PAPER TECHNOLOGY INTERNATIONAL - Talc-Free specialty chemistry concepts for deposit, pitch and stickies control in modern pulp, paper and tissue systems. BIM Kemi - Paper Technology International 2026 - Book - Page 67

PAPER TECHNOLOGY INTERNATIONAL - Talc-Free specialty chemistry concepts for deposit, pitch and stickies control in modern pulp, paper and tissue systems. BIM Kemi

PAPERTECHNOLOGYINTERNATIONAL
- Passivation: the agent coats the surface of the particle,
making it less tacky.
Figure 2: Passivation.
- Fixation: extractive particles are chemically bound to
the 昀椀bre. This typically takes place on the drying machine or, in
integrated mills, at the very end of the process.
Figure 3: Fixation.
Because pulp processes are increasingly closed systems
and traditional indicators often provide limited insight into extractive
behaviour, reliable measurement becomes essential. To address
this, BIM has developed its own camera-based measurement
system, BIMPics, which monitors the amount and size distribution
of particles in both pulp and water circuits. This provides valuable
insight into deposit-related indicators and the performance of
chemical solutions. Developing a new dosing system and the
technology behind it is not just an operational detail - it is one of the
keys to long-term success.
While a signi昀椀cant share of extractives can be washed out
of the system, it is not possible to remove them completely. The
purpose of BIM Kemi’s talc-free concept is therefore both to remove
as much as possible early on and to stabilise what remains so that it
does not form deposits later.
From pulp to paper and board – avoiding deposit problems
If extractives are not properly controlled in the pulp mill,
paper and board machines inevitably inherit the problem. Even
small, unstable extractive particles can later agglomerate under the
high shear and changing chemistry of the wet end, leading to wire
contamination, deposits, breaks, and sheet defects. When talc is
replaced by BIM Kemi’s talc-free concept, positive effects are also
seen on paper and board machines. As the amount of extractives
in the pulp decreases, runnability improves and the number of
breaks is reduced. At the same time, the need for cationic chemistry
decreases, as there is less anionic trash previously bound by talc.
(Image 5 below)
The removal of talc may in昀氀uence ash content and light
scattering properties, but these effects can be compensated for with
other pigment additions if required. Overall, the change is almost
unnoticeable from the pulp user’s perspective. No process changes
are required, but runnability and cleanliness improve. However,
if talc is completely removed without implementing an alternative
chemical solution, the effects on the process become visible quickly.
The extractive load increases, leading to higher demand for cationic
chemistry. At the same time, dewatering becomes more dif昀椀cult
and the risk of wire contamination increases, potentially resulting
in more breaks and quality defects. This clearly demonstrates that
talc-free production requires a replacement concept, not merely the
elimination of talc.
Even if talc replacement has been properly implemented
at the pulp mill, monitoring and control of deposit formation must
continue on the paper and board machine. Process control should
be systematically extended to the machine area using the same
proven tools applied earlier in the process – particularly BIMPics
analyses, which provide a detailed understanding of the system’s
chemical balance and deposit risk potential.
Image 2: The following images clearly illustrate what BIMPics detects at the pulp mill (right image) and how the ‘same’
contaminants appear in the 昀椀nished paper (left image).
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