Kalidoss Jayasankar

Mechanical exfoliation can generate graphene, but a consistent and scalable preparation of few-layer graphene (FLG) continues to be a challenge. We employed a mechanochemical milling technique to achieve maximum shear and frictional force by dual drive mode operation for preparation of FLG directly from beneficiated graphite ore. Low-grade graphite ore from Jharkhand, India, with a carbon content of 9%, was subjected to primary beneficiation by froth flotation technique using the naturally hydrophobic property of graphite as opposed to the associated impurities. The obtained graphite concentrates with an enriched carbon content above 90% after flotation was subjected to chemical treatment process including alkali roasting and acid leaching, which yielded an enriched graphite powder with fixed carbon of about 98.16%. A comparative study regarding the leaching efficiency was carried out between sulfuric acid and hydrochloric acid. The few-layered graphene was successfully prepared by mechanical milling of beneficiated graphite ore with oxalic acid at 20 hours with optimized critical speed. At various milling hours, the amplitude of the peak (002) decreased continuously, suggesting that the graphite size and thickness had decreased. Raman Spectroscopy confirmed the 20 h milled graphite is having single and few layered (<4 layers) graphene sheets.

Titanium-ferromagnetite ore has been considered as an alternate ore for making alloyed pig iron. It is also important for recovery of higher TiO₂ slag and iron as a metal by high temperature process as other chemical methods produce huge amount of oxides of iron as a by-product. In this paper an alternative way of using low-grade Indian ilmenite (< 50% TiO2) with recycling industrial waste mill scale for titania slag recovery as well as alloyed pig iron by arc smelting. The results reveal that mill scale waste for ilmenite processing is gaining iron recovery and TiO2 slag quality at very low energy consumption.

We employed simple shear-force-dominated planetary ball milling to prepare graphene on a large scale (200 g per cycle) with less structural defects.

This article illustrates the synthesis of Fe-TiC in-situ composites using cheaper raw materials, namely, mild steel scrap, ilmenite, and petroleum coke. The composite was prepared via two routes by carbothermic smelting of ilmenite and coke in a molten pool of mild steel scrap in an extended transferred arc plasma reactor. In one of the routes, the mixture of ilmenite and coke were thoroughly mixed and fed through powder feeder (in-flight plasma condition), while in the other route the mixture was fed directly into the molten mild steel scrap (static bed condition). The experiments were carried out in 50 kW DC thermal plasma reactor under argon atmosphere. The preliminary results indicate that the composite prepared by in-flight plasma processing showed a better dispersion of TiC particles in the matrix than the static bed plasma processing.