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Nepheline Syenite A270

Alternate Names: Spectrum Nepheline Syenite, Nepheline Syenite Spectrum

Oxide Analysis Formula
CaO 0.35% 0.03
MgO 0.02% -
K2O 4.80% 0.22
Na2O 10.50% 0.75
Al2O3 23.60% 1.02
SiO2 60.20% 4.41
Fe2O3 0.08% -
LOI 0.42%n/a
Oxide Weight 438.46
Formula Weight 440.31


Also available in 200, 400 grades (other grades are available for other purposes).

From data sheet: SPECTRUM® ceramic fluxes are produced from nepheline syenite; a naturally occurring, silica deficient sodium-potassium alumina silicate. The higher total alumina and alkali contribution available from nepheline syenite produces ceramic ware with greater impact and flexural strength and improved resistance to the stresses of thermal extremes and mechanical shock.
The lower melting eutectic and increased fluxing power of SPECTRUM® make possible body compositions which mature at temperatures as low as cone 3-5. It is the higher alkali to alumina ratio and greater chemical reactivity that accelerate the melt and promote a faster maturation. SPECTRUM will increase the rate of vitrification over a wider firing range, ensure smooth glazed surfaces even at lower temperatures and help to reduce the deformation typically encountered in fast fire cycling. When the objective is improved translucency, SPECTRUM will combine with and consume the available free crystalline silica to create highly translucent wares.

Particle size (% retained on):
200 mesh: 0.05
270 mesh: 0.67
325 mesh: 1.29

Melting point: 1868F/1020C
pH: 10.1
Bulk Density (lb/ft3): 38-55
Specific gravity: 2.61

Related Information


Typecodes Feldspar
The most common source of fluxes for high and medium temperature glazes and bodies.
Hazards Feldspar
Feldspars are abundant and varied in nature. They contain small amounts of quartz (while nepheline syenite does not).
By Tony Hansen
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