Weng Fu

Australian Hydrometallurgy Research and Development

Australia is a major miner of ore that requires hydrometallurgical processing. According to the 2016 US Geological Survey Minerals Commodities Summaries, the country is 1st for aluminium (bauxite) and lithium, 2nd for gold, zinc and cobalt, 4th for nickel and silver, and 6th for copper mining, not to mention its wealth in coal and iron ore. In this paper, examples of recent Australian hydrometallurgical activities are summarised. Then, selected research projects from the University of Queensland hydrometallurgy research group are profiled. The projects profiled are related to fundamental aspects of processing bauxite with organics and reactive silica as well as the development of a synergistic hydro- and pyrometallurgical process for copper. The process context and motivation for the research is introduced, key results are highlighted with the associated relevant references.

Separation of Lead from Chalcopyrite Slurry Using Resin-in-Pulp

In this study, Resin-in-Pulp (RIP) technology is used to separate Pb from a chalcopyrite slurry. Solvent-impregnated resin, Lewatit® VP OC 1026, which contains di(2-ethylhexyl) phosphoric acid (D2EHPA) in a macroporous polystyrene matrix was used, as the functional group exhibits selectivity for Pb over Cu. Adsorption pH, kinetics, as well as resin and CuSO4 concentrations were investigated. The results show that the kinetics of Pb and Cu loading are fast, reaching the adsorption equilibrium within 30 min. The equilibrium pH of 2 was chosen as optimum for operation in order to achieve a high Pb extraction rate and extent as well as selectivity for Pb over Cu. High Cu(II) concentration in solution results in Pb(II) requiring a larger amount of resin for the same degree of extraction. Regeneration and reuse tests show that the loss of adsorption capacity happens in the 1st and 2nd cycles and then the adsorption capacity stabilises for the 3rd cycle.

Magnetic dithiocarbamate functionalized reduced graphene oxide for the removal of Cu(II), Cd(II), Pb(II), and Hg(II) ions from aqueous solution: Synthesis, adsorption, and regeneration

In this study, dithiocarbamate(DTC)-modified magnetic reduce graphene oxide (rGO-PDTC/Fe3O4) was synthesized for the removal of heavy metal ions (Cu(II), Cd(II), Pb(II), and Hg(II)) in synthetic waste water. The rGO-PDTC/Fe3O4 nanocomposite was prepared via a novel synthesis route that includes GO bromination, nucleophilic substitution of polyethylenimine (PEI), the reaction with carbon disulphide (CS2) and Fe3O4 nanoparticle loading. The prepared rGO-PDTC/Fe3O4 nanocomposite was characterised by XPS, FTIR, TEM and XRD, suggesting that DTC functional groups were chemically bonded to rGO surfaces. N2 adsorption-desorption results revealed that rGO-PDTC/Fe3O4 nanocomposite exhibited high BET surface area (194.8 m2/g) and large pore volume (0.33 cm³/g) which are crucial to the function of adsorbent. Adsorption experiments showed that rGO-PDTC/Fe3O4 nanocomposite is an excellent adsorbent for heavy metal removal, which exhibits large adsorption capacities, fast kinetics and solid-liquid separation. The pseudo-second-order kinetic model and Langmuir adsorption model were used to unveil the adsorption mechanisms. The maximum adsorption capacities of the Langmuir model were 113.64, 116.28, 147.06, and 181.82 mg/g for Cu(II), Cd(II), Pb(II), and Hg(II) ions, respectively. After adsorption and desorption process, the spent rGO-PDTC/Fe3O4 nanocomposite was easily regenerated via one-step organic reaction. The regenerated rGO-PDTC/Fe3O4 composite exhibited good adsorption capacities for different metals in five adsorption-desorption-regeneration cycles.