Specialty Minerals Precipitated Calcium Carbonate (PCC) Satellite Plant History
Specialty Minerals Inc.’s (SMI’s) first precipitated calcium carbonate (PCC) satellite plant initiated a revolution in the way North American printingand writing papers were made. We commercialized the satellite concept for on-site PCC production in 1986. It was designed for a North American papermill that manufactured uncoated freesheet paper and is still in operation today. Before 1986, there were a few small captive PCC plants owned and operated by paper companies.
The timing was right. For approximately 100 years prior to 1986, most fine papers in North America were made under acidic conditions. But, acid-type papers had problems. Over time, papers made at low pH (< 7.0), discolored and became brittle. In addition, paper machinery corroded and papermill waste effluents were toxic to aquatic animals. Because calcium carbonate reacted when exposed to acid environments, papermills had to rely virtually on one mineral filling and coating material–kaolin clay, primarily from the state of Georgia. Not only did we convince papermills that on-site production of PCC was acceptable and economical, but we also assisted in converting their papermaking chemistry from acid to neutral or alkaline pH (> 7.0). Our engineers have since refined the conversion process so that today every facet of paper making chemistry is examined, monitored and controlled.
Papers made under alkaline conditions have many advantages:
- Less color and strength degradation and longer “shelf-life”
- Less corrosion of machinery and abrasion of forming cloth
- Increased sheet brightness, gloss and opacity with precipitated calcium carbonate versus clay
- Better paper porosity, smoothness and printability
- No transportation costs because of on-site plant
- Customized precipitated calcium carbonate crystals designed specifically for the host mill
- Higher percentage filler levels thereby replacing more expensive wood pulp
Today, the advantages of on-site PCC in support of alkaline papermaking have become accepted worldwide. Specialty Minerals has more than 50 PCC satellites at paper mills around the world, on most every continent.