【摘要】 本文介绍一种超细铝的氧化物及水合物的制备方法,沉淀—水热—烧结法。用碳酸钠作沉淀剂,快速沉淀硫酸铝,可获得粒径0.02～0.08μm的无定型Al（OH）₃。详细讨论了各种因素(溶液pH、温度、Al³⁺浓度、沉淀剂用量)对沉淀产物的影响。沉淀物Al（OH）₃的浆料在250～300℃下水热处理2小时,得到γ-AlOOH,其粒径和Al（OH）₃的粒径相当。实验发现,温度是影响水热过程的主要因素;在不同pH下水热脱水,脱水产物的形状不同,pH<4时为针状γ-AlOOH,pH≥7时为片状γ-AlOOH;添加某些添加剂亦可获得球形γ-AlOOH。对Al（OH）₃直接加热脱水和水热脱水进行了比较,发现在相同温度（250—300℃）和相同时间（2小时）条件下,水热脱水具有晶体结晶完全和γ-AlOOH相纯度较高的优点。文中对γ-AlOOH在温度>1000℃下烧结成Al₂O₃进行了研究。更多还原

【Abstract】 A method of preparating ultrafine powder of Al（OH）₃, γ-AlOOH and Al₂O₃ by precipitation-hydrothermal-calcining was described in this paper. Aluminum hydroxide was obtained by precipitating aluminum sulfate with Na₂CO₃, and the effects of several conditions, including pH, temperature, concentration of Al³⁺, precipitating agent amount were studied. The size distribution of Al（OH）₃ was in range of 0.02 —0.08μm.Suspension solution of Al（OH）₃ was dehydrated by hydrothermal in autoclave at 250℃ for 2 hours. The dehydrated product was aluminum monohydroxide with γ-AlOOH structure which had different morphology at various pH values, but the size of the powder did not change markedly. The transformation of γ-AlOOH or Al（OH）₃ into Al₂O₃ calcining at high temperature was also discussed. A comparison between direct heating and hydrothermal of Al（OH）₃ for crystal transformation was made.更多还原