Thermodynamic Studies on Selective Oxidation of Nb, P and C in Dephosphorization of Low Niobium Hot Metal

2013 ◽  
Vol 652-654 ◽  
pp. 2543-2551 ◽  
Author(s):  
Yong Li Jin ◽  
Zeng Wu Zhao ◽  
Jie Yu Zhang
Keyword(s):  
Selective Oxidation ◽  
Oxygen Activity ◽  
Hot Metal ◽  
Efficient Utilization ◽  
Thermodynamic Studies ◽  
Thermodynamic Condition ◽  
Equilibrium Oxygen

The main problem with the efficient utilization of Nb resource in the Boyan Obo Ore lies in the selective oxidation of [Nb], [P] and [C]. In this work, thermodynamic studies have been conducted to determine the conditions of selective oxidation of [Nb], [P] and [C] in low niobium hot metal in the process of oxidizing dephosphorization. The thermodynamic condition for dephosphorization was determined as: The condition for retaining Nb from oxidation is: The oxygen activity for oxidation of Nb, C and P is relevant to the initial [C] content in hot metal. The equilibrium oxygen activity of Nb-O reaction increases with an increase of the [C] content, whereas the equilibrium oxygen activity of C-O and P-O reactions varies oppositely with the [C] content. The reduction ofresults in a decrease of the [C] content required for removing P and retaining Nb, as well as makes the process of dephosphorization more feasible. The increase of temperature decreases the [C] content of selective oxidation of Nb and P, but is unfavorable to dephosphorization.

scholarly journals Effect of the Fe2O3 Addition Amount on Dephosphorization of Hot Metal with Low Basicity Slag by High-Temperature Laboratorial Experiments

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 417
Author(s):  
Wenkui Yang ◽  
Jian Yang ◽  
Yanqiu Shi ◽  
Zhijun Yang ◽  
Fubin Gao ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Theoretical Calculation ◽  
Oxygen Potential ◽  
Oxygen Activity ◽  
Hot Metal ◽  
Rich Phase ◽  
Addition Amount

In this paper, the influence of the Fe2O3 addition amount on the dephosphorization of hot metal at 1623 K with the slag of the low basicity (CaO/SiO2) of about 1.5 was investigated by using high-temperature laboratorial experiments. With increasing the Fe2O3 addition amount from 5 to 30 g, the contents of [C], [Si], [Mn] and [P] in the hot metal at the end of dephosphorization are decreased and the corresponding removal ratios increase. In dephosphorization slags, the phosphorus mainly exists in the form of the nCa2SiO4–Ca3(PO4)2 solid solution in the phosphorus-rich phase and the value of coefficient n decreases from 20 to 1. Furthermore, the oxygen potential and activity at the interface between the slag and hot metal are increased. When the oxygen potential and the oxygen activity at the interface are greater than 0.72 × 10−12 and 7.1 × 10−3, respectively, the dephosphorization ratio begins to increase rapidly. When the Fe2O3 addition amount is increased to 30 g, the ratio of the Fe2O3 addition amount to theoretical calculation consumption is around 175%, and the dephosphorization ratio reaches the highest value of 83.3%.

scholarly journals Contribution to Deoxidation of Austenitic Steels in a Vacuum Induction Furnace with Carbon

2015 ◽  
Vol 15 (2) ◽  
pp. 105-109
Author(s):  
J. Šenberger ◽  
V. Pernica
Keyword(s):  
Chemical Composition ◽  
Induction Furnace ◽  
Slag Sample ◽  
Austenitic Steels ◽  
Oxygen Activity ◽  
Vacuum Induction Furnace ◽  
Reduced Pressure ◽  
Before And After ◽  
Chemical Composition Of Steel ◽  
Equilibrium Oxygen

