高铝粉煤灰制备氢氧化铝的比表面积及孔隙特性

以高铝粉煤灰烧结熟料为原料，经溶出、深度脱硅和分解(碳酸化分解或晶种分解)得到高白氢氧化铝，采用低温氮气吸附法分析两种分解方法制得的氢氧化铝的比表面积和孔隙分布.结果表明:氢氧化铝的等温吸附线属III类，氢氧化铝晶粒之间的孔隙以微孔为主，存在一定数量的介孔和大孔.碳分氢氧化铝BET比表面积和平均孔径远大于种分氢氧化铝，碳酸化分解时在CO2的强推动下，氢氧化铝猛烈析出并凝聚，使得晶体结构疏松，晶间空隙大.晶种分解靠晶体的长大而使晶体变粗，晶体结构致密，晶间空隙小.

Specific Surface Area and Pore Characteristics of Aluminum Hydroxide Prepared from High Alumina Fly Ash

Using sintered high alumina fly ash clinker as raw material， high white aluminum hydroxide was obtained after dissolution， deep desilication and decomposition (carbonation decomposition or seed precipitation) process. Low temperature nitrogen adsorption method was adopted to analyze the specific surface area and pore distribution of aluminum hydroxide. The results showed that the aluminum hydroxide adsorption isotherm curve belongs to type III. Aluminum hydroxide pores most belong to micropores， and there still are some mesopores and macropores. The BET specific surface area and average pore diameter of carbonation aluminum hydroxide are much greater than those of seed precipitation aluminum hydroxide. Driven by the strong action of CO2， aluminum hydroxide precipitates and condenses fiercely in carbonation decomposition， so the crystal structure of aluminum hydroxide is loose and intergranular pores are big. In seed precipitation， the growth of crystal makes the crystal coarsen， the structure is compact and intergranular pores are small.