Nepheline Syenite

Nepheline syenite has three main areas of application;
- Ceramics
- Functional fillers
- Glass production

It is a naturally occurring, silica-free, anhydrous sodium-potassium alumina silicate, that delivers improved product performance and is accordant with modern environmental and industrial hygiene standards.

Nepheline syenite is a composed of three primary minerals: the albite form (sodium) of feldspar, the microcline form (potassium) of feldspar and nepheline (feldspathoid).

The existence of nepheline and the absence of crystalline silica is what sets this uniquely occurring rock apart from feldspar fillers, which contain just albite and microcline.

Like feldspar, it provides alkalis that act as a flux in the manufacture of glass and ceramics. In glass production, alumina acts as a matrix of stabilizer, enhancing the workability of molten glass, and increasing the resistance for scratching, breaking and chemical protection.

Glass Grade

APGlas is glass-grade nepheline syenite, which is a naturally occurring, quartz-free, alkaline alumina silicate.

In glass application, nepheline syenite primarily serves as an excellent fluxing agent and has the following advantages:
‣ Higher alumina content which improves matrix formation, stabilisation and physical resistance
‣ Higher alkali volume and improves fluxing, which lowers the melting temperature of the batch and reduces the quantity of high cost soda ash to be added
‣ Higher alkali/alumina ratio and lower fusion, which increase savings in raw materials handling, storages and energy used in production
‣ No free silica


Chemical Properties

APGlas 13APGlas 20
SiO2~ 60.0%~ 60.0%
Al2O3~ 22.0%~ 22.0%
Fe2O3~ 0.13% (±0.002%)~ 0.20% (±0.002%)
TiO2~ 0.04%~ 0.04%
Na2O~ 9.50%~ 9.50%
K2O~ 6.00%~ 6.00%
CaO~ 0.55%~ 0.55%
MgO~ 0.10%~ 0.10%
L.O.I.~ 1.80%~ 1.80%

Particle Size Distribution

+850µm (20 Mesh)Trace< 0.5%
+600µm (30 Mesh)< 3.0%< 15.0%
-106µm (140 Mesh)< 10.0%< 5.0%
AFS~ 55-70~ 45-60
Moisture< 0.3%< 1.0%

Please note, other grades and specifications are available upon request.

Download Spec. Sheet