Value addition to graphite in Sri Lanka - Graphene and green technology

26 March 2014 05:00 am Views - 14257

As a follow up to my article on value addition to minerals published in Mirror Business on March 11, 2014, I would like to highlight the attempts by the researchers in Sri Lanka and also various government entities in value addition to graphite in the light of ‘graphene’, the miracle substance produced with the base as high-grade graphite exclusively found in Sri Lanka as lump, vein and flake with carbon grades over 95 percent.

Graphite has been referred to as the material used in every industry yet in small enough quantities, which is not noticed by anyone.

Industrial Alliance Securities Inc.’s model for future graphite  supply and demand suggests that a minimum of four mines and as many as 23 will need to go into production outside India and China between now and 2020 to satisfy the growth in demand.

Graphite prices, just like most industrial metals, are negotiated directly between the buyer and the seller based on a common posted price. The main parameters used in pricing graphite are flake size and purity.

The variation in these parameters creates a price range. The benchmark purity in the industry is 94-97 percent carbon for natural graphite. Increase in flake size at a constant purity adds a gradual premium to the product, while a decrease in purity at the same flake size causes a significant decrease in price. Prices for upgraded purities or modified products, such as spherical and expanded graphite, as not commonly quoted but are known to go as high as US $ 20,000/ton.

Going back for the past 20 years, graphite prices sustained a low at below US $ 1000/ton from early 1990s to 2005, mainly due to the low cost of Chinese graphite production.

Subsequently, the demand for green technology, export restrictions mainly in China, stricter environmental regulations, mine depletion and rising energy and transportation costs, have all contributed to an increase in graphite prices.



Uses and demand for graphite
The major use of graphite is in the steel and refractory industries, which consume over 40 percent of the world production, followed by lubricants, expanded graphite applications and carbon products and the biggest growth is in the energy applications.

With the more emerging uses, graphite could be modified or engineered in the future (graphene technology) either because of high costs or owing to the emergence of superior high-quality composite material. Accordingly, there is an overlap in uses between natural and synthetic graphite that is controlled by price and purity.

Synthetic graphite is significantly more expensive and can be engineered to exact required specifications through the following forms:

• Secondary - Powder or scrap synthetic graphite is produced from heating calcined petroleum pitch and is mainly used in refractories.
• Primarily - 99 percent synthetic graphite is made in electric furnaces from calcined petroleum coke and coal tar pitch. The main use is in electrodes and carbon brushes.
• Fibrous - Produced from organic materials such as rayon, tar pitch and other synthetic organic polymer resins; the main usage is in insulation and as reinforcement in polymer composite.

Alternatively, natural graphite can be upgraded to the same specifications through intensive thermal and chemical upgrading. China introduced low-cost chemical purification methods for fine graphite in the 1990s but these methods are not economical in other countries, especially in the west.

With the advancement in technology, high-purity flake graphite could be used in applications using synthetic graphite and the overlap of these two varieties is continuing to grow.

Spherical-flake graphite (SFG) is produced form milling flake graphite into spherical shapes. Due to the strong anisotropic nature of the graphite crystal, where its properties change from one plane to another, the process is needed for applications where the basal planes are favoured to those of the crystal edges and vice versa.
This is particularly important for energy storage applications, such as Li-ion batteries, where graphite is used in the anode material.

Expanded or exfoliated graphite made by chemical treatment that forces the grapheme layers in graphite to separate and therefore expand in volume and undergo rolling to form sheets or other mechanical processes for use.

Fuel cells, Li-ion and other kinds of batteries and photovoltaic solar cells are some of the largest growth areas for graphite. The industry is still evolving and materials and compositions are highly variable. Industry Alliance research indicates that the amount of graphite used in the anode of Li-ion batteries varies between cathode and anode chemical composition, energy and size requirements and other factors. Based on these factors, a light vehicle battery could consume as much as 20 times more graphite as it does lithium metal or it could consume as little as five to 10 times.

From the earliest days of the nuclear power industry, graphite was one of the main components in the traditional reactor and for this particular application, high-grade graphite is required and the choice was synthetic.

However, fourth Generation nuclear reactors using uranium dioxide as fuel, for example pebble-bed reactors are expected to use both synthetic and natural graphite. Exact ratios are hard to estimate as the only prototype is being developed in China but industry estimates between 25 percent and 75 percent graphite is expected to be natural and synthetic, respectively. This could amount to as much as 200 tons of natural graphite for commissioning of the HTR-PM prototype in China and then an additional 40 to 70 tons each time the fuel spheres are replaced.



Graphene technology
Graphene is a one atom thick layer of carbon arranged in a honeycomb lattice that forms flakes of graphite when stacked together. Produced in laboratories for the first time less than 10 years ago, graphene has a unique set of properties that show potential to be used in a wide range of applications such as transistors, high-sensitivity sensors, transparent conductive films for touch screen displays, more efficient solar cells and electrodes in energy storage devices. IBM has already fabricated a single grapheme-based integrated circuit.

