Alternate Names: Lithium Mica
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|DENS - Density (Specific Gravity)||3.00|
|MLRG - Frit Melting Range (C)||1150-1300C|
It has a lower fusion point than most high temperature feldspars. The fluorine content can cause problems with glaze bubbles and surface pitting.
It is tricky to establish a formula weight and analysis for this material. Here are some of the factors:
-LOI varies, but we have assumed 5% water in this example.
-Lepidolite does not actually contain Li2O, it has to absorb oxygen from the atmosphere or other materials during firing since the Li is bonded to F.
-Fluorine is bonded to potassium so oxygen has to be absorbed to create K2O.
-For both Li and K only 1/2 of a molecule per input molecule of lepidolite will be yielded.
-In a complete oxidation firing all of the fluorine will volatilize and none will be in the final glass. However in real world conditions none of these is likely to happen completely, and in a reduction firing none may happen at all. In this case we are assuming it is all LOI.
Given the above assumptions, an input of LiF.KF.Al2O3.3SiO2 would yield:
Considering the F as LOI we would have the chemistry quoted here.
To properly handle a material like this in ceramic calculations fluorine conversion factors have to be employed.
Out Bound Links
The toxicity of lithium in ceramics is a hotly debated subject, especially with regards to handling raw lithium carbonate, but also with reference to leaching from glazes.
Isinglass, Muscovite, Biotite, Phlogopite
Although this material is sometimes referred to as a lithium feldspar, it is not a feldspar, but rather a lithium mica. A natural source of Li2O. It is a raw material for the production of lithium car...
In Bound Links