The steel and refractories industries go hand in hand, as
the steel sector is the main consumer of refractories and an
important driver of innovation. Around 60-70% of the
world’s refractories go into steel making, while
the rest are mostly used in the manufacturing of iron, cement,
glass and non-ferrous metals.
Refractories, made up of minerals such as alumina, bauxite,
chromite, dolomite and silicon carbide, are essential in the
steel production process and can resist ultra-high temperatures
of more than 1,500°C. They solve many problems relating to
containment involved in the metal’s manufacturing
process, which include contact with corrosive solids, melts and
gases at high temperatures.
These challenges are addressed through the use of refractory
materials as linings to furnaces, kilns, flues, reaction
vessels and ladles. The growth of the refractories sector is
driven by a variety of issues, including economic progress in
developing countries, an increase in demand for end products
made in refractory-lined furnaces and growth in crude steel
production. Therefore, when considering the future challenges
and trends for refractories, it is important to look at crude
steel production first.
Crude steel production in 2014
During the years 1950-1955, average global crude steel
production rates per annum were 7.4%, according to the World
Steel Association (worldsteel). From 2000-2005, this
figure stood at 6.2%, driven largely by growth in China. The
corresponding statistic for the period of 2010-2014 stands at
just 3.8%. This last figure demonstrates that the steel
industry is no longer enjoying the levels of growth it
experienced a decade ago.
This is due to a number of factors, succinctly summarised by
the International Monetary Fund (IMF), which recently cut its
forecast for global economic growth in 2015 from 3.5% to 3.3%.
The reduction relates to a lower than expected economic
performance from North America in the first half of the year,
due to the strengthening US dollar, the Greek debt crisis, a
subdued construction sector in China and recent Chinese
economic troubles. This is bad news, when one considers that
China represents around 49% of the global market for crude
steel production, followed by Japan at 6.6% and then the US,
India and South Korea.
Refractories manufacturing capacity, which built up to serve
the steel market during the high growth years, is now feeling
the pinch from the slowdown in steel output.
Other refractories producers, such as Austria-headquartered
RHI AG, are also focusing their economic arguments on China.
The firm says that Chinese steel imports have increased by 100%
in the first half of this year, leading to overcapacity in the
market and contributing towards high levels of competition in
the refractories industry."Due to the general decline of
steelmaking in the world and particularly in China, we can see
overproduction in the refractories industry now," Sergei
Odegov, CEO of Russia-based Magnezit Group, told
IM. "At the moment, not only big, but also
medium and small Chinese refractories companies are starting to
enter foreign markets and offer very low prices for products
and raw materials. So, only local companies with their own raw
materials, or companies with product know-how, will continue to
operate [successfully] in the market."
On the flipside of this argument, Marco Tonidandel, business
development manager of Slovenia-based Seven Refractories,
maintains: "On one side, we see Chinese sources reducing their
output of high grade refractories because of scarce
availability and mine exhausting. This is particularly true for
bauxite. But on the other side, there are regulation changes,
like the [lifting of the] anti-dumping fee on Chinese silicon
carbide, opening access to Chinese raw materials in Europe to
some extent. We have established a very reliable and flexible
supplier base in Europe and probably those changes affect us
much less than spot market-oriented refractories players."
Table 1: Major steel exporting countries in
European Union (28)
Another important ongoing trend for the refractories
industry worldwide is the decreasing specific refractory
consumption per unit of steel produced. The development and
improvement of steel producing technology in combination with
much higher process demands on refractory linings have resulted
in a constant reduction of specific refractory consumption,
from about 50kg/tonne in the 1960s to around 8-10kg/tonne today
for modern steel manufacturing, according to
Almatis’ global technical director of
refractories, Andreas Buhr.
"Even in challenged steel markets, the trend towards better
performing refractories suitable for the production of high
quality steel products is ongoing," Buhr told
IM. "Therefore, new business opportunities
exist for speciality alumina raw materials."
