Regular Article

Real-time indices focus on slag flowability and coke strength for blast furnace operation

Iron making process development section, Iron & Steel R & D Dept., China Steel Corporation, 1, Chung Kang road, 81233 Hsiao Kang, Kaohsiung, Taiwan

^* e-mail: jiashyanshiau@gmail.com

Received: 5 March 2019
Accepted: 23 September 2019

Abstract

It was well known that abnormal burden quality has a significant impact on the blast furnace (BF) permeability resulting in bad slag flowability and HM tapping, and the coke fines inside BF become much finer to reduce HM production and BF life when the coke strength is weak. Therefore, it is necessary to develop the real-time operation indices of the slag flowability and coke strength after reaction (CSR) in a lower part of BF. BF slag flowability was determined with liquidus temperature and viscosity from measured semi-synthetic slags (SiO₂-Al₂O₃-CaO-MgO-TiO₂), and the effects of MgO content, Al₂O₃ content and CaO/SiO₂ on slag flowability are investigated according to the model equations derived from above measured data by using multiple-regression method. A real-time index combined with viscosity and liquidus temperature has been also designed to indicate appropriate slag flowability. In addition, a coke sampler was used to collect the coke samples at tuyere level to analyze the strength of BF bosh coke at various HM productivities. CSR quantitative target and its online index were obtained from the data of sampling coke properties, BF operation conditions and BF permeability to provide real-time reference for coke and HM production.