Page 44 - Annual Report_21-22

Feasibility of bauxite leaching under high pressure conditions

A project on high pressure bauxite leachability studies was and high-pressure leaching. The department’s high
taken up from Hindalco, Ranchi to study two new bauxite pressure leaching facility - Hastelloy High Pressure Reactor
ores for usage in their plants that required high pressure was used for these studies. Optimal leaching conditions
leaching. Important unit operations include predesilication were identified for the new bauxite ores.

Fig. High pressure leaching studies on Hindalco bauxite ores

Nano ZnO-adsorbent for Rhodamine B

Pure ZnO-adsorbent nanoparticles (ZnO-NPs) ware (5–240 min). The optimum adsorption was established at
carefully designed via calcination of co-precipitated pH 6 in 150 min, while the maximum adsorption capacity
hydroxide of zinc at 500 °C, and used for the kinetic of RB on ZnO-NPs was 24.41 mg/g at pH 4 in 180 min
and thermodynamic studies of Rhodamine B (RB) dye using 50 mg/L RB at 313 K. while the adsorption process
adsorption from aqueous solution. The ZnO-NPs ware followed pseudo-second-order kinetics with R2 = 0.9874.
characterized using X-Ray Diffraction (XRD), Scanning The change in Gibbs free energy (ΔGo) obtained was
Electron Microscopy (SEM), and Transmission Electron negative, signifying spontaneity of the adsorption process,
Microscopy (TEM) to determine the composition, crystalline while the positive values of ΔHo (+5.35 kJ/mol) and ΔSo
and morphology of the nanomaterial, while the bonds and (+0.02 kJ/mol) for RB adsorption on ZnO-NPs indicated
functional groups were determined by Fourier-Transform endothermic adsorption and randomness at the ZnO-
Infrared Spectroscopy (FTIR) method. The adsorption of NPs-aqueous interface respectively. Therefore, it can be
RB on ZnO-NPs was investigated at varied solution pH concluded that the nanoscale ZnO-adsorbent is efficient
(2–10), concentration (10–60 mg/L), adsorbent mass for the removal of RB from wastewater.
(0.05–0.25 g), temperature (293–315 K), and contact time

Conversion of emitted CO to chemical fuels
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42 ANNUAL REPORT 2021-22