The specific focus of this study is on the boehmite–water interaction during attrition milling of a boehmite prepared by thermal dehydroxylation of gibbsite. Various characterization studies confirm the formation of a new phase, bayerite (an Al-trihydroxide polymorph) during milling of boehmite with water as the dispersant. Bayerite is a more stable (thermodynamically) phase than boehmite. By forming bayerite, the free energy of the interacting system (consisting of disordered metastable boehmite and water) gets reduced. Such a transformation is of relevance in the digestion of Al-monohydrates in the Bayer process of alumina production. Furthermore, the presence of water during attrition milling itself is essential for the transformation. Bayerite does not form during attrition milling of the same boehmite in ethyl alcohol media and subsequent soaking in water up to 36 hours. Therefore, bayerite formation does not depend solely on structural degradation.

中文翻译：

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高能研磨过程中一水铝（勃姆石）到三水铝（三羟铝石/三水铝石）的转变

本研究的具体重点是通过三水铝石的热脱羟基制备的勃姆石在研磨研磨过程中勃姆石与水的相互作用。各种表征研究证实了在用水作为分散剂研磨勃姆石的过程中形成了新相三羟铝石（一种氢氧化铝多晶型物）。拜耳石是比勃姆石更稳定的（热力学）相。通过形成三羟铝石，相互作用系统（由无序的亚稳态勃姆石和水组成）的自由能降低。这种转变与氧化铝生产拜耳法中一水铝的消化有关。此外，在磨碎过程中水的存在对于转化是必不可少的。在乙醇介质中对相同勃姆石进行研磨研磨并随后在水中浸泡长达 36 小时时，不会形成拜耳石。因此，三羟铝石的形成不仅仅依赖于结构退化。