Thermodynamic Investigations of New Cobalt Smelting for Cobalt Rich Crust

对含铁饱和的MnO-SiO2-CaO和FeO-SiO2-CaO渣体系的相图和热力学性质进行了基础研究，旨在为富钴结壳开发新的钴冶炼方法。在1573K条件下测定了MnO-SiO2-CaO体系的相图。液相线和相平衡关系与Glasser等的数据一致。在1823 k时测定了MnO-SiO2-CaO或FeO-SiO2-CaO渣和铁液中钴和磷的分布比，MnO-SiO2-CaO或FeO-SiO2-CaO渣和铁的钴值在0.001 ~ 0.01之间，钴富集到铁液中。随着渣中CaO浓度的增加，MnO-SiO2-CaO和FeO-SiO2-CaO渣中磷与铁液的比值增大。富CaO渣可用于钴-铁合金中的除磷。根据分布比，得到了MnO-SiO2-CaO和FeO-SiO2-CaO渣在1823K时CoO和PO2.5的活度系数。MnO-SiO2-CaO渣体系的CoO值为1 ~ 2，FeO-SiO2-CaO渣体系的CoO值为0.2 ~ 0.4。另一方面，PO2.5在MnO-SiO2-CaO和FeO-SiO2-CaO渣中的活度系数非常小，为γ=10^<-8>-10^<-4>。

The fundamental investigations for a phase diagram and thermodynamic properties of the MnO-SiO2-CaO and FeO-SiO2-CaO slag systems with iron saturation were carried out in an aim to develop new cobalt smelting for a cobalt rich crust.The phase diagram of the MnO-SiO2-CaO system was determined at 1573K with iron saturation. The liquidus lines and phase equilibrium relations are agreement with the previous data by Glasser et al.Distribution ratios of cobalt and phosphorus between the MnO-SiO2-CaO or FeO-SiO2-CaO slags and liquid iron were measured at 1823K. the values of cobalt between the MnO-SiO2-CaO or FeO-SiO2-CaO slags and iron showed the around 0.001-0.01, and the cobalt is enriched to liquid iron. The ratios of phosphorus between the MnO-SiO2-CaO or FeO-SiO2-CaO slags and liquid iron increased with increasing of CaO concentration in the slag. CaO rich slags are available for the elimination of phosphorus from Co-Fe alloys.Based on the distribution ratios, the activity coefficients of CoO and PO2.5 in the MnO-SiO2-CaO and FeO-SiO2-CaO slags were derived at 1823K. The values for CoO in the MnO-SiO2-CaO slag system were form 1 to 2, and these values for FeO-SiO2-CaO slags were around 0.2-0.4. On the other hand, the activity coefficients of PO2.5 in the MnO-SiO2-CaO and FeO-SiO2-CaO slags showed very small values as γ=10^<-8>-10^<-4>.