超重力碳分反应沉淀法制备分散性纳米氢氧化铝

PREPARATION OF DISPERSIVE ALUMIUM HYDROXIDE NANOMETER POWDERS BY HIGH-GRAVITY CARBONATION REACTIVE PRECIPITATION

研究了用螺旋通道型旋转床超重力碳分法在不同工艺条件下分别制备出了纳米氢氧化铝和纳米纤维状拟薄水铝石,所用原料为NaAlO2-CO2。分析了氢氧化铝纳米颗粒间形成团聚的机理,在沉淀过程中添加表面活性剂和采用异丁醇共沸蒸馏干燥工艺,有效地防止了粉体的团聚。用透射电镜、Brunauer-Emmett-Teller法对产品进行了分析表征。结果表明:用超重力碳分法可以制得纤维状的超细拟薄水铝石,其孔容为2.41ml/g,比表面积为351.6m2/g,平均孔径为28.4nm,粒径为5～10nm。焙烧后可得到孔容高达1.48ml/g,粒径约为10nm的纤维状氧化铝粉末。

Nanosized fiber-pseudoboehmite and aluminum hydroxide powder were prepared by the carbonation method in a rotating bed with Helix channels using sodium aluminates solution and carbon dioxide as materials in different process conditions. Mechanism of alumium hydroxide agglomeration nanometer powder was analyzed. Agglomeration nano-meter powder was effetively prevented by adding surface active agent in precipitation process and azeotropic distillation with additive isobutanol. The sample preparaed was characterized by transform electron microscopy and Brunauer-Emmett-Teller. The results show that the prepared panicles are a pseudo-bohmite with nano-fiber-like structure, and with a pore volume of 2.41 ml/g, a specific surface area of 351.6 m^2/g, an average pore diameter of 28.4 um, and an average diameter 5-10 urn. After calcination the pseudo-bohmite panicles transfer to the fiber nano-alumina with a pore volume of 1.48 ml/g and an average diameter about 10 um.