Steelmaking technology changes have led to new requirements
for refractories. Today, steel companies are aware of energy
losses and the cost saving made possible by better refractory
lining concepts – issues that nobody was concerned
about 20 years ago. Examples of these steel technology
movements are basic oxygen furnaces (BOF) replacing open hearth
furnaces, the introduction of continuous casting and the growth
of secondary metallurgy performed in steel ladles, helped by an
increased appetite for low impurity steel from the automobile
sector, according to Buhr.
High purity alumina for high quality
Extended processing of liquid steel in secondary metallurgy
requires continuous adjustment and improvement of refractory
linings and can be considered among the most important drivers
for refractory innovations, Buhr says. It can only be performed
with specific high-performance refractory linings, such as high
purity alumina (HPA) refractories. These refractories must be
thermodynamically stable in contact with steel, in order to
avoid re-oxidation of steel.
Bricks are either high-fired carbon free bricks or carbon
bonded spinel forming AluMagCarbon (AMC) bricks. Buhr explains
that alumina-based carbon free refractories provide two
advantages for the ladle side wall when compared to
magnesia-carbon (MgO/C) bricks with carbon contents of 10% or
higher. They avoid a carbon pick up of ultra-low carbon steels
from refractory lining and have lower thermal conductivity
– for example, 3.5 versus around 10 watts per metre
kelvin (W/mK). Refractories for steel ladle side walls
must withstand slag attack by aggressive, metallurgical
reactive slag – for example, calcium-aluminate slag
(CaO/Al2O3). Silica-containing high
alumina refractories, such as andalusite or bauxite, show high
wear-rates with aggressive, low-melting
CaO/Al2O3 slag, explains
Buhr. Therefore, there has been trend towards
HPA spinel refractories replacing andalusite and bauxite in
ladle linings. High purity spinel refractories come in the form
of either castables or bricks.
Table 2: Non-metallic mineral product US
refractory market ('000 tonnes)
Non-metallic mineral refractory market
Cement, lime and mineral products
Non-metallic mineral refractory market (mil
Source: The Freedonia
New refractories for steel ladles have also recently been
unveiled by Brazilian refractories producer, Togni S/A
Materiais Refratarios. The firm launched a new product, made
from silicon carbide carbon, for use in torpedo ladles, which
transfer melted iron from blast furnaces to steel shop areas.
The company’s vice president, Livio Togni, says
that the products have helped "the average life for a certain
steel shop in Brazil to jump from 500,000 tonnes to more than
1m tonnes of melted iron". Togni confidently asserts that this
is a "new benchmark in the market".
There has also been a drive by companies to improve optimal
performance and maintain high levels of consistency, an
achievement claimed by Alteo – a leading supplier of
speciality alumina products to the global refractories and
"Both these trends reflect the pressure from users for
longer refractory life," says Alteo’s director of
marketing, Mike Rodgers. "The key example being the ever
declining weight of refractory used per tonne of steel.
Particularly pronounced in China, the speed of this shift
towards quality raw materials is having a profound influence on
Alteo’s products and organisational direction. We
also sense that India could become the 'new
China’, in terms of growth potential."
According to a report published by market consultancy group,
TechNavio, last year, the refractories market in India is
forecast to grow at a compound annual growth rate (CAGR) of
9.85% over the period 2013-2018. K Srinivasan, managing
director of Indian refractories producer Carborundum Universal
Ltd (CUMI), says that "70% of production is still going to
steel and that remains the biggest market. This will not go
away in a hurry. Steel on its own is very, very big. We have to
be mindful of the fact that the industrial minerals sector as a
whole has to work on something that has to be the next big
thing for the steel industry. We can bring these niche
materials into market and they do tend to get absorbed into
high value refractories more quickly."
"So-called Indian refractories have mainly been taken over
by European companies, such as RHI, Saint Gobain or
[Japan’s] Krosaki in recent years. They are now
all part of global corporations."
