I. G. Sharma

Elemental analysis by radioisotope-excited XRF during thermit smelting of ferrovanadium and niobium

The energy-dispersive x-ray fluorescence (EDXRF) technique was applied to the determination of major and trace elements present in aluminothermically smelted ferrovanadium and niobium. Rapid and multielemental analysis of thermit feed and product aided in the appropriate alterations of the charge constituents to obtain the optimum charge composition. The results of analysis by the EDXRF method were verified using wet chemical analysis for a few typical samples of the product and were found to be in close agreement.

Application of the radioisotope excited X-ray fluorescence technique in charge optimization during thermite smelting of Fe-Ni, Fe-Cr, and Fe-Ti alloys

A wide range of ferroalloys are used to facilitate the addition of different alloying elements to molten steel. High-carbon ferroalloys are produced on a tonnage basis by carbothermic smelting in an electric furnace, and an aluminothermic route is generally adopted for small scale production of low-carbon varieties. The physicochemical principles of carbothermy and aluminothermy have been well documented in the literature. However, limited technical data are reported on the production of individual ferroalloys of low-carbon varieties from their selected resources. The authors demonstrate her the application of an energy dispersive X-ray fluorescence (EDXRF) technique in meeting the analytical requirements of a thermite smelting campaign, carried out with the aim of preparing low-carbon-low-nitrogen Fe-Ni, Fe-Cr, and Fe-Ti alloys from indigenously available nickel bearing spent catalyst, mineral chromite, and ilmenite/rutile, respectively. They have chosen the EDXRF technique to meet the analytical requirements because of its capability to analyze samples of ore, minerals, a metal, and alloys in different forms, such as powder, sponge, as-smelted, or as-cast, to obtain rapid multielement analyses with ease. Rapid analyses of thermite feed and product by this technique have aided in the appropriate alterations of the charge constitutents to obtain optimum charge consumption.

Synthesis of Porous Silica Grains Using PEG as Template via Evaporation Driven Self Assembly

Polyethylene glycol (PEG) templated porous grains consisting of silica nanoparticles have been synthesized using evaporation induced assembly. Micrometric grains of silica with mesoscopic and macroscopic pore structure have been confirmed by scanning electron microscopy and small angle neutron scattering. It has been observed that the porosity and pore size in the dried grains depend on the concentration of PEG. At higher concentration of PEG, the morphology of the grains gets significantly modified from spherical to disordered sponge type. It is proposed that the PEG molecule gets adsorbed on the surface of silica nano‐particles in the dispersion leading to assembly of surface modified nano‐particles during spray drying at low concentration of PEG. Further, at higher concentrations PEG aggregates and act as template material leading to macroporous grains after calcination.