Effect of Wettability on Penetration and Flotation Behavior of a Particle in Refining Process

• Published in: Tetsu to hagane Vol. 106; no. 10; pp. 697 - 707
• Main Authors: Matsuzawa, Akihiro, Sasai, Katsuhiro, Harada, Hiroshi, Numata, Mitsuhiro
• Format: Journal Article
• Language: Japanese; English
• Published: The Iron and Steel Institute of Japan 01.10.2020
• Subjects: air column; detention time of a particle; refining process; residual bubble; water model experiment; wettability of a particle
• ISSN: 0021-1575; 1883-2954
• DOI: 10.2355/tetsutohagane.TETSU-2020-020

Powder blasting is often operated in refining process in order to achieve lower sulfur content in molten steel with high desulfurization efficiency. In this study, effects of wettability of a particle on penetration and flotation behavior were examined by water model experiment. A polypropylene particle was blasted onto water surface with Ar gas through a single-hole nozzle, and particle behavior during penetration into water to flotation to water surface was recorded by a high-speed camera. Wettability between the particle and water was changed by applying repellent or hydrophilic material on the particle. According to penetration of the particle, an air column was generated and a residual bubble was remained on the particle after rupture of the air column. The repellent particle floated to the water surface in a short time because maximum penetration depth was small and diameter of a residual bubble was large. On the other hand, the detention time of the hydrophilic particle became longer than the repellent particle because maximum penetration depth was relatively large and the residual bubble was separated from the particle. The reason that wettability between the particle and water affects penetration and floatation behavior is that adhering position of the air column on the particle changed. In the case of repellent particle, the position changed to penetrating direction of the particle. Therefore, the force caused by surface tension of water increases, and the residual air column on the particle after rupture of the air column becomes large.