The world’s andalusite supply
sector is mainly dominated by mines in South Africa and France,
with some supply also found in Peru.
But it is in Peru where new
capacity is expected to come online: Australian junior Latin
Resources is working on a project in the north of the country,
while industry stalwart, Andalucita SA, is operating a mine and
plant in Paita, also in the north.
Andalucita announced an expansion
in 2012, telling the market that it would be doubling capacity,
but has since said it will invest in improving its processes so
there are fewer tailings.
“Our plant was designed to
produce 60,000 tpa. However, the contractor made mistakes and
it could not reach the original design capacity,” Carlos
De Ferrari, Andalucita CEO, told IM.
“We have made some changes and
added equipment and can now reach 42,000 tpa. If we add a
screen - which we are in the process of doing Ñ we
will be able to produce the original design capacity of 60,000
tpa,” he added.
The South African markets are
dominated by two rival groups that operate in or near the
Thabazimbi mining town in the Limpopo region. The mines are
operated by Imerys-owned Damrec and Andalusite Resources.
Both companies have recently
increased production, with Anadalusite Resources ramping up to
to 70,000 tpa from 40,000 tpa this year and planning to expand
to 120,000 tpa by 2015.
In comparison Damrec, which has
four mines run by Samrec, currently produces around 195,000 tpa
and plans to expand its combined total capacity to 250,000
tonnes.
Latin Resources - a newcomer?
Latin Resources’ Guadalupito
project is “not an andalusite resource”, Andrew
Bristow, Latin’s general manager, told
IM.
“We have a heavy mineral
resource. That heavy resource comprises everything that we have
included to date: that is, magnetite, the iron sand deposit,
andalusite, and a suite of the titanium minerals including
rutile, ilmenite, titanite and leucoxene. We have also
identified some garnet and apatite, zircon and monazite,”
he added.
Of the heavy mineral content (HMC)
identified, between 21-24% is andalusite, Bristow said.
The scale of the project could
potentially be huge. According to the company’s JORC
resource estimate, it measures 1,329m tonnes at 5.7% HMC.
However, Latin says it is first
focusing on developing the magnetite, the titanium dioxide
(TiO2) feedstock minerals and the zircon before
moving on to develop the andalusite.
“The andalusite is the
blue-sky part of the deposit,” Bristow said. “There
is a lot of future potential. We are focusing on the easiest
part of the deposit first, which is the magnetite, the titanium
suite and the zircon. That, for us, is where the focus is at
present, but we are keeping the andalusite story ticking over
in the background as a real sweetener for the
future.”
End markets
The steel and iron industries are
the main consumers of andalusite in the form of refractory
materials, but these are not its only end markets.
It is also used in the aluminium,
cement, glass, ceramic and foundry industries at some stage of
the production line.
Aluminium
In aluminium production, andalusite
is used in the anode-baking electrolytic process to extract
aluminium from cryolite (Na3AlF6) at
around 950¡C, which is around half of the melting point
of andalusite. This market is a major user of andalusite as it
is a source of the metal preliminarily used in car production,
along with other products requiring aluminium’s strong,
light-weight properties , such as aeroplanes and construction
materials.
Cement
The cement industry has seen a
increase in the use of andalusite, and other alumina-silicate
refractory minerals, during the past decade in several areas
due to the constraining of the materials used as the refractory
linings of cement rotary kilns.
This has been particularly evident
in Europe, as the use of aggressive burning materials
(industrial wastes, tyres, low-quality petroleum refining
residue) has increased.
It is employed in areas such as
precalcination equipment, which is used to improve the cement
quality and lower the heat consumption of the final product by
heating the raw materials. Andalusite also finds application in
rotary kilns and grate cooler systems, due their thermal
requirements.
Glass
Andalusite’s thermal shock
resistance and creep resistance properties make it an important
contender in the refractories mix.
At temperatures higher than
1,250¡C, andalusite and the other sillimanite group
minerals start a process called mullitisation, which is the
process by which these minerals start to convert to mullite
(Al6Si2O13).
Andalusite finds application in
melting furnaces in the form of a feeder, which is used to
bring and pack the liquid glass before forming occurs.
The main requirement of a glass
maker is glass quality. As a result, feeder refractories must
have a better corrosion resistance to avoid defects in the
finished product. Andalusite-sintered products are suitable to
achieve this appropriate quality. This, and andalusite’s
thermal properties, also provides the opportunity to produce
strengthened glass, which requires further heating.
The glass industry mainly uses
andalusite in the form of bricks, to build the regenerator
crown and walls because the full mullitisation gives a
combination of resistance to thermal shock, batch carryover and
high-temperature creep resistance.
It is additionally employed in the
upper part of the packing zone as andalusite-based bricks give
a good stability. In the middle part of the packing zone, where
chemical resistance is critical (alkali condensation),
andalusite-based bricks are currently highly recommended.
