Thermodynamic Investigations of New Cobalt Smelting for Cobalt Rich Crust

为开发富钴结壳冶炼新工艺，对MnO-SiO2-CaO和FeO-SiO2-CaO渣系铁饱和相图和热力学性质进行了基础研究，测定了1573 K时MnO-SiO2-CaO渣系铁饱和相图。测定了1823 K时钴和磷在MnO-SiO_2-CaO或FeO-SiO_2-CaO渣系与铁液之间的分配比。MnO-SiO_2-CaO或FeO-SiO_2-CaO渣系与铁的钴值在0.001-0.01之间，钴向铁液富集。MnO-SiO2-CaO或FeO-SiO2-CaO渣系与铁液之间的磷比随渣中CaO浓度的增加而增加。在1823 K下，根据CoO和PO2.5在MnO-SiO2-CaO和FeO-SiO2-CaO渣系中的分配比，计算了CoO和PO2.5在MnO-SiO2-CaO和FeO-SiO2-CaO渣系中的活度系数。MnO-SiO2-CaO渣系中CoO的值为1 ~ 2，FeO-SiO2-CaO渣系中CoO的值为0.2 ~ 0.4左右。而MnO-SiO_2-CaO和FeO-SiO_2-CaO渣系中PO_（2.5）的活度系数很小，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>.