CARBON AND COKE REACTIVITY IN ZINC-LEAD BLAST FURNACE PRACTICE

Abstract

Previous research on the oxidation of coke in air, O2 and CO2 has been reviewed, especially with regard to kinetic studies and Zn/Pb blast furnace practice. Coke "reactivity" has been discussed and correlated with surface area changes on carbon burn-off (in air and CO2 at various temperatures) for Nauitgarw and two other metallurgical cokes. Other carbons (charcoals and graphite) and a-brovnr. coal char~ have been examined by gas sorption, X ray diffraction and thermal analysis in an attempt to relate reactivity, as determined by rate of reaction in CO2 at 1000°C, with other solid state properties. Reactivity studies on coal chars have been reviewed also. The inhibition of the Boudouard reaction, by modification of the carbon surface, has been reviewed, especially by the action of'B203. Cokes and coal char have been subject to B2O3 solution treatment and the mode of action of the inhibitor investigated by isothermal and dynamic thermal analysis and estimation of surface area by gravimetric gas sorption. The action of B2O3 at both low and high degree of carbon burn o f f has been studied. The mineral matter of coke (which forms about 10% by weight of the material) and the coal char (which forms about 2%) has been examined by X ray diffraction , optical and electron microscopy and thermal and chemical analysis. Its affect upon the kinetics of oxidation has been investigated. Results have been discussed in relation to the industrial usage of coke in the Zn/Pb blast furnace.