Mass Transfer of P2O5 between Liquid Slag and Solid Solution of 2CaO·SiO2 and 3CaO·P2O5

Kitamura, Shin Ya; Saito, Shinya; Utagawa, Keita; Shibata, Hiroyuki; Robertson, David G.

doi:10.2355/isijinternational.49.1838

Cited by 67 publications

(44 citation statements)

References 5 publications

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“…Since many studies 1,[4][5][6][7][8][9] had confirmed that phosphorus in the liquid phase can be fixed into the 2CaO · SiO 2 -3CaO · P 2 O 5 solid solution or compounds by CaO contained in the steelmaking slag, the idea is proposed to innovate the present refining process by promoting the transfer of phosphorus from liquid phase to solid phase for better dephosphorization. Reduction of the lime consumption and slag emission can be achieved by improving the utilization efficiency of solid CaO or 2CaO · SiO 2 phase in the steelmaking slag.…”

Section: Introductionmentioning

confidence: 99%

Reaction Behavior of P2O5 at the Interface between Solid 2CaO·SiO2 and Liquid CaO–SiO2–FeOx–P2O5 Slags Saturated with Solid 5CaO·SiO2·P2O5 at 1 573 K

2010

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It is important to understand the role of solid phases such as solid CaO or 2CaO · SiO 2 in hot metal dephosphorization. In the present study, the reaction behavior of P 2 O 5 at the interface between solid 2CaO · SiO 2 and liquid CaO-SiO 2 -FeO x -P 2 O 5 slags saturated with solid 5CaO · SiO 2 · P 2 O 5 at 1 573 K was investigated.The result shows that the solid 2CaO · SiO 2 reacts with the liquid phase in the two phase mixture to form the P 2 O 5 condensed phases. Compared with the results by using the homogeneous slag as reported in the previous papers, the formation of P 2 O 5 condensed phases is more evident and the back dissolution of P 2 O 5 condensed phases into the surrounding slag is restrained in this study. These results indicate that the dissolution of P 2 O 5 condensed phases can be considerably restrained in the case that the bulk slag is saturated with solid 5CaO · SiO 2 · P 2 O 5 before reaction.KEY WORDS: multi phase flux; dephosphorization; dicalcium silicate; P 2 O 5 condensed phases; dissolution. phorization slag. Therefore, it is required to understand the reaction behavior of phosphorus in the heterogeneous flux in which the liquid phase is saturated with the solid P 2 O 5 condensed phase.Little information on this topic can be found in the literature. In the present study, the authors try to clarify the reaction mechanism between solid 2CaO · SiO 2 and the slag saturated with solid 5CaO · SiO 2 · P 2 O 5 , and also to verify the assumption that the dissolution of P 2 O 5 condensed phases can be considerably restrained when the bulk slag is saturated with solid 5CaO · SiO 2 · P 2 O 5 before reaction. However, since the phase diagram for the CaO-SiO 2 -FeO x -P 2 O 5 quaternary system is unavailable, it is impossible to make sure the accurate composition of the slag saturated with solid 5CaO · SiO 2 · P 2 O 5 in the experiment. Therefore, the heterogeneous CaO-SiO 2 -FeO x -P 2 O 5 slags containing solid 5CaO · SiO 2 · P 2 O 5 were used. The solid 2CaO · SiO 2 disc was reacted with the slags at 1 573 K. The formation mechanism of P 2 O 5 condensed phases at the interface between solid 2CaO · SiO 2 and the heterogeneous slag was discussed. The results were also compared with the findings in the previous study. 11,12) ExperimentalThe CaO-SiO 2 -FeO x -P 2 O 5 slag was prepared by mixing synthesized CaO, FeO x , reagent grade SiO 2 and 3CaO · P 2 O 5 . Powder of CaO was obtained by the calcination of reagent grade CaCO 3 for 24 h at 1 173 K in air. FeO x was synthesized by sintering an equimolar mixture of reagent grade Fe 3 O 4 and electrolytic Fe powders in iron crucible at 1 473 K with CO-CO 2 atmosphere (CO/CO 2 ϭ1) for 24 h. The initial composition of slags are listed in Table 1.The solid 2CaO · SiO 2 disc was prepared by the following method. Firstly, synthesized CaO and reagent grade SiO 2 were mixed on molar ratio of 2 : 1 and sintered in a platinum crucible at 1 773 K for 24 h in air. About 1.0 mass% 3CaO · P 2 O 5 was added into the mixture to prevent the phase transformation from b...

