http://ore.immt.res.in/handle/2018/1 Wed, 08 Jul 2026 21:59:53 GMT 2026-07-08T21:59:53Z http://ore.immt.res.in/handle/2018/3977 A sustainable and synergistic approach for the efficient recovery of copper from the copper slag: experimental insights and perspectives Routray, A.; Kundu, T. The untreated disposal of copper (Cu) slag raises significant environmental concerns. Besides, the swift exhaustion of primary resources and rising demand compel the recovery of Cu from the potential secondary resources, such as Cu-slag. The existing literature on recovering Cu from Cu-slag comprises studies focused on individual route-based methods, including either beneficiation or pyro-or hydrometallurgical processes. However, these individual techniques encounter several challenges and compromise Cu recovery due to the complex mineralogy of slag. Thus, the present research adopts a novel synergistic approach of integrating all three processing routes to enhance Cu recovery from the Cu-slag. The as-received Cu-slag sample used in the present research investigation analysed 3.35 % Cu. The mineralogical studies revealed the incidence of fayalite, covellite, and chalcopyrite as the major mineral phases. The flotation studies were conducted to concentrate the Cu values by varying particle size, reagent dosages, and slurry pH. Based on the results of the flotation optimization studies, a process flowsheet was developed that could enrich the Cu content to 32.46 % with a recovery of 90.5 %. The beneficiated Cu concentrate was further subjected to roasting studies using a novel additive, ammonium iron sulphate, by varying the temperature, time, and quantity of the additive. The roasted product was subsequently water-leached, and under the optimized roast-leaching conditions, about 98 % of the Cu values were recovered in the leach liquor. This research offers valuable insights into effective Cu recovery, resulting in an overall Cu recovery of 88.7 % from the feed Cu-slag. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/3977 2026-01-01T00:00:00Z http://ore.immt.res.in/handle/2018/3976 Time-dependent evolution of structural, optical, mechanical and electrical characteristics in ZnO thin films Priyadarshini, B.; Anwar, M. S.; Anwar, S. ZnO thin films were deposited on glass substrates by RF magnetron sputtering with deposition time varied from 0.5 to 2 h while maintaining constant deposition parameters. The influence of deposition time on the structural, microstructural, optical, mechanical and electrical properties of the films was systematically investigated. X-ray diffraction analysis revealed polycrystalline wurtzite ZnO with increasing peak intensity and progressive crystallite growth from similar to 6.6 to similar to 9.9 nm as deposition time increased, indicating improved crystalline ordering. FESEM observations confirmed grain coalescence and enlargement with increasing film thickness. Optical measurements showed high transparency in the visible region (74-81%), while the optical band gap decreased from 3.26 to 3.18 eV with increasing deposition time due to combined effects of thickness evolution, strain relaxation and defect redistribution. Photoluminescence spectra exhibited enhanced near-band-edge and visible emissions with increasing deposition time, reflecting improved crystallinity and reduced non-radiative recombination at grain boundaries. Nanoindentation measurements revealed a maximum hardness of 12.08 +/- 1.2 GPa for the film deposited for 1 h, corresponding to an optimal crystallite size governed by the transition between Hall-Petch and inverse Hall-Petch strengthening mechanisms. Impedance spectroscopy indicated thermally activated electrical transport dominated by grain and grain-boundary contributions, with the lowest overall resistance observed for the 1 h film. Overall, the results demonstrate that deposition-time-induced microstructural evolution strongly governs the multifunctional performance of ZnO thin films, with the 1 h deposition condition providing the most balanced combination of optical transparency, mechanical strength and electrical conductivity. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/3976 2026-01-01T00:00:00Z http://ore.immt.res.in/handle/2018/3974 Recent advances in SnTe-based thermoelectric materials: Synthesis, band engineering, and performance optimization Behera, A.; Velu, N. K. Tin telluride (SnTe) has gained renewed attention as a sustainable alternative to lead-based thermoelectrics for mid-temperature waste-heat recovery. Its rock-salt structure, high carrier mobility, and suitable band structure make it an attractive candidate; however, the high intrinsic hole concentration and relatively high lattice thermal conductivity limit its figure of merit (ZT). In recent years, significant progress has been made through strategies such as aliovalent doping, alloying, band convergence, and microstructural engineering to improve its thermoelectric efficiency. This review summarizes key developments in the synthesis and optimization of SnTe-based materials prepared by melt growth, mechanical alloying, solution processing, and spark plasma sintering. Emphasis is placed on the correlation between synthesis conditions, resulting defect chemistry, and their influence on carrier concentration, Seebeck coefficient, and lattice thermal conductivity. Recent advances, including multi-doping, nanoscale precipitate formation, and defect-controlled phonon scattering, are critically examined to highlight their impact on transport properties. The review concludes with an outlook on scalable synthesis, long-term stability, and future opportunities for achieving high-performance, lead-free SnTe thermoelectrics suitable for practical energy-harvesting applications. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/3974 2026-01-01T00:00:00Z http://ore.immt.res.in/handle/2018/3973 Enhanced Piezoelectric and Mechanical Performance in Electrospun PVDF-HFP/BCZT Nanofiber Composites for Energy Harvesting Sahoo, S.; Nayak, B.; Anwar, S.; Mohapatra, M.; Anwar, S. Highly polarized electrospun PVDF-HFP/BCZT nanofiber composite films were successfully fabricated and systematically investigated for their dielectric, ferroelectric, piezoelectric, mechanical, and energy-harvesting performance. The electrospinning fabrication process, along with the incorporation of Ba0.8 5Ca0.1 5Zr0.1Ti0.9O3 (BCZT) nanoparticles, significantly enhanced beta-phase content along with the interfacial polarization within the polymer matrix. Optimal performance was achieved at 30 wt % ceramic loading. The optimized composite exhibited a high dielectric constant, improved remnant polarization, low leakage current density (similar to 10-6 A/cm2 at 350 kV/cm), and superior energy storage performance, with a recoverable energy density of 26.41 mJ/cm3 and an efficiency of 52.47%. Nanoindentation analysis revealed enhanced mechanical stability, with an elastic modulus of 9.26 +/- 0.2 GPa, enabling efficient mechanical stress transfer for piezoelectric applications. Piezo-response force microscopy confirmed enhanced electromechanical coupling, with the effective piezoelectric coefficient (d3 3*) improving from similar to 38.3 to similar to 161 pm/V. The piezoelectric energy harvester based on the optimized nanofiber film delivered an output voltage of 68.4 V and a power density of 406.4 mu W/cm3 under cyclic loading, demonstrating excellent durability and real-world applicability. These results establish PVDF-HFP/BCZT nanofiber composites as promising candidates for flexible, self-powered energy-harvesting and sensing systems. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/3973 2026-01-01T00:00:00Z