(東北大學(xué) 材料冶金學(xué)院，沈陽 110004)
摘 要: 以Mg(OH)2·4MgCO3·6H2O和SiO2為原料，采用高溫固相法合成Mg2SiO4，利用XRD和Raman光譜表征其結(jié)構(gòu)。通過正交試驗，優(yōu)化高含量NaOH中Mg2SiO4的浸出反應(yīng)條件，得出最佳試驗條件為：溫度220 ℃，時間120 min，液固比6:1，NaOH溶液含量85%(質(zhì)量分?jǐn)?shù))。在優(yōu)化試驗基礎(chǔ)上，采用拉曼光譜對堿浸出過程進(jìn)行在線檢測，利用X射線衍射儀分析堿浸后的水浸渣，研究高含量NaOH中Mg2SiO4浸出反應(yīng)機(jī)理，結(jié)果表明：在反應(yīng)過程中硅氧四面體中的Si—O鍵被破壞，NaOH介入硅酸鹽晶格中，Mg2+經(jīng)過堿浸過程可以脫離SiO4陣列，以Mg(OH)2形式從其硅酸鹽中得以釋放。
關(guān)鍵字: Mg2SiO4；NaOH溶液；拉曼光譜；反應(yīng)機(jī)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
