Hydrometallurgical processing of anode slime for recovery of valuable metals

The anode slime obtained from Indian Copper Complex, Ghatsila was used for the recovery studies with the aim of developing a hydrometallurgical processing route. The chemical analysis of the slime showed that it contained valuable metals like copper, nickel, selenium, tellurium, gold, silver and platinum group metals. Characterisation study by XRD analy¬sis revealed the presence of various phases like NiO, CuSO4.5H20, NiSe, a-CuSe, Cu4SeTe. Cu2Te, (Cu02Ni08)O, Cu7Tey AgCu7 Te1,y Si02 etc. in the slime. Presence of free moisture, combined moisture, selenium and tellu¬rium were detected by TG/DTA studies. Preliminary leaching experiments of the anode slime in sulphuric and hydrochloric acid media at different conditions were carried out to recover copper, nickel and tellurium. Maxi¬mum copper recovery in sulphuric acid and hydrochloric acid leaching experiments at normal pressure was found to be about 55% and 77% respectively. In both the cases nickel and tellurium recoveries were poor. In the autoclave leaching copper and tellurium recoveries improved with increasing time and pressure. Maximum copper and tellurium recoveries to the tune of 85% and 71% respectively were achieved using 1 % sulphuric acid as leachant. On increasing the sulphuric acid concentration to 20% in the pressure leaching, the recoveries of copper and nickel improved to 95% and 46% respectively

Generation of a strong reverse shock wave in the interaction of a high-contrast high-intensity femtosecond laser pulse with a silicon target

We present ultrafast pump-probe reflectivity and Doppler spectrometry of a silicon target at relativistic laser intensity. We observe an unexpected rise in reflectivity to a peak approximately9 ps after the main pulse interaction with the target. This occurs after the reflectivity has fallen off from the initially high “plasma-mirror” phase. Simultaneously measured time-dependent Doppler shift data show an increase in the blue shift at the same time. Numerical simulations show that the aforementioned trends in the experimental measurements correspond to a strong shock wave propagating back toward the laser. The relativistic laser-plasma interaction indirectly heats the cool-dense (ne 10^23 cm^-3 and Te ~10eV) target material adjacent to the corona, by hot electron induced return current heating, raising its temperature to around 150eV and causing it to explode violently. The increase in reflectivity is caused by the transient steepening of the plasma density gradient at the probe critical surface due to this explosive behavior

Evidence for weak antilocalization-weak localization crossover and metal-insulator transition in CaCu3_{3}Ru4_{4}O12_{12} thin films

Artificial confinement of electrons by tailoring the layer thickness has turned out to be a powerful tool to harness control over competing phases in nano-layers of complex oxides. We investigate the effect of dimensionality on transport properties of $d$-electron based heavy-fermion metal CaCu$_{3}$Ru$_{4}$O$_{12}$. Transport behavior evolves from metallic to localized regime upon reducing thickness and a metal insulator transition is observed below 3 nm film thickness for which sheet resistance crosses $h/e^{2} \sim 25~$k$\Omega$, the quantum resistance in 2D. Magnetotransport study reveals a strong interplay between inelastic and spin-orbit scattering lengths upon reducing thickness, which results in weak antilocalization (WAL) to weak localization (WL) crossover in magnetoconductance.Comment: 10 pages, 4 figure