The efficacy of monosodium glutamate (MSG) as a lixiviant for the selective and sustainable leaching of zinc and copper from electric arc furnace dust was tested. Batch leaching studies and XRD, XRF and SEM-EDS characterization confirmed the high leaching efficiency of zinc (reaching 99%) and copper (reaching 86%) leaving behind Fe, Al, Ca and Mg in the leaching residue. The separation factor (concentration ratio in pregnant leach solution) between zinc vs. other elements, and copper vs. other elements in the optimum condition could reach 11,700 and 250 times, respectively. The optimum conditions for the leaching scheme were pH 9, MSG concentration 1 M and pulp density 50 g/L. Kinetic studies (leaching time and temperature) revealed that the saturation value of leaching efficiency was attained within 2 h for zinc and 4 h for copper. Modeling of the kinetic experimental data indicated that the role of temperature on the leaching process was minor. The study also demonstrated the possibility of MSG recycling from pregnant leach solutions by precipitation as glutamic acid (>90% recovery).

X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy energy dispersion spectroscopy (SEM–EDS), and differential thermal analysis (DTA) measurements were used to investigate the mineralogical characteristics and distribution of data set in limonite soil from Indonesia. The findings point to a complicated inner core in laterite ore. Ni, Fe, Mg, Al, and Si levels in limonite are 1.4, 50.5, 1.81, 4.86 and 16.5 wt %, respectively. The iron oxide/oxyhydroxide content of limonite is 94.4 and 5.6 % silicate. DTA shows that limonite has a phase transition in the low temperature (200 – 300 °C) with the goethite transformation to hematite. This phase is good optimalization for nickel diffusion in the iron. Moreover, for this limonite, the thermal upgrading was used as a good method.