FELDSPAR comprises a group of minerals containing potassium, sodium, calcium and aluminium silicates. It is the universal flux used in all types of ceramic bodies & glaze. Feldspars are primarily used in industrial applications for their alumina and alkali content. They are the most common rock-forming minerals.

Quality Aspect

We produce both high quality sodium and potassium feldspar as per client’s requirement. Our high performance magnet and silica lined machineries minimize the iron content.

In the glass industry also, potash feldspar is used in varying proportions. It may contain 10 to 15% of the batch. Feldspar, in this industry, is valued for two purposes, firstly, it acts as a flux and secondly, for alumina content. Alumina provides the resistance in glass to impact, bendings, and thermal shock.

In ceramic bodies, potash feldspar is preferred although soda feldspar works as a good flux and can be satisfactorily used in developing ceramic bodies. Potash feldspar has p.c.e. value 10, while soda feldspar has 8-9. Anorthite (the calcium feldspar), though it contains twice as much alumina as soda and potash feldspars and also contains lime which is an important ingredient of glass, is not preferred in the glass industry because it is more refractory (p.c.e. 12). Glass industry prefers to use mainly orthoclase (potash feldspar) because it tends the melt to clear glass while albite (soda feldspar) tends the melt to a translucent glass.

Feldspar is used as bonding agent along with magnesium oxide, magnesium chloride and other synthetic glue in the manufacture of abrasives, wheels, discs and other shapes. In the preparation of glazes the fine powder of feldspar is mixed with silica powder and a thin slurry is made. The fired up goods are dipped into the slurry and fired again. This imparts glaze to the surface. Some other ingredients are also added to the slurry to impart glaze and lustre. Each pottery factory has its own technique of preparing slurry which is regarded as a trade secret.

Orthoclase - usually light colored white, pink, yellow, or cream, and not transparent. The gem variety is clear to pale yellow, and some called "noble orthoclase"

Microcline - white, pink, pale yellow, or sometimes green-blue, and not transparent. The green-blue variety is called "amazonite"

Plagioclase - gray to grayish-white is common, but may also be white, pink or pale yellow. More semi-opaque than the other feldspars on average, and contains striations on some crystal faces or cleavage surfaces.

The feldspars make up the major constituent of many igneous and metamorphic rocks, they form at medium to high temperature and at some depth. Microcline can form in granite pegmatites and at lower temperatures.