What is Pyrophyllite?
Pyrophyllite is a hydrous aluminum silicate mineral Al2Si4O10(OH)2. It occurs in phyllite and schistose rocks, often associated with kyanite, of which it is an alteration product. It also occurs as hydrothermal deposits. Typical associated minerals include: kyanite, andalusite, topaz, mica and quartz – in the case for Trinity Resources, the deposit is associated with quartz and mica.
Physical & Chemical Properties:
Pyrophyllite and talc are monoclinic (ie have the same crystal structure) giving rise to similar physical properties. The only difference is that talc is magnesium based and pyrophyllite is aluminum based. Talc and pyrophyllite are platy belonging to the same phyllosilicates sub-class of minerals. The weak Van der Wall forces which separate the platelets, aids in the delamination of these minerals and platelet structure retention during processing. Trinity’s pyrophyllite is macro crystalline with a high aspect ratio.
The mineral has a pronounced pearly lustre and has flexible (but not elastic) properties. When heated, the mineral exfoliates and swells up to many times its original volume, hence the name pyrophyllite, from the Greek pyros (fire) and phyllos (a leaf). The color is white, pale green, greyish or yellowish; very soft and greasy to the touch. Pyrophyllite’s specific gravity is 2.65 – 2.85. Pyrophyllite has an abundance of aluminum which allows it to have a high heat resistance and as a result, has been widely used in the manufacturing of ceramics, ceramic tiles, and refractories.
What is pyrophyllite used for?
Phyrophyllite’s properties can be used in the manufacturing process of a variety of products in industries such as Fiberglass, Plastics, Pulp & Paper, Agriculture, Ceramics, Paint & Coatings, Rubber, Personal Care, Refractory and Foundry as an alternative to talc and kaolin.
Why use pyrophyllite as alternative to talc and kaolin in product manufacturing?
Talc and kaolin are functional minerals used as fillers and extenders in a wide range of industries including: ceramics, paints, coatings, plastics and rubber to name a few. The macro crystalline structure (high aspect ratio) of Trinity’s pyrophyllite products offer reinforcing properties in plastics similar to talc. As an aluminum silicate, the optical characteristics and refractive index of Trinity’s pyrophyllite are similar to kaolin making it ideal as a prime pigment extender in coatings, paper, plastics, and adhesives.