Deinking of Printed Chemical Waste Papers and its Effect on Printing Paper from CMP Pulp

In this research, the recycling of chemical waste paper has been taken into consideretion.To produce printing paper, the effect of various combinations of deinked pulp with CMP pulp has studied. Deinking results showed that, besides of the chemicals effect, temperature and repulping time directly affect the brightness of deinked pulp so that when the temperature or repulping time or both go up, the brightness of deinking pulp goes up too. Test results of deinked pulps mixed with CMP pulp indicated that by adding deinked chemical pulp, with the percentage of 10, 20, and 30 to CMP pulp, optical and physical features and also mechanical strengths of paper improve. From optical and physical features and also mechanical strengths point of view, the best circumstances to combine deinked chemical pulp with CMP pulp and long-fiber pulp included 60% CMP Pulp, 30% Deinked Pulp, 10% Long-fiber Pulp. It can be suggested that %30 deinked pulp can be used to produce printing paper. Also, optimum Deinking variables were %2 NaOH (on the oven dry pulp), repulping time 10 minute and repulping temperature 65°c.