(东北大学 材料冶金学院，沈阳 110004)
摘 要: 以Mg(OH)2·4MgCO3·6H2O和SiO2为原料，采用高温固相法合成Mg2SiO4，利用XRD和Raman光谱表征其结构。通过正交试验，优化高含量NaOH中Mg2SiO4的浸出反应条件，得出最佳试验条件为：温度220 ℃，时间120 min，液固比6:1，NaOH溶液含量85%(质量分数)。在优化试验基础上，采用拉曼光谱对碱浸出过程进行在线检测，利用X射线衍射仪分析碱浸后的水浸渣，研究高含量NaOH中Mg2SiO4浸出反应机理，结果表明：在反应过程中硅氧四面体中的Si—O键被破坏，NaOH介入硅酸盐晶格中，Mg2+经过碱浸过程可以脱离SiO4阵列，以Mg(OH)2形式从其硅酸盐中得以释放。
关键字: Mg2SiO4；NaOH溶液；拉曼光谱；反应机理
（School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China）
Abstract:Mg2SiO4 was finely prepared by high temperature solid state method using Mg(OH)2·4MgCO3·6H2O and SiO2 as raw materials. The structure of Mg2SiO4 was investigated by XRD and Raman spectroscopy. The optimized conditions for dissolution reaction of Mg2SiO4 in high NaOH content system were investigated by orthogonal test, and the optimal parameters were obtained as follows: reaction temperature of 220 ℃, reaction time of 120 min, liquid-solid ratio of 6:1 and NaOH content of 85% (mass fraction). Based on the optimal experiment, the leaching reaction mechanism of Mg2SiO4 in high NaOH content system was investigated. Raman spectra were measured for the reactions between the silicates and sodium hydroxide in-situ during the alkali dissolution process. Meanwhile, the water-leaching residue of the dissolution products was characterized by X-ray diffractometry. The results show that the bindings Si—O in silicates can be destroyed by aggression of sodium hydroxide, the magnesium ions in Mg2SiO4 can be separated from the silica arrays and liberated in the form of Mg(OH)2 from the silicates.
Key words: Mg2SiO4; NaOH solution; Raman spectrum; reaction mechanism
