Abstract:
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There is an environmental challenge for the metallurgical and mining industries, especially for smelting, mining and processing of copper, due to the numerous environmental regulations imposed as well as the human health impact of heavy metal pollution. Copper metallurgical
processes is generating complex residuals streams with high copper contents where it is
accompanied by other base metals as zinc, nickel and cadmium and toxic non-metals as arsenic and bismuth, among others. Due to the economic value of such copper streams several techniques such as chemical precipitation, adsorption and ion exchange, among others, are being proposed for its selective separation and concentration. In this study the use of ion selective membrane electrodialysis (IX-ED) has been evaluated to achieve a double objective: the separation and concentration of Cu(II) from streams containing mixtures of H2SO4/H3AsO4 by using an ion exchange membrane process with cation monovalent selective membranes, named ‘‘selectrodialysis (SED)”.
The SED configuration is based on conventional ED (PCCell ED 64–004 with a cell of 11×11cm) by adding one monovalent selective cation exchange (MVC) membrane between the standard anion (AEM) and cation exchange (CEM) membranes. In addition, the SED system
was composed by four streams: electrode rinse (0.1 M Na2SO4), feed solution (10 g/L CuSO4 and 8.5 g/L Na2HAsO4, pH=2.3), Cu-rich product (0.1 M H2SO4) and As-rich product (0.1 M H2SO4). The initial volume introduced in each tank was 1L, the flow rates were set at 90–100 L/h in the electrode rinse stream and 15–20 L/h in the others, and the voltage was constant at 7V.
The preliminary results show that the feed stream was deconcentrated from approximately 7.5 to 0.4 g/L of CuSO4 reaching arsenic free pure copper concentrates of 5 g Cu/L after 100 min. |