Preferred Method for Removal of Filler From Deinked Pulp, 1994 Recycling Symposium Proceedings

I. Mathur

This paper relates to a preferred method for removal of fillers from deinked waste paper pulp. Filler removal from deinked pulp is particularly important when waste paper is used for the production of tissue. Conventionally, filler removal is achieved by a washing deinking process which generates more waste water and gives a lower fibre yield than the flotation process. Addition of cationic and anionic surface active agents has been proposed by other researchers to promote selective flotation of tillers. This study confirms that sodium silicate suppresses removal of filler during flotation deinking of a waste paper furnish containing 70% newsprint and 30% magazines. It has been shown that filler can be selectively removed without the addition of tiller removal

collectors if deinking is performed without sodium silicate. To achieve the required brightness, optimum amounts of DTPA (diethylenetriaminepentaacetic acid) and alkalinity must be added.