块状菱镁矿的烧结特性

Study on Sintering Characteristics of Block Magnesite

使用高温电炉、XRD和SEM等手段,研究了不同尺寸块状菱镁矿的烧结特性。结果表明:在400-800℃温度范围内试样的分解率、活性和体积密度与块度有关,块度小的分解率高、活性大,体积密度减小得快。在800-1000℃烧结尚未开始;在1000-1300℃体积密度上升至2.00 g/cm^3,以固相烧结为主,烧结速度较低;在1300-1600℃体积密度上升至2.60 g/cm^3,固相烧结逐渐向固相-液相烧结转变,烧结速度有所提高;在1600℃以上完全转变为液相烧结,烧结速度迅速提高,体积密度上升至1800℃的3.27 g/cm^3;在1800℃烧后,块度对其体积密度基本上没有影响。

The sintering characteristics of block magnesite with different sizes were investigated. The results show that after firing in 400–800℃, the smaller size of the specimens, the higher the decomposition rate and activity of the specimens, as well as the faster decreasing of the bulk density. Sintering of the specimens did not start when fired in 800–1000℃. The sintering speed of the specimens is slow fired in 1000–1300℃, the bulk density increases to 2.00 g/cm^3, because magnesite pseudomorph impedes the diffusion of particle during solid sintering. However, the sintering speed increases in 1300–1600℃, the solid sintering turns to liquid sintering, and the bulk density increases to 2.60 g/cm^3. Sintering speed of the specimens increases rapidly fired at 1600℃ or higher. The specimens are densified in the completely liquid sintering, bulk density increases to 3.27 g/cm^3. The size of specimens have little effect on the final bulk density fired at 1800℃.