Development of RH-powder top blowing process

Mass Transfer Characteristics between Molten Steel and Particles under Conditions of RH-PB(IJ) Refining Process

“…In the case of the powder particle with a same size, relatively, the velocity of powder particle attained in the carrier gas stream and after entering the molten steel are also much larger; appropriately, the local Reydolds number of the steel at the particle/molten steel interface is larger. Comparing to the data obtained by Wei et al under the RH-PTB conditions, 12,13) the values of Re s evaluated for the modeling experiments are about (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) times of those given in the present work at the close powder particle sizes to each other. As a result, for a given degasser and RH refining technology, the mass transfer rate in the liquid between molten steel and powder particles under the PTB conditions would be larger than that in the PB(IJ) process, also dependant on the concrete PTB and PB(IJ) operations.…”

“…In the process of powder injection in a ladle, however, the effectiveness of desulphurization, to a great extent, would be closely related to the conditions of the top slag; and the liquid steel treated may unavoidably pick up nitrogen from the atmosphere, thus resulting in a higher nitrogen concentration. In recent years, some different desulphurization technologies with powder injection and blowing in the RH refining process of molten steel have been developed, for instance, RH-PB(IJ) (in which the powder flux is injected into the molten steel through a lance positioned beneath the upsnorkel), [1][2][3] RH-PB(OB) (in which the powder flux is blown into the liquid steel from the oxygen blowing nozzles located in the lower part of the vacuum vessel), [3][4][5] and RH-PTB with the powder blowing through a top lance from the top of the vacuum vessel, [6][7][8] and others. Although the vacuum is unable to directly affect thermodynamically the desulphurization reaction by powder injection, compared to the processes of powder injection in a ladle and powder top blowing in vacuum oxygen decarburization (VOD-PB), [9][10][11] the desulphurization by powder injection in the RH process will have some evident advantages as a result of the distinctive flow and mixing characteristics of liquid steel, which can provide better refining conditions.…”

Effect of Particle Penetration Depth on Solid/liquid Mass Transfer Rate by Particle Blowing Technique

“…Azhar UDDIN, 2) Yoshiei KATO, 2) * Sang Beom LEE 3) and Yong Hwan KIM 3) 1) Department of Material and Energy Science, Graduate School of Environmental and Life Science, Okayama University. Now at Okayama Gas Co., Ltd., 1-1 Sakurabashi, 2-chome, Naka-ku, Okayama, 703-8285 Japan.…”

“…A procedure for refining ultra-low sulfur steel by blowing desulfurizing agent on the molten steel in the vacuum vessel of RH degasser has been put to practical use. 2,3) Nitrogen removal with decarburization was increased under reduced 4) or ordinary 5) pressure by blowing oxidizing flux. Copper and tin removal 6) rate in molten scrap was enhanced by using oxidizing powder by a combination of plasma heating.…”

Dessulfuração Do Aço Em Desgaseificador Rh Por Meio De Modelo Matemático

“…A prática de remoção de enxofre em reator RH é recente, tendo seu início nos anos de 1990 [1]. A partir disso, resultados de remoção de enxofre do aço em RH são divulgados na literatura como uma prática viável e de bons resultados [2][3][4][5][6][7]. A prática baseia-se na injeção de material dessulfurante à base de cálcio por meio de lança de partículas finas no seio do metal.…”