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CARBONATES

Miscellaneous

• Family: None
• Region: None
• Mined At: Unspecified
• Raw Mineral: Yes
• Generic: No

Notes

(Richard Willis)

Molecular compounds of RO BASE elements in their carbonized-ash, CO₃ forms: Na₂CO₃ (soda ash), K₂CO₃ (potash), etc.
When heated, CO₃ becomes O + CO₂, thus creating an oxide to continue heating and a gas freed to escape, e.g., CaCO₃ becomes CaO + CO₂ becomes CaO becomes Ca. The escaping CO₂ can be seen when the glaze begins bubbling.
Whether to introduce an element via a carbonate is sometimes a matter of choice but often is simply using the more commonly available materials at hand. Many base elements are more abundantly available in their carbonate forms than in their oxide forms, Ca being a prominent example, since it would seem that nature favors forming bases as carbonates. To avoid the cratering and pinholing on glaze finishes which can result from the bubbling caused by escaping carbon dioxide gas one may either use an oxide form rather than a carbonate form or effect a calcination by heating slowly during the 100-1000ºC period, and regulating heat rise periods to half-hour intervals in order to allow “settling” and “filling in” of the crater-making bubbling. On the other hand, a pre-firing calcination is preferred when feasible. see minerals, and refer to calcination in Appendix II.

Authors

• Richard Willis (Owner)

XML

<?xml version="1.0" encoding="UTF-8"?>
<material name="CARBONATES" descrip="" generic="0" rawmineral="1" searchkey="" loi="0.00">
<notes>
<note>Molecular compounds of RO BASE elements in their &lt;B&gt;&lt;I&gt;carbonized-ash&lt;/I&gt;&lt;/B&gt;, CO&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt; forms: Na&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;CO&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt; (soda ash), K&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;CO&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt; (potash), etc.&lt;BR&gt;
When heated, CO&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt; becomes O + CO&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;, thus creating an oxide to continue heating and a gas freed to escape, e.g., CaCO&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt; &lt;I&gt;becomes&lt;/I&gt; CaO + CO&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt; &lt;I&gt;becomes&lt;/I&gt; CaO &lt;I&gt;becomes&lt;/I&gt; Ca. The escaping CO&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt; can be seen when the glaze begins bubbling.&lt;BR&gt;
Whether to introduce an element via a carbonate is sometimes a matter of choice but often is simply using the more commonly available materials at hand. Many base elements are more abundantly available in their carbonate forms than in their oxide forms, Ca being a prominent example, since it would seem that nature favors forming bases as carbonates. To avoid the cratering and pinholing on glaze finishes which can result from the bubbling caused by escaping carbon dioxide gas one may either use an oxide form
rather than a carbonate form or effect a calcination by heating slowly during the 100-1000&amp;ordm;C period, and regulating heat rise periods to half-hour intervals in order to allow &amp;#147;settling&amp;#148; and &amp;#147;filling in&amp;#148; of the crater-making bubbling. On the other hand, a pre-firing calcination is preferred when feasible. &lt;FONT SIZE=2&gt;see &lt;B&gt;&lt;I&gt;minerals, &lt;/I&gt;&lt;/B&gt;and refer to &lt;B&gt;&lt;I&gt;calcination&lt;/I&gt;&lt;/B&gt; in Appendix II.&lt;/FONT&gt;&lt;BR&gt;

</note>
</notes>
</material>

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