A Study of the Changes in Coke Structure and Strength Brought about by Reaction with Carbon Dioxide at 1000 deg C

摘要

The objective of the experiment was to study the chemical, physical and mechanical characteristics of cokes at normal and elevated temperatures with the aim of providing guidance to the formulation of blend composition and coal preparation conditions for the production of metallurgical coke. Coke specimens in the form of thick discs of 1.5cm diameter were subjected to partial gasification in CO2 at 1000 degrees C for various lengths of time. The progress of the increasing gasification was charted by measuring the weight loss and dimensional changes of the specimens, the changes in the larger features of the porous structure and the deterioration of the tensile strength. Differences in the reactivity to CO2 and in the associated rate of loss of strength of metallurgical cokes produced from different coal blends were confirmed. High reactivity was associated with high porosity and a large number of large pores. The changes in strength could be related to changes in the porous structure by using the previously established coke strength-structure relation. Differences in the rate of change of porous structure with burn-off could be detected. This could influence coke performance in smelting.