Hydrogen Reduction of Liquid Iron Oxide Fines in Gas-conveyed Systems.

Abstract

A laboratory scale fine particles-gas conveyed system was utilized to measure the reduction rates of liquid wustite with hydrogen at high temperatures. N2-H2 mixtures having various flow rates and compositions were flowed downward through a cylindrical reactor maintained at a constant temperature of 1723 to 1823 K. A batch of pure spherical wustite particles (mean dia.; 58μm) was concurrently fed into the reactor at a small constant rate and reduced in a hot zone. The reduction process was found to proceed in such a manner that metallic iron particles were enclosed inside a wustite droplet. Rate analysis was made of one dimensional mass balance equations for particle taking the shrinkage into consideration. Under relatively small reducing potentials, it was concluded that the major fraction of overall reaction resistance is attributable to chemical reaction. However, under higher reducing potentials, the reduction process was estimated to include an appreciable diffusion resistance within the liquid phase. >From the temperature dependence of forward chemical reaction rate constants, the activation energy was evaluated to be 110 kJ/mol.