Temperature Dependence of Phosphorus Distribution Ratio between CaO-SiO2-CaF2 Slags and Fe-Cr-C Alloys

1995 ◽  
Vol 81 (7) ◽  
pp. 769-771 ◽  
Author(s):  
Daisuke TAKAHASHI ◽  
Kazuki MORITA ◽  
Nobuo SANO
Keyword(s):  
Temperature Dependence ◽  
Distribution Ratio ◽  
Phosphorus Distribution ◽  
Phosphorus Distribution Ratio

Thermodynamic Modelling of Phosphorus in Steelmaking Slags

2013 ◽  
Vol 32 (3) ◽  
pp. 237-246 ◽  
Author(s):  
Chunlin Chen ◽  
Ling Zhang ◽  
Jean Lehmann
Keyword(s):  
Liquid Iron ◽  
Distribution Ratio ◽  
Operating Conditions ◽  
Model Parameters ◽  
Steelmaking Slag ◽  
Maximum Point ◽  
Phosphorus Distribution ◽  
Steelmaking Slags ◽  
Model Database ◽  
Phosphorus Distribution Ratio

AbstractThe published phase diagrams of some key P2O5-containing systems which are relevant to the steelmaking slag and the available experimental data on phosphorus partitioning between liquid iron and slags consisting of SiO2-Al2O3-Fe2O3-FeO-MnO-MgO-CaO-Na2O have been reviewed and assessed. A set of data under carefully controlled experimental conditions, which was considered to be more reliable based on the assessment, was selected for optimising the generalised central atom (GCA) model parameters of phosphorus-containing slag systems. The developed model database is proved to be able to represent the liquidus temperature of some key P2O5-containing systems and the phosphorus distribution ratio between the steelmaking slags and liquid iron reasonably well. With the developed GCA model database, the dephosphorization reaction in the steelmaking process was modelled under various operating conditions such as slag chemistry and temperature. The results show that the phosphorus distribution ratio between the slags and liquid iron displays a maximum point with variation of the FeOx content in the slag. It also shows that the phosphorus deportment to the slag is favored by decreasing the operating temperature and MgO content, and increasing the CaO/SiO2 ratio in the slag. Comparison with the model of the phosphorus distribution data from a commercial BOS furnace shows that operating conditions do not permit to reach P equilibrium contents. The dis-equilibrium degree of P was found to be increased with increasing slag viscosities.

scholarly journals Mechanism of Phosphorus Enrichment in Dephosphorization Slag Produced Using the Technology of Integrating Dephosphorization and Decarburization

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 216
Author(s):  
Haimeng Xue ◽  
Jie Li ◽  
Yunjin Xia ◽  
Yong Wan ◽  
Liangjun Chen ◽  
...  
Keyword(s):  
Solid Solution ◽  
Distribution Ratio ◽  
Thermodynamic Calculation ◽  
Slag Composition ◽  
Slag Basicity ◽  
Hot Metal ◽  
Phosphorus Enrichment ◽  
Phosphorus Distribution ◽  
Dephosphorization Slag ◽  
Phosphorus Distribution Ratio

In order to better understand and develop the technology of integrating dephosphorization and decarburization in a single converter (abbreviated as IDDSC), the relevant thermodynamic issues were discussed by calculation. Based on the thermodynamic calculation, the bridges between the phosphorus distribution ratio, temperature, and slag composition were constructed. Besides, the connections between the dephosphorization behavior and the microstructure of slag were also established by investigating four heats of hot metal smelt using IDDSC technology. As a result, the mechanism of phosphorus enrichment in the dephosphorization slag was revealed. Also, the results show that the dephosphorization efficiency increases gradually with increasing slag basicity. While the dephosphorization efficiency increases first and then decreases with the increase of FeO content in slag. There is a competition relationship between P2O5 and FeO in reacting with CaO and SiO2. When CaO/FeO is relatively high, not enough FeO is provided. Thus P2O5 is in priority to react with CaO and SiO2 through [3n + 2](CaO) + 2SiO2 + n(P2O5) = n(3CaO·P2O5)-2CaO·SiO2(s), generating P2O5-rich nC2S-C3P solid solution which promotes the removal of [P] from the hot metal. When CaO/FeO is relatively low, FeO competes over P2O5 in reacting with CaO and SiO2 through a(CaO) + b(SiO2) + c(FeO) = aCaO·bSiO2·cFeO(s), generating CaFeSiO4 instead of P2O5-rich solid solution. As a consequence, the slag with low CaO/FeO shows a poor dephosphorization ability.

