[Default] On Sat, 15 Jun 2013 17:44:56 +1000,Stephen Joseph <[email protected]> wrote:
>There has been a lot of work done on formation of crystobalite. The rate >of formation is both a function of time and temerature > >If you have low temperatures (450c) and short times (<60 minutes)you wont >produce it. Fly ash from wood boilers has always been considered hazardous in UK, typically wood ash is 50% silica, I think, so rice is only different in having a higher ash content. The period that any fuel is exposed to the pyrolysis front of a tlud burn must only be a few minutes but the char above will be subject to the offgas temperature for the remainder of the burn. Even so as has been pointed out the bulk of the silica will remain in the char matrix. I'm interested to see a bit more analysis of the "grey" particulates Dean mentioned but overall it doesn't seem to be a big part of the health problem when one considers how hotspots of silicosis have been flagged up in industry. AJH _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
