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Leaching with Acids
Published in C. K. Gupta, T. K. Mukherjee, Hydrometallurgy in Extraction Processes, 2019
The Shituru plant of Union Miniere at Katanga4 treats copper oxide ores associated with an extremely altered gangue, a product of the decomposition of limestone rock or dolomitic schists into argillaceous, siliceous, or even talcose schists. The copper mineralization consists mainly of malachite (azurite) or hydrated carbonates and, to a lesser extent, pseudomalachite or hydrated phosphate and chrysocolla or hydrated silicate, with complex hydroxides of the lampadite and “wad” type. The process adopted is leaching electrolysis. The principles of this treatment are well known; they are based on the solubility of copper oxide ores in H2SO4 and the ease of removing copper from the solution by electrolysis.
Accelerating copper leaching from a complex ore containing atacamite: optimisation and kinetic studies
Published in Canadian Metallurgical Quarterly, 2023
Sepideh Javanshir, Hojat Imantalab, MohammadBagher Fathi
The copper processing varies depending on the nature of copper minerals [5]. Table 1 shows the solubility of different copper minerals based on the leachability index used for the amenability of different minerals to dissolve in acid, where 1 indicates complete leaching and 0 represents no dissolution. As can be seen, sulphide-rich ores have limited dissolution in acid with a poor leachability index, for example, up to approximately 20% of the chalcocite can leach, however, copper oxides have a high tendency for acid leaching. It is expected that 100% of the copper present in the following minerals: chrysocolla, malachite/azurite, brochantite, chalcanthite, atacamite, antlerite, tenorite, pseudomalachite, and neotosite can be dissolved in acidic media. Therefore, these criteria can predict the dissolution rate based on mineralogical properties. Hence, copper processing varies depending on the nature of copper minerals [6].
Reexamining the Adsorption of Octyl Hydroxamate on Malachite Surface: Forms of Molecules and Anions
Published in Mineral Processing and Extractive Metallurgy Review, 2020
Zhili Li, Feng Rao, Shaoxian Song, Alejandro Uribe-Salas, Alejandro López-Valdivieso
The malachite sample obtained from the Lupe mine, Mexico, was crushed, hand-sorted, and ground to obtain particles of the size fraction −75 + 38 µm for microflotation and adsorption experiments, and finer particles with d50 and d85 of 1.7 and 2.9 µm, respectively, for zeta potential and XPS measurements. X-ray diffraction (XRD, Bruker D8) pattern of the sample showed a high purity malachite (Cu2CO3(OH)2), with minor amounts of pseudomalachite (Cu5(PO4)2(OH)4). The setting parameters for the XRD were: Cu Kα radiation, 40 keV accelerating voltage, 30 Ma current, and 0.1 s/step (0.01945°/step) scan rate. Atomic absorption spectroscopy (AAS) measured 54.3 wt% of Cu and 0.5 wt% of P. Based on the XRD characterization, P and Cu were assumed to be from pseudomalachite and from malachite and pseudomalachite, respectively. It was estimated that the sample contains 4.3 wt% pseudomalachite, 90 wt% malachite, and 5.7 wt% of other gangue minerals. The surface area of malachite (−75 + 38 µm) was measured to be 1.36 m2/g using BET method.
Flowsheet Options for Cobalt Recovery in African Copper–cobalt Hydrometallurgy Circuits
Published in Mineral Processing and Extractive Metallurgy Review, 2019
Kathryn C. Sole, John Parker, Peter M. Cole, Michael B. Mooiman
In the first step, iron, aluminum, and manganese are removed by a combination of oxidation and precipitation. Iron needs to be oxidized to the 3+ state and manganese to the 4+ state. This can be done with air, but the kinetics are very slow. Mixtures of air and SO2 have been shown to increase to rate of oxidation by an order of magnitude. In practice, such oxidation is implemented using aqueous SO2 or SMBS with air (Schulze-Messing et al. 2007; Van Rooyen et al. 2007; Mulaudzi and Mahlangu 2009). Once oxidation is complete, the three metals will precipitate with lime at pH 3.5. Iron and aluminum removal can be further enhanced by the presence of phosphate that often occurs in these ores as pseudomalachite (Cu5(PO4)2(OH)4); iron and aluminum phosphates begin precipitating at lower pH values than the hydroxides.