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Formula: LiF.KF.Al2O3.3SiO2
Alternate Names: Lithium Mica

Oxide Weight476.52
Formula Weight558.64
If this formula is not unified correctly please contact us.
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:
1/2 Li2O
1/2 K2O
2 F
1 Al2O3
3 SiO2
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.

Lepidolite Stone

Lepidolite ore

Lepidolite ore close-up

Out Bound Links

In Bound Links

By Tony Hansen

XML for Import into INSIGHT

<?xml version="1.0" encoding="UTF-8"?> <material name="Lepidolite" descrip="" searchkey="Lithium Mica" loi="0.00" casnumber="12168-80-8"> <oxides> <oxide symbol="Li2O" name="Lithium Oxide, Lithia" status="" percent="3.000" tolerance=""/> <oxide symbol="K2O" name="Potassium Oxide" status="" percent="7.300" tolerance=""/> <oxide symbol="Al2O3" name="Aluminum Oxide, Alumina" status="" percent="26.900" tolerance=""/> <oxide symbol="SiO2" name="Silicon Dioxide, Silica" status="" percent="47.700" tolerance=""/> </oxides> <volatiles> <volatile symbol="H2O" name="Water" percent="4.700" tolerance=""/> <volatile symbol="LOI" name="Loss on Ignition" percent="10.000" tolerance=""/> </volatiles> </material>

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