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.