Hydrogen Peroxide, A Plus to Obtain an Adequately White Deinked Pulp at Proper Tint, 1990 International Printing & Graphic Arts Conference Proceedings
These days, there is more and more pressure to utilize the deinked fibre from newsprint in the production of new newsprint. However, there is a lot of resistance for its reuse on account of the low optical properties of those pulps.
In aiming to favour its use, the brightness of the pulp must be increased and its coloration decreased. The hydrogen peroxide was chosen as bleaching agent because it bleaches without decreasing the yield of the mechanical pulp which is the most important constituant of the newsprint.
In this paper, we present some results of brightness and of tint of the pulp in relation with the concentration of the bleaching agent added and with the consistency of the pulp in the pulper. To evaluate the efficiency of bleaching on the optical properties, we measured the brightness at 457 nm and the coloration and luminosity at other wave lengths. The reading were converted to L’, a’ and b’.
Hydrogen Peroxide, A Plus to Obtain an Adequately White Deinked Pulp at Proper Tint, 1990 Internatio