Electrostatic Assisted Flotation to Decontaminate Recycled Pulp, 2001 Pulping Conference Proceedings

J. A. Lawson, A. A. BaOsman, J. S. Hsieh

De-inking technology and recycled pulp decontamination is enhanced using electrostatic forces in combination with flotation equipment. This study presents data compiled using recent developments in applying high voltage electrostatic forces to various recycled pulp furnishes. Power consumption, brightness gains, and decontamination are commercially considered in applying this technology.

The recycled paper industry is faced with ever challenging conditions of producing better pulp with poorer quality paper supplies. As paper recycling increases, high demand results in lower quality. To offset this trend an effective means must be discovered to remove higher quantities of undesirable particles.

Recycled paper furnishes will contain more envelopes, wax, dirt, labels, magazines, and coated materials. This in turn will increase flexographic ink contamination, micro-stickies, and dirt. Recycled paper grades include many troublesome contaminant particles that become highly dispersed and remain in the mill water effluent streams. Current technology is unable in many situations to be effective in reducing or removing these particles after they are in the effluent. As water conservation increases (9), water loops will become more closed loop and will increase paper production problems and decrease sheet quality with recycling. It is important to consider a good strategy for fines and contaminant control.

This technology addresses both treatment of main stream pulp and or effluent. In addition, troublesome particles that include flexographic ink particles, highly dispersed melted waxes, micro-sticky particles, toner ink, laser ink, newsprint ink, biological activity, and dirt particle reductions will be discussed. Samples from each of these furnishes are presented for both visual inspection and data analysis.