Assessment of Deinking Chemistry Performance: From Laboratory Flotation Tests to the Simulation of an Industrial Pre-Flotation Line, 2007 TAPPI 8th Research Forum on Recycling

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The influence of different de-inking chemistries on ink removal selectivity was investigated by using a continuous laboratory flotation column. A surfactant-fatty acid blend was compared to conventional fatty acid soap under alkaline conditions with two silicate dosages, namely 2 and 1%. As expected, the decrease in silicate dosage induced a general decrease in ink removal selectivity. However, the surfactant/fatty acid blend gave ink removal selectivity higher than that obtained with fatty acid soap for both silicate dosages.

In order to better understand the influence of the pulping chemistry on particle and water removal during pulp flotation, experimental data were interpolated with model equations recently developed to describe water, ink, fillers, fines and fibres transport in a flotation cell. Transport coefficients showed that, under the tested conditions, the increase in ink removal selectivity obtained when using the surfactant/fatty acid blend and when increasing silicate dosage were due to the depression of fibre, fines and fillers transport from the aerated pulp to the froth.