FeV50合金浇铸沉降理论的应用及其影响因素

Theoretical application and factors influencing casting settlement of FeV50 alloy

采用近似无限大流体重力沉降原理分析了多期法FeV50合金浇铸过程渣金分离及浇铸渣层钒的分布规律,考察了熔渣黏度、沉降粒度、浇铸温度、渣层厚度以及保温制度对渣中钒含量的影响.结果表明,浇铸渣中钒的赋存形式除了未还原完全的钒氧化物之外,还存在部分未完全沉降的初级合金;合金沉降速度随合金粒度的增加而增大,随熔渣黏度的增加而减小.1850℃条件下,当渣层厚度为50 mm,熔渣组分质量分数为65.2%Al2O3、15.5%CaO、14.6%MgO、1.9%Fe2O3、0.9%SiO2时,粒径为100μm的合金沉降时间及熔渣上浮时间分别为24.9和1.2 min.基于此,进行浇铸工艺优化试验,在渣层厚度35 mm,浇铸温度1900℃、熔渣主要成分质量分数Al2O360%~65%、CaO 15%~20%、MgO 9%~15%、浇铸锭模保温层厚度9 cm的条件下,浇铸渣中平均TV质量分数由1.39%降低至0.58%.

The process of separation of slag and alloy and distribution of vanadium in casting slag during the casting process of muhiperiod FeV50 preparation were analyzed using the principle of infinite fluid gravitational settling. The effects of slag viscosity, particle size, casting temperature, molten-slag thickness, and insulation system on total vanadium （TV） content in slag were investigated. The analysis demonstrates that vanadium mainly comprises vanadium oxide and incompletely deposited primary ferrovanadium alloy in the casting slag. The sedimentation rate of settlement alloy increases with an increase in the particle size and decreases with an increase in the slag viscosity. The dropping time of FeV50 alloy and floating time of molten slag is 24.9 and 1.2 rain, respectively, when the casting conditions are as follows-casting temperature： 1850℃ , slag layer thickness： 50 mm, particle size： 100 μm, and slag composition mass fraction： 65.2% Al2O3 , 15.5% CaO, 14.6% MgO, 1.9% Fe2O3 , and 0. 9% SiO2. Through optimization experiments, the average vanadium mass content in the slag is reduced from 1.39% to 0.58% for the following casting conditions-slag layer thickness： 35mm, casting temperature： 1900℃, slag component： 60% -65% Al2O3, 15% -20% CaO, 9% -15% MgO; and casting insulation thickness ： 9 cm.