Dephosphorization Kinetics of Hot Metal by Lime Injection with Oxygen Gas

Ono, Hiroki; Masui, Tamenori; Mori, Hisashi

doi:10.2355/tetsutohagane1955.69.15_1763

Cited by 19 publications

(9 citation statements)

References 6 publications

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“…However, the formation mechanism of the CaO-SiO 2 -P 2 O 5 solid phase has not been fully clarified. Several researchers [2][3][4][5] reported that P 2 O 5 exists in 2CaO · SiO 2 phase in steelmaking slag. Ito et al 6) and Hirosawa et al 7) measured phosphorus partition equilibria between 2CaO · SiO 2 and FeO x -CaO-SiO 2 -P 2 O 5 slag at hot metal temperatures.…”

Section: Introductionmentioning

confidence: 99%

Formation Reaction of Phosphate Compound in Multi Phase Flux at 1573 K

2007

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Section: Introductionmentioning

confidence: 99%

Formation Reaction of Phosphate Compound in Multi Phase Flux at 1573 K

2007

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“…4,[7][8][9][10][11][12] Inoue and Suito 9) found that the mass transfer of phosphorus from 2CaO · SiO 2 saturated slag to the 2CaO · SiO 2 particles was fast and a uniform CaO-SiO 2 -P 2 O 5 solid phase was formed within 5 s. Ito et al 10) and Hirosawa et al 11) measured phosphorus partition ratio between solid 2CaO · SiO 2 and molten CaO-SiO 2 -FeO x -P 2 O 5 slag at hot metal temperatures. Kitamura et al 12) investigated the P 2 O 5 content in different phases for hot metal dephosphorization slag and found that partition ratio of phosphorus between liquid slag and 2CaO · SiO 2 phase increased as the increase in the slag basicity.…”

Section: Introductionmentioning

confidence: 99%

“…The only exception is the case of slag A at 1 573 K. In this case, an additional 3CaO · 2SiO 2 layer was formed and restrained the reaction of P 2 O 5 by separating solid 2CaO · SiO 2 and molten slag. P 2 O 5 was not condensed until the layer split after certain reaction time.Previous researches [7][8][9][10][11][12]14) have already proved the formation of 2CaO · SiO 2 -3CaO · S 2 O 5 solid solution at the interface between 2CaO · SiO 2 and slag. Accordingly, the P 2 O 5 condensed phases in the present study are identified as the mixture of 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution and the surrounding liquid slag because the size of the formed solid solution particle is not big enough to be detected separately by the current analysis method.…”

mentioning

confidence: 99%

Condensation of P2O5 at the Interface between 2CaO·SiO2 and CaO–SiO2–FeOx–P2O5 Slag

