Researcher biography

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 the 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.