Kosfeld Fenna Thesis - Flipbook - Page 71
Bone char that has been pyrolised
with technique A , in about 350 ºC.
The bones are heated to a degree,
where carbonisation has not started, but the release of gases and
bone tar is activated. Bone tar is a
black, sticky substance that occurs
through destructive distillation.
The material is liquid in heated
state and flows over bones and
other surrounding materials. When
cold it hardens and smells like
smiky barbeque.
This material has ancient use as an
adhesive, waterproo昀椀ng, herb and
insecticide, medicinal purposes.
3
4
In the process of burning cattle
bones with retort stacking technique ( B ) the temperature rose
to 675 ºC, which is on the highest
spectrum of pyrolisis and resulted
in full carbonisation. Yet, due to
the heat and little amount of oxygen in the kiln, calcium carbonate
((CaCO3) formed on the surface
area of all bones. This is a stage between carbonisation and the material turning into 昀椀ne ash. The calcium carbonate is a by-product from
this product and can be carved off
with a knive from the main structure. Due to high temperature and
quick process time, the biochar
has a less
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