Experimentation, Modeling, and Optimum Conditions of Pyro-Hydrometallurgical-Precipitation Reaction Technology for Recovery of Copper as Oxide of Nanoparticles from a Copper Dust
Conventionally, the leach-solvent extraction-electrowinning technology has been preferred for copper recovery from its primary and secondary sources as cathode slabs even though its recovery as copper oxide nano-particles (CuO NPs) is more preferred. Hence, this paper is aimed at presenting the production of CuO NPs from purified pregnant leach solution (PPLS) of a copper smelter dust (CSD); a by-product of primary copper ore smelting. This aim was achieved in four steps of roasting pretreatment, dissolution, precipitation reaction, and thermal decomposition. The CSD was first roasted in a muffle furnace; after which, its copper value was taken into solution via sulphuric agitation leaching using a magnetic stirrer with heater. The reduction of iron in the resultant pregnant leach solution is followed; it was achieved by optimizing the compositional proportion of H2SO4:FeSO4·7H2O. Copper precursor was then produced from the PPLS via dropwise addition of Na2CO3. The precipitate from reaction between chemical species in the PPLS and Na2CO3 served as copper precursor; this copper precursor was thermally decomposed to produce the CuO NPs. The optimum conditions for this process route are as follows: 2 h, 2 M, and 90 °C (agitation leaching); 800 °C for 2 h (oxidative roasting); 25 °C and 740 rpm (precipitation of copper precursor); 750 °C for 2 h (precipitation of copper nanoparticles). A grade of 51.30% CuO NPs was achieved from an initial 18.02% Cu content. The average crystallite size was estimated at 35 nm. The predicted outputs proportions obtained using the models were in good conformance with the experimental outputs with error margins between 0.00 and 0.07%.
KeywordsCopper dust Mathematical modeling Phase change Precipitation reaction Thermal decomposition
The authors would like to thank the following institutions for their financial support towards the success of this paper:
1. Department of Science and Technology, Republic of South Africa
2. Council for Scientific and Industrial Research (CSIR), Pretoria, Republic of South Africa
3. National Research Foundation (NRF), Republic of South Africa.
We also extend our sincere gratitude to Palabora Copper (PTY) Ltd, Limpopo, Republic of South Africa, for providing the CSD used for this study and to Tshwane University of Technology (TUT), Pretoria for finance and facilities.
- 3.SANS (2005) South African National Standard: ambient air quality—limits for common pollutantsGoogle Scholar
- 5.Gao J, Huang Z, Wang Z, Guo Z (2019) Recovery of crown zinc and metallic copper from copper smelter dust by evaporation, condensation and super-gravity separation. Sep Purif Technol 115925Google Scholar
- 6.Raborar SC, Campos MB, Penaranda AH (1991) Philippine Associated Smelting and refining corporation, process for removing impurities from flue dusts. U.S. Patent 5,032,175Google Scholar
- 9.Yin ZB, Caba E, Barron L, Belin D, Morris W, Vosika M, Bartlett R (1992) Copper extraction from smelter flue dust by lime-roast/ammoniacal heap leaching. Residues Effluents Process Environ Consider 255–267Google Scholar
- 10.Magagula F (2012) High temperature roasting of sulphide concentrate and its effect on the type of precipitate formed. Doctoral DissertationGoogle Scholar
- 13.Okanigbe D, Olawale O, Popoola A, Abraham A, Michael A, Andrei K (2018) Centrifugal separation experimentation and optimum predictive model development for copper recovery from waste copper smelter dust. Cog Eng 5(1):1551175Google Scholar