Method for producing waste paper deinked pulp

摘要

PROBLEM TO BE SOLVED: To provide a method for producing deinked waste paper pulp, which reduces a chemical cost.SOLUTION: The method for producing the deinked waste paper pulp regenerates waste paper containing coated paper having print thereon, and comprises conducting deinking treatment by adding an acid to the waste paper in a step of disaggregating the waste paper and without adding an alkaline chemical to the waste paper. The deinking treatment and the dispersion treatment are conducted after the disaggregation step in this order. Alternatively, the dispersion treatment and the deinking treatment are conducted after the disaggregation step in this order. It is preferable that an ash content in the waste paper is 15% or more.