为了研究可水合氧化铝在硅溶胶中的水化行为和流变性，将可水合氧化铝分别在水和硅溶胶中配制成固含量约60％（w）的料浆，在25℃恒温水浴中分别水化1～120 h 后，再烘干并检测其质量变化率，观察水化后的物相组成和显微结构，并研究可水合氧化铝分别在水和硅溶胶中的 Zeta 电位随 pH 的变化及料浆黏度随时间和切变速率的变化。结果表明：1）可水合氧化铝在水中的水化速率比在硅溶胶中的快，尤其在反应前期；可水合氧化铝在硅溶胶中料浆的流变特性近似牛顿流体，而在水中料浆表现出剪切变稀的特征；可水合氧化铝在硅溶胶中料浆的黏度和颗粒表面的等电点 pH 均比在水中的小。产生这些差异的主要原因是可水合氧化铝颗粒表面被硅溶胶中的 SiO2粒子包覆。2）可水合氧化铝在水中水化后的主要物相为三羟铝石和少量勃姆石，而在硅溶胶中水化后的主要物相为勃姆石。%s:To study the hydration behavior and rheological properties of hydratable alumina in silica sol,the hydratable alumina was added into silica sol and water,respectively,to prepare two kinds of slurries with 60 mass% solid content.After thermostatic waterbath at 25 ℃ for 1 -120 h and drying,the mass changing rates of hydratable alumina in the water and silica sol were characterized;the phase composition and mi-crostructure of the hydration products were analyzed;the relationships between Zeta potential and pH val-ue of hydratable alumina in water and silica sol were investigated;and their slurry viscosity as a function of the testing time or the shear rate was studied.The results indicate that:(1)the hydration of hydratable alu-mina in the water is faster than that in the silica sol,especially at the prior stage of the reaction;as for the rheological behavior,hydratable alumina in the silica sol behaves as an approximate Newtonian fluid,while the hydratable alumina in the water shows a shear thinning behavior;compared with the slurry of hydratable alumina in the water,the slurry with silica sol has lower viscosity and pH value of isoelectric point on the particle surface;the main reason for such differences is the hydratable alumina particles are covered with SiO2 in the silica sol;(2)the main phases of hydration products in the water were bayerite and a small amount of boehmite,while that in the silica sol was boehmite.
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