Effect of CaO/SiO2 and Fe/SiO2 ratios on phase equilibria in PbO-ZnO-CaO-SiO2-“Fe2O3” system in air

Experimental studies on phase equilibria and liquidus temperature in the PbO-ZnO-CaO-SiO2-“Fe2O3” system, with the mass ratios of CaO/SiO2=1-1.6 and Fe/SiO2= 1.3-1.7, and 40% PbO and 8% ZnO, were carried out between 1273 and 1573 K. Slags were equilibrated at 1273 to 1573 K and cooled rapidly by quenching. The XRD and SEM-EDS results showed that the slag compositions are in the franklinite primary phase field. Calcium and lead silicates are formed between 1373 and 1473 K. The Ca/Pb silicate and magnetoplumbite phases are partially formed by an incongruent reaction. The experimental and thermodynamical results showed that the liquidus increased by increasing CaO/SiO2 mass ratio and decreasing Fe/SiO2 mass ratio.