采用水热均匀沉淀法,以硫酸铝和过量的尿素直接合成了低密度薄水铝石,结合ICP-AES、XRD、FT-IR、SEM和BET等分析和表征手段,着重考察了[Al3+]对反应过程和产物性质的影响.140℃时氧化铝水合物沉淀的析出已基本完成,进一步升温导致多孔、类球形针状团簇体粉体的形成,[Al3+]从0.05mol/L升高到0.40mol/L时,产物的结晶度变好,但这种结构随之逐渐受到破坏,比表面从104.3m2/g迅速下降为59.1m2/g,堆密度却从127.1kg/m3增加到234.6kg/m3.将其分别在725℃下焙烧2.0h,灼烧失重率从18.4%下降到15.4%,接近薄水铝石晶体的理论含水量15.0%,产物γ-Al2O3同样表现为前驱体形貌,比表面虽然从159.3m2/g下降为115.5m2/g,但均大幅度高于前驱体的比表面.研究表明,低[Al3+]有助于合成堆密度极低和比表面较高并呈空心、类球形针状团簇体状的薄水铝石晶体.
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