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水热法制备碱式硫酸镁晶须的过程机制

刘峰; 向兰; 金涌   

  1. 清华大学化学工程系反应工程教研室 北京 100084
  • 收稿日期:2003-07-11 修回日期:2003-09-08 出版日期:2004-07-20 网络出版日期:2004-07-20

Hydrothermal Synthesis Process of Magnesium Oxysulfate Whiskers

LIU Feng; XIANG Lan; JIN Yong   

  1. Department of Chemical Engineering; Tsinghua University; Beijing 100084; China
  • Received:2003-07-11 Revised:2003-09-08 Published:2004-07-20 Online:2004-07-20

摘要: 以MgSO4和NaOH为原料,采用常温合成-水热反应方式制备出直径0.5-1.0μm、长30-50μm的碱式硫酸镁(5Mg(OH)2·MgSO4·3H2O)晶须。电导率实验表明:添加氢氧化镁可显著提高硫酸镁水热溶液的电导率,由此初步推测晶须的水热合成属溶解-结晶机制:氢氧化镁首先溶解,然后溶液中Mg2+、SO42-和OH-发生反应生成碱式硫酸镁晶须。晶须的水热合成过程受晶体生长控制,宏观动力学方程为:-dc/dt=0.438(c-0.417)4

关键词: 水合碱式硫酸镁, 晶须, 水热合成

Abstract: Magnesium oxysulfate whiskers (5Mg(OH)2·MgSO4·3H2O) with a diameter of 0.5--1.0μm
and a length of 30--50μm were synthesized via precipitation in room temperature followed with the hydrothermal reaction, using MgSO4 and NaOH
as the raw materials. The experimental results indicate that the addition of magnesium hydroxide increases the specific conductance of the magnesium sulfate
hydrothermal solution obviously, implying that magnesium oxysulfate whiskers may be formed via the dissolution of Mg(OH)2 followed with the interaction
of Mg2+, SO42- and OH^- ions. The hydrothermal process of the whiskers is controlled by the crystal growth step and the corresponding
kinetic model is as follows: -dc/dt=0.438(c-0.417)4.

Key words: magnesium oxysulfate, whiskers, hydrothermal synthesis

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