以硫酸镁作助剂从石灰石免煅烧合成文石碳酸钙晶须  

Synthesis of Needle-like Aragonite from Limestone without Calcinations in the Presence of Magnesium Sulfate

作　　者：蔡强[1] 邵明浩[2] 胡泽善[1] 丁社光[1] 魏小平[2] 傅敏[1] 

机构地区：[1]重庆工商大学环境与生物工程学院,重庆400067 [2]解放军后勤工程学院,重庆400016

出　　处：《材料导报（纳米与新材料专辑）》2008年第2期244-247,共4页

基　　金：重庆市自然科学基金

摘　　要：采用溶液中可逆反应由石灰石免煅烧合成了针状文石,用光学显微镜、扫描电子显微镜(SEM)及X射线衍射分析(XRD)表征了产物与中间产物的形貌与晶相结构。在硫酸镁溶液中采用空气吹扫回流溶解了GCC(研磨碳酸钙)粉末,用EDTA滴定分析了GCC溶解反应的反应速度,建立了溶解反应动力学方程,该方程表现出对硫酸镁浓度的二级反应动力学特征,反应速度常数为0.0015 L^(-3)·mol^(-1)·h^(-1)。GCC溶解反应产生了纤维状碱式硫酸镁及石膏晶体,可由溶解反应产物合成出针状文石,70℃采用纯二氧化碳碳酸化中间产物得到长度为8～10μm,长径比为4～7的文石晶体。The needle-like aragonite is synthesized with a reversible solution reaction from limestone without calcination. Optical microscope, Scan electron microscope （SEM） and X-ray diffraction （XRD） are used to characterize the morphology and crystal structure of intermediate and product aragonite. The GCC （Grinding calcium carbonate） powder is dissolved in aqueous solution of magnesium sulfate with reflux and air flush. EDTA titration is used to evaluate the reaction rate of GCC dissolution. A kinetics equation of the dissolution reaction is constructed, which displays a second-order kinetics feature to the concentration of magnesium sulfate. A rate constant of 0. 0015L^-3·mol^-1·h^-1 is obtained. The dissolution reaction produces the fiber-like magnesium hydroxide sulfate and gypsum crystal. Then the needle-like aragonite can be synthesized from the dissolution product. CO2 bubbling of the suspension at 70℃ produces the needle-like aragonite of 8-10 μm in length with an aspect ratio of 4-7.

关 键 词：文石 合成 针状 晶须 碳酸钙 

分 类 号：TQ460.72[医药卫生—药物分析学] Q959.21[化学工程—制药化工]