Precipitated Calcium Carbonate (PCC) is chemically the same compound as ground calcium carbonate (GCC), but produced differently — and that difference in production is what gives it distinct, controllable properties. This page covers its classification and what the research shows about controlling its crystal shape and surface area during manufacturing.
What is it?
PCC is classified under ASTM D1199 as Type PC — prepared either by complete solution or by carbonation of lime — distinct from Type GC (ground calcium carbonate). The same specification classifies both types into six grades by particle size, from fine paint grade to ultrafine grade.
Why should I use it?
- It’s produced by a chemical process (solution or carbonation of lime) rather than mechanical grinding — see “What is it?” above.
- Research has directly demonstrated that this production process lets crystal shape and surface area be engineered, not just grinding fineness — see Limitations for what that control requires.
How it’s used
In Plastics & Polymers, PCC is used as a filler classified under the grade system set by ASTM D1199.
Limitations — when it isn’t the right choice
- Hitting a specific target crystal shape and surface area requires precise, simultaneous control of multiple production variables. A 2020 peer-reviewed study on a semi-continuous carbonation process found that temperature, milk-of-lime solids content, CO₂ injection rate, and agitation together determined the resulting surface area and morphology — achieving high-purity PCC with specific surface areas ranging from 5.99 to 26.69 m²/g and morphologies from scalenohedral crystals to chain-like agglomerates, without needing external crystal-growth modifiers. This was documented for one specific production process; it should not be assumed that every PCC grade achieves the same morphology or surface area consistency without checking a supplier’s own batch data.
