Kinetic Analysis of Defosphoration Process of Synthetical Oxide Melts

Abstract

РАЦИОНАЛЬНОЕ ПРИРОДОПОЛЬЗОВАНИЕ В ЧЕРНОЙ МЕТАЛЛУРГИИ. Для определения факторов, влияющих на степень удаления оксида фосфора из оксидного расплава в газовую фазу, были проведены серии экспериментов с различной основностью (CaO / SiO 2 ) и продувкой с разным соотношением СО / СО 2 . Установлено, что максимальная степень удаления фосфора в газовую фазу достигается при основности расплава, равной 0,5. При большей основности газовая дефосфорация затруднена по термодинамическим причинам, при меньшей ей препятствует высокая вязкость расплава. Получен-ная в ходе кинетических расчетов величина кажущейся энергии активации процесса Е = 140 ± 56 кДж/моль позволяет предположить, что процесс лимитируется диффузионным массопереносом оксида фосфора в жидкой фазе.Ключевые слова: оксидный расплав, лимитирующая стадия процесса, кинетическое уравнение, уравнение Аррениуса, кажущаяся энергия акти-вации, диффузия в жидкой фазе, дефосфорация кислых шлаков.

Dephosphorization and Desulfurization of Acid Oxide Melts and Produced Iron

“…Dephosphorization of acid oxide melts. In previous work, the authors have studied the possibility of gas dephosphorization of oxide melts and the effect of various factors on this process [18,19]. In this work, these studies were continued and supplemented.…”

“…In the course of experiments, a melt was blown with mixtures containing CO and CO 2 , the oxygen partial pressure was of the order of 10 −6 -10 −8 , and no reducing agent was added to the melt. On the whole, the procedure for performing an experiment was similar to that described previously [18,19]. Results of experiments are given in Table 1.…”

“…Results of experiments are given in Table 1. From the results of experiments and thermodynamic calculations [18,19], it may be concluded that phosphorus is capable of transfer from an oxide melt into a gas phase with a reduction in basicity to 0.9 or less, since with this basicity (according to thermodynamic calculations) silicon cations bond calcium cations, as a result of which there is a reduction in the effect of calcium cations as the main component capable of forming strong bonds with phosphorus ions through a common oxygen anion. An acid oxide melt for phosphorus is an unstable "matrix" from which phosphorus may be transferred into a gas phase since the boiling temperature of phosphorus oxide (605°C) is much lower than the melt temperature.…”

“…According to the value of dephosphorization process activation energy (140 ± 56 kJ/mole [19]), it was concluded that the process is limited by diffusion mass transfer of phosphorus oxide within a liquid phase. A criterion governing the limiting stage of the process is mixing.…”