De-inking recycled paper using column flotation

The degree of waste paper recycling has been increasing steadily in North America over the last decade. Flotation is a popular method for removing ink from fibres (deinking) and is traditionally performed in mechanical cells. Column notation has been proposed as a low cost alternative for the deinking process. Two types of columns ate tested: the conventional (or open) column and the packed column. Packing inside a column reduces mixing and eliminates the need for spargers to disperse air into bubbles. In the work reported here, open and packed laboratory scale columns were operated to determine their relative merits and how they compare to a circuit of mechanical cells.