Srinivasan says that China is using recycled scrap more to
produce its steel, so the country’s reliance on
iron ore is declining. "That changes the kind of refractories
they will use and the type of steel making that they will do
– probably moving towards smaller furnaces. I think we
will see disruptions; I am pretty bullish about the new
materials driving the next big change. [The technology] will be
lighter, more energy efficient and cleaner."
Like India, Japan’s steel industry is also a
large market for refractories. Japan-based Shinagawa
Refractories Co. Ltd produces refractories primarily for the
steel industry and 80% of its client base is from this sector.
Heiki Miki, Shinagawa’s executive officer of
overseas business for Americas and EMEO, says that Japan has a
mature steel market and its steel producers make around 110m
tpa of steel. He explains that the group’s local
customer base is important to the firm, however, the company
has plans to expand and seek growth opportunities outside of
Japan, in Asia, Oceania and the US, with its own brand of
long-life refractory bricks. "Traditional bricks typically live
for 2,000 charges but we produce bricks that can last for
around 3,000 charges," Miki told IM.
Shinagawa is developing new refractories, such as
magnesia-carbon bricks, called "super-dense highly-durable
multi-hole plug (MHP) tuyere bricks", to help "make the best
refractories for these steel companies to help them stay ahead
of the competition".
Development of more "attractive" products and high
performance materials are key trends in the sector. In the long
term, Magnezit’s Odegov believes that
nanomaterials are the future. "Today, experts across the world
are going in this direction," he says. "In Japan, for example,
there is the Institute of Refractories, which develops and uses
nanoadditives. And we understand that in five years or more, a
real qualitative leap in the production of refractories will be
possible, thanks to the use of nanocomponents – for
example, nanooxides or carbon nanocomponents. Our specialists
are already deep in this process and working in close
connection with scientists from the Moscow Institute of Steel
and Alloys, South Ural State University, Ural Institute of
Metals and production companies, which manufacture nanocarbon
Building up: Many of the materials used
such as iron and steel, are manufactured in
lined with refractory bricks.
The steel industry’s drive to cut costs has
been noted by Australia-based commodity trader, Ferrochem Pty
Ltd. The company’s director, John Svynos, says
that steel production in Australia has shrunk over the last
five years from 8m tpa to 2.4m tpa and that this sector could
be "in jeopardy, given the cheaper imports available in Asia".
Syvnos says this issue is contributing to the drive to make
cost savings. He notes that the steel industry in Australia has
been approving many refractory finished goods from China, which
were originally produced in Australia.
"The production of refractory bricks has now stopped in
Australia since last year, as they could not compete with the
imported products from China," Svynos said. "Monolithic
products are the only refractory products now produced here. We
used to import in excess of 1,500 tpm [refractory products],
but we are now importing 300 tpm."
"We are lucky to be associated with Refmin China and as such
I also look after several key customers for export in places
such as Indonesia, the US and Thailand. The growth from these
countries is coming from their cement markets. This additional
business helps keep us afloat."
Aluminium filling the void
With the steel sector remaining lethargic in certain
regions, India’s Technology, Information,
Forecasting and Assessment Council predicts that the aluminium
sector will be the only one to show sustained increased
percentage consumption of overall refractories production in
the next 10 years. It is not entirely clear what proportion of
the world’s refractories goes into the aluminium
sector, although estimates suggest that the figure is around 1%
– a total of approximately 100,000-200,000 tpa.
Refractories have many functions in the aluminium process
and are used in everything from electrolysis cells to furnaces.
