FIELD: paper-and-pulp industry. SUBSTANCE: method is accomplished by passing liquid suspension of broken cellulose fiber material with concentration of dissolved organic material too high for negatively effecting principal characteristics of industrial-grade cellulose in direction of mesh point and farther, draining part of liquid with specified concentration of dissolved organics at the screen point, recycling part of drained liquid back into digester towards screen point, and introducing digesting alkaline agent into recycle circuit. In particular, alkaline agent introduced into recycle circuit is diluting one with reduced concentration of dissolved organics, whereas reduced concentration of dissolved organics in liquid recycled into digester differs from this value in diluting alkaline agent. Continuous digester, in addition to discharge and recycle pipelines, is provided with means for loading replacing alkaline agent with reduced concentration of dissolved organics, which is connected to discharge pipeline. EFFECT: enhanced efficiency of digestion and in cellulose strength of sulfate cellulose. 22 cl, 25 dwg, 2 tbl
