Fiberglass — both E-glass reinforcement fiber and insulation wool — uses feldspar or nepheline syenite as a source of alumina (Al2O3) and alkali flux in the glass batch.
Application Overview
E-glass, the standard reinforcement fiber for composites (boats, wind turbine blades, automotive parts, circuit boards), requires tight compositional control with specific Al2O3 levels (12-15%) for the required mechanical and electrical properties. Nepheline provides Al2O3 more efficiently than feldspar (20-24% vs 17-19%), meaning less raw material is needed per ton of glass. For insulation fiberglass (building insulation batts and loose fill), nepheline serves primarily as a flux to lower the melting temperature and improve fiberization. Our K100 grade serves most fiberglass applications with reliable quality and competitive pricing.
Technical Details & Formulation

Contact us for fiberglass-grade specifications and batch calculation assistance..

