镁砂对高铝质可塑料性能影响

Effect of Mg O on Property of High-alumina Refractory Plastics

以高铝矾土、二氧化硅微粉和氧化铝微粉为原料,以磷酸二氢铝和磷酸为结合剂,制备了用于CFB锅炉的高铝质可塑料,重点研究镁砂细粉用量对高铝质可塑料性能的影响。按照不定形耐火材料检测标准对热处理后耐火可塑料的常温力学性能、致密性及耐磨性能进行检测,通过XRD和SEM分析手段对热处理后试样的物相组成和微观结构进行表征。结果表明:镁砂对可塑料起到促凝和促烧结作用,随着镁砂加入量增大,促凝时间缩短,经110℃热处理后试样常温强度逐渐增大,经1100℃热处理后试样常温强度呈先增大后减小趋势。当镁砂加入量为5%,1100℃热处理后试样常温强度和结构致密性可处于最高值,耐磨性有所降低,试样矿物相组成中包括刚玉、莫来石和堇青石相。

High-alumina plastics in CFB Boilers were prepared from the raw materials including high alumina bauxite, silica fume and aluminum powder. The binding agent was Aluminum dihydrogen phosphate and phosphoric acid. The effect of magnesia on the property of high-alumina plastic was studied. The mechanical properties at room temperature, compactness and wear resistance of specimens dried and sintered were detected according to the national standard of unshaped refractory. The phase composition and microstrueture of specimens dried and sintered were characterized by XRD and SEM. The results show that the property of clotting and sintering could be promoted by magnesia. The clotting time was gradually shortened by the increasing magnesia. The strength of specimens dried at 110 ℃ increased with magnesia. The strength of specimens sintered at 1100 ℃ firstly increase and then decrease with magnesia. The bulk density and cold rupture strength and cold crushing strength of high-alumina plastic sintered at 1100 ℃ would be the highest of all when 5% magnesia was added. The specimen was composed of corundum, mullite and a small amount of cordierite.