Effects of coal and iron ore blending on metallurgical properties of iron coke hot briquette

摘要

Utilization of iron coke hot briquette (ICHB), prepared by carbonizing coal-iron ore composite agglomerate, is considered as an effective countermeasure to achieve low carbon emission blast furnace (BF) ironmaking. ICHB shows high reactivity and thereby presents low post-reaction strength, which could have serious impact on the permeability of BF. In this paper, the effects of coal and iron ore blending on the metallurgical properties of ICHB were experimentally investigated and related mechanism were revealed based on Chinese raw material and fuel conditions. The results showed that with increasing coal B addition ratio, the compressive strength of ICHB is slightly improved. The gasification reaction ratio of ICHB is gradually decreased while the post-reaction strength is increased. Furthermore, with increasing coal C ratio, the compressive strength of ICHB tends to slightly increase firstly and then mildly decrease. The reaction ratio of ICHB is decreased firstly and then increased while the post-reaction strength and the crystallite size (L-c) tend to be enhanced initially and then reduced. Additionally, with increasing the addition ratio of iron ore from 0 to 20%, the compressive strength of ICHB is reduced from 5602 N to 4594 N while the porosity of ICHB is increased. The reaction ratio of ICHB is accelerated from 48.22% to 75.02% while the post-reaction strength is reduced from 74.08% to 26.84%. In terms of coal blending and iron ore blending, the reasonable preparation parameters of ICHB are conducted, namely 55% coal A, 10% coal C, 20% coal D, and 15% iron ore. Under the conditions, the compressive strength, the reaction ratio, and the post-reaction strength of ICHB are 4861 N, 63.00%, and 46.45%, respectively. (C) 2018 Elsevier B.V. All rights reserved.