Netherlands-based Gouda Refractories BV provides refractory
lining products for equipment in the aluminium, petrochemical,
waste incineration and steel sectors. Around 45% of its
customers are from the aluminium sector, 55% from waste
incineration and only 5% from steel. Traditional industrial
minerals used for the aluminium process have barely changed,
according to Gouda’s engineer, Marcel
Most carbon baking furnaces are constructed from tongue and
groove alumina-silicate bricks in two main qualities but in
many shapes, Jarvis explains. These are either 65% alumina or
45% alumina, based on high purity raw materials pressed into
dense shapes with minimum porosity and maximum strength in the
form of creep resistance.When alumina, the raw material for
aluminium smelting, is delivered into the primary smelters, it
is added with cryolite to large, high capacity electrolytic
cells with prebaked graphite cathodes and anodes incorporated
into the linings, which are otherwise mainly brick and
insulation, according to UK-based refractories specialist and
consultant, David Jarvis. The cells then need to be baked in
carbon in baking furnaces.
Alumino silicate bricks are also used in aluminium melting
and holding furnaces. In her academic paper entitled
"Refractory considerations for aluminium melting and holding
furnaces", refractories expert, Ruth Engel, owner of
US-based Refractory Consulting Services, says that there has
been a recent trend globally to switch from bricks to
monolithics, due to their availability and cost advantages.
This is because modern furnaces need to treat much greater
quantities of molten aluminium and alloys more quickly and at
significantly greater heat inputs in the case of melters, she
says. These furnaces are frequently also tilting furnaces
rather than the traditional static design and this puts much
higher metallurgical and mechanical load on the furnaces in
operation, according to Jarvis.
Consequently, modern furnaces need to operate at higher
loads and last much longer between major repairs. Monolithics
are used to meet this demand, due to their ease of
Nevertheless, Franken, disagrees with Engel and Jarvis and
says that this trend is being reversed and aluminium producers
are now going back to bricks because of the challenge of
"Not everyone is using monolithics," Franken says. "There is
a risk when you use monolithics as you need well-educated,
skilled people to make these kinds of installations because it
is not easy to do. You also need to heat monolithics up slowly.
If you heat them up too quickly, you get explosions."
He concedes there are some good reasons to prefer
monolithics, however. "The advantage of using monolithics is
that they are simple to make. You have raw materials, you put
this in a bag, mix it and there it is. In contrast, with bricks
you need a delivery time of three months and you have to think
in advance. A lot of people do not think in advance."
Several approaches are available to counter the ability of
the aluminium in the process to wet and subsequently penetrate
and interact with the refractory, Engel maintains. The use of
anti-wetting additions to refractories in contact with molten
aluminium is a common approach, especially for calcium
Additives commonly used include barium sulphate and
different types of fluorides, like aluminium fluoride
(AIF3) and calcium fluoride (CaF2).
Another approach is to add a phosphate, as this imparts highly
non-wetting properties to the refractory and does not decompose
until temperatures reach >1,500°C, Engel says. In
bricks, the additives are incorporated into the mix prior to
firing; in monolithics it can be the bonding agent. In
addition, she says that the use of phosphate as a component of
monolithics helps in bonding new and used refractories, which
is particularly important when carrying out repair.
Franken concurs with Engel, maintaining that end users will
increasingly look to extend the life of refractories and will
need to add "special additives" in order to do so. He
says aluminium producers will need to use refractories that
will also reduce downtime.
Franken notes that a lot of aluminium producers are putting
new alloys in their aluminium. He explains: "In the old days,
Finished product: Only about 1% of the
goes into the aluminium sector – a total of
100,000-200,000 tpa. (Source: George
was 100% alumina. Just like steel was 100% iron ore.
However, now you put in magnesia, zinc and all kinds of special
additives to make aluminium. This is due to a drive to
improve the quality of aluminium or produce a special, thinner
type of aluminium."
"So, if end users change this process, then your
refractories will also need to be adapted. A lot of companies
are saying 'we want to change the process, but we do not know
what types of refractories can withstand this new
process’. To a certain extent, a lot of firms are
very conservative and do not want to change their
Franken points out that the aluminium industry accounts for
only a small percentage of total refractories usage and in most
companies, the focus tends to be much more on steel and cement.
