Effect of slag composition on desulfurization during recycling rejected electrolytic manganese metal by electroslag remelting

To reduce the Mn vaporization during recycling rejected electrolytic manganese metal by electroslag remelting, it is proposed to reduce the temperature of molten slag pool, but which leads to the degradation of slag desulfurization. The desulfurization by interaction between CaF2–CaO–Al2O3–Na2O slag and rejected electrolytic manganese metal scrap was studied from the view of thermodynamics in this study. The results show that sulfur distribution ratio decreases with increase of CaF2 content, and increases with the increase of Na2O content and temperature. Na2O increases sulfur distribution ratio of slag by increasing CaO activity. Na2O addition in CaF2–CaO–Al2O3–Na2O slag can enhance desulfurization ability of slag due to the larger sulfur distribution ratio and lower viscosity. Thus, sulfur content in test of slag T3 bearing 45.8 wt% CaF2-23.2 wt% CaO-22.7 wt% Al2O3-8.3 wt% Na2O is much lower than that of slag without Na2O, implying that 45.8 wt% CaF2-23.2 wt% CaO-22.7 wt% Al2O3-8.3 wt%Na2O slag is the promising slag for recycling rejected electrolytic manganese metal by ESR.

Distribution Ratio of Sulfur between CaO-SiO2-Al2O3-Na2O-TiO2 Slag and Carbon-Saturated Iron

To explore the feasibility of hot metal desulfurization using red mud, the sulfur distribution ratio (LS) between CaO-SiO2-Al2O3-Na2O-TiO2 slag and carbon-saturated iron is evaluated in this paper. First, the theoretical liquid areas of the CaO-SiO2-Al2O3 (-Na2O-TiO2) slag are discussed and the fluxing effects of Al2O3, Na2O, and TiO2 are confirmed. Then, LS is measured via slag-metal equilibrium experiments. The experimental results show that LS significantly increases with the increase of temperature, basicity, and Na2O content, whereas it decreases with the increase of Al2O3 and TiO2 content. Na2O in the slag will volatilize with high temperatures and reducing conditions. Furthermore, based on experimental data for the sulfur distribution ratio between CaO-SiO2-Al2O3-Na2O-TiO2 slag and the carbon-saturated iron, the following fitting formula is obtained: log L S = 45.584 Λ + 10568.406 − 17184.041 Λ T − 8.529

Thermodynamic Model of Calculation of Sulfur Distribution Ratio between B2O3-Containing Slag and Molten Steel

A thermodynamic model of calculation of sulfur distribution ratio between B2O3-containing slag and molten steel has been developed on the basis of the ion and molecule coexistence theory. Based on the model, the effects of B2O3 content and slag basicity on the sulfur distribution ratio in 1873K were investigated respectively. The results indicate that the sulfur distribution ratio decreased with increasing the content of B2O3, and when the content of B2O3 exceeds 6%, the sulfur distribution ratio was lower than 2.0. Therefore, in order to ensure the desulphurization ability of slag, the content of B2O3 should be controlled at about 6%. Moreover the sulfur distribution ratio can be increased by increasing the slag basicity.

Numerical Simulation and Optimization Practice of Oxygen Lance for Converter Steelmaking

The lance system is one of the important link of converter. Stable and secure of the system is a necessary condition for whole production system to function normally. The numerical simulation for a three-dimensional oxygen lance nozzle was carried out according to the fundamental parameters of PZH steel, the characteristics of the oxygen jet were analyzed and discussed. The oxygen lance nozzle with the optimum design has achieved good results in practice: the average formation time of early slag was reduced by 1 min and 23 seconds, the pure blowing time was reduced by 46 seconds, the oxygen consumption per ton steel decreased by 1.05 m3/t, the rate of dephosphorization was increased by 1.35%, the basicity of slag was reduced by 0.38, the phosphorus and sulfur distribution ratio between slag and liquid iron were also increased effectively.