(1. 東北大學(xué) 材料與冶金學(xué)院，沈陽 110819；
2. 大連交通大學(xué) 無機(jī)超細(xì)粉體制備及應(yīng)用遼寧省重點(diǎn)實(shí)驗(yàn)室，大連 116028)
摘 要: 以水合硫酸鋁為原料、尿素為沉淀劑、乙醇水混合液為溶劑，采用水熱處理方法制備了塊狀堿式硫酸鋁及花形薄水鋁石，利用XRD和SEM等表征手段，探討了水熱溫度和水熱時(shí)間對產(chǎn)物微觀形貌的影響，并對其晶體結(jié)構(gòu)和形貌變化的形成機(jī)制進(jìn)行了初步分析。結(jié)果表明：水熱溫度較低或水熱處理時(shí)間較短時(shí)，尿素分解量小，溶液pH值低，且大量乙醇及SO42−的存在阻止了Al3+和OH−的過快成核，有利于形成塊狀 (H3O)Al3(SO4)2(OH)6；隨水熱溫度的提高或水熱處理時(shí)間的延長，尿素分解量增大，溶液pH值增大，塊狀堿式硫酸鋁在OH−侵蝕作用下發(fā)生原位分化，形成片狀薄水鋁石，最后形成以片組裝的花形薄水鋁石。煅燒后，氧化鋁粉體的微觀形貌繼承了其前驅(qū)體氫氧化鋁粉體的微觀形貌。
關(guān)鍵字: 水熱處理；薄水鋁石；堿式硫酸鋁
（1. School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China;
2. Liaoning Key Laboratory for Fabrication and Application of Superfine Inorganic Powders,
Dalian Jiaotong University, Dalian 116028, China）
Abstract:The block aluminum hydroxide sulfate and flower-like boehmite were synthesized using Al2(SO4)3·18H2O as precursor, urea as precipitator, and mixture solution of ethanol and water (volume ratio is 2:1) as solvent by a hydrothermal treatment method. The effects of hydrothermal temperature and time on the morphology were studied by XRD and SEM. The mechanisms of the crystal structure and morphology changes were also analyzed. The results show that block aluminum hydroxide sulfate can be obtained at lower hydrothermal temperature or shorter hydrothermal time since the amount of urea decomposition is little, the solution pH value becomes low, and a large amount of ethanol and SO42− stop the rapid nucleation of Al3+ and OH− under the condition of lower hydrothermal temperature or shorter hydrothermal time. As the hydrothermal temperature increases or hydrothermal time prolongs, the block aluminum hydroxide sulfate begins to in situ differentiate by OH− erosion because of the increased decomposition amount of urea and higher pH value. At the end, the flower-like boehmite assembled by flakes forms. After the calcination, the morphology of alumina powder inherits that of its precursor of powder aluminum hydroxide.
Key words: hydrothermal treatment; boehmite; aluminum hydroxide sulfate
