Fang Xia

PhD Candidate

B.E. & Master (East China University of Science and Technology)

Location: Room A210 Engineering Annex & Science Center, SA Museum
Email: fang.xia@adelaide.edu.au
Phone: + 61 8 8207 7448
Fax: + 61 8 8207 7222

Supervisors

Dr Yung Ngothai, School of Chemical Engineering
A/Prof Brian O'Neill, School of Chemical Engineering
Prof Allan Pring, South Australian Museum
Prof Guorong Chen, East China University of Science and Technology

Research Topic

Mineral replacement reactions: understanding mineral formation under hydrothermal conditions

Research Abstract:

The principal theme of this project is to understand the processes occurring at the dissolution and the reprecipitation fronts and their role in controlling mineral replacement reactions. The approach is experimental, aiming to correlate reaction kinetics, textures and porosity with systematic variations in composition and texture of the starting material, temperature, fluid composition (salinity, PH, redox, concentrations of sulphur and metals) and fluid transport properties. The secondary aim of the project is to further develop flow-through reaction vessels to study hydrothermal reaction in situ by neutron diffraction in an OPAL reactor facility Wombat, the high intensity powder diffractometer. Two different model systems involving sulphide and framework aluminosilicate minerals will be chosen because of their direct relevance in understanding mineralization processes and ore processing, but also because they are well-suited to study the fundamental, molecular-scale processes involved in dissolution- reprecipitation reactions: (1) the replacement of pentlandite by violarite, and (2) the replacement of leucite by analcime.

Interests

• Hydrothermal mineral reactions
• Thermodynamic modeling
• Reaction mechanism and kinetics
• Neutron scattering

Recent Publications

• F. Xia, J. Zhou, J. Brugger, Y. Ngothai, B. O'Neill, G. R. Chen and A. Pring. 2008. Novel route to synthesize complex metal sulfides: Hydrothermal coupled dissolution-reprecipitation replacement reactions. Chemistry of Materials 20, 2809-2817.
• F. Xia, J. Zhou, A. Pring, Y. Ngothai, B. O'Neill, J. Brugger, G. Chen and C. Colby. 2007. The role of pyrrhotite (Fe7S8) and the sample texture in the hydrothermal transformation of pentlandite ((Fe,Ni)9S8) to violarite ((Ni,Fe)3S4). Reaction Kinetics and Catalysis Letters 92, 257-266.
• F. Xia, G. Chen, A. Pring, J. Brugger, Y. Ngothai, B. O'Neill, C. Colby, C. Tenailleau, H. Wang and Y. Yang. 2007. Kinetics and mechanism of hydrothermal alteration from pentlandite to violarite. Acta Geologica Sinica 81, 1378-1390.
• F. Xia, A. Pring, Y. Ngothai, B. O'Neill, J. Brugger, G. Chen and C. Colby. 2007. The catalytic role of pyrrhotite in hydrothermal alteration of pentlandite to violarite. Chemeca 2007, 23-26th September, Melbourne, Australia.
• F. Xia, A. Pring, Y. Ngothai, B. O'Neill, J. Brugger, G. Chen and C. Colby. 2007. Hydrothermal synthesis of FeNi2S4, a thiospinel. Chemeca 2007, 23-26th September, Melbourne, Australia.
• F. Xia, A. Pring, Y. Ngothai, B. O'Neill, J. Brugger, G. Chen and C. Colby. 2007. The kinetics of pentlandite oxidation in the temperature range 530-600ºC. Chemeca 2007, 23-26th September, Melbourne, Australia.
• F. Xia, A. Pring, Y. Ngothai, B. O'Neill, J. Brugger, G. Chen and C. Colby. 2007. The mechanism of pentlandite oxidation in the temperature range 530-600ºC. Chemeca 2007, 23-26th September, Melbourne, Australia.
• J. Brugger, F. Xia and A. Pring. 2008. Mineral synthesis using the coupled dissolution-reprecipitation route. Geochimica et Cosmochimica Acta 71, A118-A118.
• H. Wang, A. Pring, F. Wu, G. Chen, J. Jiang, F. Xia, J. Zhang, Y. Ngothai and B. O'Neill. 2006. Effect of cation vacancy and crystal superstructure on thermodynamics of iron monosulfides. Journal of Sulfur Chemistry 27, 1-12.