Deinking of Mixed Office Waste, 1994 Recycling Symposium Proceedings

Mark Gilkey

Deinking of mixed office waste (MOW) is described, focusing on ink speck removal, but also measuring system brightness increase, ash reduction, freeness change, and other factors. Particular interest is given to the flotation step, looking at the efficiency of flotation for ink particle removal in the 75-750 micron size range in both the pre and post dispersion positions, as well as looking at the cumulative effects of ink speck removal going through a typical deinking system which includes pulping, screening, cleaning, washing, and dispersion, as well as flotation, The contribution of each process step for ink removal in terms of particle size and efficiency is discussed.

Test work on MOW with a new flotation cell design is described, evaluating the effects of retention time, air:stock ratios, and consistency for optimal flotation cell operating conditions. In addition, a sample of MOW is evaluated to determine its composition.