Precipitated calcium carbonate, or PCC, is derived from
limestone, a fine-grained material that is generally greyish in
color due to its organic content.
If the limestone were crushed and fine ground, it would only
have a brightness of ~80 ISO (on a scale of 0-100), which is
too low for the material to be used as a filler and coating
pigment. But greyish limestone is often pure and the organic
components will be driven off by the calcining process.
Arcos in Brazil is a major area for lime production, with
grey limestone deposits. Vietnam meanwhile produces a whitish
limestone, from a deposit owned by TLD Vietnam, in Hai Duong
The ideal chemistry of limestone that is suitable for
processing into PCC, and corresponding details for the
Vietnamese material, are shown in Table 1.
The two raw materials necessary for the production of PCC
are quicklime and carbon dioxide. These are purified
separately, then the quicklime is mixed with water to produce
calcium hydroxide, Ca(OH)2, in either liquid form (milk of
lime) or as a solid (hydrated lime).
Cooled and purified CO2-bearing kiln gas is then bubbled
through the milk of lime in a reaction vessel known as a
carbonator. The gassing process continues until all of the
calcium hydroxide has been converted to carbonate. This is
monitored by checking the acidity level (pH) or by other
Chemical reactions in the carbonation process can be
- Calcination of limestone in a kiln to drive off carbon
dioxide and to produce lime
- (CaO)CaCO3 + heat » CaO (lime) + CO2
- Lime delivered to satellite plant, lime slaked (water
- CaO + H2O » Ca(OH)2 (Hydration or slaking)
- Carbon dioxide bubbled through in a carbonator to give
chemically precipitated carbonate
- Ca(OH)2 + CO2 » CaCO3 + H2O (carbonation)
After the carbonation process is complete, screening is used
to further purify the PCC, because any impurities will be
coarser than the PCC particles. Most commercial grades have a
minimum purity of around 98%, with magnesium carbonate, silica
and unconverted lime as the main contaminants.
In a satellite plant, PCC can then be used in the
manufacture of paper. Particle shape and size (crystal
engineered PCC) can be determined during the processing.
PCC satellite plants
The three main companies involved in establishing PCC
satellite plants at paper mills are Minerals Technologies
(MTI), Omya and Imerys.
Okutama Kogyo of Japan, Schaefer Kalk of Germany and others
have satellite plants.
Minerals Technologies (MTI) United States-based MTI has two
main businesses, Specialty Minerals and Performance Materials,
and generated total revenue of $1.32 billion in 2017, according
to its annual report for that year.
Specialty Minerals accounted for 44% of MTI’s
total sales in 2017, from four product lines: paper PCC,
specialty PCC, ground calcium carbonate (GCC) and talc. The
paper PCC sector had sales in 2017 of $377.7 million, which was
29% of MTI’s total sales, as shown in Figure
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paper markets have lagged.
MTI created the satellite concept where production
facilities are built on site at paper mills. It is the world
leader in the production of PCC, with capacity for 4.2 million
tonnes per year for paper, from 56 satellite plants (see Table
The company said in its 2017 annual report that it has the
capacity to double its global production capacity, with Asia
showing the strongest growth. But it did not give a timescale
or say whether it actually plans to do so.
The company has signed seven satellite agreements in China
since 2012, and has two new satellite agreements in Indonesia.
MTI will also continue to advance its PCC technology in India,
where it has been able to establish leadership in the market
with five satellite PCC plants in the past eight years.
Since it introduced its first PCC plant in China in 2004, it
now has nine satellite plants (see Table 3) and more are
MTI is receiving increased interest from papermakers which
are conducting trials with its PCC FulFill® high-filler
technology, as well as evaluating its NewYield® platform of
technologies that it hopes will drive further penetration of
The FulFill® technology is intended to allow papermakers
to increase the amount of PCC in paper, replacing more
The NewYield® technology platform is said to convert a
papermaker’s waste stream into usable pigment.
This waste stream is mostly found in China, where environmental
regulations prohibit burning the material or sending it to
NewYield® is intended to provide papermakers with a
number of benefits. It should eliminate landfill costs, provide
an effective paper filler, and reduce emissions and energy
The prospects for these new technologies in China are
bright, and MTI is pursuing more than 20 opportunities in the
region for PCC filler and new satellites. It is also engaged in
discussions with packaging manufacturers in several locations
around the globe for the use of coating products in various
applications, including white container board and boxboard
MTI also has new technologies for brown box packaging.
In the paper industry, MTI’s PCC is used in:
- Production of coated and uncoated wood-free printing
and writing papers, such as office papers
- Filler in the production of coated and uncoated
groundwood (wood-containing) paper such as magazine and
catalogue papers; and
- Coating pigment for both wood-free and groundwood
PCC markets for MTI - paper
MTI estimates that, during 2017, more than 90% of North
America’s production of uncoated wood-free paper
used alkaline technology.
