Method for de-inking printed paper

In the method for de-inking printed waste paper which includes converting the paper into a pulpy suspension, separating the ink from the suspension in successive phases, and using the de-inked pulp for producing recycled paper, the steps of sequentially:

• disintegrating a quantity of waste paper in the absence of alkaline reagents, said quantity having a mixture of water-based and non-water-based printing inks, to a pulpy suspension having a pH between 4.5 and 8, and simultaneously detaching water-based inks from said pulp to yield coarse ink particles in said pulpy suspension;
• substantially removing said detached coarse ink particles from said pulpy suspension by selective flotation, leaving a remaining suspension;
• thickening said remaining suspension a first time;
• reintroducing water resulting from said step of thickening into a subsequent batch of pulpy suspension prior to said step of removing detached coarse ink particles;
• mixing said thickened remaining suspension with alkaline reagents to form a more alkaline pulpy suspension;
• detaching non-water-based inks from the pulp in said alkaline pulpy suspension;
• removing said detached non-water-based inks from the alkaline pulpy suspension leaving a remaining alkaline pulpy suspension;
• and
• thickening the remaining alkaline pulpy suspension, so that the de-inked pulpy suspension may be utilized in a paper-making process;
• whereby said water-based inks are removed prior to said pulpy suspension becoming more alkaline.