Filling the void: calcium carbonate markets look to grow

By IM Staff
Published: Sunday, 25 March 2018

Consumption of mineral filler is growing rapidly, with the market forecast to grow to a worldwide total value of $62.54 billion by 2024, according to some estimates, with global economic growth supporting expansion of the paper, plastics, rubber, paints and construction industries. Industrial Minerals explores the key drivers of this growth, and asks what makes calcium carbonate so attractive as a filler?

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 average*.

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 product.

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 carbonate.

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.

Fillers2  

Paper industry: calcium carbonate displacing kaolin

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, kaolin.

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 GIA.

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 chloride (PVC).

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 sector.

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 resin (9%).

Fillers3  

Paints and coatings: CaCO3 competes with TiO2

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 demand, respectively.

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 paint performance.

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 products.

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.

Fillers4  

Adhesives, sealants

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 reasonable strength.

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 chains.

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.

Outlook

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 particularly strong.

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 November 2017.

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

Nanofillers

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 points out.

But the additional refining process required for NPCC makes it more expensive than other calcium carbonate products.