Magnetic separation for wastepaper recycle mills

An alternative approach to the conventional washing and flotation techniques for de-inking of mixed office waste (MOW) is magnetic separation. The use of magnetic de-inking has great potential to improve the efficiency of ink removal due to the magnetic content of toners. It is shown experimentally that the magnetic susceptibility of toners typically found in MOW varies from weakly paramagnetic to ferromagnetic. The magnetic de-inking of MOW in itself is not sufficient to achieve a high quality final product due to variations in the magnetic susceptibility of the toner particles. Nevertheless a combination of magnetic separation with flotation appears to be able to produce a final product of superior quality with 92.7% of the dirt removed. Considering these findings appropriate flowsheet modifications are suggested for improved plant performance