Professor Yongjun Peng

Professor

School of Chemical Engineering
Faculty of Engineering, Architecture and Information Technology
yongjun.peng@uq.edu.au
+61 7 336 57156

Overview

Yongjun Peng is a Professor at University of Queensland with a joint appointment between the School of Chemical Engineering and JKMRC to enhance the excellence of research and teaching in metallurgy. 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 gangue 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 mining industry today. His research is supported by the Australia Research Council, the Australian Coal Industry’s Research Program and the mining industry.

New technologies developed

Depressing hydrophobic gangue minerals in the flotation of sulphide ores. 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. Flotation tests using chalcopyrite and organic carbon show that the 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. 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.

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. 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. This technology is commercialized by interchem.

Research Interests

  • 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.
  • 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.
  • 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.
  • Particle and Reagent Interactions in Saline Water and Water with Cyanide Species
    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.

Qualifications

  • Doctor of Philosophy, S.Aust.

Publications

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Supervision

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Available Projects

  • Candidates should have a Master's or honours degree from Chemical Engineering, Metallurgy Engineering or a relevant discipline.

  • Candidates should have a Master's or honours degree from Chemical Engineering, Metallurgy Engineering or a relevant discipline.

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Publications

Journal Article

Conference Publication

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Master Philosophy — Principal Advisor

    Other advisors:

  • Master Philosophy — Associate Advisor

  • Doctor Philosophy — Associate Advisor

    Other advisors:

  • Doctor Philosophy — Associate Advisor

    Other advisors:

Completed Supervision

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.

  • Candidates should have a Master's or honours degree from Chemical Engineering, Metallurgy Engineering or a relevant discipline.

  • Candidates should have a Master's or honours degree from Chemical Engineering, Metallurgy Engineering or a relevant discipline.