钢液RH精炼中喷粉脱硫的动力学

考察和分析了钢液ＲＨ喷粉脱硫过程及机理，探讨了该过程的速率，基于双重阻力传质理论和体系内的质量衡算，建立了ＲＨ喷粉脱硫动力学模型，确定了模型各有关参数，包括各传质系数和钢液内参与脱硫反应的粉量等。以该模型对３００ｔＲＨ装置内设定的不同初始硫含量和喷粉量下喷吹石灰基粉剂脱硫作了计算和模拟，相应的钢液环流量和喷粉速率分别取为１００ｔ／ｍｉｎ和１５０ｋｇ／ｍｉｎ；设定的初始硫含量和喷粉量分别为７０，６０

KINETICS OF DESULPHURIZATION BY POWDER INJECTION AND BLOWING IN RH REFINING OF MOLTEN STEEL

The desulphurization process by powder injection and blowing in RH refining of molten steel and its mechanism have been considered and analyzed. Based on the two-resistance mass transfer theory and the mass balance of sulphur in the system, a kinetic model for the process has been developed. The ralated parameters of the model have been determined. Calculating and modelling for the process by injecting and blowing the lime based powder flux under the assumed operating modes in a RH degasser of 300 t capacity have been carried out using the model. The corresponding circulation rate and the powder injection and blowing rate were taken as 100 t/min and 150 kg/min, respectively. The initial contents of sulphur and the amounts of powder injection and blowing were respectively assumed to be 70, 60, 50, 40, 30, 20×10-4% (massfraction) and 10, 8, 6, 5, 4, 3 kg/t-steel. The total treatment time for desulphurization under each mode was set up to be 24 min that is equivalent to eight circulation cycles of liquid steel to be treated. The results indicated that the prediction made by this model is in good agreement with some data of the industrial experiments and production practice, injecting and blowing the lime-based powder flux(85%CaO+15%CaF2)of 3-5 kg/t-steel with the total treatment time of 12-20 min, it is entirely possible to make the sulphur content in molten steel decrease to the ultra-low level below (5- 10)× 10-4% from (60-80)×10-4%; intensifying the powder injection and blowing operation and increasing the circulation rate of liquid steel may effectively raise the rate of the process in RH refining.