Examples of calcium carbonate (top) and dolomite (bottom). Both are mixed with 25% bentonite to make them plastic enough to form test bars. They are fired to cone 9. In spite of the significant bentonite present, which melts at this temperature, both of these bars are very porous and refractory, even powdery. However, put either of these in a glaze batch with other ceramic minerals, and they interact strongly to become fluxes!
| Materials |
Calcium Carbonate
In ceramics, calcium carbonate is primarily a source of CaO in raw stoneware and porcelain glazes. |
| Materials |
Quicklime
Made by heating limestone sufficiently to drive off carbon dioxide. The only ceramic use is the production of refractories (because of its high melting point). |
| Materials |
Dolomite
An inexpensive source of MgO and CaO for ceramic glazes, also a highly refractory material when fired in the absence of reactant fluxes. |
| Glossary |
Oxide Interaction
In ceramic glazes each oxide generally makes a specific contributions to the melting and freezing behavior of the glaze. However interactions are also important. |
| Glossary |
Refractory
In the ceramic industry, refractory materials are those that can withstand a high temperature without deforming or melting. Or can be sintered into super materials. |
| Temperatures | Decarbonation (200-1000) |
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