Experimental Study of Phase Equilibria in the PbO-ZnO-'Fe_2O_3'-CaO-SiO_2 System in Air for High Lead Smelting Slags (CaO/SiO_2=0.35 and PbO/(CaO+SiO_2)=5.0 by Weight)

摘要

Experimental studies on phase Equilibria in the multicomponent system PbO-ZnO-CaO-SiO_2-FeO-Fe_2O_3 in air have been conducted to characterize the phase relations of a complex slag system used in commercial lead oxidation smelting. The liquidus in the pseudo-ternary section ZnO-"Fe_2O_3"-(PbO+CaO + SiO_2) with the CaO/ SiO_2 weight ratio of 0.35 and the PbO/(CaO + SiO_2) weight ratio of 5.0 has been constructed using results of over 100 high-temperature equilibration and quenching experiments followed by electron probe X-ray microanalysis. The liquidus in this pseudoternary section contains primary phase fields of spinel (zinc ferrite) Zn_xFe_(3-x)O_(4+y), zincite Zn_uFe_(1-u)O, melilite Pb_vCa_(2-v)Zn_wFe_(1-w)Si_2O_7, hematite Fe_2O_3, magneto-plumbite PbFe_(10)O_(16), and dicalcium silicate Ca_(2-t)Pb_tSiO_4. The laboratory results are compared with the slags obtained from an industrial reactor.