Review

Factors affecting the hearth activity of blast furnace and corresponding measures

¹ College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, P.R. China
² Yanzhao Iron and Steel Laboratory, North China University of Science and Technology, Tangshan 063210, P.R. China
³ College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan 063210, P.R. China

^* e-mail: dengyong@ncst.edu.cn
^** e-mail: liulu@ncst.edu.cn

Received: 28 August 2024
Accepted: 23 January 2025

Abstract

To improve the hearth activity and provide a theoretical basis for the blast furnace (BF) smooth operation, this paper introduced indirect indicators of hearth activity, such as the descent of burden, fluctuations in air volume and pressure, hearth temperature, iron tapping conditions, and the heat of slag iron. The factors influencing hearth activity were analyzed, primarily focusing on the permeability provided by deadman, the viscosity of slag iron, and the position and size of the tuyere raceway. Control measures for hearth activity were summarized, including adjusting the permeability provided by deadman by controlling the particle size distribution and strength of coke. Maintaining the appropriate viscosity of slag iron by controlling the temperature of slag iron, the binary alkalinity of slag, the magnesia-to-alumina ratio, and the elemental content of sulfur, silicon, manganese, and titanium in the iron. Adjusting the position of the tuyere raceway by controlling parameters such as air volume, air pressure, tuyere area, and oxygen enrichment rate. Finally, it was concluded that providing more permeability channels through deadman, maintaining the viscosity of slag iron within a suitable range, and promoting the development of the tuyere raceway towards the lower and central parts of the furnace are all beneficial for improving hearth activity.