Dispersion and flotation - Process info
Dispersion and flotation
After the washer(s) the pulp will be conveyed to a pulp screw, which will increase the consistency to 30%. The pulp will then be preheated with steam to About 80 °C before passing the disperger. The disperger will separate a majority of the ink particles from the fibers. After the disperger the pulp will be diluted in two steps to About 4% consistency on its way to the Flotation Feed Tank.
The filtrate from the pulp screw will be fed by gravity to a standpipe and from there pumped to the Cloudy Water Tank. The cloudy water will be used for dilution.
In following systems: waste paper pulper, HD and LDcleaning, coarse screening, cleaner system and fine screening system.
After the Flotation Feed Tank the pulp will be consistency controlled to About 1% and pumped to the primary and secondary flotation units. Before the primary flotation unit a polymer will be added. The accepted pulp will go to the Washer Feed Tank. Sludge from secondary cells will be transported to the Sludge Tank in the reject system.