It must be stressed that one of the main obstacles to all the above applications is the lack of economically viable large-scale graphene production.
The commercial potential of graphene has triggered an explosion of activity in patent offices in the world. Currently there are over 10,000 graphene-based patents pending.



World reserves of graphite and production
World reserves of graphite are estimated at 76 million tons with China holding 70 percent, followed by India and Mexico at 14 percent and 4 percent, respectively.
It must be stressed that the total reserves of graphite in Sri Lanka, the highest quality in the world in both lump, vein and flake varieties, in the form of inferred and proven categories, are not available. However, during the two world wars, there were over 6000 shallow pits and mines and it could be inferred that the total reserves could be over five million tons, as mineralization extends as a fairly broad belt from the southwest to northeast, a distance of over 250 kilometres, with untapped areas close to Vavuniya and no systematic and integrated exploration has been done covering this promising area.

China still holds the largest reserves of graphite and should be in a position to scale up production. However, with an introduction of an export duty of 20 percent and 17 percent value-added tax, new regulatory measures and the consolidation of existing deposits, it is trying to preserve its deposits and import most of its requirements from abroad.

From 1994 to 2010, production of natural graphite was maintained by stable demand until 1990, when consumption stated to increase at an annual rate of 4 percent to 6 percent. This growth is attributed to both traditional uses of graphite from BRIC countries (Brazil, Russia, India and China) as well as from advances in high-tech uses.

Industrial Alliance Securities (a full service brokerage firm) base-case indicates growth in graphite demand of 2.5 percent. It assumes that new mines will open in Canada, Europe, Brazil, Australia, Africa and Mexico with an annual production ranging between 15,000 to 20,000/year.

Vein graphite from Sri Lanka is unique and has its own niche market where present policies of the government impede growth. It forms in veins, a few centimetres to several meters in width. The material is of very high purity, above 90 percent C and requires little purification. However, lack of consistent supply prevents it from penetrating high-growth markets such as Li-ion batteries. However, similar to an increase of exploration activities in the world, Sri Lanka has seen its own re-emergence of exploration in recent years.



Proposed strategy to develop graphite deposits in Sri Lanka
It must be stressed that although Sri Lanka has very high-grade deposits with carbon ranging from 95-99.5 percent and least impurities, no attempts have been made to develop these deposits except for the two companies Bogala Graphite Ltd and Kahatagaha Graphite Ltd, where the former is a joint venture (JV) with a German company, which is mainly a trading outfit and the latter is a wholly-owned government entity. Both these mines have gone very deep and the cost of production is high compared to the prices realized.
In order to be competitive in the graphite market, where this mineral has now been identified as a strategic mineral, the Government of Sri Lanka (GOSL) should consider the following:

• Assist the private sector to go into JVs with foreign companies in value addition to minerals especially in graphene technology, photo voltaic cells, Li-ion batteries and other high-tech green technology.
• Support the foreign companies presently in Sri Lanka to prove the exploitable high-grade graphite deposits, especially in abandoned areas with close supervision and coordination by the GSMB geologists and geophysicists.
• Encourage the private sector under the guidance of the GSMB to carry out a detailed exploration programme using airborne electromagnetic (EM) surveys followed by detailed electromagnetic ground surveys. The Geological Survey Department (Present GSMB) had perfected ground EM surveys in the 1980s covering abandoned graphite mines in selected areas of Sri Lanka and the results could be used as models to look into deep-seated deposits.
• Amend the Mines and Minerals Act No 33 of 1992 and the Mines and Minerals (Amendment) Act No 66 of 2009 and related regulations to allow both private and foreign exploration and mining companies to carry our mining operations if the exploration is successful after review by a committee appointed by the Environment and Renewable Energy Ministry that administers the GSMB.
• Appoint a high-level committee chaired by the Secretary for Environment and Renewable Energy and other relevant officials, including those from the Finance Ministry, to formulate a national policy for value addition to graphite to gain maximum benefits to Sri Lanka.

Conclusions
It must be stressed that the key to development of graphite- based industries is vertical integration through upgrading of graphite, although it will require a competent management team with knowledge and experience. Feasible low-cost projects will be acquired by leading manufacturers such as IMERYS and GK Graphite, with potential for larger downstream producers such as Superior Graphite and Asbury Carbons returning to mining and exploration.

At the end of April 2012, Industrial Alliance has identified 36 public exploration companies that are targeting graphite. The number of projects exploded in November 2011 and acquisitions from private owners grew to over 12 a month. In January 2012, it accounted for 98 projects distributed across North and South America, Europe and Australia.

Further, aggressive moves by companies in China and India are expected to increase and secure supply on a long-term basis from outside its borders.
With such a large number of projects being added, it is inevitable that a substantial portion of these projects will end up unsuccessfully as low-quality targets and Sri Lanka will have a comparative advantage, if projects are initiated and catalysed by the GOSL with FDI due to its superior quality of natural graphite, the best in the world.
Most of the above information is extracted from the Mining Journal of January 8, 2012 and is acknowledged.

(Dulip Jayawardena, a retired United Nations ESCAP Economic Affairs Officer, can be contacted at fasttrack @eol.lk)