Crystallite size control of aluminium sulphate precipitated in ethanol from kaolin-derived leach liquor

摘要

Aluminium sulphates are of interest as precursor materials for the formation of aluminium oxide [1,2]. The fabrication of high-density ceramic bodies by the sintering of powder is usually conducted from empirically established procedures. The main emphasis has been on producing a small crystallite size and controlling agglomeration. It is now possible to produce metal hydroxides [3] of various sizes and shapes by precipitation from solution. It is the ability to control the size, size distribution, degree of agglomeration and shape of the precipitates that makes these processes interesting. Aluminium hydroxide precipitation from basic sulphate and chloride solutions yields a range of particle sizes and shapes, depending on the precipitation conditions [4]. No precipitation conditions have been reported that yield aluminium sulphate of desired crystallite sizes directly from kaolin-derived aluminium sulphate solutions. This study follows previous work [5] in our laboratory as part of a series on the preparation of alumina from kaolin.