制备高纯碱式碳酸镁和氧化镁的热解及煅烧条件

Pyrolyzation and Calcination Conditions in Preparation of High-purity Basic Magnesium Carbonate and Magnesium Oxide

以内蒙古产白云石为原料,通过加入有机添加剂而改进的碳化法制得精制重镁水,在不同温度下热解得到高纯碱式碳酸镁,进而于不同温度、不同时间下煅烧得到高纯氧化镁。研究了热解温度对高纯碱式碳酸镁纯度、物相和形貌的影响;以及煅烧温度和时间的选择及其对高纯氧化镁物相和形貌的影响。结果表明,重镁水热解温度为95~100℃;热解温度>70℃时,碱式碳酸镁物相为4MgCO3·Mg(OH)2·4H2O;随着热解温度的升高,碱式碳酸镁晶体形貌从板条状逐渐转变为球状。

Fine emulsion of magnesium was prepared by modified carbonation method with organic additive,for which dolomite produced from Inner Mongolia as the raw material.Then,Fine emulsion of magnesium was pyrolysised at different temperature to synthesize high-purity basic magnesium carbonate,which was calcinated to prepare high-purity magnesium oxide at diverse temperature and time.Prepared samples were characterized by ICP spectroscopy,X-ray diffraction,scanning electron microscopy,respectively.Influences of pyrolyzation temperature as well as the calcination temperature and time on the purity,phase and feature of the product were well studied.Results indicate that the pyrolyzation temperature is 95~100℃.Phase of magnesium carbonate is 4MgCO3·MgCO3·4H2O at the temperatures higher than 70℃.And as the temperature increase,the morphology of magnesium carbonate is altered gradually from lath to sphere.Calcination temperature and time of high-purity basic magnesium carbonate are 450℃and 45~60min,respectively.