Magnesite
Formula: MgCO3
| DENS - Density (Specific Gravity) |
3 |
| HMOH - Hardness (Moh) |
4-4.5 |
| SLBY - Solubility |
Soluble in warm acids |
Magnesite is used in pottery bodies, glazes, and glass. Magnesite is used in low fire glazes to produce opacity and matteness.
Dolomite and talc are more practical sources of MgO for most higher temperature applications.
In glaze melts it is an active flux at higher temperatures (2150C+), and it produces elasticity, a lower expansion coefficient and smooth buttery surfaces. At lower temperatures it is a refractory and will matte glazes and make them crawl due to its high shrinkage and contributions to the surface tension of the melt.
Magnesium carbonate by itself is very refractory, and is used to make bricks for the cement and metal industries. It is 'dead burned' in rotary kilns, then reground, sized, and dry pressed using organic binders.
Mechanisms
Glaze Matteness - White Opaque In low temperature glazes magnesium carbonate in amounts to 15% acts as a refractory, remaining in suspension in the glaze melt to produce a white opaque matte glaze.
Glaze Surface Texture - Crawling Magnesium carbonate is commonly added to glazes, especially at low fire, to make them crawl (it shrinks and cracks the glaze layer at the low end of firing and then its high melt viscosity pulls the glaze melt into islands). This often produces dramatic visual effects, especially if the crawling glaze color contrasts with the underlying body or slip. Additions vary from 10-30% depending on the host glaze.
Out Bound Links
- (Materials - Related)
Dolomite - CaCO3.MgCO3 or CaMg(CO3)2 - Double carbonate of magnesia/calcia
Calcium Magnesium Carbonate, Raw Limestone
- (Materials)
Light Magnesium Carbonate - Mg5(CO3)4(OH)2.4H2O
Hydrated Magnesium Carbonate Mineral, Hydromagnesite, Magnesium Carbonate Light
- (Minerals - Mineral equivalent)
Magnesite
A magnesium carbonate mineral. It is quarried in C... - (Typecodes)
1: GNM - Generic Material
- (Typecodes)
1: FLS - Flux Source
- (URLs - Technical inforamtion)
Magnesite at Wikipedia
http://en.wikipedia.org/wiki/Magnesite - (Temperatures)
Magnesite decomposition (500C-600C)
The process of removing the CO2 from magnesite to ... - (MDT - Member)
Glass Industry
The materials included in this MDT were selected i... - (MDT - Member)
Enamel Industry
We are working on this database and would apprecia... - (MDT - Member)
UK
We are working on this database and would apprecia... - (MDT - Member)
Ron Roy
This is the traditional Ron Roy materials file. He... - (MDT - Member)
North America
The decision about what materials to include in th... - (MDT - Member)
New Zealand
We are working on this database and would apprecia... - (MDT - Member)
Latin and South America
Latin America and South America. We are working on... - (MDT - Member)
Europe
Countries of Eastern Europe and former Soviet Unio... - (MDT - Member)
Australia
We are working on this database and would apprecia... - (MDT - Member)
Asia
All of Asia including Turkey, Russia, Indosnesia, ... - (MDT - Member)
Africa
All of continental Africa. We are working on this ... - (Typecodes)
1: REF - Refractory
In Bound Links
XML for Import into INSIGHT
<?xml version="1.0" encoding="UTF-8"?>
<material name="Magnesite" descrip="" searchkey="Mag Carb, MgCO3, Anhydrous Magnesium Carbonate" loi="0.00" casnumber="7757-69-9">
<oxides>
<oxide symbol="MgO" name="Magnesium Oxide, Magnesia" status="" percent="47.800" tolerance=""/>
</oxides>
<volatiles>
<volatile symbol="CO2" name="Carbon Dioxide" percent="52.200" tolerance=""/>
</volatiles>
</material> | 
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