高长径比氢氧化镁晶须的室温高效制备工艺与机理

The present use of the salt lake resources in our country is focused mainly on the fabrication of K/Na-bearing products and the continuous accumulation of Mg-bearing resources inhibited the further development of the related industries.Based on the former technology for Mg(OH)2 retardent,a new method is suggested in this project to produce efficiently the Mg(OH)2 whiskers with high aspect ratios at room temperature:MgCl2 and the cheap inorganic bases were used as the major raw materials,active Mg(OH)2 was produced and converted to magnesium hydroxide chloride hydrate (MHCH)whiskers with high aspect ratios,MHCH whiskers were converted to Mg(OH)2 whiskers with high aspect ratios by release of Cl- and phase conversion. The key points were the effective one dimensional growth and conversion of MHCH whiskers at room temperature. The surface active agents or the ultrasonic treatment will be adapted to enhance the activity of Mg(OH)2 precursor,the organic acids/alcohols with long chain structures will be used to induce the one dimensional growth of MHCH whiskers,the mixing solvents will be used to release Cl- slowly from MHCH whiskers and to convert to Mg(OH)2 whiskers with high aspect ratios.The induced crystallization, the removal of Cl- and the phase conversion of MHCH whiskers will be studied by means of knowledges of the crystallization, structure, solution, interphase and molecular simulation,etc, the theoretical model for the formation of Mg(OH)2 whiskers with high aspect ratios at room temperature will be established and used to optimize the formation process.Finally the surface modification, the dispersion and the composite making technologies for Mg(OH)2 whiskers will be studied,and the corresponding whisker enhanced industrial plastics and the papers will be fabricated. It is expected that the present project will establish an internative new way and provide some basic data for the effective industrial utilization of the rich MgCl2 resource in salt lakes.

我国盐湖镁资源丰富，但侧重钾钠资源开发，卤镁资源不断富集，严重制约可持续发展。立足现有氢氧化镁阻燃剂制备技术，本课题提出具有节能减排特征的高长径比氢氧化镁晶须室温高效制备新思路：以氯化镁和廉价无机碱为主要原料，首先制备活性氢氧化镁前驱体，再通过诱导结晶制备高长径比碱式氯化镁晶须，后者脱氯转化为高长径比氢氧化镁晶须。如何实现碱式氯化镁晶须的室温高效定向生长和物相转化是关键。拟通过表面活性剂或超声处理提高氢氧化镁活性，通过长链状有机酸/醇诱导效应促进碱式氯化镁晶须定向生长，后者在混合溶剂中缓释脱氯转化为高长径比氢氧化镁晶须。利用结晶/结构/溶液/界面理论和分子模拟技术研究碱式氯化镁晶须诱导结晶习性和脱氯转化机制，建立室温制备高长径比氢氧化镁晶须的理论模型并指导工艺优化。在此基础上研究氢氧化镁晶须的改性分散与复合，试制大宗复合塑料和生态纸品，为盐湖氯化镁资源的规模化高值利用提供新途径和基础数据。

11我国盐湖镁资源丰富，但侧重钾钠资源开发，卤镁资源不断富集，严重制约可持续发展。立足现有氢氧化镁制备技术，本课题提出具有节能减排特征的高长径比氢氧化镁晶须室温高效制备新思路。纯度约95%含杂氢氧化镁，经过水洗-碱洗强化-选择性络合等工艺处理，可制得纯度＞99%的高纯氢氧化镁。在此基础上建立了固固分离除杂技术，通过界面活性剂消解晶间粘结物、高选择性药剂控制结晶颗粒表面特性，强化不同组分沉降性能差异，实现了快速高效分离，可广泛适用于工业固废回收及原料提纯。通过熔盐辅助焙烧-表面活性剂辅助水化工艺，可制得高分散、高活性的氢氧化镁前驱体。活性氢氧化镁在MgCl2溶液中具有更快的溶解速率，可用于高效制备长径比大于100的碱式氯化镁晶须；在水热条件下，可制得长径比大于1000的碱式氯化镁晶须。碱式氯化镁晶须在NaOH乙醇溶液中反应，可以抑制溶解，促进原位转化，生成高长径比的氢氧化镁晶须。以无机晶须为原料，利用改性、分散、发泡和复合技术，制备出低密度、高力学强度的无机晶须/PVC复合材料。