Phase equilibria in high MgO ferro-manganese and silico-manganese smelting slags

Liquidus isotherms and phase equilibria have been determined experimentally for a pseudo-ternary section of the form MnO-(CaO+MgO)-(SiO2+Al2O3) with a fixed Al-2,O-3,/SiO2, weight ratio of 0.17 and MgO/CaO weight ratio of 0.17 for temperatures in the range 1473-1673 K. The primary phase fields present for the section investigated include manganosite (Mn,Mg,Ca)O; dicalcium silicate alpha-2(Ca,Mg,Mn)O (.) SiO2; merwinite 3CaO(.) ((Mg,Mn)O.2SiO(2); wollastonite [(Ca,Mg,Mn)(OSiO2)-Si-.]; ;tephroite [2(Mn,Mg)O.SiO2]; rhodonite [(Mn,Mg)O. diopside [(CaO,MgO,MnO,Al2O3)(SiO2)-Si-.]; tridymite (SiO2), SiO2] and melilite [2CaO (.) (MgO,MnO,Al2O3).2(SiO2,Al2O3)]. The liquidus temperatures relevant to ferro-manganese and silico-manganese smelting slags have been determined. The liquiclus temperature is shown to be principally dependent on the modified basicity weight ratio (CaO+Mgo)/(SiO2+Al2O3) at low MnO concentrations, and dependent on the mole ratio (CaO+ MgO+MnO)/(SiO2+Al2O3) at higher MnO concentrations.

Phase equilibria in high MgO ferro- and silico-manganese smelting slags

Phase equilibria have been determined experimentally for pseudo-ternary sections of the form “MnO”- (CaO+MgO)-(SiO2+Al2O3) with a fixed Al2O3/SiO2 weight ratio of 0.17 and MgO/CaO weight ratios of 0.25 and 0.17 respectively for temperatures in the range 1473-1673 K. The primary phase fields present for the MgO/CaO weight ratio of 0.17 include manganosite (Mn,Mg,Ca)O; dicalcium silicate α-2(Ca,Mg,Mn)O·SiO2; merwinite 3CaO⋅(Mg,Mn)O⋅2SiO2; wollastonite [(Ca,Mg,Mn)O·SiO2]; diopside [(CaO,MgO,MnO,Al2O3)·SiO2]; tridymite (SiO2); tephroite [2(Mn,Mg)O·SiO2]; rhodonite [(Mn,Mg)O·SiO2] and melilite [2CaO·(MgO,MnO,Al2O3)·2(SiO2,Al2O3)]. For the section with MgO/CaO weight ratio of 0.25 the anorthite phase (CaO⋅Al2O3⋅2SiO2) is also present. The liquidus temperatures of ferro- and silico-manganese smelting slags have been determined. The liquidus temperatures at low MnO concentrations are shown to be principally dependent on the modified basicity weight ratio (CaO+MgO)/(SiO2+Al2O3).