Sticking of iron ore pellets in direct reduction with hydrogen and carbon monoxide: Behavior and prevention

YI Ling-yun(易凌云), HUANG Zhu-cheng(黄柱成), LI Tie-hui(李铁辉), JIANG Tao(姜涛)

(School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)

Abstract:A series of reduction experiments of iron ore pellets with hydrogen, carbon monoxide and their mixture were carried out in a laboratory scale shaft furnace. The sticking behavior accompanying reduction of iron ore pellets was investigated. And morphology of the sticking interface forming during reduction was analyzed by SEM equipped with EDS. In order to evaluate the effects of the temperature and gas composition on sticking properties, reduction of iron ore pellets were conducted at 800-1000 °C. The results show that the sticking strength of the pellets increases with temperature, however, decreases with hydrogen content in reducing gas. For an efficient shaft furnace operation in direct reduction (DR), relative prevention of sticking such as coating of pellets was also developed to solve sticking problem. The results show that CaO is a suitable material for the coating method.

Key words:iron ore pellet; direct reduction; sticking; coating of pellets