关键词: 铁水, 脱磷, 硅铁, SiO2, CaSiO3, 传质系数

Abstract: In the context of increasing domestic demand for hot-metal dephosphorization and advocating the utilization of solid waste, it is of great practical value to understand the effect of silicon impurities on the hot-metal dephosphorization when industrial solid waste is used to prepare dephosphorizer. Therefore, in order to explore the effect of silicon-based substances on dephosphorization efficiency, the dephosphorization experiments were carried out by using ferrosilicon and SiO2 to prepare hot-metals containing different mass fraction of silicon and dephosphorizers containing different mass fraction of SiO2. Meanwhile, to further understand the characteristics of hot-metal dephosphorization when different silicon-based substances were used as initial conditions in the slag-iron system, under the condition of ensuring the same molar amount of silicon-based substances, the dephosphorization experiments were carried out by selecting different silicon-based substances involved in desiliconization process as an additive to hot-metal or dephosphorizer, including ferrosilicon, SiO2 and CaSiO3, and the overall mass transfer coefficient of phosphorus in the three experiments was calculated by theoretical derivation and curve fitting. The results had shown that under the conditions of temperature 1400℃ and initial hot-metal phosphorus content of 0.3wt%, when the initial hot-metal silicon content was 0.4wt%, the highest dephosphorization efficiency can be obtained. The effect of initial SiO2 content in the dephosphorizer on dephosphorization efficiency can be ignored. In addition, under the condition that the molar amounts of silicon, SiO2 and CaSiO3 were the same, a higher overall mass transfer coefficient of phosphorus can be obtained in the hot-metal dephosphorization by using the dephosphorizer containing CaSiO3.

Key words: hot metal, dephosphorization, ferrosilicon, silicon dioxide, calcium silicate, mass transfer coefficient