Regular Article

Kinetics of limestone decomposition in hot metal

¹ School of Materials Science and Engineering, Jiamusi University, Jiamusi, 154007 Heilongjiang, PR China
² Metal wear-resistant materials and surface technology ministry of education engineering center, Jiamusi University, Jiamusi, 154007 Heilongjiang, PR China
³ Northeastern University Metallurgy College, Northeastern University, Shenyang, 110819 Liaoning, PR China

^* e-mail: tanglaobiao@163.com

Received: 3 August 2017
Accepted: 1 June 2018

Abstract

Compared with the traditional limestone calcination, this paper focuses on the conditions and temperature in hot metal where limestone calcines in converter steelmaking process. Considering heat transfer, mass transfer driven by concentration gradient and mass transfer (CO₂ gas flow) driven by pressure gradient, macro kinetic models are established to describe limestone decomposition rate respectively. The method of rotating cylinder sample is used in the experiment of limestone decomposition in hot metal. The image processing software Image-Pro Plus is used to analyze the cross section of limestone calcined to get the unreacted core radius of cross section of cylindrical limestone. The results show that the decomposition mechanism of limestone follows the unreacted shrinking core model, the heat conduction of lime layer is the controlling step, the heat conduction and CO₂ migration through the product layer determine the rate of limestone decomposition, and the corresponding kinetic equations are established.