Powder Blasting in Hot Metal Desulfurization by Mechanical Stirring Process

• Published in: ISIJ International Vol. 57; no. 6; pp. 1029 - 1036
• Main Authors: Nakai, Yoshie, Sumi, Ikuhiro, Kikuchi, Naoki, Tanaka, Kotaro, Miki, Yuji
• Format: Journal Article
• Language: English
• Published: The Iron and Steel Institute of Japan 01.01.2017
• Subjects: desulfurization; hot metal; mechanical stirring; powder blasting
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2017-063

The effect of adding CaO-based desulfurization flux on desulfurization efficiency in hot metal desulfurization by mechanical stirring was investigated. It was found that desulfurization flux dispersion is enhanced by powder blasting with a carrier gas. In this research, the behaviors of the desulfurization powder under different blasting conditions were investigated, and the optimum blasting conditions for achieving higher desulfurization efficiency were examined. The velocities of the gas jet and particles were measured by pressure measurement by the pitot tube technique and LDV (Laser Doppler Velocimeter), respectively. The results showed that the powder velocity was accelerated by the gas jet, which agreed with the calculated velocity. The condition of powder penetration into the hot metal was examined based on the calculations. As a result, the higher carrier gas flow rate, 200 Nl/min, was categorized as a penetrating condition, and the lower carrier gas flow rate, 100 Nl/min, was not a penetrating condition. The difference in the desulfurization behaviors under those carrier gas flow rate conditions is caused by the difference in the penetrating condition. Based on the obtained blasting conditions, powder blasting tests were carried out in 300 t-scale hot metal desulfurization, and desulfurization flux consumption was decreased by 19% compared with conventional top addition.