By Selene Rebane
Calcium carbonate is very versatile. It not only acts as a
filler, but also as an extender which changes the mechanical
properties of the end-product.Calcium carbonate (CaCO3) is by
far the most commonly used filler in the polymer industry, with
a market share of 34% in 2017. And over the past eight years,
demand for calcium carbonate has increased by 2.7% per year on
Its relatively low cost and superior qualities have made
calcium carbonate the preferred filler in the paper,
plastics, paints and coatings industries, making it the
market leader in fillers.
GCC and PCC
Calcium carbonate comes in two varieties. In its natural
form, ground calcium carbonate (GCC) is mined, while
precipitate calcium carbonate (PCC) is its synthesised form.
PCC is made by purifying the mined base mineral via dissolution
and precipitation, in a process which allows the producer to
adjust the properties of PCC according to its needs.
Due to the additional refining process, PCC tends to be more
expensive than its ground form.
CaCO3 is markedly cheaper than other fillers, such as kaolin
and talc. In February 2018, on the online marketplace
Indiamart.com, producers were offering GCC for $91-121 per
tonne on average. Meanwhile, prices of kaolin, one of its
closest competitors in the paper market, were in the range of
$180-360 per tonne depending on the purity and whiteness of the
With close links between population growth and filler
demand, it is not surprising that China is both the
world’s largest producer and consumer of calcium
The country produced 230 million tonnes of CaCO3 in 2015,
according to statistics website Statista. The second - and
third- largest producers were the United States and India,
lagging far behind with outputs of 19 million tonnes and 16
million tonnes, respectively.
Paper industry: calcium carbonate displacing
According to research by Global Industry Analysts (GIA), the
paper industry was the biggest consumer of calcium carbonate
products in 2013, accounting for 37% of global GCC demand and
43.3% of PCC demand, respectively.
GCC and PCC are gradually becoming the preferred fillers for
the paper industry, displacing the previous favourite,
Plastics: PVC driving CaCO3 demand
PCC and GCC products also have a stronghold in plastics
production, where they account for nearly 60% of all the
fillers used, with the remaining market share divided by
kaolin, muscavonite, wollastonite and others.
In plastics, CaCO3 can account for as much as 30% of the
material’s weight, with both forms of the mineral
in high demand. Globally, demand from plastics accounted for
25.3% of GCC and 27.8% of PCC consumption in 2013, according to
Calcium carbonate can improve heat-deflection temperature,
thermal conductivity, impact strength, stiffness and barrier
properties in plastics. It can also help plastics to heat up
and cool down faster, and is compatible with a wide range of
polymer resins, such as polypropylene compounds or polyvinyl
It is perhaps the demand from the PVC industry - which is
closely linked to the construction, automotive, packaging and
electricity sectors - that has been driving the recent boom in
calcium carbonate’s use in the plastics
For example, PVC is widely used for flexible tubing, cable
insulation, latex gloves, rubbish bags, extruded pipes,
conduits and window profiles. Calcium carbonate accounts for
roughly 80% of all the fillers used in PVC, with the remainder
made up of titanium dioxide and calcined clay.
Expansion of the packaging and construction industries, both
of which are closely linked to economic growth, has
dramatically increased demand for PVC, especially in the
Asia-Pacific region. This region currently accounts for more
than 50% of global PVC demand.
While economic growth in the rest of the world is lagging,
the economies of two of the Asia-Pacific region’s
behemoths, India and China, grew at annual rates of 7.3% and
7.8% respectively over the decade to 2017, according to the
International Monetary Fund (IMF).
PVC in the automotive industry makes vehicles much more
durable. According to PVC Today magazine, the average age of
automotive vehicles in use has increased by five-and-a-half
years over the past 40 years, to 17 years today from 11.5 years
in the late 1970s.
Additionally, PVC makes vehicles more affordable. Research
from Mavel Consultants indicates that the typical cost of using
alternative materials is 20-100% higher per component.
In the construction industry, cost savings are also the key
reason for the popularity of PVC, which is used for flooring,
roofing, windows, pipes and electrics. For example, the
builders of a housing renovation project at Bielefeld in
Germany estimated that if they were to replace PVC with other
materials, it would lead to a cost increase of about
€2,250 ($2,785) per apartment.
But, as with paper products, using a filler in PVC can have
a negative effect on some of its properties. Calcium carbonate
fillers in the short term can improve the strength and
stiffness of a material, but they can decrease its long-term
strength and environmental stress-crack resistance, a document
by Rinker Materials suggested. It added that filler use in PVC
pipes should be limited to 10 parts by weight to 100 parts of
Paints and coatings: CaCO3 competes with
The third-largest application for calcium carbonate is in
paints and coatings, which, according to GIA research,
accounting in 2013 for 11.1% and 12.2% of global GCC and PCC
In paints and coatings, calcium carbonate is also an
important component and, as in the paper and plastics
industries, cost reduction is one of the key reasons. Titanium
dioxide (TiO2) usually makes up the majority of the pigment in
white paints, but the white color of GCC and PCC is increasing
their attractiveness for use as a filler and pigment agent.
