298 94 307/02 Untersuchungen zum Stand der Umsetzung des ...

See description under 1 Limed bone process.
J Drying
See description under 1 Limed bone process.
4 HEAT AND PRESSURE PROCESS
A Degreasing
See description under 1 Limed bone process.
N Pre-heating
Teil 3 Seite 6-21
An autoclave of about 6800 litres is filled with 2300 kg of degreased bone chips. It is
pre-heated for 10 minutes by blowing steam of 1.7 bar and 115 ºC through it, from bottom
to top.
O Autoclaving and extraction
The bone chips are pressurised and extracted in eight steps.
i - After pre-heating the exhaust is closed and the autoclave is pressurised and heated
from the bottom with steam at 3 bar and 133 - 135 ºC for at least 23 minutes. The auto-
clave is depressurised in 4 – 5 minutes and then 1500 litres of water is sprayed over the
bone chips to extract the gelatine. The water is pumped out during the extraction and is
continued for 12 minutes after the spraying is stopped.
ii - The autoclave is pressurised again for 20 minutes, with steam at 3 bar and 133 -
135 ºC, after which it is depressurised and the gelatine is extracted as described in step i.
iii - The autoclave is pressurised during 20 minutes with steam of 3 bar and 133 -
135 ºC, after which the autoclave is depressurised in 4 to 5 minutes. The autoclave is
filled with 1500 litres of water at 10 ºC, which is left in the autoclave for 20 minutes and
then forced out with steam under pressure. From the third autoclaving and extraction on,
the extract is not pumped out but forced out with steam.
iv - The bone chips are autoclaved and extracted as in step ii. Instead of water the bone
chips are, however, extracted with the extracts coming from steps 5 – 8 of the previous
batch.
v and vi - The chips are autoclaved and extracted as in step ii. Parts of the extracts are
saved for use as extraction liquid for this batch and the next batch.
vii and viii - The chips are autoclaved and extracted as in step iii. The bone chips are left
to drain for 20 minutes and the liquid is pressed out by steam. All of the extract is saved
for use in the extractions of the next batch.
F Filtration
See description under 1 Limed bone process.
G Ion exchange
See description under 1 Limed bone process.