ruchi yadav
Last Activity: 10 Years ago
Alumino thermic process
Athermite reactionis a type ofaluminothermic reactionin which aluminium metal is oxidized by the oxide of another metal, most commonly iron oxide. The name thermit is also used to refer to a mixture of two such chemicals. The products are aluminium oxide, free elemental iron, and a large amount of heat. The reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation. The reaction is used for thermite welding, often used to join rails. Some other metal oxides can be used, such as chromium oxide, to generate elementary metal
Alternative Technologies for Chromium-Metal Production
The geologic sources of chromium are essentially mixtures of spinels of the ideal form RO·R2O3 (e.g., chromite is FeO·Cr2O3), although a more accurate representation of an ore source would be (Mg,Fe)Cr2O4 with silica and alumina gangue materials. Therefining processesfor chromium metal have been thermodynamically defined by their spinel origins. The two processes of electrolytic deposition, discussed in the previous chapter, and aluminothermic reduction have evolved over time as more efficient than such other processes as carbon and silicon reduction. Both the electrolytic and the aluminothermic processes have been successfully improved over time to result in lower levels of impurities so that the requirements of high-purity applications have continued to be met, even though purity specifications have become increasingly stringent over time. Improvements in the efficiencies and economics of the processes are probably still possible, but no obvious quantum-jump increase in the purity obtainable appears likely. This chapter discusses the strengths, weaknesses, uses, limits, and possible improvements to alternative processes for producing chromium metal.
Thank You
Ruchi
Askiitians Faculty