Improvement of Refining Method by using Reaction between Multi-component Mesoscopic Phase and Liquid Iron

在介观精炼过程中，与传统的渣精炼相比，无论固液质量比如何，都具有较高的Lp ^<固/渣>值，从而大大提高了脱磷率，理论上降低了渣耗。然而，不利的是，在介观精炼过程中，只有距离金属/介观相界面约1 × 2 mm长的扩散区域有助于脱磷反应，而所有炉渣都用于炉渣精炼过程，并且在与金属的界面处形成致密层。因此，将1 × 2 mm的介观精炼剂颗粒喷入铁液中是有效的，可避免致密层的形成，由于L_p^<固体/渣>对温度的依赖性小，介观精炼工艺在钢液脱磷中的应用是有益的。在铁水脱磷过程中，由于液态渣中碳的还原作用而析出C_2S颗粒的介观相C_2S-C_3 P颗粒的尺寸和分散性与介观相的反应活性无关。C_2S析出后，渣中保持较高的FeO含量是很重要的。P_2O_5从C_2S-C_3 P（C_4P、C_3P）颗粒向炉渣的返速低也是有利的。采用混压法制备的细观细化剂，由于细观细化剂的均匀性，细化效率高。在使用通过沉淀法获得的介观细化焊剂时，其中使用冷却和/或碳还原技术，由于固相在介观细化焊剂中的精细分散，细化效率变得更高。

In mesoscopic refining process, the dephosphorization rate is improved considerably due to high L_p^<solid/slag> value irrespective of solid/liquid mass ratio compared with a conventional slag refining, and slag consumption decreases theoretically. However, it is disadvantageous that only the diffusion area of about 1〜2mm length from the interface of metal/mesoscopic phase contributes to the dephosphorization reaction in mesoscopic refining process, while all slag is used in a slag refining process, and the dense layer is formed at the interface with the metal. Therefore, it is effective to inject the 1〜2 mm particles of the mesoscopic refining flux into liquid iron and to avoid the formation of dense layer.Application of the mesoscopic refining process to steel dephosphorization is thought to be useful because of the small temperature dependence of L_p^<solid/slag>. Although L_p^<slag/metal> becomes disadvantageous at higher temperature, it can he improved by increasing CaO/SiO_2 ratio.When the mesoscopic phase, in which C_2S particles precipitate by the carbon reduction of liquid slag, is used in hot metal dephosphorization, the size and dispersion of C_2S-C_3P particles are not related to the reactivity of the mesoscopic phase. It is important to keep the large content of FeO in slag after C_2S precipitation. The low reversion rate of P_2O_5 from the C_2S-C_3P (C_4P, C_3P) particles to slag is also advantageous.In the present slag refining process, large amount of flux is used inevitably because the flux is not completely melted. In the use of mesoscopic refining flux obtained by the mixing-pressing method, the efficiency of refining becomes high because of the uniformity of mesoscopic refining flux. In the use of mesoscopic refining flux obtained by the precipitation method, in which cooling and/or carbon reduction technique is used, the efficiency of refining becomes higher because of the fine dispersion of solid phase in mesoscopic refining flux.