CRISTOBALITE
1. WHAT IS CRISTOBALITE
Cristobalite is a high temperature variant of quartz . Chemical formula SiO 2 , but has a different chemical structure than quartz. Both quartz and cristobalite are isomorphic to other minerals in the quartz group. Examples include coesite, tridymite and stishovite .
Cristobalite is another allotrope of SiO2 . Has outstanding physical and mechanical properties such as density 2.35 g/cm 3 . Mohs hardness 6.5 and especially very high whiteness.
2. PRODUCTION PROCESS OF CRISTOBALITE
Cristobalite is produced by heating silica sand or natural quartz to 1470 o C and then cooling rapidly so that the SiO 2 crystals exist in the form of Cristobalite. The heating of materials can be done in a rotary kiln using gas fuel. This method ensures that no dust or smoke is generated that affects product quality.
3. PROPERTIES OF CRISTOBALITE
Cristobalite can be characterised by:
- High brightness
- The Mohs hardness is relatively high at 6.5
- Relatively low refractive index. Makes it a transparent filler in various adhesives
- Easy to wet
- High inertness in different environments
- Transparency to ultraviolet radiation. (Suitable for UV absorption process).
