Effect of the CaO/SiO2 mass ratio and FeO content on the viscosity of CaO–SiO2–“FeO”–12wt%ZnO–3wt%Al2O3 slags

• Published in: International journal of minerals, metallurgy and materials Vol. 24; no. 7; pp. 756 - 767
• Main Authors: Lü, Jian-fang, Jin, Zhe-nan, Yang, Hong-ying, Tong, Lin-lin, Chen, Guo-bao, Xiao, Fa-xin
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01-07-2017; Springer Nature B.V; School of Metallurgy, Northeastern University, Shenyang 110819, China
• Subjects: Aluminum oxide; Calcium oxide; Cathode ray tubes; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion and Coatings; Degree of polymerization; Depolymerization; Fourier transforms; Glass; Hazardous wastes; Infrared analysis; Infrared spectroscopy; Materials Science; Metallic Materials; Natural Materials; Raman spectroscopy; Silicon dioxide; Slag; Spectroscopy; Spectrum analysis; Structural analysis; Surfaces and Interfaces; Thin Films; Tribology; Viscosity; Viscous flow; Zinc oxide; lead smelting; slag viscosity; basicity; slag structure; ferrous oxide
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-017-1459-5

An effective process for recycling lead from hazardous waste cathode ray tubes（CRTs） funnel glass through traditional lead smelting has been presented previously. The viscous behavior of the molten high lead slag, which is affected by the addition of funnel glass, plays a critical role in determining the production efficiency. Therefore, the viscosities of the CaO–SiO2–'FeO'–12wt%ZnO–3wt%Al2O3 slags were measured in the current study using the rotating spindle method. The slag viscosity decreases as the CaO/SiO2 mass ratio is increased from 0.8 to 1.2 and also as the FeO content is increased from 8wt% to 20wt%. The breaking temperature of the slag is lowered substantially by the addition of FeO, whereas the influence of the CaO/SiO2 mass ratio on the breaking temperature is complex. The structural analysis of quenched slags using Fourier transform infrared（FTIR） spectroscopy and Raman spectroscopy reveals that the silicate network structure is depolymerized with increasing CaO/SiO2 mass ratio or increasing FeO content. The [FeO6]-octahedra in the slag melt increase as the CaO/SiO2 mass ratio or the FeO content increases. This increase can further decrease the degree of polymerization（DOP） of the slag. Furthermore, the activation energy for viscous flow decreases both with increasing CaO/SiO2 mass ratio and increasing FeO content.