Deinking Non-Impact Printed Office Waste: A Mill's Perspective, 1993 Recycling Symposium Proceedings

Non-impact inks, for example laser and xerographic, pose a difficult problem for white paper deinking mills.

Repulping paper with non-impact inks results in large, flat toner flakes that are too large to be removed by flotation and too small to be removed by screens and cleaners.

Three primary options are available to a mill to deal with these inks. One option is to not purchase the waste paper in the first place. While practical this is an expensive alternative, $lOO/ton separates close to laser-free from laser-containing waste paper. The second option is to use mechanical means to break down the size to either the floatable range (kneaders) or washable range (dispergers). The third alternative, and the subject of this paper, is the

chemical approach. The chemical suppliers have been working hard and long to solve this problem. Two approaches are taken - one, is to disperse-the toner flakes to a size

removable by flotation or washing; and the second, is to agglomerate the particles such that they can be removed by the cleaners and screens. Agglomeration has had the most success at Vancouver mill so far, and is the subject of this paper.