I guess another aspect I recall of "calcining" was removal of organic matter.
That was one of the benefits of ceramic- over chemical engineering - no organic chemistry needed. It's merely a matter of "at what temperature does it burn out" and "what does it leave behind". I honestly don't know if it goes on in the processing of diatomite, but I suppose there might be some "sintering", the process by which some of the surface atoms have enough thermal energy - hence mobility - to reorder themselves in the lattice of adjacent particles, forming a bond between them at less-than-the melting point. Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! ----- Original Message ----- From: "John Stanley" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, July 22, 2007 12:52 PM Subject: Re: [OGD] Orchids Digest, Vol 9, - 232 calcining > Re; 232-1,2 calcining > Thanks Russel and Ray. Trouble is, silica skeletons are neither reduced, > oxidised nor decomposed by heating to less than fusion point although the > skeletons may aggregate as dry lumps as in natural induration. My point > was > more to do with derivation of the term though, which is often (mis)taken > to > imply 'calc'-areous materials like calcite or limestone. No doubt the > advantage for an orchid substrate is that, like rock-wool, it is pretty > inert silica and is porous and permeable. Otherwise, what's its > attraction? > John > > ----- Original Message ----- > From: <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Sunday, July 22, 2007 11:00 AM > Subject: Orchids Digest, Vol 9, Issue 232 > > >> Send Orchids mailing list submissions to >> [email protected] >> >> To subscribe or unsubscribe via the World Wide Web, visit >> http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com >> or, via email, send a message with subject or body 'help' to >> [EMAIL PROTECTED] >> >> You can reach the person managing the list at >> [EMAIL PROTECTED] >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of Orchids digest..." >> >> >> Today's Topics: >> >> 1. Calcined (Russell M. Tyler) >> 2. Re: Calcined (Ray B) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Sat, 21 Jul 2007 06:58:20 -0500 >> From: "Russell M. Tyler" <[EMAIL PROTECTED]> >> Subject: [OGD] Calcined >> To: <[email protected]> >> Message-ID: <[EMAIL PROTECTED]> >> Content-Type: text/plain; charset="Windows-1252" >> >> A Google search resulted in the following: >> >> "To heat (a substance) to a high temperature but below the melting or >> fusing point, causing loss of moisture, reduction or oxidation, and the >> decomposition of carbonates and other compounds." >> >> Russ Tyler, Brainerd, MN >> >> ------------------------------ >> >> Message: 2 >> Date: Sat, 21 Jul 2007 08:52:12 -0400 >> From: "Ray B" <[EMAIL PROTECTED]> >> Subject: Re: [OGD] Calcined >> To: "the OrchidGuide Digest \(OGD\)" <[email protected]> >> Message-ID: <[EMAIL PROTECTED]> >> Content-Type: text/plain; format=flowed; charset=iso-8859-1; >> reply-type=original >> >> More-or-less exactly how they taught us in the Georgia Tech Ceramic >> Engineering department.... >> >> Ray Barkalow - First Rays Orchids - www.firstrays.com >> Plants, Supplies. Books, Artwork, and lots of Free Info! >> >> >> ----- Original Message ----- >> From: "Russell M. Tyler" <[EMAIL PROTECTED]> >> To: <[email protected]> >> Sent: Saturday, July 21, 2007 7:58 AM >> Subject: [OGD] Calcined >> >> >>>A Google search resulted in the following: >>> >>> "To heat (a substance) to a high temperature but below the melting or >>> fusing point, causing loss of moisture, reduction or oxidation, and the >>> decomposition of carbonates and other compounds." >>> >>> Russ Tyler, Brainerd, MN >>> _______________________________________________ >>> the OrchidGuide Digest (OGD) >>> [email protected] >>> http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com >> >> >> >> >> ------------------------------ >> >> _______________________________________________ >> the OrchidGuide Digest (OGD) >> [email protected] >> http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com >> >> >> End of Orchids Digest, Vol 9, Issue 232 >> *************************************** >> >> >> -- >> No virus found in this incoming message. >> Checked by AVG Free Edition. >> Version: 7.5.476 / Virus Database: 269.10.12/910 - Release Date: >> 21-07-2007 15:52 >> >> > > _______________________________________________ > the OrchidGuide Digest (OGD) > [email protected] > http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
