Andalusite – what does the future hold?

By Siobhan Lismore-Scott
Published: Tuesday, 02 July 2013

Andalusite supply looks set to increase dramatically in the near term as several producers work to increase capacity. Charles Carmichael and Siobhan Lismore-Scott, editor, look into the relevant producers and discuss what impact the increase in capacity will have on the market.

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