European Database for Cartonboard and Carton Production 2023

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When the raw material source is recovered paper and board, fibre separation is
achieved by mechanical agitation in water. Recovered paper and cartonboard has been
printed, sometimes varnished and for packaging applications, often has been glued. In
products where high purity and whiteness is important, it is necessary to remove the
printing inks, glues and other impurities.
After the recovered paper and board has been immersed in water, disintegrated and
the fibres dispersed, heat and/or dispersion agents are used to remove any sticky
impurities from the fibre surfaces. Then flotation techniques, screening and
washing, and sometimes additional bleaching, are used to remove the impurities.
For pulps from both primary fibres and recycled fibres, functional chemicals, fillers
and other pulps can be added to give the final paper the properties required.
Energy
Energy sources depend on the way pulp is made and the location of the mill. Where
paper for recycling is utilised as a fibre source, rejects from the recovered paper
(plastics, etc) may be incinerated with energy recovery on-site. Where pulp is
produced from virgin fibres, bark chips from debarking may be used as an internal
energy source. Chemical pulping also results in a by-product (black liquor) which is
used as a significant internal energy source. Finally, biogas from wastewater treatment
may also be used as an internal fuel source. For virgin cartonboard mills, internal fuels
account for more than 50% of the fuels consumed onsite, whereas for recycled
cartonboard mills internal fuels account for less than 1% of the fuels consumed onsite.
Where internal fuel sources are not available or are not sufficient to meet the full
energy needs of the mill, external fuels will also be consumed, including fossil fuels
(mostly natural gas, but also heavy fuel oil, light fuel oil, diesel oil, liquid petroleum
gas, and in some cases coal or peat) and renewable fuels (e.g., bark, pitch oil).
Fuels consumed onsite can be used to produce both thermal energy and electricity.
Some mills are able to generate enough electricity to meet all of their needs, and may
even be net exporters of electricity, but most mills also purchased some of the
electricity needs. In this case, electricity may be purchased from the national grid, or
specific electricity product agreements (e.g., for electricity produced from renewables
and/or zero carbon electricity) may be in place.
Water
Water is an essential element for paper and board production. Water acts as a
bond between the fibres and in the production process it is needed for transporting,
cleaning, as a solvent, carrying energy in the form of steam and it is used in cooling
process units. Water is usually taken from a nearby surface source such as a lake or
river. >95% of the water used in the industry is cleaned and reused on site. All water is
purified (usually at a wastewater treatment facility operated by the mill) in
accordance with European regulations and standards before being returned to the
environment.
© RISE Research Institutes of Sweden