suppose the fireclay is kaolin. the formation of metakaolin at about 600 C- can it be reverted? Progressive temperature rise causes spinel-like 2Al2O3.3SiO2 at about 950 C and mullite formation at about 1050 C, every time giving away SiO2 Upon progressive disassociation. After firing to 1600 c and cooling, the structure is mainly various polymorph of silica plus mullite. (or other aluminosilicates?). acn the fired product be chemically reverted back to kaolin? if yes , How? if no, why not?
First of all you must determine with XRD the mineralogical composition of your clay before firing.
Thera are several methods and chemicals to make plastic and flowable powders which were not plastic and flowable before.
Not. Dehydration of kaolinite occurs at temperatures of 450-650 degrees. Kaolinite loses chemically bound water irrevocably.
Mullite, as a rule, begins to appear at 970-1000 degrees, and after 1300 there is an active growth of mullite crystals and melting of quartz particles (the intensity depends on their size). After 1600 there will be mullite and residual quartz (the modification depends on the firing conditions).
The conversion of kaolinite to mullite is associated with a strong restructuring of the material structure, therefore it is irreversible
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Inorganic Materials
- Ceramics