Feldspar is a common raw material used in glass making. It is an important ingredient in the glass sand batch. Often, feldspar can comprise of 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 from feldspar improves product hardness, durability, and resistance to chemical corrosion. Alumina provides the resistance in glass to impact, bendings, and thermal shock.
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. Anorthite (the calcium feldspar), though it contains twice as much alumina as soda and potash feldspars and also contains lime, another important ingredient of glass, is not preferred in the glass industry because it is more refractory, having high melting point.
Feldspar acts as a fluxing agent, reducing the melting temperature of quartz and helping to control the viscosity of glass thereby reducing production costs. Anand Talc offers high purity feldspar powder containing as low as 0.1% iron oxide. This is highly advantageous as the presence of iron in the batch composition for glass would otherwise color the glass. The feldspar can be powdered to the required size. All in all, our feldspar powder gives highly successful results in the manufacture of even high class, colorless glass.