Carbonates

Calcium Carbonates, Limestone, Chalk, Marble, PCC & Dolomite

The attributes of carbonate fillers that determine their usefulness are particle size, whiteness, and mineralogical and chemical purity. Production of fine calcium carbonate may be achieved by either wet-grinding natural limestone (GCC) or by chemical precipitation (PCC).

Their main application areas are for paper, paint and plastics, where carbonate is used for functional fillers to reduce costs, while maintaining physical attributes such as colour.

Different carbonates are used for different applications, depending on their attributes. For example, around 15-20% loading of chalk is commonly used in UPVC drain pipe, whereby the grain shape (aspect ratio) improves mechanical properties such as tensile strength. Other uses, such as food additives and pharmaceutical, rely on the chemical purity and consistency.

PCC is typically used in paper manufacture, with growing markets in paint and polymer. Dolomites are typically used in applications demanding high brightness and superior hardness such as paints and tiles adhesives. Marble is a metamorphosed (geological) limestone, which results in higher brightness and hardness, which is ideal for particularly demanding applications such as specialty paints, thermoset polyesters, acrylic sealants and food additives.