Slides for the eLearning course Separation and purification processes in biorefineries (https://open-learn.xamk.fi) in IMPRESS project (https://www.spire2030.eu/impress). Section: Crystallization Subject: 1.2 Uses and advantages

1. This project has received funding from the European Union’s Horizon 2020
research and innovation programme under grant agreement No 869993.
Uses and
advantages of
crystallization

2. Salt
• Crystallization of salt is probably
the oldest unit operation
known to mankind.
• On the coastal areas, the salt
was crystallized in large open
ponds, called salines.
• Nowadays salt is crystallized in
industrial continuous vacuum
crystallizers to guarantee faster
process and higher purity.

3. Sugar
• Sugar is extracted from plants
and then crystallized to reach a
specific particle size distribution,
typically in the range of 700-800
µm.
• Crystallization of sugar is a serial
process and it usually has three
crystallization steps A, B and C.
• Crystals and mother liquor are
separated in centrifuges.
• Overall recovery of sugar from
cane juice is 70-80 %.

4. Chocolate
• Cocoa fat is one of the main
components of chocolate.
• The cocoa fat need to be
crystallized to achieve the
special mouth taste of
chocolate.
• This certain crystal
modification is unstable
at room temperature and it is
achieved via melt
crystallization.

5. Pharmaceuticals
• Crystallization has a major role
in almost all processes in the
manufacturing of
pharmaceuticals.
• Crystallization is needed
in purification, separation and
formation of the product.
• In pharmaceuticals,
the maximum purity is often
needed, which sets extra
requirements for the processes.

6. Paper industry
• Many fillers and pigments used in
the paper industry are produced by
precipitation.
• For example, precipitated
calcium carbonate (PCC)
is prepared from calcium oxide by
precipitation.
• Particle size, particle size distribution
and particle morphology may have
significant influences on the
properties of the fillers and pigments.

7. Wastewater
treatment
• Crystallization is an effective
purification method in
wastewater treatment in the
industry.
• By freezing the wastewater at
low rate, extremely pure ice
crystals are formed.
• Those crystals can then
be transferred into pure water.
• No other treatment is needed to
purposes like process or cooling
water.

8. Other applications
• Crystallization has numerous other applications.
• One everyday life example is an orange juice
concentrate.
• Water has been freezed out to reduce the
volume. The process is called freeze
concentration.
• Crystallization can also be used in different
separation and purification processes that
would be difficult or expensive to carry out with
other methods.

9. Purification via crystallization
• Crystals with high purity are formed and impurities remain in the solution.
• The process can be repeated to get even purer product.

10. Advantages
• Crystallization may have many
advantages compared to alternative
processes:
• High purification in a single step
• Could be more economic than
alternative separation processes
• Lower temperatures make the
process safer.
• Lower energy requirements
compared to distillation

11. This project has received funding from the European Union’s Horizon 2020
research and innovation programme under grant agreement No 869993.
References
Beckmann, W (ed.) 2013. Crystallization: Basic Concepts and Industrial Applications. Weinheim:
Wiley‐VCH Verlag GmbH & Co. KGaA. pp. 1-5.
Singh, P. R. & Clarke, M. A. 2019. Sugar. Encyclopedia Britannica. Available at:
https://www.britannica.com/science/sugar-chemical-compound (Accessed: 4 December 2020)
Hullin, N. J. 2011. Crystallization. Available at: http://thermopedia.com/content/679/
Negi, B. 2012. Crystallization in the pharmaceutical industry. Pharmaceutical Regulatory Affairs.
India. Available at: https://www.hilarispublisher.com/conference-abstracts-files/2167-
7689_S1.008_008.pdf (Accessed: 15 July 2020)
Videos:
• Understanding recrystallization: https://youtu.be/04HWovMzkAk
• Recrystallization demonstration: https://youtu.be/Q1nKbx05IbM