REDUCTION OF INDIAN NICKELIFERROUS ORE IN A FIXED-BED REACTOR WITH GAS FLOWING HORIZONTALLY OVER THE BED

Background/purpose: Low grade lateritic ore recently discovered in Suk inda, India is likely to be commercially reduced in a multiple hearth furnace set-up where the reducing gas flows horizontally over the bed. A detailed study of such gas-solid contacting is made in this paper, on which there is a genuine paucity in the published literature. Metho ds: Fixed bed reduction experiments of Indian nickeliferrous ore pelle ts were conducted at 900 K and 100 K in a rectangular reactor with gas flowing horizontally over a packed bed of ore pellets. A quasi-steady state model was then developed for the process, involving a steady st ate solution of the fluid flow over the bed by using a stream function and vorticity formulation of the Navier-Stokes equation, and coupled transient equations for the gas-solid heat and mass transfer, and the kinetics of reaction. Results: Despite the cumbersome nature of experi ments, and rather involved computational procedure, the simulated and measured data were found to be in reasonable agreement. Furthermore, t he effects of various parameters like gas velocity, pellet size and ga s composition were successfully computed during this investigation. Ba sed on the complex mineralogy of the ore, the conventional grain model for gas-solid reaction has been modified and a new complex oxide redu ction mechanism is proposed.