Effect of pre-briquetting on the granulation of sinter mixture containing high proportion of specularite concentrate

Abstract

Specularite concentrate assays high iron grade and little impurities, but has been blended in sinter mixtures only with lower ratio because of its poor granulating performance. Nearly all of existing methods for improving granulation of sinter mixtures comprising specularite concentrate all need finely grinding of it, which means higher energy consumption and production cost. In this paper, granulating characteristics of specularite concentrate were investigated and the pre-briquetting process was employed to improve granulation of sintering mixture containing specularite concentrate. The experimental results show that granulating efficiency was debased obviously when the ratio of specularite fines in sinter blends exceeded 24%. Most specularite particles distributed in the fine granules of −1 mm and adversely affected the permeability of sinter bed. In granulation with specularite concentrate pre-briquetted, the average granule size and permeability of sinter bed increased by 11.17% and 12.69% respectively when the sinter blend contained 36% of specularite concentrate, compared with that in traditional granulation. The pre-briquetting process made the specularite concentrate into independent quasi particles preliminarily, thus changed granulation model and distribution of specularite particles in sinter bed and improved the granulation of sinter mixture containing high ratio of specularite concentrate.