Some research suggests that PCC partly substituted for TiO2
can improve the stability, scrub resistance, brightness and
coverage of produced paints. Calcium carbonate makes paints and
coatings last longer, eases spreading, lowers oil absorption,
improves anti-corrosion characteristics and improves resistance
to adverse weather conditions.
Omya, one of the world’s largest mineral
producers, says that calcium carbonate has established itself
as the main extender in paints and coatings and should be
considered as a functional filler due to its ability to enhance
Growth in the global construction activity also trickles
down to the paints and coatings sector. The Freedonia Group
estimated that growth in global demand for paints and coatings
would average 3.7% over the four years to 2020, with its value
reaching $183 billion, boosting demand for calcium carbonate
The group estimated that India will overtake China as the
largest consumer of paints. "In India, paint use will be
fuelled by rapidly expanding investment to build or update
homes, commercial businesses and industrial facilities," In a
2016 study, the Freedonia Group suggests.
In China, the growing middle class will continue to boost
demand for architectural paint, and expanding manufacturing
output is expected to bolster industrial coatings sales. But
growth in Western Europe is likely to be more subdued.
Research & Markets forecasts that PCC consumption in the
paints, coatings and plastics industry is expected to grow
considerably over the next three or four years, as it gradually
erodes the market share of TiO2, driven by the high brightness,
opacity and absorption level of PCC.
Adhesives and sealants comprise one of the smallest demand
sectors for CaCO3 filler producers, only accounting for 6.6% of
GCC and 8.6% of PCC demand globally, according to GIA.
Conversely, calcium carbonate is the most common filler in
adhesives and sealants, mainly finding applications in
improving product strength.
In a 1992 GIA study, different formulations with varying
percentages of calcium carbonate filler were prepared, and the
strength of the applied adhesive on wood was measured. It was
concluded that, after 24 hours, the adhesives develop a
The filler is also used to increase viscosity in the final
products. In a study titled "Addition of precipitated calcium
carbonate filler to thermoplastic polyurethane adhesives"
conducted in 2011, PCC was added to a thermoplastic
polyurethane adhesive (TPU). The addition of PCC produced a
moderate increase in the flow of the matter and viscoelastic
properties of TPU, due to the poor dispersion of filler
(meaning that it was found to be in clusters) and the weak
interactions between the PCC nanoparticles and the polymer
It is likely that the use of calcium carbonate in adhesives
and sealants will also increase over the coming years,
especially considering the advances in the NPCC field (see
box) and the increase in construction output.
With such wide-scale applications, it is not surprising that
calcium carbonate producers are optimistic about the future,
with demand from the Asia-Pacific region expected to be
Furthermore, intensifying construction activity and demand
from the automotive sector will drive the consumption of
plastics, paints, coatings, adhesives and sealants. Filler
substitution of kaolin and TiO2 in the paper, paints and
coatings sector will add more impetus to CaCO3 demand.
China, for example, is forecasting strong demand for calcium
carbonate, and is opting to increase its production capacity,
with the Guangxi Zhuang Autonomous Region in Lambin signing
agreements for more than 10 new calcium carbonate projects in
There are currently 36 calcium carbonate projects which are
under construction or are being planned in Lambin, involving a
total investment of Rmb1.35 billion ($213.25 million).
Meanwhile, France-based industrial minerals producer and
processor Imerys is expanding its presence in calcium carbonate
in the Indian market with the takeover of local producer Vimal
Microns. Vimal has a total staff of 200 and had turnover of 500
million rupees ($7.69 million) in 2016.
*According to figures from Cersana Research
The bulkiness of calcium carbonate products is exactly why
they are so widely used as a filler – it adds weight
and strength to the end-product. But in the long-term, some of
these properties, such as strength, might suffer.
GCC particle distribution usually ranges from 1-10 microns,
with some of the coarser products ranging from 10-20 microns.
PCC particle size distribution can be modified to suit the
client, but the lower end is 0.4-0.7 microns. At less than 0.1
micron, ultra-fine PCC or nano-PCC (NPCC) particle size is
markedly lower than both PCC and GCC.
The finer structure of NPCC allows for improved impact
strength, finish and better thermal conductivity. NPCC is
widely used in sealants, rigid PVCs and rubber. The ultra fine
particle size and narrow particle distribution allows for
exceptionally high filler loading without compromising impact
strength or conductivity, Indian nano-ventures company Reinste
But the additional refining process required for NPCC makes
it more expensive than other calcium carbonate products.