Effect of metallised burden on softening–melting–dripping behaviors of burden

Abstract

The utilisation of metallised burden in blast furnaces stands as a method for advancing low-carbon ironmaking. In this study, we investigate the effect of metallised burdens with different metallisation ratios on softening–melting–dripping behaviours, gas permeability, and gas utilisation ratio of the comprehensive burden. It provides theoretical guidance for utilising metallised burden effectively. The results show that the effect of metallised burdens on the melting properties of comprehensive burden depends on its composition. The metallised burden is acidic. As the metallisation ratio is ≤55%, the metallised burden cannot increase the initial melting temperature T_S of the comprehensive burden. The lower metallisation ratio is not conducive to the formation of a suitable cohesive zone for comprehensive burden. Under experimental conditions, the suitable metallisation ratio of metallised burden is ≥73%. Within this range, the metallised burden possesses a certain degree of deformation resistance. That enable the formation a cohesive zone conducive to smelting, thereby improving the gas permeability of the comprehensive burden. With increasing metallisation ratio of metallised burden from 20% to 92%, the T_S increases from 1275°C to 1316°C, the dripping temperature T_D increases from 1435°C to 1455°C and the cohesive zone shows a gradually narrowing trend. The permeability index S value decreases from 1658.91 kPa °C to 862.24 kPa °C. The gas permeability is improved.