The results of laboratory studies on super deep desilication of alumina liquors based on hidrocarboalyuminat calcium supplements 4CaO×Al2O3×0,5CO2×11H2O in advance of entering into the process of working hydrogranat sludge. Obtained qualitatively new alumina liquors with a silicon module (weight ratio Al2O3/SiO2) of 50 000 units. Impact of type-ahead hydrogranat sludge to a desilication depth given from the viewpoint of heterogeneous catalysis.