Chalcopyrite (CuFeS2) Leaching: the Rate Determining Solution Species Under Stirred Reactor and Column Leach Conditions at pH 1
The effect of the acid anion on chalcopyrite (CuFeS2) leaching has been examined, under carefully controlled conditions, in a range of acids in stirred reactors and columns at pH 1. Solution speciation calculations were performed to determine possible rate controlling species. The relative leach rates of Cu from chalcopyrite can be explained quantitatively entirely on the basis of solution speciation without the need to invoke any rational relating to surface structure/speciation. The rate of Cu release is first order with respect to Fe3+ activity.The stirred batch reactor experiments at fixed pH 1, Eh of 750 mV (SHE) and 75℃ showed that chalcopyrite leach rates were rapid in both HClO4 and H2SO4 with 100 % Cu recovery after 73h and 97 h respectively. However, the leach rate in H2SO4 was slower as compared to the HClO4 leach due to a slower increase in the activity of Fe3+ due to the formation of FeSO4-. The presence of Cl- in the leaches (HCl and H2SO4 with NaCl added) led to a low activity of Fe3+, due to the high activity of FeCl2+, resulting in very low leach rates.For the column leach experiments dissolution of Fe and Cu from the pH 1 HCl eluted chalcopyrite column with quartz proceeded at several times the rate of any other column (chalcopyrite with and without quartz and/or pyrite leached with H2SO4. HClO4. HCl). Three observations indicate that galvanic interactions are not leach rate controlling role: a) The rate of leaching was not uniformly increased for the non-quartz containing columns where the two sulfide minerals, chalcopyrite and pyrite, are in physical contact as compared to the analogous quartz containing columns where they are not; b) there exists a reasonable correlation between the rate of Cu release and the effluent Fe3+ activity for all columns thus indicating that the leach rate is determined by solution speciation; and c) in all cases the proportion of Fe to Cu leached indicates preferential dissolution of Cu over Fe.However, the proportion of Fe to Cu is either the same or greater than expected on the basis of the single mineral columns. This indicates that chalcopyrite is not dissolving preferentially to pyrite.
Chalcopyrite Dissolution kinetics Acid leaching Column leaching Oxidation Speciation Ferric ions
J. Li L. West A.R. Gerson
Applied Centre for Structural and Synchrotron Studies, University of South Australia,H2-20 Mawson Lakes Campus, University of South Australia, Adelaide, Australia
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
3028-3038
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）