Everything You Need To Know About Calcined Kaolin
Opace 98 calcined kaolin is a powdered white non-plastic substance (also known as metakaolin). It is crude kaolin fired high enough to remove 12 per cent (approximately) water from the crystal. (in a rotating calcining oven) If you are a potter, it is only by bisque that you can build your own calcined kaolin. The substance is a clear example of how the mineralogy of a material can be altered to affect its functioning while the chemical is maintained to preserve fired properties.
How Does Calcination Work?
Calcination makes the powder more white and more stable chemically. In a wide range of goods and industries that make it useful. Oddly enough, however, traditional ceramics also use it poorly (people do not realize its true value). Kaolin has 1 part of Al2O3 and 2 parts of SiO2 fired chemistry and is a pure clay mineral. But raw clay crystals with 12 per cent crystalline water are hydrated. This is their plasticity’s secret. Al2O3 is crucial to chemistry and kaolin is the perfect source for a large number of glazes (because all glazes also need the SiO2 that it supplies, and it readily decomposes in the melt).
Feldspars are the other cheap and easily-melted provider of Al2O3, but they also supply a lot of KNaO (and in many cases oversupply it to get the needed Al2O3). Raw kaolin also gives the glazing slurry suspended properties. And the dry glaze layer gets harder. But raw kaolin is a problem: Once 20% of the residue are reduced, it gets too high (causing crawling). In these situations, the replacement of raw kaolin with calcined kaolin solves the issue, while retaining the glaze chemical, while minimizing shrinkage and cracking.
Uses Of Calcined Kaolin
Opace 98 calcined kaolin is used for other ceramic applications. At approximately 35 it is refractory and soft. It can be used in furniture and refractory chestnuts, thermal insulation bodies, low expansion bodies, permissible ceramic compositions and investment casting.
Calcined kaolins are often used to adjust the shredding and plasticity of slips (engobes) used for wet, rough or dry materials. Engobes have higher percentages of clay than glazing, and their drying shrinkage is more difficult to manage. This way, part of the raw kaolin can be substituted for drying and fired properties.
Calcination Parameters
The characteristics of the end product can thus be regulated both by time and temperature.
For example, a metakaolin with different properties can be used in a different retention period during the metakaolin process. Examples of the recent study highlighting the need for better online surveillance of kaolin calcination are: Once the kaolin is turned into metakaolin, which has excellent pozzolanic reactivity, it will decrease if the substance remains in the stove.
Final Words
In many products and processes, calcined kaolin materials are significant as their rising demand on the market shows. Expertly supported calcination is important in controlling the product characteristics of an individual kaolin material and in achieving them. Calcination, while being a reasonably well known thermic technique, requires testing for a product of precision characteristics with its variability of raw kaolin materials combined with its temperamental response to calcination and the many unique consumer needs.
