In this study, the sulfation roasting characteristics of copper-bearing ore and its flotation products as chalcopyrite concentrate and tailings were investigated in detail. For this aim, the roasting-leaching experiments and thermal analyses were conducted on the samples. As a result of the leaching of sulfated products obtained from the roasting experiments, the maximum Cu extractions were achieved as 94.7%, 99.5% and 82.7%, for run of mine, chalcopyrite concentrate and the flotation tailings, at the roasting temperatures of 550, 650 and 525°C, respectively. It was also found that the copper extractions began to decrease owing to decomposition of copper sulfates above these temperatures. It was indicated that the decomposition temperature of copper sulfates differ for each samples. On the other hand, thermal gravimetric and differential thermal analyses were subjected to identify the thermal behaviors of the samples. The results showed that the formation of metal sulfates occurred in a wide temperature range (394-650°C) for chalcopyrite. On the contrary, copper sulfation reactions took place at narrow temperature ranges of 450-560°C and 480-550°C for the run of mine ore and the flotation tailing, respectively. Figure 5. Differential thermal analyses (DTA) and thermal gravimetric (TG) curves for run of mine ore (a) and flotation tailing (b).
Asia-Pacific Journal of Chemical EngineeringROASTING OF COPPER-BEARING MATERIALS 371
The possibility of recovering metallic values from end of life Li ion secondary batteries by a precipitation technique using ethanol was investigated. This work aimed to maximise the recovery of the reusable materials and thereby minimise the environmental impact resulting from end of life batteries. After digestion in sulphuric acid, copper was recovered with 96% recovery efficiency as copper sulphate (CuSO 4 .3H 2 O) with the addition of ethanol at a volume ratio of 3 : 1. Cobalt was recovered in two steps. During the first step, 92% of the cobalt is recovered as CoSO 4 by the use of ethanol at a volume ratio of 3 : 1. The ethyl alcohol removes water ligands from the Co 2z cation, and caused the precipitation of cobalt as cobalt sulphate monohydrate. In the second step, the remaining cobalt was precipitated as cobalt hydroxide (Co(OH) 2 ) by increasing the pH value up to 10 with the addition of lithium hydroxide (LiOH). Lithium, which remained in the solution, was then recovered as lithium sulphate (Li 2 SO 4 ) with up to 90% recovery efficiency by the addition of ethanol at a 3 : 1 volume ratio. Aluminium was recovered as aluminium hydroxide (Al(OH) 3 ) with 99% recovery efficiency. It was shown that metals could be precipitated separately by the ethanol/sulphate precipitation technique depending on their concentrations present in the solution. The proposed process proved to be conceptually straightforward.
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