With a proportion of almost 60 % by weight of the accessible structure of the earth’s crust, feldspars are by far the most frequent group of minerals. Feldspar is a chemically resistant tectosilicate with a thick-slated grain morphology. HPF offers potash as well as sodium feldspars which are processed and separated by an elaborate screening technique, then classified and micro-ground.
Nepheline syenite: a silica-free mineral
Nepheline syenite consists of feldspars and feldspar-type minerals such as albite, microcline and nepheline. This mineral raw material contains no crystalline silica. Exactly as feldspar, nepheline syenite is inert and is characterized by a Mohs hardness of 6, and a high degree of whiteness. HPF only offers surface-treated types.
• hardness 6 (Mohs)
• density 2.6 g/cm³
• thick-slated structure
• high chemical resistance
• high degree of whiteness
• low refraction index of 1.53 – 1.55
• transparent behaviour in many binder systems
• dispersion paints as well as silicate paints and plasters
• clear lacquer systems, i.e. UV-hardening lacquer systems
• anti blocking in plastic films
High Performance Fillers based on feldspar and nepheline syenite: