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Processing
The pulping process for hemp is different from that
for wood fibre. Wood fibre is very dense compared
to hemp which allows for it to be economically
transported long distances for processing. Although the volume of hemp fibre per hectare is comparable to wood in the long term, the annual harvesting area is much larger to achieve equal volume. Traditional hemp processing plants are small, labour intensive, and quite polluting when compared to modern wood pulping operations. Since hemp production has been banned for decades,the technological advancements that have occurred in the pulping industry have not occurred for hemp pulping. 

[HR]

A process where water (moisture), micro-organisms
or chemistry break down the bark tissue that binds
the fibre and non fibre portions together making
them easy to separate.
1. Dew Retting – left in field where rain, dew and/
or irrigation is used to keep the stems moist. May
take up to five weeks. Produces a coarse fibre
with light brown colour.
2. Water Retting – bundles are submerged in water
where bacteria break down the pectin. Takes
seven to ten days. Produces better quality fibre.
3. Warm Water Retting – bundles are soaked for
24 hours then the water is replaced. Heat is then
applied to warm this batch for two to three days.
Gives a very uniform, clean fibre.
4. Green Retting – this type uses an all mechanical
process to separate the component parts. This is
used when the stem will be used for textile/paper
and fibreboard products.
5. Chemical Retting – chemicals are used to
dissolve the pectin allowing the components to be
separated. This shortens the time to as little as 48
hours when the next process can proceed. This
producers a very high quality product.

 

Hemp Retting

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