Deinking Of Used Paper By Flotation Or Washing: Conventional And Radiation Cured Printing Inks

In view of ever-rising waste amounts in all highly
industrialized countries, the need for an intensified
recycling of used paper has been reinforced by acute
waste disposal problems. Actually, the paper industries
of most developed countries can look back on
many decades experience of recycling. Within the
countries of the European Community, recycled
fibre pulps today account for the highest share in
total pulp inputs in paper manufacture. Even in the
EPTA states with their ample resources of virgin
fibre, waste paper pulps have meanwhile attained
usage levels (Fig. 1). Today's typical
strategy of waste paper recycling is to use highquality
consumed papers of superior brightness,
cleanness and strength as raw material for new
papers of a comparatively inferior quality.

It was about three decades ago that - originally out
'of economic considerations - the paper industries of.
countries with a scarcity of raw materials initially
used recycled fibre furnishes in the manufacture of
higher-grade papers. This policy has boosted the
development of processes for ink removal from
waste papers, the so-called deinking technology.
Simultaneously, traditional recycling processes for
non-deinked papers have been further developed
with a view to minimiiing costs. All these factors
have contributed to the presently high levels of
secondary fibre usage as are reflected in current
statistics of waste paper utilization and consumption
within the European Community (Fig. 2).

Against the background of ever-aggravating waste
problems, the use of recycled fibre has meanwhile
entered legislation in Germany and abroad so that
profitability is no longer the sole determining aspect.
Now that waste paper usage in packaging paper and
cartonboard manufacture has reached a maximum
in many countries which can hardly be exceeded -
just take Germany with a utilization rate of some 90
% - the paper industry is making a concentrated
effort to increase secondary fibre furnishes in graphics
and tissue production. Since newsprint as part
of the graphics sector has already realized high
waste paper utilization rates - FIg. 3 illustrates the
scenario in Germany - interest has recently focused
on higher-grade graphic papers. In this context,
deinkirig processes have become key technologies of
waste paper treatment.