Phosphorus Distribution Equilibrium between CaO-FeO*-SiO2-P2O5(15%)-CaF2(B2O3) Slag System and Carbon-Saturated Hot Metal at 1573K

2011 ◽  
Vol 402 ◽  
pp. 227-234
Author(s):  
Jin Dong Zhou ◽  
Xue Gong Bi ◽  
Zhi Cheng Huang ◽  
Zhi Jun Wen ◽  
Fu Yang ◽  
...  
Keyword(s):  
Distribution Ratio ◽  
Equilibrium Condition ◽  
Slag System ◽  
Dramatic Reduction ◽  
Hot Metal ◽  
Phosphorus Distribution ◽  
High Phosphorus ◽  
Solid Iron ◽  
The One ◽  
Phosphorus Distribution Ratio

In order to understand the equilibrium condition of phosphorus between slag and hot metal saturated with carbon in the high phosphorus hot metal dephosphorization process, the dephosphorization capacity of CaO-FeO*-SiO2-P2O5(15%) -CaF2(B2O3) slag system at 1573 K was studied, by applying the method that phosphorus distribution ratio between slag and solid iron was firstly measured and the one between slag and hot metal was then calculated. The results showed that phosphorus distribution ratio decreased with increase in basicity of CaO/(SiO2 +P2O5), a proper increase in SiO2 content is helpful to the absorption of phosphorus into slag, an increase in FeO* content from 10.52% to 13.40% resulted in a dramatic reduction of phosphorus distribution ratio from 126.43 to 33.25, by completely substituting CaF2 with B2O3 at 2.5 of basicity and 0.07 of B2O3/CaO ratio not only was acquired a high phosphorus distribution ratio of 171, but also was decreased pollution to the environment.

Dephosphorization Ability Estimation of FetO-Rich Demanganization Slag during Hot Metal Pre-Treatment

2012 ◽  
Vol 560-561 ◽  
pp. 1027-1034
Author(s):  
Cheng Yi Zhu ◽  
Jun Liu ◽  
Guang Qiang Li ◽  
Zhao Ping Chen
Keyword(s):  
Phosphorus Content ◽  
Hot Metal ◽  
Phosphorus Distribution ◽  
Equilibrium Quotient ◽  
Multiple Regression Method ◽  
Solid Iron ◽  
Thermodynamic Conditions ◽  
Pre Treatment ◽  
Phosphorus Distribution Ratio ◽  
Pure Argon Atmosphere

In order to find out the optimum thermodynamic conditions for hot metal dephosphorization and predict phosphorus content after demanganization pretreatment, thermodynamic equilibrium experiments between CaO-FetO-SiO2-MnO-P2O5 slag and silver/solid iron were carried out in an iron crucible at different temperature under pure argon atmosphere in an electric resistant furnace. The results indicate that phosphorus distribution ratios increase with an increase of basicity in the slag at the experiment temperature, and then they decrease with an increase of basicity at 1573K and 1623K. The phosphorus distribution ratios decrease with an increase of FetO content in the slag at 1573K, while they increase with an increase of FetO content in the slag and then decrease with an increase of FetO content in the slag at 1623K. The results indicate that the maximum phosphorus distribution ratio between slag and hot metal is 92.4 when basicity of the slag is 1.7 and FetO content in slag is 49.75 mass% at 1623K, and the correspondent phosphorus content in the carbon saturated iron is 0.019mass%. Dephosphorization is easier under low temperature. The equilibrium quotient of phosphorus obtained in the present work is formulated as a function of slag compositions and temperature using the multiple regression method which is used to predict phosphorus content equilibrium with the demanganization slag and optimum conditions needed for ideal phosphorus contents in demanganization pretreatment.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

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