The Deinking and Bleaching of Pulp Produced from Household Wastes

One of the problems that Americans have had to continually deal with is what to do with household and municipal wastes. The National Center for Resource Recovery in New Orleans has partially solved this problem by recycling usable materials from the garbage. At the present time, they are recycling iron, glass, aluminum, and other non-ferrous metals. They are also separating out approximately 350 tons per day of paper fiber. This study was designed to try and clean up that fiber, so that it could be sold as usable fiber. A garage pulp was synthesized in the recycling plant at Western Michigan University. It was run through screens and cleaners before being deinked. The final pulp was then bleached using four different bleaching sequences. The most interesting results of this work came in the cooking stage. All forms of plastic attracted and retained ink particles. Because of this, the final unbleached pulp was very clean and had a brightness of 43.7. The best bleaching process was a 1.2%-1.2% peroxide-hydrosulfite type. This gave a final brightness of 54.5. The pulp was deinked using two different methods. These were sidehill washing and flotation cell deinking. A Clark classification showed that the amount of fines in the flotation cell stock was much higher than the amount in the sidehill stock. This led to large differences in strength tests