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 me....thanks 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 the perlite > is > > > > very light-weight, > > > > >reducing the overall mass of the structure. > > > > >-- > > > > >Martin K > > > > > > > > Perlite gives very similar results to rice > husk > > > ash. > > > > Michael Allen > > > > and I discussed Perlite in this context when I > > > made > > > > that page on rice > > > > husk ash. You used the same ratio of cement as > I > > > do > > > > with RHA, after > > > > trying it 20 different ways in tests. > > > > > > > > Regards > > > > > > > > Keith > > > > > > > > > > > > > > > > >Keith Addison wrote: > > > > >>Hi Doug > > > > >> > > > > >>Nothing to do with soap, but do you know > about > > > > this? > > > > >> > > > > > > > > > > >>http://journeytoforever.org/at_woodstove-allen.html > > > > >>Rice-husk stoves - Appropriate technology: > > > Journey > > > > to Forever > > > > >> > > > > >>This stuff is great! We're using it to build > > > > charcoal-burning > > > > >>stoves, it's an excellent insulator. Have a > look > > > > at this picture: > > > > >> > > > > > >>http://journeytoforever.org/bflpics/rhahand2.jpg > > > > >> > > > > >>Those coals are really hot! > > > > >> > > > > >>Reduced strength, as you say, but we find > that a > > > > mix of 1:3 up to > > > > >>1:1 cement to rice husk ash by weight is > pretty > > > > strong, and since > > > > >>the RHA is much lighter than the cement, in > fact > > > > you don't use a > > > > >>lot of cement. It's a bit like pumice or > > > > something. Doesn't weigh > > > > >>very much. > > > > >> > > > > >>The rice husk burner works very well, but if > you > > > > want to put it in > > > > >>a 55-gal/200 litre oil drum, as we did, > you'll > > > > have to make the > > > > >>cage slightly smaller. > > > > >> > > > > >> > > > > >>>Hi, > > > > >>>I am searching for information on making > > > aerated > > > > concrete. For those > > > > >>>interested, basically foam is added to a > mortar > > > > mix, and the > === message truncated === __________________________________ Do you Yahoo!? Yahoo! Mail - You care about security. So do we. http://promotions.yahoo.com/new_mail _______________________________________________ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
