Digitalfire Ceramic Materials Database

Logged in as Level 2 access: Logout


You should always be testing. But it is wasted without an audit trail. Document your lifetime of recipes, firing schedules, test results, pictures and much more in a private account at insight-live.com. It is the future, the next step after desktop Digitalfire Insight.

Watch the video, learn more or sign-up at http://insight-live.com.

Colemanite

Formula: 2CaO.3B2O3.5H2O or CaB3O4(OH)3·H2O

OxideAnalysisFormula
CaO27.30%1.000
B2O350.80%1.500
LOI21.90
Oxide Weight160.49
Formula Weight205.49
Enter the formula and formula weight directly into the Insight MDT dialog (since it records materials as formulas).
Enter the analysis into an Insight recipe and enter the LOI using Override Calculated LOI (in the Calc menu). It will calculate the formula.
DENS - Density (Specific Gravity) 2.95
HMOH - Hardness (Moh) 4.5
MLPT - Melting Point (MP) 1050C
SLBY - Solubility in HCl but not in water

Colemanite has been a popular natural source of insoluble boron for many decades. It is similar to Ulexite in its oxide contribution to glazes (although the latter sources Na2O also). Frits are used as boron sources in industry whereas potters and smaller companies have used colemanite.

Colemanite does not melt as low or as uniformly as Ulexite. Gerstley Borate contained significant amounts of colemanite. Pure colemanite, however, is much higher in B2O3 than Gerstley Borate.

Colemanite is available from Turkey, Chile and California. The chemistry of these varies quite a bit, and of course, none of the available materials have the theoretical chemistry shown here.

Very high percentages of colemanite in a glaze can result in wrinkling of the fired surface, likely due to to a phenomenon called 'decrepitation' that occurs when colemanite is heated. Be sure to screen out any materials coarser than 200 mesh, or ball mill the glaze. Gum or other binders also help.


Out Bound Links

In Bound Links


By Tony Hansen

XML for Import into INSIGHT

<?xml version="1.0" encoding="UTF-8"?> <material name="Colemanite" descrip="" searchkey="" loi="0.00" casnumber="1318-33-8"> <oxides> <oxide symbol="CaO" name="Calcium Oxide, Calcia" status="" percent="27.300" tolerance=""/> <oxide symbol="B2O3" name="Boric Oxide" status="" percent="50.800" tolerance=""/> </oxides> <volatiles> <volatile symbol="LOI" name="Loss on Ignition" percent="21.900" tolerance=""/> </volatiles> </material>


Feedback, Suggestions

Your email address

Subject

Your Name

Message


Copyright 2003, 2008 http://digitalfire.com, All Rights Reserved
Get a free INSIGHT software trial

INSIGHT is ceramic chemistry
calculation software that runs on
Windows, Mac and Linux and talks
to this web site. ()