Abstract Deoxidation of steel with carbon under reduced pressure is often used for increasing the steel purity. Suitable units for this purpose in foundries are vacuum induction furnaces. Possibilities of increasing the steel purity by deoxidation with carbon in the vacuum induction furnace were studied for the steel for the petrochemistry of specific composition 25Cr/35Ni. The charge composed of the return material only was melted in the air. During melting the charge oxidized and the oxidizing slag formed. Chemical composition of steel, morphology, chemical composition of inclusions in the steel and chemical composition of slag after vacuuming were studied on the basis of samples taken before and after vacuuming. Temperature and oxygen activity were measured before and after vacuuming. Globular inclusions with dominant content of silicon and manganese were observed in steel before and after vacuuming. Contents of total oxygen in steel didn’t change significantly during vacuuming. On the basis of composition of inclusions and measured oxygen activity the activity of Cr2O3 in inclusions was calculated. A slag sample was taken after vacuuming and equilibrium oxygen activity in steel with regard to the Cr2O3 content in the slag was estimated from the slag composition. Equilibrium oxygen activity in relation to the Cr2O3 content in the slag was higher than equilibrium activity measured in the steel. For this reason it is not possible, under the studied conditions, to decrease oxygen content in steel during vacuuming.

Selective oxidation of aniline into azoxybenzene catalyzed by Nb-peroxo@iron oxides at room temperature

2020 ◽  
Vol 44 (21) ◽  
pp. 8710-8717
Author(s):  
André L. D. Lima ◽  
Humberto V. Fajardo ◽  
André E. Nogueira ◽  
Márcio C. Pereira ◽  
Luiz C. A. Oliveira ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Selective Oxidation ◽  
Room Temperature ◽  
High Selectivity

Nb-peroxo@iron oxides show high selectivity and activity in aniline conversion to azoxybenzene.

Increase of desulphurization potential of technological systems of hot metal injection desulphurization by various reagents

2019 ◽  
Vol 75 (11) ◽  
pp. 1237-1243
Author(s):  
A. F. Shevchenko ◽  
I. A. Manachin ◽  
B. V. Dvoskin ◽  
A. S. Vergun ◽  
S. A. Shevchenko ◽  
...  
Keyword(s):  
Technological Systems ◽  
Hot Metal

Review of methods of slag removal from melt surface in hot metal and steel ladles

2020 ◽  
Vol 76 (12) ◽  
pp. 1243-1252
Author(s):  
B. A. Sivak ◽  
A. V. Protasov ◽  
L. A. Smirnov
Keyword(s):  
Settling Tank ◽  
Necessary Condition ◽  
Hot Metal ◽  
Slag Removal ◽  
Production Scale ◽  
Technical Parameters ◽  
Ecological Requirements ◽  
The Usa ◽  
Work Done ◽  
Technological Methods

The removal of slag from melt surface of hot metal and steel ladles is a necessary condition to provide a deep desulphurization and dephosphorization of hot metal and steel in the process of their processing. A review of methods of slag skimming presented, mainly based on slag mechanical shoveling and its removal out of ladles by vacuum sucking. It was shown, that manipulators design for the slag skimming working instrument moving depends on the production scale, mass of the processed heats, amount and properties of the slag to be removed, production process intensity and ecological requirements. Peculiarities of designs and technical parameters of machines for slag skimming presented, designed by Irkutsk plant of heavy machinery, Scientific and Production Enterprise n.a. M.I. Platov, VNIIMETMASH, Kuznetsk and Novolipetsk steel plants. Technological methods of control of slag composition and physical properties considered, first of all of viscosity and fluidity, which have significant effect on selection of a method of slag skimming. Advantages and drawbacks of actions, aimed at more complete slag removal from metal surface by a scraper noted including bath blowing off by an inert gas, liquid slag tapping into am intermediate settling tank following its removal into a slag bowl. In case of satisfactory fluidity it is possible to slag removal by vacuum sucking, which at the same time promoted the melt degassing. Work done in this area abroad noted. Methods of vacuum slag removal developed in the USA and Japan described.

Prediction of Mass Transfer in Hot Metal Reactors

2019 ◽  
Author(s):  
L. Oliveira Campos ◽  
P. Gardin ◽  
S. Vincent
Keyword(s):  
Mass Transfer ◽  
Hot Metal
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