Ceramics
As it is a good source of mullite,
andalusite has become increasingly applied in the ceramic
industry. It is used as tunnel kiln for the heavy-clay industry
(bricks, roof tiles, clay pipes), as kiln furniture for
sanitary ware, tableware and tiles, and as kiln furniture for
technical ceramics (ferrite).
Foundry
In foundry applications, andalusite
has been successfully used with all the most common mould and
core processes, whatever the pH, including, but not limited to,
Shell moulding (Kroning), Cold-box, Hot-box, uranic no-bake,
Shaw process, green sand and all of the most-diffused binding
systems.
Andalusite as a substitute for
refractory bauxite
Andalusite is used in refractories
because it has a high melting point of >1,800ºC. It is
employed in the lining of blast furnaces because of its
resistance to temperature and pressure fluctuations, while not
affecting the product’s composition.
Although andalusite can be a
substitute to bauxite in refractories, it cannot replace it in
all applications.
“We have conducted many trials
in the industry to substitute bauxite with andalusite and can
confirm that this will work in some of the applications,”
Dirk Auge, of Germany’s Cofermin, told
IM.
“The decision [on whether or
not to do this] will be based on the cost calculation and
driven by economical aspects. Andalusite can also be used to
substitute mullite in certain applications,” Auge
added.
Refractory consumption of
andalusite has been boosted in recent years by the curbing of
bauxite exports from China and Indonesia.
China
Bauxite licences for 2013 were
cancelled amid pressure from the World Trade Organization,
which in January 2012 found China guilty of restricting trade
of certain key steelmaking minerals, including refractory-grade
bauxite.
China’s export quotas for
bauxite were reduced to 700,000 tonnes in 2012 from 830,000
tonnes in 2011, according to an announcement by China’s
Ministry of Commerce. This was in response to an oversupply of
licences, which became apparent in the last quarter of 2011
The curbing of bauxite exports last
year meant that there was an increase in demand for andalusite
as a substitute mineral, De Ferrari told IM.
This increase in demand has been maintained, he added.
“We’ve had a look at the
market for andalusite, which is not huge, and we do have rather
a lot [but] because of the quantity that we have there may be
opportunities for substitution in other commodities, like
bauxite,” Bristow said.
Indonesia
Restrictions on the export of
bauxite are not limited to China.
Indonesia will implement a ban on
the export of all mining products in raw material form from
January 2014 in an effort to promote the development of its own
domestic mineral industry. This will affect bauxite as well as
other key industrial minerals, including copper, gold, nickel
and coal.
Bauxite makes up a large proportion
of exports from Indonesia, but according to the new law, mining
products in raw materials can only be exported until January
2014. After the ban, mining products will only be allowed for
export after processing.
Until the ban is implemented, raw
material exports will need to be certified and technically
verified by authorities appointed by the Minister of Trade.
“We already put out a
statement in 2009, so the law already gave investors and
companies five years to prepare. That [is] enough time We
believe the policy is fine to be enforced in 2014,”
Thamrin Latuconsina, director of export of industrial and
mining products, Ministry of Trade of Indonesia, said.
However, so far only 10 or 12
companies have made any progress towards building smelters and
downstream processing facilities in Indonesia.
These restrictions will continue to
force traditional bauxite foundries to use alternatives such as
andalusite, even though this process can take up to 18 months
to achieve.
The cutbacks have also seen
suppliers joining with their customers to find solutions. For
example, Andalusite Resources is working closely with German
refractory engineers at Mine Feuerfest, which specialises in
steel blast furnaces, foundries and the lime and cement
industries, to develop new applications that would replace
strategically important minerals such as bauxite currently
sourced from China or Indonesia.
However, these restrictions may
lead to the development of synthetic replacements, forcing a
possible downturn in the production and consumption of bauxite
and andalusite.
Supply and demand
There is a degree of uncertainty
over the future for the whole andalusite industry, with some
positive signs tempered by the overall economic climate.
Production rates are set to
continue to increase, with further investment planned in
extraction and processing technology.
Damrec will continue to be the
largest major worldwide supplier, even if Andalusite Resources
continues its policy of a “cruise-controlled”
production rate.
New products are coming onto the
market and expansions have been announced across the board.
“Compared to all the years
before, we have seen many new products,” Auge told
IM.
Andalucita has added more size
fractions to its standard grade, and Damrec has released a
second-grade Purusite, named “P57”.
Elsewhere, Andalusite Resources has
developed a second-grade Marlsuite, M56, which is available in
premium and standard grade.
A new player such Latin Resources
entering the market is significant because of the sheer scale
of its resource, although this does not appear to be a near-
term development.
A potential area of growth is
likely to be andalusite as a substitute for bauxite, but in the
very short term, Cofermin believes the market will
decrease.
“While we can confirm that
some of the customers in the market are taking more andalusite
than expected, we believe that the global demand will decrease
in 2013,” Auge told IM.
“The main reason being the slowdown in the economy and
lower production of steel in most parts of the world,” he
added