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Qin W.,State Key Laboratory of Comprehensive Utilization of Low Grade Ores | Qin W.,Central South University | Wei Q.,State Key Laboratory of Comprehensive Utilization of Low Grade Ores | Jiao F.,State Key Laboratory of Comprehensive Utilization of Low Grade Ores | And 4 more authors.
International Journal of Mining Science and Technology | Year: 2013

The interaction mechanism between dextrin and minerals has been investigated through micro-flotation, adsorption density measurements, Fourier transform infrared ray (FTIR) spectroscopic studies and dissolution tests. Dextrin shows a good depressing action towards galena but not chalcopyrite. FTIR spectroscopic studies indicate that dextrin chemically adsorbed on galena surface in alkaline pH range. Dissolution tests confirm leaching action of metal ions from chalcopyrite and galena surfaces, and dextrin-lead ion interaction. Adsorption measurements present that the higher adsorption density of O-isopropyl-N-ethyl thionocarbamate (IPETC) onto chalcopyrite than that onto galena, and IPETC adsorbed on galena decrease with increasing dextrin concentrations in the presence of dextrin, attesting the flotation results. © 2013 Published by Elsevier B.V. on behalf of China University of Mining & Technology.

Wang P.-P.,Central South University | Qin W.-Q.,Central South University | Ren L.-Y.,Central South University | Wei Q.,Central South University | And 3 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2013

Solution chemistry and flotation of cassiterite in the presence of alkyl hydroxamic acid collector were investigated. Results show that the alkyl hydroxamic acid is able to float fine cassiterite very well at relatively alkaline conditions, and the pH range of better flotability broadens with the increase of chain length of the collector. Moreover, the metal cations influence the flotation mostly depending on the pH of the medium and to some extent on the concentration of metal cations. Theoretical calculation on the group electronegativity indicates that the alkyl chain length of about seven is of great superiority in the synthetization of hydroxamic acid collector for cassiterite flotation. A co-adsorption between molecules and ions onto cassiterite surface is considered according to the lg c-pH diagram analysis. In terms of zeta potential and infrared spectra, the main interaction involves electric charge interaction, hydrogen bonding interaction and complexation, with the proposed formation of an O, O-five membered rings chelate compound.

Qin W.,Central South University | Qin W.,State Key Laboratory of Comprehensive Utilization of Low Grade Ores | Liu K.,Central South University | Diao M.,University of Queensland | And 4 more authors.
Hydrometallurgy | Year: 2013

The oxidation of As(III) by Fe3 + in the presence of pyrite and a mixed moderately thermophilic culture with high As(III)-resistance was investigated under various conditions. The oxidation of As(III) took place on the pyrite surface, and in the presence of excessive Fe3 + the reaction could be classified as a zero-order reaction or a first-order reaction, which depended on whether or not the catalytic sites on the pyrite surface were saturated by As(III). The rate constant of the first-order reaction, 0.0214 h- 1, was calculated from the experimental data, and the rate constant of zero-order reaction was correlated to the pulp density of pyrite. A simple model was built to model the change of As(III) concentration during the biooxidation of arsenic bearing gold concentrates. The model showed that when the content of As in the concentrate was less than 11.4% (w/v) and that of pyrite was more than 60%, the As(III) level in the solution did not significantly increase over time. © 2013 Elsevier B.V.

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