2009

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In order to clarify the reaction behavior of phosphorus in the multi phase flux, the solid 2CaO · SiO 2 piece was reacted with the CaO-SiO 2 -FeO x -P 2 O 5 slag for 1 to 180 s at 1 573 or 1 673 K. The interfaces between the original solid and liquid phases were observed and compositions of both phases were analyzed by SEM/EDS.The result shows that P 2 O 5 is condensed at the rim layer of 2CaO · SiO 2 piece very fast in less than 1 s. The P 2 O 5 condensed phases are identified as the mixture of 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution and the surrounding liquid slag. After reaction for longer time, the reaction behavior of P 2 O 5 depends on the reaction temperature and initial slag composition. Reaction temperature and mole ratio of CaO/SiO 2 in the initial slag influence the stability of P 2 O 5 condensed phases. Higher temperature induces the dissolution of P 2 O 5 condensed phases while larger mole ratio of CaO/SiO 2 has the opposite effect.KEY WORDS: multi phase flux; hot metal dephosphorization; dicalcium silicate; P 2 O 5 condensed phase; reaction mechanism.The present study is aimed to clarify the microscopic reaction behavior of phosphorus at the interface between solid 2CaO · SiO 2 and liquid CaO-SiO 2 -FeO x -P 2 O 5 slag on the basis of the previous studies. A solid 2CaO · SiO 2 piece was reacted with the CaO-SiO 2 -FeO x -P 2 O 5 slag with different composition at 1 573 or 1 673 K. The interface between the original solid and liquid phases was observed and analyzed by SEM/EDS. The formation mechanism of P 2 O 5 condensed phase at interface between 2CaO · SiO 2 and the P 2 O 5 containing slag was clarified. The influence of temperature and initial slag composition on the condensation behavior of phosphorus was discussed. ExperimentalThe CaO-SiO 2 -FeO x -P 2 O 5 slag was prepared by mixing the synthesized wustite, CaO obtained by the calcination of reagent grade CaCO 3 , reagent grade SiO 2 and 3CaO · P 2 O 5 . With different FeO x content and CaO/SiO 2 mole ratio, three types of slags were used in the present study as shown in Table 1. The 2CaO · SiO 2 piece was prepared by pressing a mixture of CaO and reagent grade SiO 2 on mole ratio of 2 : 1 at 50 MPa, followed by heating at 1 773 K for 24 h. About 1 mass% of 3CaO · P 2 O 5 was also added into the mixture to prevent the dusting of 2CaO · SiO 2 .Ten grams of slag were charged in an alumina crucible (I.D.: 34 mm, O.D.: 38 mm, height: 45 mm) with the coexistence of solid iron (3 g) and melted in a furnace at argon atmosphere. In the previous study on reaction between CaO and slag at 1 673 K, both the Al 2 O 3 crucible and Fe crucible were used. The results proved that about 15 mass% of dissolved Al 2 O 3 at maximum does not affect the reaction significantly.13) Accordingly, it is supposed that the influence of Al 2 O 3 impurity is also limited in the present study. Solid iron was used to control the oxygen partial pressure determined by the Fe/FeO equilibrium. The solid 2CaO · SiO 2 piece (0.5 to 1 g, f10ϫ1 mm cylinder shape) attached to the ti...

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“…Therefore, if phosphorus in the slag were condensed in the solid calcium silicate phase, it would be possible to use the solid phase including multi-phase flux to the hotmetal dephosphorization process. Several investigations have been carried out for the reaction of solid CaO and slag, [1][2][3][4][5][6][7][8][9][10][11][12][13] however, the mechanism of reaction is not yet fully clarified.…”

Section: Introductionmentioning

confidence: 99%

Reaction Mechanism between Solid CaO and FeOx–CaO–SiO2–P2O5 Slag at 1 573 K

2006

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Solid CaO and FeO x -CaO-SiO 2 -P 2 O 5 slag were reacted for 2 to 2 400 s at 1 573 K. The interface of CaO and slag were observed and analyzed by SEM/EDS. The CaO-FeO layer was formed beside solid CaO. The thickness of the CaO-FeO layer increased with time. Next to the CaO-FeO layer, 2CaO · SiO 2 phase was formed in the melt and high content of FeO was included in the liquid. The activities of FeO and CaO for each phase were evaluated and reaction mechanism between solid CaO and FeO x -CaO-SiO 2 -P 2 O 5 slag was discussed. The activity of FeO for 2CaO · SiO 2 saturated melt is larger than that for the CaO-FeO layer, therefore, Fe 2ϩ diffuses from slag phase to solid CaO. Then the CaO-FeO layer is formed beside solid CaO. The pass of the slag composition change accompanied by CaO dissolution are represented in the phase diagram for the FeO x -CaO-(SiO 2 ϩP 2 O 5 ) pseudo ternary system.

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Dephosphorization Kinetics of Hot Metal by Lime Injection with Oxygen Gas

Cited by 19 publications

References 6 publications

Formation Reaction of Phosphate Compound in Multi Phase Flux at 1573 K

Formation Reaction of Phosphate Compound in Multi Phase Flux at 1573 K

Condensation of P2O5 at the Interface between 2CaO·SiO2 and CaO–SiO2–FeOx–P2O5 Slag

Reaction Mechanism between Solid CaO and FeOx–CaO–SiO2–P2O5 Slag at 1 573 K

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