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 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
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