| abstract |
The invention relates to a method for extracting aluminium oxide from coal ash. The method comprises the following steps: (1), mixing coal ash with ammonium sulphate and granulating; (2), roasting particles through a two-section type fluidized roasting system; (3), adding dilute sulphuric acid into a clinker, and dissolving out and filtering materials, wherein filtrate is a crude NH4Al(SO4)2 solution; (4), filtering after removing impurities from the solution by adopting a combination method to obtain a fine NH4Al(SO4)2 solution; (5), absorbing ammonia gas released in the roasting reaction process by the purified and separated fine NH4Al(SO4)2 solution, and carrying out ammonia settlement reaction of ammonia gas and the fine NH4Al(SO4)2 solution so as to generate Al(OH)3; and (6), calcining Al(OH)3 sediment at 1100 DEG C so as to obtain Al2O3. By adopting the two-section type fluidized roasting system including roasting of coal ash and ammonium sulphate, impurity removing through the combination method and oxygen-enriched combustion, the problems of being high in corrosion, sticky to roast, cake and coke of equipment in the background technology are solved. |