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Science

A monthly newsletter about current science topics by Margaret Franklin

Ireland’s Valuable Lithium Deposits Ireland’s mineral resources are sometimes under-estimated. We have the largest lead-zinc deposits in Europe. Our mines at Navan, Galmoy and Lisheen make Ireland the top zinc producer in the EU. It now appears that Ireland has useful deposits of a very different and rather rare metal: Lithium.

A Canadian company, International Lithium Corporation, (ILC) has prospecting licences for lithium on the Carlow side of the Blackstairs mountains. This area is in the Leinster pegmatite belt, which is rich in lithium. It extends roughly from the town of Borris in a NE direction, for over 50 kilometres. With the help of Chinese investors, ILC may develop the resource.

A Chinese investment company, ‘Ganfeng Lithium’ is financing the Canadian company’s project in the Blackstairs.

Lithium-bearing pegmatite was first reported in the area in the 1970s, when Irish Base Metals carried out an exploration programme of sampling and geophysical surveys.

Because of the scarcity of outcrop, they used boulder samples. The location, size and quantity of pegmatite boulders within the dry stone field boundaries indicated the presence of buried pegmatites.

The Picture shows the Wexford side of the Blackstairs Mountains, viewed from Vinegar Hill

TOPICAL SCIENCE JULY 1, 2017

PEGMATITE Pegmatite is an igneous rock, similar to granite, but more coarse grained, with very large crystals. It forms near the margins of a magma chamber during the crystallization process and often contains rare minerals not found in the main magma body. Samples taken from the Leinster pegmatite belt at Moylisha have been found to contain around 4% of the mineral, as lithium oxide. This is considered a high-grade deposit. The samples analysed were taken from boulders found in the area. Because of the thick layer of soil and clay covering the bedrock, there are very few outcrops of the underlying rock. In fact, some of the pegmatite minerals were identified visually, from veins seen in the dry stonewalls surrounding the fields.

The main lithium-bearing mineral within the rock is spodumene, a silicate of lithium and aluminium, belonging to the pyroxene group of silicates. (Chemical formula: LiAlSi2O6).

It forms large crystals, which are sometimes prized as gemstones.

Samples of Spodumene Crystals THE ELEMENT LITHIUM Lithium is element number 3 in the Periodic Table of Elements and it is the lightest metal. Its chemical properties are similar to those of sodium, but it is far less abundant. Like sodium, it reacts vigorously with air and water. For this reason, it is never encountered in nature as the free element, but always chemically combined with other elements, mainly oxygen, aluminium and silicon. It also occurs dissolved in salt lakes.

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TOPICAL SCIENCE JULY 1, 2017

Commercial Importance of Lithium Lithium and its compounds have a number of industrial applications, such as in heat-resistant glass and ceramics. The metal is used in combination with other metals to make strong but lightweight alloys for use in aircraft. In the pharmaceutical industry, lithium salts are used for mood-stabilizing medication in the treatment of bipolar disorder.

In recent years, the metal has found widespread use in lithium batteries and lithium-ion batteries and this is the reason for the current interest in lithium deposits.

Currently, ILC has 9 active rare metals projects around the world, including lithium-potash brines in Argentina and Nevada as well as hard-rock pegmatites in Canada and now this latest prospect in Ireland. The Company’s principal project at the moment is the Mariana lithium-potash brine project, which is a ‘salar’ or salt lake in South America. It is located in the South American 'Lithium Belt' on the borders of Argentina, Bolivia and Chile, covering an area of 160 square kilometres. The Mariana lithium-potash brine project ranks as one of the more prospective salars in the region, which holds the vast majority of global lithium resources.

Lithium mining is usually of the large-scale open cast variety with high visibility, noise and dust elements. John Harrop of International Lithium Corporation said: “The type that is most likely, should it be feasible here, would be something more like a quarry than a typical zinc mine. The shape of the pegmatites tends to be long and thin so you're probably looking at a long thin quarry a few field lengths in size and not particularly wide. We see potential that there could be a number of these along the 50km trend rather than one very large deposit in the middle somewhere.”

ILC exploring for Lithium | Image: Kieran Cuddihy.

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TOPICAL SCIENCE JULY 1, 2017

Future Applications of Lithium Minerals Up to now, most lithium compounds and minerals were used to produce ceramics, glass, aluminum alloys and high temperature grease. However, there is now a rising demand for rechargeable batteries, for use in devices such as mobile phones, tablet computers, cameras, music players, GPS units and other portable electronic devices. This is increasing the demand for high purity lithium. It is cheaper to produce lithium from brines, but it is possible to obtain a far higher purity of lithium from spodumene.

According to a report published in 2011 in the Journal of Industrial Ecology, the world has just about enough lithium resources to power electric vehicles for the rest of the century. At present, the global lithium deposits are estimated to be about 39 million tons.

The amount of material that can realistically be recovered, considering economics and processing issues, is at least 19 million tons. The projected lithium demand, including uses other than batteries, does not exceed 20 million tons between 2010 and 2100. But if demand continues to rise, there could be a supply crisis. The expected demand for lithium from electric vehicles, including hybrid cars, has made lithium a possible ‘critical material’.

Most hybrid electric vehicles currently use nickel-metal hydride batteries, but the use of Lithium ion batteries is increasing. Lithium batteries have a much higher charge-toweight ratio and power-to-weight ratio than conventional lead/acid batteries or the newer nickel-metal hydride batteries. Other technologies are also being developed, such as fuel cells and ultra-capacitor batteries.

If Lithium becomes generally regarded as a critical material and if Ireland’s Lithium deposits turn out to have economic potential, the future is looking good for the mining industry in this country.

The Author Margaret Franklin is a retired chemistry lecturer, who spent most of her career at Athlone Institute of Technology, in the midlands of Ireland.

For several years, Margaret wrote a column entitled ‘Topical Science’ for the local weekly newspaper, The Westmeath Independent’. It is now published on-line as a monthly newsletter, covering science topics for the information of the general public.

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