(中國科學(xué)院 過程工程研究所 綠色過程工程實驗室，北京 100080)
摘 要: 提出一種新的反應(yīng)結(jié)晶過程，即采用Na2CO3溶液為沉淀劑，選擇合適條件與MgCl2溶液進行均相(不加晶種)結(jié)晶反應(yīng)，實現(xiàn)從鹵水中沉淀鎂，制得MgCO3·3H2O晶體。研究溫度、反應(yīng)液初始濃度及滴加速率對MgCO3·3H2O晶體生長及晶形的影響，采用XRD和SEM對得到的晶體進行表征。結(jié)果表明：MgCO3·3H2O晶體的收率為98.1%，純度為99.9%，所得到的晶體為MgCO3·3H2O，且溫度、反應(yīng)液初始濃度及滴加速率對MgCO3·3H2O晶體的生長、形態(tài)及顆粒大小都有著顯著的影響。
關(guān)鍵字: MgCO3·3H2O；晶體生長；沉淀劑
（Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences,
Beijing 100080, China）
Abstract:MgCO3·3H2O was selected as target precipitate in extraction of magnesium from brine due to its good filtration properties and its excellent dewatering characteristics. A novel homogeneous (unseeded) precipitation of MgCO3·3H2O by the reaction of MgCl2 with Na2CO3 in supersaturated solutions was investigated for the precipitation of magnesium from brine. The factors influenced the crystal growth and morphology of MgCO3·3H2O, such as reaction temperature, initial concentration and titration speed were studied. The results show that the yield of MgCO3·3H2O is 98.1% and the purity of MgCO3·3H2O is 99.91%. MgCO3∙3H2O as prepared were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM). The results show that the product is club-shaped MgCO3·3H2O and the temperature, initial concentration and titration speed all have significant effect on the crystal growth, crystal morphology and particle size distribution.
Key words: MgCO3·3H2O; crystal growth; precipitate
