化学改性氢氧化铝的反团聚研究

Study on Anti-agglomeration of Chemically Modified Aluminium Hydroxide

以磷酸钠为分散剂,通过测定颗粒的SBET和观察TEM图片,从分散剂加入方式、加入量(0.5、1、2、3%(wt))、作用时间(30、50、70、90min)等方面对化学改性后氢氧化铝进行了反团聚研究。结果表明,当分散剂与改性剂一起加入氢氧化铝溶胶中时,分散剂影响改性过程的进行,而化学改性完成后加入分散剂能明显改善产物的分散性能且能控制其形貌;当分散剂作用时间均为60min时,改性后加入1%(wt)的分散剂反团聚效果最佳,可使颗粒的SBET由未加分散剂时的9.6m2?g?1增加到20.8m2?g?1;在分散剂加入量均为1%(wt)时,随着分散剂作用时间的延长,颗粒的形貌逐渐由团聚在一起的球形变为松散且规则的纺锤形,其SBET逐渐增加,但当分散剂作用时间达到70min后颗粒的SBET几乎保持不变,

In a stirred tank reactor, sodium phosphate was used as dispersant to study its anti-agglomeration effect on chemically modified aluminium hydroxide. The experiments of different adding dispersant sequence, variations of dispersant proportion and dispersing time were conducted, during which, the specific surface areas SBET of the modified particles were measured and the TEM photos were studied. The results show that sodium phosphate restrains modification process of aluminium hydroxide when it is added to aluminium hydroxide sol with modifier at the same time, whereas it can obviously improve the dispersive properties of the modified aluminium hydroxide and even can control its morphology when the dispersant is added after the completion of the modification. It is found that dispersing time set at 60 min, l%(wt) dispersant added after modification is a desirable option, which can help powder's SBET rise from 9.6 (without dispersant) to 20.8 m2&middotg-1. When l%(wt) dispersant is added after modification, with the prolongation of dispersing time, the morphology of powder is changing from agglomerate spherical to regular and incompact spindly. Meanwhile, its SBET rises gradually and approaches a maximum after 70 min.