Study on Mass Transfer of Phosphorus Based on New Hot-Metal Dephosphorization Kinetic Model

Abstract

To investigate mass transfer of phosphorus in hot-metal dephosphorization process, it is necessary to reduce the deviation of traditional dephosphorization models in fitting accuracy. According to the change in hot-metal phosphorus content during dephosphorization, a new dephosphorization model was established by introducing the concept of “dynamic relative area”. With the help of literature data and comparative analysis of the new and old models, the rationality of the new model was verified. On this basis, in order to reveal the effects of CaO and its derivatives on mass transfer of phosphorus, based on the dephosphorization effect of FetO–CaO–SiO2–CaCl2 slags on high-phosphorus hot metal at 1673 K (1400 °C), the mass transfer process of phosphorus was investigated by calculating, analyzing, and discussing the overall mass transfer coefficients of phosphorus using CaO, Ca(OH)2, and CaCO3 with equal molar amount as fixatives (slag formers) in dephosphorizer respectively. The results show that the overall mass transfer coefficients of phosphorus under the action of Ca(OH)2 and CaCO3 are 0.0216 cm/s and 0.0363 cm/s, respectively, which are significantly lower than 0.0840 cm/s under the action of CaO.

Keywords

• hot metal
• dephosphorization
• kinetic model
• mass transfer coefficients
• calcium oxide
• calcium hydroxide