Research on Recycling and Deinking of Money Paper

Money paper is one of the moist tolerant kinds of papers along with other kinds of bank document papers, about 1000 ton/year of which is at disposal in IRAN. Research in this field not only clears the way to recycling of this kind of paper but also leads to other moist resistant papers recycling. The results of this research indicated that, preparation of pulp from money paper while using usual methods is impossible. Recycling of this kind of paper needs acidic pretreatment (pH=3) of 4 hour duration in ambient conditions and a second stage treatment (pH=3) of 1.5 hour treatment time in 95°C. Screen yeild of pulp after the two-stage acidic treatments was about 67% and the amount of acid consumed 1% of the waste money paper. Deinking of the pulp prepared through acidic treatment showed that there appears no change in pulp brightness. This shows that no hydrolysis takes place on the ink and ink can not be seprated from fiber surface through acid treatment. However, alkaline treatment of the pulp preapared through acid treatment causes breakdown of ink. Pulp brightness after alkaline treatment of 3% NaOH (dry pulp) and, at 95°C with a duration of 2 hours increases from 57% to 75% ISO.