纳米氧化镁制备工艺研究

【作者】 王训；

【导师】 郭人民；

【作者基本信息】 西北大学 ， 化学工程， 2001， 硕士

【摘要】 本文简要介绍了纳米氧化镁的性质、用途及国内外研究和生产现状；重点讨论了纳米粉体制备的基础理论；提出了沉淀转化法制备纳米氧化镁的新工艺。本文首先设计方案对沉淀转化法的基本过程进行分析，找出了实验方法的基本过程特征。然后利用单因素和正交试验法对纳米氧化镁制备工艺进行了研究，探索了各个因素对纳米氧化镁制备的影响及各因素间的交互作用。最后以单因素和正交试验法对纳米氧化镁改性进行了研究，筛选出改性的最佳工艺条件。结果表明：（1）沉淀转化法制备纳米氧化镁的过程，反应初期为CO32-扩散控制，反应后期为CO32-扩散与Mg(OH)2离解共同控制，过程中存在Mg(OH)2向MgCO3的晶型转化过程。（2）沉淀转化法制备纳米氧化镁较佳工艺条件为：反应时间20min;反应温度300C；加水量200ml;改性剂加入方式应采用在反应10min后滴加方式；煅烧温度6000C。在此工艺条件下所得粒子平均粒径小于10nm。（3）纳米氧化镁经月桂酸钠处理可以得到表面亲油化的粒子，改性最佳工艺条件为：改性温度600C；改性pH条件在5左右；改性剂用量10%。在此条件下亲油度最佳值0.55。月桂酸钠与氧化镁间发生化学键合。更多还原

【Abstract】 This paper has reviewed the properties and application of nanometer magnesia. Both the progress in research and the synthesis of nanometer magnesia has been reconsidered. It puts emphasis on the reaction mechanism of precipitation method to prepare nanometer particles, and puts forward a new technics named " precipitation-transforming-method " .The essence of the experiment process has been studied through a series of designed experiment. In order to get the optimum processing conditions and the effects of various factor in preparation of nanometer magnesia and surface modification of prepared magnesia, monofactor method and multifactor orthogonalizing design method have been applied. The following has been obtained through lots of expriments: (1) The velocity of the initial stage of " precipition -transforming - method" is mainly influenced by the diffusion of CO32-,while that of the upper stage is equally influenced by both the diffusion of CO32- and the ionization of the Mg(OH)2. The phenomenon of precipitation transforming exists in the process. (2) The optimum processing conditions in preparation of nanometer magnesia: the reaction time is 20 min; the reaction temperature is 300C;the dosage of water is 200 ml;the modification reagent should be added to the reaction system in drops after 10 min; the calcination temperature is 6000C. The average diameter of the nanometer magnesia under the above conditions is 5.22nm. (3) The optimum processing conditions in the surface modification of nanometer magnesia : the modification temperature is 600C;the modification pH is about 5; the dosage of modification reagent is 10%. The value of the wetting properties in methanol under the above processing conditions is about 0.55. <WP=4>Wang ,Xun (Graduate of the department of chemical engineering) Directed by Prof. Guo,Renmin更多还原