The uncoated groundwood paper market, including newsprint,
represents about 20% of worldwide paper production, and paper
mills producing wood-containing paper still generally employ
acid papermaking technology.
But the conversion to alkaline technology by these mills has
been hampered by the tendency of wood-containing papers to
darken in an alkaline environment. For this reason, MTI has
developed proprietary application technology for the
manufacture of high-quality groundwood paper in an acidic
environment using PCC (AT® PCC).
Furthermore, because groundwood or wood-containing paper
mills use larger quantities of recycled fiber, there is a trend
toward the use of neutral papermaking technology in this
segment for which MTI supplies traditional PCC chemistries.
MTI now supplies PCC at six groundwood paper mills around
the world, and licenses its technology to a ground calcium
carbonate (GCC) producer to help accelerate the conversion from
acid to alkaline papermaking.
MTI continues to pursue satellite PCC opportunities in the
coated paper markets. The Opacarb product line is designed to
create value for papermakers and can be used alone or in
combination with other coating pigments such as kaolin.
PCC coating products are produced at eight of
MTI’s PCC plants worldwide.
MTI has three merchant plants producing PCC. In Germany,
there is a plant at Walsum with capacity for 125,000 tonnes per
year of PCC for paper coating. PCC is produced for industrial
uses in the UK at Lifford, with capacity for 35,000 tpy, and in
the United States at Adams, with capacity for 100,000 tpy, also
for industrial uses.
MTI announced in June 2014 that its Paper PCC group was to
enter the packaging market through an agreement with Zhengda
The company built a 50,000 tpy satellite PCC plant to
produce coating-grade PCC in Zhejiang province, China, for use
in coated bleached cartonboard for packaging. This was
MTI’s first on-site satellite plant to produce PCC
for the coated packaging market, and represented an entry point
to a market worth as much as $100 million per year.
The end-market for this type of packaging paper is in such
areas as containers for food and beverages, cosmetics,
pharmaceuticals, and electronic and luxury products.
Imerys PCC plants for paper are shown in Table 4, with Omya
satellite plants listed in Table 5.
Okutama Kogyo has five PCC plants with total capacity for
288,000 tpy. The majority of this capacity, 276,000 tpy, is in
Japan and is used to produce 198,000 tpy of filler grade
material, with the remaining 90,000 tpy of pigment grade.
The Fuji satellite plant produces 48,000 tpy of filler and
12,000 tpy of pigment. The Nigata satellite plant produces
54,000 tpy of filler. The Fukuyama merchant plant produces
48,000 tpy of filler and 24,000 tpy of pigment, with the
Mizuho merchant plant producing 48,000 tpy of filler and
42,000 tpy of pigment.
There is also a merchant plant in Shanghai, producing 12,000
The company sells PCC under the tradename TamaPearl® and
produces two groups of products: calcite and aragonite.
Schaefer Kalk has been producing PCC since 1954, marketed
under the trade name Schaefer Precarb.
PCC is produced in different crystal modifications and grain
shapes. For each of these precipitation products, the physical
parameters are optimized for the application, with regards to
particle size and particle size distribution, single particles
or agglomeration of primary crystals, and specific surface and
The largest of Schaefer’s PCC satellite plants
is the Schafer Kalk Finland Oy UPM Kymmene paper mill in
Selluntie, Finland. This company was established in 2007, and
in 2010 it commissioned a plant for the production of highly
concentrated PCC slurries. Current capacity is 155,000 tpy.
Schaefer Kalk also has satellite plants at Wattens in
Austria, with capacity for 15,000 tpy; at Olsany in the Czech
Republic, with capacity for 15,000 tpy; and at Neidenfels in
Germany, with capacity for 15,000 tpy.
At Huangzhou in China, there is a satellite/merchant plant
with capacity for 30,000 tpy (20,000 tpy satellite and 10,000
tpy merchant) and merchant plants in Germany at
Hahnstätten with 80,000 tpy capacity, and in Malaysia at
Kuala Ketil with capacity for 30,000 tpy.
At the Hahnstätten merchant plant, some products for
paper are produced such as printing papers, thermosensitive and
carbonless auto-copying papers, and paper boards with high
brightness and opacity. But the relevant capacities are not
Overall, Schaeffer Kalk has satellite capacity estimated at
217,000 tpy and merchant capacity at 120,000 tpy, giving a
total of 337,000 tpy.
Global production of PCC in 2017
It is estimated that global production of PCC in 2017 was 17
million tonnes. PCC capacity in China was 8.5 million tonnes,
which was 50% of global production. PCC satellite production
was 6.8 million tonnes, divided as shown in Table 6 and Figure
MTI accounts for 62% of PCC satellite production for paper,
with Omya at 15%, Imerys 10%, Okutama Kogyo 4%, Schaeffer
Kalk 3%, and others 6%.