Deinking Sorted Office Paper to Produce White Linerboard, 1997 Recycling Symposium Proceedings

Pilot plant tests were conducted to study deinking of sorted office paper to produce white liner-board and other grades of paper less expensive than printing and writing paper. The furnish contained high levels of computer printout and laser printed paper. Two different types of deinking agent chemistry were evaluated: dispersion and agglomeration. The deinking process equipment was configured as a satellite system. The dispersion process unit operations included pulping, detrashing, screening, flotation, through-flow cleaning, and forward cleaning, followed by washing.

The agglomeration process configuration was pulping, detrashing, fine screening, trough-flow cleaning and forward cleaning, and washing.

Target deinked pulp optical properties were achieved using 0.25% (based on dry furnish weight) of a dispersing deinking surfactant and the process sequence described above. Using a different deinking agent and the described agglomeration process also produced deinked pulp meeting the target optical properties.

Using a dispersing surfactant, both washing and flotation removed a considerable fraction of the microscopic (<60 micron)="" ink="" particles.="" flotation="" was="" the="" most="" effective="" unit="" operation="" for="" removal="" of="" 60="" -="" 225="" micron="" ink="" particles.="" in="" both="" the="" dispersion="" and="" agglomeration="" processes,="" washing="" provided="" the="" largest="" brightness="" gain="" of="" any="" unit="" operation.="" in="" the="" dispersion="" process,="" centrifugal="" cleaning="">