水镁石制取高活性氧化镁的探究

Research on Preparation of High Acitive MgO by Brucite

活性氧化镁与轻质氧化镁的生产工艺大同小异,大体都采用将前驱物通过煅烧法获得。实验以水镁石作为前驱物,分别探究煅烧温度及时间对其煅烧后Mg O产物的失重率,柠檬酸活性(CAA值),碘吸附值和水化率的影响。当煅烧温度为550℃~650℃,煅烧时间为1.0 h^2.0 h所得Mg O的CAA值最小,碘的吸附值最大,且平均水化率相对而言也是最大的,即产物Mg O活性最强,从而在工业上就拥有更大的应用价值。另外发现在600℃煅烧下得到Mg O的结构在SEM图呈棉絮状。在经80℃水解,抽滤,烘干后得到的Mg(OH)2的粒径很细小,电镜(SEM)图上也呈棉絮状,较其他煅烧温度所得到的产物结构明显不同。

The active magnesium oxide and Iight magnesium oxide all use the same producing technology, which generally adopt calcination method on the obtained precursor. Using brucite as precursor, it was discussed that the influence of the calcination temperature and time on its weight- lessness rate, citric acid activity（CAA）, iodine sorption value and the hydration rate of calcined MgO product. When the calcination temperature is 500 ℃ - 600 ℃ and burning time is from 1 to 2 hours, the value of CAA is the lowest and iodine sorption value is the highest, meanwhile, the aver- age hydration rate is the highest, the activity of MgO powder is the strongest, so it will have greater application in industry. We found that the electron microscopy figure of obtained MgO which was calcined under 600 ℃ was cotton fiber. Then after hydrolyzing MgO in 80 ℃, filtering and drying, obtained Mg（OH）2 is very fine and its electron microscopy figure also looks like cotton fiber, that obviously differ from others with different calcination temperature.