METHOD FOR PRODUCING DEINKED PULP FROM PRINTED WASTE PAPER

PROBLEM TO BE SOLVED: To provide a method for producing deinked pulp from printed waste paper, by which the deinked pulp can efficiently be produced at a low production cost, while effectively using the deinking agent. SOLUTION: This method for producing the deinked pulp from the printed waste paper is characterized by using at least one deinking agent and at least one different deinking agent in a process A and a process D, respectively, and disposing a process C (ash-removing apparatus) for concentrating the concentration of 2 to 4% of the raw material after the process B to a concentration of 4 to 9% and for reducing an ash content of 5 to 50wt.% in the raw material, between the process B and the process D, in waste paper-pulping processes comprising a process A for disintegrating the printed waste paper, a process B for diluting the disintegrated waste paper to a raw material concentration of 2 to 4%, and a deinked pulp-producing installation process D comprising a process D1 (screening) for removing dust/a process D2 (bleaching) for bleaching/a process D3 (kneading) for dispersing/a process D4 (flotation) for deinking/a process D5 (washing) for washing. COPYRIGHT: (C)2004,JPO