation Using Saline Water
Principal Advisor
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2021
Master Philosophy
LIBERATION OF DIFFERENT PYRITE TYPES IN REFRACTORY GOLD ORES
Associate Advisor
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2013
Doctor Philosophy
A Quantitative Risk-Based Approach for Improving Water Quality Management in the Minerals Industry: Flotation as an Example
Associate Advisor
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