This is an interesting read on expandable graphite from IMX resources (IXR on ASX) who owns the Chilalo graphite deposit in Tanzania. Enjoy reading and happy easter holidays !
Quotes (highlights are mine) :
Expandable Graphite
Expandable graphite is a compound of graphite that expands or exfoliates when heated. This material is manufactured by treating flake graphite with various reagents (such as acid) that migrate between the layers in the graphite. When the graphite is heated it rapidly expands to several hundred times its original size (the expansion ratio). The expansion ratio is the volume of expandable graphite produced per gram of graphite product at a specified temperature. In general, coarser flake graphite typically has higher expansion ratios than smaller flakes.
Producing expandable graphite is a relatively inexpensive process and there are no issues with product recoverability with 1 tonne of flake graphite producing between 1.1-1.2 tonnes of expandable graphite with the additional mass coming from reagents and water. This is a positive compared to production of spherical graphite where the yield of spherical graphite from flake graphite is approximately 40%.
China dominates the expandable graphite market producing 95% of the world’s expandable graphite, with the balance produced in the US and Germany (source: Benchmark Mineral Intelligence 2015). Given China’s diminished reserves of coarse flake graphite, there is a substantial shortage of coarse flake graphite capable of producing the quantity of expandable graphite required to meet China’s demand, representing a substantial opportunity for IMX. The Company’s recent visit to a Chinese factory that is currently producing expandable graphite illustrated this shortage of quality graphite – the graphite feedstock was +100 mesh with an expansion rate of ~200 times (far inferior to Chilalo graphite).
Figure 1: Expandable Graphite
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Natural flake graphite possesses certain properties including heat resistance, corrosion resistance and self-lubrication. Expandable graphite also possesses other properties including softness, compression resilience, adsorption and radiation resistance.
Expandable graphite is not transported great distances as a finished product because its properties change if it is compressed and it is not cost-effective to do so as it is a low weight but high volume product. As a result, IMX will not produce expandable graphite in Tanzania, but will export directly to the end user for manufacturing.
Expandable graphite market
Expandable graphite is one of the fastest growing markets for graphite and has multiple uses, including:
The production of high-value graphite foils as shown below in Figure 2 (market price of ~US$ 50,000/t) which are used as heat shields in electronic devices such as mobile phones, laptops and TV screens. Examples of the use of graphite foil in electronic devices is shown in Figure 3.
Figure 2: Graphite foil produced from expandable graphite
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Figure 3: Electronic devices using graphite foil as a heat shield
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To view the graphic in its original size, please click here
The production of graphite paper used in the manufacture of heat shield gaskets and other products such as fire and thermal seals for machinery and electronic parts.
With its unique fire and heat resistant characteristics, expandable graphite is being increasingly used in the manufacture of flame retardant and thermally efficient building materials, such as insulation for example, with a rapidly growing market for these products. This is discussed further below.
A video demonstrating the flame retardant characteristics of expandable graphite has been placed on the IMX website (www.imxresources.com.au).
The radiation resistant properties of expandable graphite also have military applications.
Discussions with Chinese end users over the last six months have revealed that the market size has been entirely restricted by supply and that coarse flake graphite with the expansion characteristics of Chilalo graphite can be readily absorbed by current demand.
End users capable of producing these expandable graphite products are moving to continuous 24 hour plant operations and are still unable to keep up with demand. The current supply / demand imbalance has resulted in long wait times for expandable graphite products with significant up-front payments required to secure orders.
Flame Retardant Building Materials
The addition of expandable graphite to ordinary insulation foam or cement provides the material with flame retardant properties. It also provides thermal efficiency improving the material’s ability to assist in heat retention.
The Company understands that China has recently mandated the use of flame retardant building materials for all future new construction or building renovations. Note that flame retardant building materials are only required in certain aspects of the construction. These regulatory changes are expected to significantly increase the demand for expandable graphite and result in a large volume market.
Whilst IMX hasn’t sighted the new Chinese building regulations, they are understood to be made up of four categories of building materials with varying levels of expandable graphite required in each. Category 1 flame retardant building materials being for single storey, lower quality buildings are required to use 5% expandable graphite in their manufacturing. The use of expandable graphite increases up to category 4 flame retardant building materials which are required in buildings consisting of several storeys and are required to use 50% expandable graphite in their manufacturing. IMX is in discussions with end users requiring 10% expandable graphite for their manufacturing of cement and gypsum.
End user feedback still being verified by the Company has estimated the size of the flame retardant building materials market at 5 million tonnes per annum. Assuming that these materials contain anywhere from 5-50% expandable graphite, it is clear to see the potential size of this market which is a game-changer for graphite demand.
The type of expandable graphite suitable for the manufacture of flame retardant building materials can be produced from fine and medium flake graphite (<180 microns), with expansion rates exceeding 100 times. The grade of the graphite can range anywhere from 85-94% total graphitic carbon (‘TGC’).
Expandable Graphite Pricing
According to existing manufacturers of expandable graphite products, higher end expandable graphite products range in pricing from US$4,000 to US$10,000 per tonne depending on the quality and the end use. At the lower end of this range are gaskets, seals and other products used in the manufacturing industry where the expandable graphite has been produced from large flake graphite between 92-94% TGC with high expansion rates.
The upper end of this range is graphite foil and paper produced from high purity (95-96% TGC), coarse flake graphite with high expansion rates. At the extreme, high purity, high expansion graphite capable of producing <3mm graphite foil could fetch up to US$50,000/t but this requires the application of highly technological processes.
Expandable graphite-based flame retardant insulation foam shown in Figure 4 below currently sells for 350RMB (US$52.50) per m3. This equates to US$52.50 per 20kg or US$2,625 per tonne.
Figure 4: Flame retardant insulation foam
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(20min delay)