EFFECT OF DEINKING CHEMICALS ON THE DEPOSITION OF FINES AND FILLERS ON AN AIR-WATER-INTERFACE

The deposition of precipitated CaCO3 (PCC) fillers and thermomechanica l fines onto an air-water interface was studied by the impinging jet t echnique. It was found that, in the absence of deinking chemicals, PCC deposits on the air-water interface while fines do not. In the presen ce of sodium oleate and calcium chloride, an appreciable deposition of fines and fillers occurred. The mechanism of deposition is the same a s that for ink particles depositing on an air bubble: calcium soap par ticles, which can adsorb onto fillers, fines and an air-water interfac e form a bridge between fines or fillers and the air-water interface. The rate of deposition of fillers can be reduced by dispersants. Fibri llated fines form entangled webs in the interface in which larger part icles can be captured. Fines can be removed from the air-water interfa ce by high shear.