On Jan 29, 2009, at 9:50 AM, Stephen A. Lawrence wrote:
Horace Heffner wrote:
One of the products
of tetrasilane combustion, SiO2, is a solid and is valuable for many
things, including the making of solar cells.
If I'm not mistaken, its common name is quartz, AKA "glass" (but
without
the impurities).
Pure SiO2 powder is called silica. It comes in a variety of
crystalline forms. One form is called sand. Google it. For example see:
http://www.azom.com/details.asp?ArticleID=1114
Presumably the stuff comes out of the combustion process as individual
molecules, not bound to anything -- i.e., as a gas.
Thinking about this as a possible combustion product from zillions of
futuristic cars, one wonders, is it safe to breath vaporized glass?
As I seem to recall, the liquified version -- sodium silicate, aka
water
glass -- is considered bad stuff to drink. I've never heard anything
about breathing glass gas, though, as it's not something one commonly
encounters, the vapor pressure of silica being very low at ordinary
temperatures.
This low vapor pressure for sodium silicate doesn't sound right.
Water glass is a solution - and if you leave it sit out the *water*
evaporates, just as with salt water. As a kid I used to grow
"crystalline gardens" in it by adding various chemicals to it from my
chemistry set.
Note that I said: "I think this kind of fuel might best be used in
external combustion engines, which are also easily made multi-fuel,
even solid fueled." One reason this is important is that silicon can
be combusted with *zero* emissions. The water vapor is condensed and
the SiO2 trapped by bubbling the emissions through the water. The
SiO2 emissions are in the form of a powder, i.e. can be compacted
into a solid. Another reason is that silicon in solid form can be
directly used as fuel.
The article I referenced thought there would be a high economic value
to the recovered SiO2, especially to the electronics industry. See:
http://www.dbresearch.com/PROD/DBR_INTERNET_EN-PROD/
PROD0000000000079095.pdf
http://tinyurl.com/cuaryk
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
