The invention provides a method for producing aluminum
oxide and co-producing active
calcium silicate through high-
alumina fly ash. The method comprises the following steps that: the high-
alumina fly ash firstly reacts with a
sodium hydroxide solution to carry out pre-desilication to obtain a liquid-phase desiliconized solution and a
solid-phase desiliconized
fly ash;
lime cream is added to the liquid-phase desiliconized solution to carry out a causticization reaction, the resulting
solid phase is active
calcium silicate which is prepared through carrying out filter pressing,
flash evaporation and
drying to obtain the finished product; limestone and a
sodium carbonate solution are added to the desiliconized fly ash to blend qualified raw
slurry, then the blend qualified raw
slurry is subjected to baking into the clinker, the
liquid phase generated from
dissolution of the clinker is a crude solution of
sodium aluminate; the crude solution of the
sodium aluminate is subjected to processes of first-stage deep desilication, second-stage deep desilication,
carbonation, seed
precipitation, baking and the like to obtain the metallurgical grade aluminum
oxide meeting requirements. According to the present invention, the defects in the prior art are overcome; purposes of less
material flow and small amount of slaggling are achieved;
energy consumption,
material consumption and production cost are relative low; extraction rate of the aluminum
oxide is high; the
calcium silicate with high added value is co-produced; the method provided by the present invention can be widely applicable for the field of
chemical engineering.