分解产生Al(OH)3和Al2O3的影响
(1. 东北大学 理学院, 沈阳 110004;
2. 东北大学 材料与冶金学院, 沈阳 10004)
摘 要: 研究了疏水性添加剂脂肪酸类阴离子表面活性剂与21-碳烷不同配比对铝酸钠溶液分解产生氢氧化铝和氧化铝的粒度、强度及分解率的影响, 考察了产物Al(OH)3和Al2O3的强度和粒度之间的关系， 探讨了添加剂影响铝酸钠溶液晶种分解的相关机理。结果表明： 脂肪酸质量分数在32％～49%， 添加剂加入量为150×10-6 g/L时， 有利于提高分解率， 但对提高Al(OH)3和Al2O3的强度和粒度不利； 脂肪酸质量分数在15％～22.5%时， Al(OH)3和Al2O3在强度和粒度方面呈相一致的对应关系, 添加剂可促进Al(OH)3的附聚， 提高Al(OH)3和Al2O3的粒度和强度， 但对提高分解率作用不大； Al(OH)3的粒度过大时， 会引起其强度降低， 导致Al2O3粒度下降；加入添加剂后， 可形成球状的Al(OH)3晶体， 有利于形成粒度大、 强度高的氧化铝。
关键字: 铝酸钠； 阴离子表面活性剂； 种子分解； 强度； 粒径
Al2O3 made by seed precipitation from
sodium aluminate solution
（ 1. School of Science, Northeastern University, Shenyang 110004, China;
2. School of Materials and Metallurgy,
Northeastern University, Shenyang 110004, China）
Abstract: The effect of hydrophobic additive on the seed precipitation from sodium aluminate solution was studied by adding fatty acid and heneicosane at different proportions. The results show that when the mass fraction of fatty acid is in the range of 32%-49% and the additive concentration in sodium aluminate solution is 150×10-6 g/L, the rate of precipitation increases, but the particle size of Al (OH)3 and Al2O3 reduces. When the mass fraction of fatty acid is in the range of 15%-22.5%, there is compatible corresponding relation in intensity and grain size for Al(OH)3 and Al2O3, and the particle size of them increases with the quantities of fine particles reduced and the particle strength improved, but the rate of precipitation reduces slightly. After adding additives, Al(OH)3 generates a large globe crystal, this is good for getting a large particle and high intensity Al2O3.
Key words: sodium aluminate；anionic surfactant；seed precipitation process； particle strength；particle size
