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Alumina Hydrate

Formula: Al2O3.3H2O

Chemistry %

Al2O365.39
 

Volatiles %

LOI34.61
DENS - Density (Specific Gravity) 2.42
XREF - Index of Refraction 1.57
HMOH - Hardness (Moh) 2.5-3.5
DNLP - Density, loose packed (lbs/cu fut) 1.0-1.4
MLPT - Melting Point (MP) 3000C D
SAMG - Surface Area (m2/gm) 0.1-0.15
BDGC - Bulk Density g/cc (Packed) 1.4-1.7

Hydrated alumina contains significant water in its crystal structure. There are differing water contents depended on the type of alumina hydrate, but the main refined article of commerce in the market is known as alpha aluminum trihydroxide (with an LOI of 34%). If you are unsure about the alumina hydrate you have in stock you can do a simple LOI test.

Hydrated aluminas are fine granular white powders that have good flow properties. As with any form of alumina, this material has a very high melting temperature. It can be useful in glazes as a source of aluminum oxide, however the powder must be very fine. The hydrated version of alumina stays in suspension better in glaze slurries and has better adhesive qualities. Also using hydrated alumina in glazes and glass can promote the fining operation of coalescing and removing finely dispersed gas bubbles. Small additions of fine alumina hydrate added to a glaze can also enhance the color of Cr-Al pinks. Larger additions of fine material can impart matteness if the glaze is able to take it into solution (sourcing alumina from kaolin and frits may be more practical).


Mechanisms

Out Bound Links

In Bound Links


Pictures
Corundum On Feldspar


XML for Import into INSIGHT

<?xml version="1.0" encoding="UTF-8"?>
<material name="Alumina Hydrate" descrip="" searchkey="Alum Hydrate, Alumina Trihydrate, Hydrated Alumina, Alpha Aluminum Trihydroxide, Gibbsite" loi="0.00" casnumber="16657-47-9">
<oxides>
<oxide symbol="Al2O3" name="Aluminum Oxide, Alumina" status="" percent="65.390" tolerance=""/>
</oxides>
<volatiles>
<volatile symbol="LOI" name="Loss on Ignition" percent="34.610" tolerance=""/>
</volatiles>
</material>


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