原料对直接结合镁铬砖体积变化的影响

以印度铬矿、西藏铬矿、中高档镁砂及电熔镁砂为原料,在200 MPa下制成50 mm×40 mm的圆柱形试样,于1 700~1 750℃烧成.通过测量试样烧成前后直径和高度的变化,从而获得其体积变化.根据体积变化讨论了不同原料及粒度配比对直接结合镁铬砖体积变化的影响,提出控制烧成体积变化的措施,即改变细颗粒中印度铬矿的加入量,同时调整细粉内中档镁砂与高纯镁砂的配比.研究结果表明,当印度铬矿与西藏铬矿的质量比大、细粉内中档镁砂与高纯镁砂的质量比小时,试样的体积变化率较小;反之,试样的体积变化率较大.

Effect of Raw Materials on the Volume Change of Direct-Bonded Magnesia-Chrome Refractory Bricks

Using the chrome ores from India and Tibet, middle/high-grade magnesia and fused magnesia as raw materials, the φ50 mm × 40 mm cylindrical specimens were compacted under 200 MPa and sintered at 1700-1750°C. The aspect ratio of specimens was measured before and after sintering to obtain their volume changes by which the effects of different raw materials used and their mixture proportions of grain sizes on the volume change of direct-bonded magnesia-chrome refractory bricks were discussed. Some measures were therefore proposed to control the volume change of those bricks, i.e., changing the amount of the chrome ore from India to be added in fine grain and adjusting the mixture proportion of middle-grade magnesia to high-grade one in fine powder. The experimental results showed that when the mass ratio of chrome ore from India to that from Tibet is high and the mass ratio of middle-grade magnesia to high-grade one is low, the volume change is relatively small and vice versa.