水菱镁石制备轻烧氧化镁的热选工艺研究

Heat-Dress Study on the Preparation of Light-Burned MgO from Hydromagnesite

以粒度-2 mm的水菱镁矿石作为原料,考察不同煅烧温度和保温时间等因素对轻烧氧化镁活性及热选分级脱除其硅、钙等杂质的影响规律。结果表明:轻烧氧化镁的活性随着煅烧温度的升高及保温时间的延长呈先升高后降低的趋势,当煅烧温度为900℃,保温时间为3 h时,轻烧氧化镁活性最大,为58.62%。通过热选分析后,+0.25 mm中水菱镁石轻烧粉MgO含量为96.76%,产率为70.98%。热选后硅、钙等杂质的脱除率随着煅烧温度的升高呈先减小后增大的趋势;随着保温时间的升高呈先升高后降低的趋势。当煅烧温度为900℃,保温时间为3 h时,热选CaO脱除率为6.67%,SiO2脱除率为7.69%。对不同温度煅烧的水菱镁石轻烧粉进行X射线衍射分析与红外光谱分析,进一步考察水菱镁石热解机理。

Hydromagnesite ore with a particle size of-2 mm was used as raw material to investigate the effects of different calcination temperature and holding time on the activity of light burned magnesia and the thermal separation of silicon,calcium and other impurities.The results showed that the activity of light burned magnesia increased first and then decreased with the increase of calcination temperature and the holding time.When the calcination temperature was 900℃and the holding time was 3 h,the activity of light burned magnesia was 58.62%,which was the highest.After hot-sort analysis,the content of MgO in+0.25 mm medium water magnesite light burning powder was 96.76%,and the recovery rate was 70.98%.After heat-dress,the removal rate of impurities such as silicon and calcium decreases first and then increases with the increase of calcination temperature;it increases first and then decreases with the increase of holding time.When the calcination temperature is 900℃and the holding time is 3 h,The hot-dress CaO removal rate was 6.67%,and the SiO2 removal rate was 7.69%.In order to further investigate the pyrolysis mechanism of hydrotalcite,XRD and infrared spectroscopy were carried out on different calcined calnesite light burning powder.