The structural change and mineralogy of Al gel during aging time were investigated by using spectroscopy techniques.The results indicated that:1) the aggregation extent of solution-gel system increases with aging time,and the structure of amorphous gel becomes more short-ordered;2) after six months,the gel formats nordstrandite and little gibbsite;3) a marked decrease in the number of(Al-OH)oh bands occurring at 610 cm-1 and increase in the number of(Al-OH2)oh bands occurring at 555 cm-1 indicate that the gel undergoes rearrangement-like process during aging;4) the gel constantly contains Al-O tetrahedron of Keggin structure,but the signal peak occurring at ≈61×10-6 of 27Al MAS NMR have a slight shift to downfield with aging time.A mineralogical transformation mechanism for hydrolysis Al(Ⅲ) solution was proposed.
