Keith: I checked the California Rice Commission
website http://www.calrice.org/a5_ricestraw.htm and
only found an arctile on rice straw. Looks like
rice straw also in need of alternative uses cause
they used to burn it but affected air quality.
It's easy to find uses for straw, easy to compost it too. Rice husks
are a bit more intractable.
I
will do more search on rice husks.
thanks
Phillip Wolfe
We touched on this before, a bit of a mystery what happens to
Califonian rice husks. They're mostly silica so it's not very active
stuff, difficult to compost or to recycle back to the soil, for
instance. Please let us know what you find.
I've seen mountains of rice husks outside rice centrals in 3rd World
countries. Here in Japan there's currently a flavour-of-the-month
myth that rice husks suppress weed growth so people are using them as
a mulch. Well, that won't hurt, but their theory's without any basis.
Possibly it's filtered through from what Biodynamic farmers do with
silica, but that's altogether different, and not without basis. I'm
more than somewhat amused (in a dark sort of way) at rice farmers
constantly complaining about weed problems.
Best wishes
Keith
Wolfe [EMAIL PROTECTED] wrote:
Keith, Thanks for the info on rice husks as one of
the
world's most under-utilized waste materials. I
imagine
the Rice Cooperative in California knows a lot about
rice husks. I plan to read more about rice husks.
All new to methanks again.
Phillip Wolfe
--- Keith Addison [EMAIL PROTECTED]
wrote:
Hello Phillip, Peter
Perlite is made from a siliceous volcanic rock for
horticultural use
and also for insulation. When heated to a
suitable
point in its
softening range, it expands from four to twenty
times its original
volume. This expansion is due to the presence of
two
to six percent
combined water in the crude perlite rock. When
quickly heated to
above 1600°F (871°C), the crude rock pops in a
manner similar to
popcorn as the combined water vaporizes and
creates
countless tiny
bubbles which account for the amazing light weight
and other
exceptional physical properties of expanded
perlite.
So it's very similar to rice husk ash, which, when
properly prepared,
consists mainly of myriad tiny glass bubbles.
A major difference is that Perlite is a product,
rice husk is one of
the world's most underutilised waste materials.
Perlite is very fragile and makes an unpleasant
dust. Wear a
breathing mask. Reject perlite of a suitable
grade
can often be
obtained free of charge (or at low cost) from the
manufacturers.
Best wishes
Keith
Perlites and found with the Borates and all part
of
the volcanic geological evolution. We have a lot
of
Perlites in our Sierra Nevadas in California.
Same
with borates (borax). Borates, perlites,
colemanites,
- all that stuff can be found anywhere you have
an
escarpment of raised mountains due to ancient
volcanic
magma scarns and earthquake activity especially
next
to an arid desert bowl.
What is Perlite?
http://www.perlite.info/hbk/0034409.htm
Perlite is not a trade name but a generic term
for
naturally occurring siliceous volcanic rock. The
distinguishing feature which sets perlite apart
from
other volcanic glasses is that when heated to a
suitable point in its softening range, it expands
from
four to twenty times its original volume.
This expansion process is due to the presence of
two
to six percent combined water in the crude
perlite
rock. When quickly heated to above 1600 F (870 C)
the
crude rock pops in a manner similar to popcorn as
the
combined water vaporizes and creates countless
tiny
bubbles in the softened glassy particles. It is
these
tiny glass-sealed bubbles which account for the
amazing lightweight and other exceptional
physical
properties of expanded perlite.
The expansion process also creates one of
perlite's
most distinguishing characteristics: its white
color.
While the crude perlite rock may range from
transparent to light gray to glossy black, the
color
of expanded perlite ranges from snowy white to
grayish
white.
Expanded perlite can be manufactured to weigh
from
2
lbs/ft3 (32 kg/m3) to 15 lb/ft3 (240 kg/m3)
making
it
adaptable for numerous uses, including
filtration,
horticultural applications, insulation, inert
carriers
and a multitude of filler applications.
--- Guag Meister [EMAIL PROTECTED] wrote:
Hi All ;
Could I ask a stupid question? What is
Perlite?
Best Regards,
Peter G.
Thailand
--- Keith Addison [EMAIL PROTECTED]
wrote:
Hi Martin
Hi Keith et al,
I used Perlite mixed with refractory cement
in my
aluminum casting
furnace. The walls saw temperatures
surpassing
2000F, it was working
well. The mixture was 50/50, and
