Structure and adaptability of FexO-SiO2-MgO-15 wt% CaO-0.026 wt% NiO slag with the Fe/SiO2 mass ratio of 1.2 in flash matte smelting. Issue 2 (15th January 2023)

• Record Type: Journal Article
• Authors: Wang, Guohua; Cui, Yaru; Li, Xiaoming; Shi, Ruimeng; Yang, Jian; Yang, Shufeng; Zhao, Junxue; Nan, Junfang
• Is Part Of: Ceramics international. Volume 49:Issue 2(2023)
• Page Start: 2531
• Page End: 2539
• Publication Date: 2023-01-15
• Subjects: Chemical properties -- Silicate polyanion -- Depolymerization -- MgO -- Molecular dynamics simulation; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.09.232
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The high-magnesium gangue severely affects the melting performance and fluidity of slag in nickel matte smelting. To detect the adaptability when the CaO-modified slag for treating high-magnesia nickel sulfide concentrate in flash smelting, the synergistic effect of MgO and other oxides on the microstructure and physicochemical properties of slag were analyzed through molecular dynamics simulation associated with the experimental analysis. The results indicate that the MgO content increases from 5 wt% to 11 wt%, part of the Fe 2+ ions in silicate are gradually replaced by Mg 2+, and some of them are transformed into Fe 3+ in the external atmosphere. Accordingly, the generated Fe 3+ may destroy the bridge oxygen between Si 4+ -O 2- -Si 4+ and more complex silicate ions will be dissociated into SiO4 4+ . As a consequence, the Q 0 proportion in the modified high-magnesia smelting slag improved from 24.33% to 29.69%, and the n (BO/T) decreased from 1.45 to 1.29. However, when MgO content is high enough, SiO4 4+ tetrahedron ions may attract Fe 2+ and Mg 2+ to form (Fe, Mg)2 SiO4 with a more robust interaction network structure, resulting in an adverse effect on melting temperature and ions diffusion coefficient. The modified nickel slags with 5–11 wt% MgO represent hospitable melting temperature less than 1320 °C, viscosity lower than 0.091 Pa s, and surface tension between 0.4811 N/m to 0.4838 N/m. In brief, the CaO-modified slag turned out to be conducive for treating high-magnesium nickel sulfide concentrates in flash matte smelting, especially for those containing MgO less than 7 wt%.