Original Article

The characteristics and mechanism of ultrafine iron ore powder reduction by coal under mechanical activation

¹ School of Metallurgical Engineering, Anhui University of Technology, Ma’anshan 243002, Anhui, PR China
² Key Laboratory of Metallurgical Emission Reduction & Resources Recycling (Anhui University of Technology), Ministry of Education, Ma’anshan 243002, Anhui, PR China

^* e-mail: weirufei@ahut.edu.cn, un_rain@126.com

Received: 8 May 2024
Accepted: 20 June 2024

Abstract

The ultrafine iron ore powder produced through mechanical activation is a crucial technology for achieving low-temperature ironmaking. This study employs thermogravimetric analysis to investigate the reduction properties of coal powder to iron ore powder under mechanical activation conditions. The Malek method is utilized to analyze and elucidate the reaction mechanism. Experimental findings reveal that mechanical activation enhances the reduction of iron ore powder by coal powder, with the reduction characteristic temperature decreasing as the activation time increases. Mechanical activation alters the coal powder reduction reaction process of iron ore powder, changing the limiting step from gas diffusion at the interface in unactivated raw material to carbon gasification in activated raw material with 30 min of activation time. Moreover, the activation of raw material with activation times of 120 min and 480 min results in the interfacial reduction reaction becoming the limiting step. The activation energy of coal powder for reducing iron ore powder decreases continuously with increasing activation time, with a rapid decrease before 120 min and a slower decrease after 120 min.