高硅Fe-Si-Ni熔体还原脱磷反应动力学

Kinetics of reductive dephosphorization reaction for high-silicon Fe-Si-Ni melt

基于电硅热法生产300系列不锈钢镍、铬铁合金基料工艺开发,着重研究高硅Fe-Si-Ni熔体的还原脱磷问题。试验证明,Fe-Si-Ni熔体的脱磷率主要取决于熔体中的硅含量,固态脱磷渣的物相结构检测表明,磷元素在渣中的存在形式不仅有Ca_(3)P_(2)简单组分,还存在Ca_(4)SiP_(4)和Ca_(10+x)Si_(12-2x)P_(16)等复杂组分。提出了Fe-Si-Ni熔体还原脱磷过程发生"回磷"现象的反应机理,根据试验数据给出了10 kg感应炉的脱磷宏观反应动力学公式通式为dw([P])/dt=-Aw([P])+Bt(A、B为经验常数)。对于沉淀脱磷(SiCa合金作为脱磷剂,CaO-CaF_(2)为吸附渣),其宏观反应动力学公式为[%P]=0.101e^(-0.101t)+1.06×10^(-4)t^(2)-0.0301([%P]表示合金中磷的质量分数w([P])乘以100,t表示脱磷时间)。对于界面脱磷(CaO_((饱和))-CaF_(2)为脱磷渣),其宏观反应动力学公式为[%P]=0.113e^(-0.113t)+7.76×10^(-5)t^(2)+0.001 43。

The behavior and kinetics of reductive dephosphorization(de-P) reaction for high-silicon Fe-Si-Ni melt was studied, which was one important part for developing a thermal-silicon reduction method to produce the nickel and chromium-iron based alloy for 300 series stainless steel production. The results showed that the de-P rate of Fe-Si-Ni melt mainly depends on the silicon content of the alloy melt, and the X-ray diffraction(XRD) analysis indicates that not only Ca_(3)P_(2) but also Ca_(10+x)Si_(12-2x)P_(16) and Ca_(4)SiP_(4) existed in the de-P slag. Besides, the mechanism of "rephosphorization" phenomenon in the de-P experiment for high-silicon Fe-Si-Ni melt was proposed. According to the experimental data, the kinetic formula of dephosphorization reaction in 10 kg induction furnace is given as dw([P])/dt =-Aw([P]) + Bt,(A and B were the empirical constants). For precipitation dephosphorization(SiCa alloy as dephosphorization agent, CaO-CaF_(2) as adsorption slag), the macro reaction kinetics formula was [%P] = 0.101 e^(-0.101t)+1.06×10^(-4)t^(2)-0.030 1([%P] was the mass fraction of phosphorus in the alloy w([P]) multiplied by 100, t was dephosphorization time). For interfacial dephosphorization(CaO(saturated)-CaF_(2) was dephosphorization slag), the macro reaction kinetic formula was [%P] = 0.113 e^(-0.113t)+ 7.76×10^(-5)t^(2)+0.001 43.