High Efficiency Dephosphorization by Mixed Injection during Steelmaking Process

Abstract

A new dephosphorization technology with introduction of partial CO2 into O2 is proposed in this paper. Thermodynamic characteristics and dephosphorization mechanism by introduction of CO2 are analyzed and the results show that using CO2 as partial dephosphorization oxidant can change the selective oxidation condition of steelmaking system, control the temperature of bath, strengthen the stirring ability, and finally obtain a high efficiency of dephosphorization. Meanwhile, the relationship between selective oxidation temperature T of C and P, partial pressure of CO gas, slag activity, and compositions of melt is obtained as follows. T ¼ ðP CO =P 0 Þ 0:0401 a 0:0080 4CaOÁP 2 O 5 Á expðÀ0:0403½%C À 0:0030½%Si þ 0:0011½%Mn þ 0:3515½%P þ 7:3986Þ Furthermore, dephosphorization trails are carried out in a 30t steelmaking converter and a 300t special dephosphorization converter, respectively. It is concluded that the new technology of injecting CO 2 -O 2 mixture is beneficial to reduce phosphorus content in liquid steel, increase the partition ratio of phosphorus, and reduce iron loss of slag.

New trends in basic oxygen furnace dephosphorization

“…It was concluded that all plant trials resulted in higher dephosphorization and phosphorus partition ratio (i.e. (%P)/%P) values while iron losses decreased [48]. Those results may be regarded as promising and even challenging, especially for the future works.…”

Industrial Application of Bottom–Blown CO2 in Basic Oxygen Furnace Steelmaking Process

“…Dephosphorization is provided by a reaction at the slag-steel interface. [63][64][65][66] The slag-forming speed in the early stage of smelting has a great influence on dephosphorization.…”

Study on Final Equilibrium State and Process of CO2 Reacting with Fe–C Melt

“…Table I gives an overview of the applications of CO 2 in steelmaking processes and the results that have been obtained from the former research. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] The theoretical basis for achieving the preceding effects is that CO 2 exhibits weak oxidation, which occurs through the reaction CO 2 + [C] = 2CO. The reaction characteristics mainly include the endothermic effect that reduces the temperature of the fire point zone and controls the heating rate of molten steel, generating nearly twice the amount of gas to improve the stirring intensity in the furnace, and selective oxidation of carbon and other valuable elements under different pressures and liquid steel compositions.…”