He says: "In the steel industry, you normally have one or two
furnaces. In contrast, the aluminium industry has five or six.
If one furnace is out of operation in the latter, this will not
be a critical situation. However, in steel, if one furnace goes
out, you lose 50-100% of your capacity."
"The steel maker is always a close neighbour to their
refractories supplier. In contrast, with aluminium, there tends
to be a distance between user and producer. Maintenance is also
The use of refractories per tonne of aluminium will also go
down in the future, in a similar trend to steel, due to process
improvements and the increasing quality of refractory
materials, he explains.
"You will never get to zero, because you will always need
refractories but it will be less and less in the future.
However, the products will become more expensive on one hand,
but the costs for end users will go down on the other hand,
because they will get more uses out of it," Franken adds.
As well as the drive for optimal performance, environmental
challenges are also impacting refractories producers,
especially ahead of the United Nations Conference on Climate
Change – COP21 – in Paris in
Industrial minerals giant Imerys has one of its many feet in
the refractories business through its monolithic refractories
John Maxwell, vice president and general manager of
Calderys, says: "Production of monolithic refractories leads to
limited CO2 emissions because, contrary to
refractory brick production, there is no heating nor drying in
the manufacturing process."
Calderys has launched a company-wide initiative to increase
usage of recycled raw materials. The scheme, which has
intensified since 2011, reclaims materials from steel,
aluminium and glass plants. "The materials are reclaimed,
sorted, cleaned, dried and crushed to be re-used as raw
material for Calderys’ products," says Maxwell.
"For example, in Sweden, we reclaim 500 tpa of porcelain
insulator production scrap from a local producer to manufacture
refractory flooring tiles for the local steel plants."
Customers are also getting involved, Maxwell says. "They now
save and sell back a large range of materials, such as bauxite
and andalusite-based bricks. Some of the Calderys plants, like
in Italy, are now equipped with crushing equipment allowing
them to handle such materials."
The firm is also buying recycled raw materials to reduce its
carbon footprint. Ultimately, Maxwell says: "In order for
refractory recycling to work, the European Commission and
national governments must promote recycling as a means for the
European Union refractories industry to become more competitive
It seems that most refractories producers with an eye on the
future are pushing ahead improvements to their products and
trying their best to jump, rather than dodge, macro-economic
hurdles. As Joachim Paschke, director of business division in
technical ceramics at Germany-based Nabaltec, concludes: "To be
ahead of the game, you always have to adapt your material to
meet the needs of your customers. This is an ongoing process
and will never stop."
Use of chromite in refractories
There are two families of refractories that use chrome, one
as chrome ore, also called chromite, and the other as chromic
oxide. Magnesia-chrome (MgO>50%) or chrome-magnesia
(Cr2O3>50%) refractories use chrome ore.
According to the International Chromium Development
Association (ICDA), refractory chromite consumption has
decreased over the last 35 years, due to changes in steelmaking
technology. Production of chromite as a refractory material is
only 1% global chrome ore output, the ICDA states and according
to industry sources, 100% of this is currently sourced from
South Africa. However, it still has an important niche in the
Mag-chrome refractories are used mainly in lead melting
furnaces for battery recycling, some stainless steel
production, in small argon-oxygen decarburisers
(AOD’s), RH degassers. Incineration/gasifiers use
chromic oxide bearing refractories. In this case, they are
alumina-chrome with a very high chromic oxide content
The ICDA states: "Cement and lime kilns are the second
largest user of these refractories but only consume about 7% of
world production. The use of mag-chrome bricks has virtually
disappeared in cement kilns in Europe and North America, due to
regulations and costs of disposal of the used bricks, which may
contain hexavalent chromium as a result of the oxidising
atmosphere in the kilns. In the rest of the world, the use of
mag-chrome bricks is still widespread."
Source: International Chromium Development Association,