Ron Roy on thu 20 sep 07
Hi Ivor,
We are now talking about a cone 6 version - using boron as a flux. That
changes things because boron never crystallizes. The TiO2 is going to be
handy in that situation.
Silica is low because it is a high alumina matte glaze - ratio below 5 -
which means clay matte. Clay mattes are all the same - low silica.
RR
>Dear Ron Roy,
>
>I appreciate that crystallisation can be encouraged by using nucleating agents.
>
>But in the case of the Rhodes 32 it would seem as though the vitreous melt
>will be supersaturated with refractory ingredients, that is if all the
>Dolomite and whiting actually dissolve. So in cooling the pressure is on
>to crystallise.
>
>If you look at the Unity Formula you might like to say something about the
>amount of Silica present. Seems low to me for a Cone 10 melt.
>
>Best regards,
>
>Ivor
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Ivor and Olive Lewis on thu 20 sep 07
Dear Ron Roy,
I appreciate that crystallisation can be encouraged by using nucleating =
agents.
But in the case of the Rhodes 32 it would seem as though the vitreous =
melt will be supersaturated with refractory ingredients, that is if all =
the Dolomite and whiting actually dissolve. So in cooling the pressure =
is on to crystallise.
If you look at the Unity Formula you might like to say something about =
the amount of Silica present. Seems low to me for a Cone 10 melt.
Best regards,
Ivor
Ivor and Olive Lewis on sat 22 sep 07
Dear Ron Roy,=20
<That
changes things because boron never crystallizes. The TiO2 is going to be
handy in that situation.>>
So it would seem that Rutile is insoluble in a boric oxide melt and =
provide crystal nuclei for the compounds that normally dissolve in Boric =
oxide.=20
<- which means clay matte. Clay mattes are all the same - low silica.>>
Surely that high magnesia and lime content needs silica if they are to =
contribute to the matness and opacity by crystallising as Wollastonite =
and Enstatite.
Thanks for the information.
Best regards,
Ivor
| |
|
