<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body data-blackberry-caret-color="#00a8df" style="background-color: rgb(255, 255, 255); line-height: initial;">
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Yes exactly, Andrew. </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Good memory. </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
If it was setting with water then that reaction‎ is undone with heating. I was wondering if there was a form if fly ash cement that was working like the fireclay cement which is a mix of regular cement and clays chosen to start melting at low temperatures. </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Anything is possible. </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br name="BB10" caretmarkerset="INVALID" class="markedForCaretMarkerRemoval">
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
The ash melting point is included in a standard coal analysis. Maybe someone got imaginative. With some fluxes included it would be a 'fireclay' based on fly ash. Ever heard of that?</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
The limiting temperature would be the melting point of the major ash constituent - some kind of silica. </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
I have used castable refractories but never one that claimed to be based on fly ash. Fly ash cement is common in Africa. It is about 5% cheaper that OPC, maybe. It is definitely slower curing in the first few days.
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
What's the elemental composition of wood ash? Where's Lodoysamba...?</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Regards </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Crispin </div>
<table width="100%" style="background-color:white;border-spacing:0px;">
<tbody>
<tr>
<td colspan="2" style="font-size: initial; text-align: initial; background-color: rgb(255, 255, 255);">
<div id="_persistentHeader" style="border-style: solid none none; border-top-color: rgb(181, 196, 223); border-top-width: 1pt; padding: 3pt 0in 0in; font-family: Tahoma, 'BB Alpha Sans', 'Slate Pro'; font-size: 10pt;">
<div><b>From: </b>ajheggie@gmail.com</div>
<div><b>Sent: </b>Sunday, February 8, 2015 02:33</div>
<div><b>To: </b>Discussion of biomass cooking stoves</div>
<div><b>Reply To: </b>Discussion of biomass cooking stoves</div>
<div><b>Subject: </b>Re: [Stoves] Fly ash cement, Curiosity.</div>
</div>
</td>
</tr>
</tbody>
</table>
<div style="border-style: solid none none; border-top-color: rgb(186, 188, 209); border-top-width: 1pt; font-size: initial; text-align: initial; background-color: rgb(255, 255, 255);">
</div>
<br>
<div class="BodyFragment">
<div class="PlainText">[Default] On Sat, 7 Feb 2015 13:28:09 -0500,Crispin Pemberton-Pigott<br>
<crispinpigott@outlook.com> wrote:<br>
<br>
>It is however still a hydrating mix (sets with addition of water which is absorbed and converts the lime back into limestone).<br>
<br>
Careful Crispin I think you are mixing up two different processes,<br>
hydrating will be the re attaching of water molecules to the oxidised<br>
ash. Typically I think it is silicates of aluminium which re absorb<br>
their waters of crystallisation and it is the growth of these crystals<br>
that causes setting before the lime reaction. Lime is first slaked<br>
from CaO to Ca(OH)2 and this gradually re absorbs CO2 from the air to<br>
form the calcium carbonate again.<br>
<br>
Either will presumably fail when heated past your 400C temperature. I<br>
thought it was you who recently pointed out a successful cement and<br>
clay mixture works because the clay particles vitrify as the water and<br>
carbon dioxide are driven off and hence hold the matrix together?<br>
<br>
AJH<br>
<br>
_______________________________________________<br>
Stoves mailing list<br>
<br>
to Send a Message to the list, use the email address<br>
stoves@lists.bioenergylists.org<br>
<br>
to UNSUBSCRIBE or Change your List Settings use the web page<br>
<a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><br>
<br>
for more Biomass Cooking Stoves, News and Information see our web site:<br>
<a href="http://stoves.bioenergylists.org/">http://stoves.bioenergylists.org/</a><br>
<br>
<br>
</div>
</div>
</body>
</html>