Recovery of copper from a mixture of printed circuit boards (PCBs) and sulphidic tailings using bioleaching and solvent extraction processes

Publication date: Available online 2 July 2019Source: Chemical Engineering and Processing - Process IntensificationAuthor(s): Seifollah Akbari, Ali AhmadiAbstractThe extraction of copper from a mixture of a Cu-Ni-Co bearing sulphidic tailing and printed circuit boards was investigated by bioleaching process followed by solvent extraction of the pregnant leach solutions. Bioleaching was conducted in both batch and continuous modes in 2- and 50-L stirred tank bioreactors using a mixed culture of iron- and sulphur-oxidizing microorganisms. The results of bioleaching in three 50-L reactors showed that 92% copper, 67% zinc and 45% aluminum were extracted in a batch mode. The process was then performed in the continuous mode in which 96.8% of copper was leached with 10 days’ residence time. Afterward, the bioleach solutions containing 2.85 g/l Cu was purified by solvent extraction with LIX 984 N extractant diluted in kerosene. The effect of some critical parameters namely extraction time, pH, stirring rate, aqueous/organic phase ratio and extractant concentration on the extraction efficiency of copper was investigated. Results showed that copper can be efficiently extracted from the bioleach solution in two stages (96% extraction). The co-extraction of zinc and nickel was increased at the higher level of pH (2.5). A new flowsheet was proposed to treat both electronic wastes and sulphidic tailings.Graphical abstractThe flowchart of metals recovery from a mixture of the PCBs an...
Source: Chemical Engineering and Processing: Process Intensification - Category: Chemistry Source Type: research