The invention discloses a technological method for producing high-purity low-iron aluminum
sulfate by using
coal ash and comprehensively utilizing the
coal ash, comprising the following steps of: carrying out mechanical activation, flotation
decarburization,
magnetic separation for deferrization, aluminum extraction with
sulfuric acid,
solid-liquid separation, concentration of aluminum
sulfate crude liquor, organic
alcohol alcoholization for acid rinse, organic
alcohol alcoholization for deferrization and aluminum
sulfate dewatering and
drying on the
coal ash to obtain the high-purity low-iron aluminum sulfate with low
Fe content. The invention solves the problems on
impurity removal and purification of the aluminum sulfate in the recycling process of the coal ash, simplifies the process flow, reduces the
energy consumption, solves the technical problem of overlarge accumulation of secondary residue quantity, achieves high
extraction ratio of aluminum contained in the coal ash, and realizes the recycling of organic
alcohol and
sulfuric acid and the comprehensive utilization of side products including unburnt black, magnetic
iron powder, iron-containing aluminum sulfate crystals, high-
silicon-dust active mineral blending materials or novel
silicon-
magnesium cement, and the like. The technological method has the advantages of simple process, short flow, easiness for control of a production process,
high aluminum extraction ratio, low
impurity content of products and stable quality.