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Section: Introductionmentioning

confidence: 99%

Reaction Behavior of P2O5 at the Interface between Solid 2CaO·SiO2 and Liquid CaO–SiO2–FeOx–P2O5 Slags Saturated with Solid 5CaO·SiO2·P2O5 at 1 573 K

2010

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“…[8][9][10] Current levels of understanding have extended beyond equilibrium conditions to include the description of mass transport in the slag and metal phases. [11][12][13][14] It is however known that under dynamic conditions the interface between phases can display significant perturbation in comparison to a relaxed planar state, and may even lead to emulsification. [15][16][17][18][19][20] A proper description of the slag/metal reaction necessitates an elucidation of the dynamic change of interfacial area and the coupling of this change to the interfacial reactions.…”

Section: Introductionmentioning

confidence: 99%

Investigation into the Cause of Spontaneous Emulsification of a Free Steel Droplet; Validation of the Chemical Exchange Pathway

Spooner

Assis

Warnett

et al. 2016

Metall Mater Trans B

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Small Fe-based droplets have been heated to a molten phase suspended within a slag medium to replicate a partial environment within the basic oxygen furnace (BOF). The confocal scanning laser microscope (CSLM) has been used as a heating platform to interrogate the effect of impurities and their transfer across the metal/slag interface, on the emulsification of the droplet into the slag medium. The samples were then examined through X-ray computer tomography (XCT) giving the mapping of emulsion dispersion in 3D space, calculating the changing of interfacial area between the two materials, and changes of material volume due to material transfer between metal and slag. Null experiments to rule out thermal gradients being the cause of emulsification have been conducted as well as replication of the previously reported study by Assis et al. [1] which has given insights into the mechanism of emulsification. Finally chemical analysis was conducted to discover the transfer of oxygen to be the cause of emulsification, leading to a new study of a system with undergoing oxygen equilibration.

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“…Some scholars have made a lot of research on the slag phosphorus existence form [6][7][8][9][10][11] and magnetic separation behavior, [12][13][14][15][16] K. Yokoyama et al 17) found that phosphorus existed mainly in the form of nC 2 S-C 3 P solid solution in the slag, and firstly proposed phosphorus recover from the steelmaking slag by magnetic separation. But the systematic research on the effect of Na 2 O on resource utilization of P-bearing slag is less.…”

Section: )mentioning

confidence: 99%

“…When the temperature is dropped to about 1 623 K, the early precipitated low phosphorus solid solution (6C 2 S-C 3 P) reacts with Na 2 O in slag to produce high phosphorus solid solution (Na 2 Ca 4 (PO 4 ) 2 SiO 4 ). The generation reaction of P-bearing solid solution in P-bearing slag is as follows: ( ) can also reflect the occurrence of the reaction (5) and (7).…”

Section: Thermodynamic Analysis Of Effect Of Na 2 O Onmentioning

confidence: 99%

Effect of Na<sub>2</sub>O on Phosphorus Enrichment and Separation in P-Bearing Steelmaking Slag

Bao

Jiang

et al. 2015

ISIJ Int.

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Mass Transfer of P2O5 between Liquid Slag and Solid Solution of 2CaO·SiO2 and 3CaO·P2O5

Cited by 67 publications

References 5 publications

Reaction Behavior of P2O5 at the Interface between Solid 2CaO·SiO2 and Liquid CaO–SiO2–FeOx–P2O5 Slags Saturated with Solid 5CaO·SiO2·P2O5 at 1 573 K

Reaction Behavior of P2O5 at the Interface between Solid 2CaO·SiO2 and Liquid CaO–SiO2–FeOx–P2O5 Slags Saturated with Solid 5CaO·SiO2·P2O5 at 1 573 K

Investigation into the Cause of Spontaneous Emulsification of a Free Steel Droplet; Validation of the Chemical Exchange Pathway

Effect of Na<sub>2</sub>O on Phosphorus Enrichment and Separation in P-Bearing Steelmaking Slag

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