Metals such as copper, molybdenum, tungsten and zinc are of great technical and economic importance but are only partially recovered from industrial wastewater. The recovery of these metals from three weakly concentrated industrial wastewaters (sample A: 250 mgL-1 Zn; sample B: 29.2 mgL-1 Cu; sample C: 110 mgL-1 Mo, 37 mgL-1 W) from metal processing companies is therefore the subject of this thesis. Hence, the suitability of the ferrodecont process in combination with further hydro- and pyrometallurgical treatment was examined. Chemical analyses of initial and treated water samples using inductively coupled plasma mass spectrometry (ICP-MS) showed a decrease of the Zn concentration in sample A and of the Mo and W concentration in sample B by around 99%. In addition, 67.7% of dissolved copper was removed from wastewater of sample C. These results correlate with the accumulation and fixation of metals in the subsequently separated solids which were also analysed by ICP-MS (10.5 wt% Zn (sample A), 33.1 wt% Cu (sample B), 17.8 wt% Mo, 2.36 wt% W (sample C)). Mineralogical analysis of solids conducted by X-ray diffraction (XRD) showed, depending on the initial sample, that different corrosion products of iron and in some cases, mineral phases of the elements previously in solution were present. Furthermore, the analyses indicated amorphous phases for some samples. Subsequent hydrometallurgical treatment of solid sample A (3d, 32% HCl) did not result in a significant selective extraction of zinc. The thermal treatment of solid sample B at 1300 °C caused reduction of copper-containing phases to metallic copper according to differential scanning calorimetry (DSC), thermogravimetry(TG) and XRD. In addition, magnetite (Fe3O4) was identified with XRD. A subsequent separation of the magnetic phases from the copper with magnetic separation was successful. The hydrometallurgical treatment of solid sample C (3d, 1.5 M NaOH) at 50 and 70 °C resulted in a highly concentrated filtrate with Mo concentrations of 6300 and 5820 mgL-1 and W concentrations of 840 and 800 mgL-1, whereby selective leaching was confirmed.
|Translated title of the contribution||Recovery of Cu, Mo, W and Zn from industrial waste waters|
|Award date||18 Dec 2020|
|Publication status||Published - 2020|
Bibliographical noteembargoed until null
- zerovalent iron
- wastewater treatment
- metal recovery