Process of producing high-yield pulp

The present invention relates to a process for preparing a high-yield pulp comprising a) treating a lignocellulose containing material chemically by means of an oxidising system comprising at least one non-enzymatic oxidant substantially free from ozone and chlorine dioxide and an activator at a pH from about 2 to about 6.5; and b) treating the lignocellulose containing material mechanically for a time sufficient to produce a high-yield pulp, wherein the lignocellulose containing material is chemically treated prior to and/or during any mechanical treatment stage, and wherein the lignocellulose containing material is not chemically treated at a pH from about 11.5 to about 14 between stages a) and b).