Kosfeld Fenna Thesis - Flipbook - Page 98
Hydraulic pressure
After the different tests of creating solid biochar composites with either ground biochar
or more signi昀椀cant pieces of biochar that left
the end material very brittle and fragile, I tested
with a hydraulic press of 5 bar pressure and a
diversity of composites.
Pressing and extrusion of Biochar is a technique
used for making biomass briquettes, which, in
low-income countries, are used for heating and
cooking.
Biochar + Urine
Biochar + Urine + Corn Starch
Biochar + Urine + Tapioca Starch
Biochar + Urine + Soil
= the pressure and the starch-based glue
held the material well together
The bound also depends on the particle size of
input Bichar. Bone char turned out to be more
rigid due to its increased surface area, and
when crushed together, it forms a more solid
structure.
biochar ground into a powder has such a high
surface structure it has no internal structure
or bond with other particles
Dimensions:
Two disks 10x1 cm and one smaller 5cm
diameter to distribute the pressure
Pressure was applied to around 5.5 bar
due to water holding capability, and airdrying took at least 4-5 days. Baking would
speed up the process.
Briquettes can also be charged with urine.
The smaller the particles of biochar, the
more moisture and nutrients it can absorb, but the smaller the surface area gets.
The shaping is dif昀椀cult as it depends on
the mould and accessible removal. Yet, no
electricity is required, and the 昀椀nal material, when fully dry, has a great rigidity!
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