Effect of ZnO/PbO and FeOX/SiO2 ratio on the viscosity of lead smelting slags

Abstract

The effect of ZnO/PbO and FeO X /SiO 2 on the viscosity of the PbO-ZnO-Fe 3 O 4-SiO 2-CaO slag was measured using the rotating spindle method. The slag viscosity decreased with decreasing ZnO/PbO mass ratio because of the depolymerization of the silicate structures. The viscosity decreased with increasing FeO X /SiO 2 mass ratio as the experimental temperature was above 1623 K, while the viscosity increased significantly with the increase of FeO X /SiO 2 as the experimental temperature below 1623 K because of the phase transition and the change of slag melting point. According to XRD analysis of as-quenched slag, the spinel and the zincite phase increased with increasing FeO X /SiO 2. Increasing ZnO/PbO and FeO X /SiO 2 could enhance the crystallization capacity of the slag. FTIR analysis revealed that the degree of polymerization of the as-quenched slags decreased with decreasing ZnO/PbO and increasing FeO X /SiO 2. The temperature dependencies of the viscosity on ZnO/PbO and FeO X /SiO 2 were investigated, and the apparent activation energies of each system were found to be between 169.5 to 227.4 KJ/mol, and 151.1 to 676.4 KJ/mol, respectively.

Influence of iron ore concentrate on the characteristics of sintering and reduction of sinter

“…The reaction (1), (3) and (4) was endothermic reaction, the Gibbs free energy was decreased with the increase decomposition temperature; In the case of the reaction temperature was below 811K, the reaction (1), (3) and (4) cannot occur. The main chemical reaction of sintering process occurred endothermic, as shown reaction (1), (3) and (4), and the exothermic reaction was only a small part in the sintering process, as shown in reaction (2) and (5). The higher reaction temperature was beneficial to the process of sinter, so the higher ignition temperature (1073K) was advantageous for the reaction in sintering process.…”

“…The melt fluidity of iron ore depends on the liquid phase amount and viscosity, and can influence on the sintering process [2]. Viscosity is also one of the important physiochemical properties of slag, and low viscosity could promote the efficiency of the desulfurization reaction of slag [3]. Additionally, the fluidity of iron ore increased with the increase of SiO2 and the decrease of Al2O3.…”

Towards More Reliable $${\text{ {PbO}-{SiO}}}_{2}$$ Based Slag Viscosity Measurements in Alumina via a Dense Intermediate Spinel Layer

“…No information was given on the stability of the viscosity measurement over time nor the slag composition after the measurement. However, very low viscosity values (15-200 mPa.s) were reported at temperatures up to 1300 C. Ouyang [8,9] also performed viscosity measurements with alumina spindles and crucibles on very similar slag compositions as the one that will be considered in this work. Sample preparation involved melting of a PbO-SiO 2 master slag.…”

“…This interaction of PbO-SiO 2 based slag with alumina was also previously identified as a source for errors in viscosity measurements in literature. [2,6,9] Slag viscosity measurements consist of a sequence of pre-programmed measurements. The specific measurement sequence at 1200 C and 1150 C is presented in Table II.…”

“…This increase makes it hard to define an unique steady-state viscosity and therefore the measurement is inaccurate. Moreover, the commonly reported alumina increase in the bulk slag [6,8,9] is not sufficient to reflect the overall measurement error in the case an intermediate layer is formed. Additional images of the cruciblemeasurement gap-spindle section are necessary in such a case to measure changes in geometry occurred during measurement.…”