Reaction mechanism of molten NaOH decomposing Zn2SiO4 in willemite
来源期刊：中南大学学报(英文版)2015年第4期
论文作者：ZHAO Chang-ming ZHAI Yu-chun ZHANG Chong-min LI Jun-li LI Sheng-li
文章页码：1227 - 1231
Key words：Raman spectroscopy; Zn2SiO4; alkali melting; reaction mechanism
Abstract: Based on the existing form of Zn2SiO4 in willemite, the chemical precipitation method was used to synthesize Zn2SiO4. Through the orthogonal experimentation, the reaction conditions of melten NaOH decomposing Zn2SiO4 were optimized, and the optimal experimental conditions include reaction temperature of 400 °C, reaction time of 4 h, and alkaline-to-ore molar ratio of 20:1. Based on the optimized experiment, on-line detection for the alkali leaching was made by using Raman spectroscopy; XRD was used to analyze the structure of water leaching residue, to explore the reaction mechanism of NaOH decomposing Zn2SiO4. The results show that during the reaction process, the Si—O bond in SiO4 is destroyed, and the NaOH inserts itself into the silicate lattice, producing an immediate Na2ZnSiO4 product. After the alkali leaching process, Zn2+ can be separated from the SiO4 array, which can be released out of the silicate in the form of ZnO.
ZHAO Chang-ming(赵昌明)1, 2, ZHAI Yu-chun(翟玉春)2, ZHANG Chong-min(张崇民)1, LI Jun-li(李军丽)1, LI Sheng-li(李胜利)1
(1. School of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan 114051, China;
2. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China)
Abstract:Based on the existing form of Zn2SiO4 in willemite, the chemical precipitation method was used to synthesize Zn2SiO4. Through the orthogonal experimentation, the reaction conditions of melten NaOH decomposing Zn2SiO4 were optimized, and the optimal experimental conditions include reaction temperature of 400 °C, reaction time of 4 h, and alkaline-to-ore molar ratio of 20:1. Based on the optimized experiment, on-line detection for the alkali leaching was made by using Raman spectroscopy; XRD was used to analyze the structure of water leaching residue, to explore the reaction mechanism of NaOH decomposing Zn2SiO4. The results show that during the reaction process, the Si—O bond in SiO4 is destroyed, and the NaOH inserts itself into the silicate lattice, producing an immediate Na2ZnSiO4 product. After the alkali leaching process, Zn2+ can be separated from the SiO4 array, which can be released out of the silicate in the form of ZnO.
Key words:Raman spectroscopy; Zn2SiO4; alkali melting; reaction mechanism
