A METHOD OF HYDRO-CHEMICAL PROCESSING OF ALUMINOSILICATE FEEDSTOCK, including the preparation of suspension in the high-module liquor, the autoclave digestion of red mud in presence of lime containing additive, the separation of hydrogarnet mud from the middle-module aluminate liquor, the introduction of recycled calcium hydroxide into the middle-module aluminate liquor for the extraction of three-calcium hydroaluminate precipitate from it and for the production of high-module liquor, the evaporation of high-module liquor and its return to the preparation of red mud suspensions and lime containing additive, the regeneration of calcium hydroxide from three-calcium hydroaluminate and its return to the treatment of middle-module aluminate liquor, wherein the suspension of ground mix of calcium oxide and/or hydroxide and sodium ferrite in high-module liquor is used as lime containing additive; the autoclave digestion of red mud suspension in high-module liquor with weight ratio liquid/solid of 3-7 is carried out together with lime containing additive at the rate of producing middle-module aluminate liquor with mole ratio Na₂O_ku/Al₂O₃ of 7.5-9.5; and the regeneration of calcium hydroxide from the three-calcium hydroaluminate precipitate is carried out in autoclaves at the temperature of 205-240°C by treating with high-module aluminate liquor, having a Na₂O_ku concentration of 240-280 g/dm³ and a mole ratio of Na₂O_ku/Al₂O₃ equal to 25-35.