Fundamental Study On Intensified Digestion Of Diaspore Under Extra-fields

In view of the digestion properties of diaspore, intensifying the digestibility of diaspore by activating roast mechanical activation and employing additives during roasting process has been systematically studied in this paper, the influential factors of intensified digestion of diaspore and the mechanism of activating roast improving the digestibility of bauxite have been investigated.The major results of the research are as follows: after roasted under certain proper conditions, the solubility of the roasted diaspore is greatly improved; the addition of A1F3 during roasting of diasporic bauxite can further improve the extraction rate of alumina, the extraction rate of alumina digesting at 200℃ will reach the one digesting at 260℃; mechanical activation only can improve the digestibility of diaspore to some extent; results of fluid-bed roasting experiments on the fluid-roasting device designed by ourselves indicate that fluid-roasting will be a feasible approach of intensified digestion; the way of cooling has no effect on the extraction rate of roasted bauxite; by means of IR DTA and XRD of bauxite and roasted bauxite, analysis shows that diaspore under low-temperature roasting can transform into low-temperature homogeneities of alumina crystalloid (transition-alumina), i.e. p-A12O3, x-A12O3, η-Al2O3 and γ-Al2O3; the reason improving the digestibility of diaspore by activated roast lies in the transformation of high-activity low-temperature homogeneities of alumina crystalloid (p-A12O3, x-A12O3, η-Al2O3 and γ-Al2O) under low-temperature roasting; adding of AlF3 in roasting process of diaspore resulted in descending of dehydration temperature of diaspore, changing of de-hydroxyl and phrase transformation course, restraining transition-alumina from transforming into a - A12O3, so the digestibilityof roasted diaspore will be further improved.