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Rare Earths |
AIMR 2009 |
Rare Earths
Rare earths are a group of 15 elements with atomic numbers ranging from 57 to 71. In order of their respective atomic numbers the elements are: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Two other elements, scandium (Sc) and yttrium (Y), are commonly classed as rare earths because of their natural association with rare earths.
The group of rare earth elements (REE) is variously, and inconsistently, reported by companies as light REE (LREE) consisting of La, Ce, Pr, Nd, and sometimes Sm. Heavy REE (HREE) may start with Sm, followed by Eu through to Lu. However, the HREE are sometime subdivided further into Middle REE (MREE) comprising Sm, Eu, Gd, Tb, and Dy with the remainder of the group, Ho to Lu referred to as the HREE. Because of inconsistent reporting, the component elements of LREE, MREE and HREE are best noted in each case. Instead of REE, the rare earth components are often reported as rare earth oxides (REO).
The rare earths are a relatively abundant group of elements that range in crustal abundance from cerium, which is the 25th most abundant element at 60 parts per million (ppm), to lutetium, the 61st most abundant at 0.5 ppm.
The demand for REE is forecast to maintain a strong growth from the current level of around 124 000 tonnes per annum (tpa) REO, which has an estimated value of US$1.5 to $2 billion, to about 200 000 tpa in 2015 (Kingsnorth 2009)1. According to Kingsnorth, supply for Tb, Dy and Y will be tight in 2014, but the demand for the other REOs of 170 000 to 190 000 tpa will be met by existing and emerging suppliers.
The most significant increases in demand are attributed to a predicted expansion in hybrid cars, followed by petroleum catalyst, glass manufacturing and polishing and multi-level electronic components. The smallest sector by volume, but largest by value, are europium and terbium which are used in the production of phosphors for televisions and energy efficient light globes.
Table - Applications for rare earth elements in the emerging advanced technology areas
| Application | Rare Earth Element |
|---|---|
Light Weight Magnets |
|
|
Nd, Dy, Pr, Sm, Tb |
Catalyst |
|
|
Ce, Nd, La |
Hybrid vehicles |
|
|
Nd, Pr, Dy, Tb |
|
La, Nd, Ce |
Compact fluorescent lights |
Eu, Tb, Y |
Polishing powders |
|
|
Ce, La, Pr |
Glass additives |
|
|
Ce, Er, Gd, Tb, La, Nd, Yb, Pm |
Ceramics |
Dy, Er, Pr, Gd, Ho, Ce, La |
The main consumers of rare earths are China, the USA, Japan, Korea and Thailand with China reportedly accounting for about 60% of the world's consumption. The Chinese government has imposed production and export restrictions, adding upward pressure on prices for rare earths and contributing to incentives for development of rare earth resources outside China.
Resources
Geoscience Australia's latest estimate of Australia's rare earths reported as REO amounted to 1.65 million tonnes (Mt) of Economic Demonstrated Resources (EDR), 0.36 Mt Paramarginal and 34.3 Mt in the Submarginal Resource categories. There is a further 20.17 Mt in the Inferred Resources category. About 49 Mt of the Submarginal and Inferred Resources are in the Olympic Dam iron oxide-copper-gold deposit in South Australia (SA) (predominantly 0.2% La and 0.3% Ce) and are not currently economic. Small quantities of scandium (3140 tonnes Paramarginal and 770 tonnes Inferred Sc), commonly included with rare earths, also were reported. In addition, about 4160 tonnes of Paramarginal Resources and 51 980 tonnes of Inferred Resources were reported as REE.
Very significant resources of rare earths are contained in the monazite component of heavy mineral sand deposits, which are mined for their ilmenite, rutile, leucoxene and zircon content. Monazite is a rare earth-thorium phosphate mineral found within heavy mineral sand deposits in Australia. Using available information, Geoscience Australia estimates Australia's monazite resources to be in the order of 6.2 Mt. Assuming the REO content of monazite to be about 60%, the heavy mineral deposits could hold an REO resource of around 3.72 Mt. Currently, extraction of rare earth from monazite is not viable because of the cost involved with the disposal of thorium and uranium present in the monazite.
Production
Historically, Australia has exported large quantities of monazite from heavy mineral sands mined in Western Australia (WA), New South Wales (NSW) and Queensland (Qld), for the extraction of both rare earths and thorium. Between 1952 and 1995, Australia exported 265 kilotonne (kt) of monazite with a real export value (2008 dollars) of $284 million (ABS 2009)2.
Small-scale production of rare earths has taken place in Australia although information records on this activity are incomplete. The following information on historical attempts to establish a rare earth production industry in Australia is drawn from Cooper 19903. In the 1950s, Zircon Rutile Ltd at Byron Bay, NSW, processed a small quantity of monazite to produce cerium oxide for use in glass polishing. In 1969, Rare Earth Corporation of Australia Ltd, operating at Port Pirie, SA, began producing cerium, lanthanum, yttrium and thorium compounds from locally produced monazite. However the plant ceased operations in mid 1972 because of a lack of working capital and the difficulty of breaking into world markets for processed rare earths.
In January 1987 it was announced that the French chemical company Rhone-Poulenc would build a two-stage monazite processing plant at Pinjarra in WA to produce rare earths from monazite, but this project was suspended. Deckhand Pty Ltd, a wholly owned subsidiary of Currumbin Minerals, were blocked in 1988 on environmental grounds from establishing a rare earths processing plant at Lismore, NSW. SX Holdings Ltd of SA was planning to establish a plant at Port Pirie to process monazite with a 2000 tpa cracking and separation plant but the project did not proceed.
Barrie (1965)4 reported that a pegmatite deposit 6 kilometres (km) east of the Cooglegong crossing, WA was worked in 1913 and 1930 and yielded about 2 tonnes of gadolinite (yttrium iron beryllium silicate (Ce,La,Nd,Y)2FeBe2Si2O10). An analysis of Cooglegong gadolinite yielded 45.78% of yttrium trioxide (Y2O3) and 4.81% of other REO. Note that gadolinite does not contain more than trace amounts of gadolinium.
More recently, mining operations commenced at the Mount Weld deposit in WA in 2007 and around 98 000 cubic metres of ore has been stockpiled pending the completion of a concentration plant at the mine site. There has been no recorded production of REO in Australia during 2007 or 2008.
Globally, the production and resources of rare earths is dominated by China, which accounts for about 97% of the production followed by India with about 2%. These figures are only approximate because the production for the Commonwealth of Independent States, which is made up of former members of the Soviet Union, is not available.
World Ranking
China holds 27 Mt (32%) of the EDR for REO, followed by the Commonwealth of Independent States with 19 Mt (22.5%) REO and the USA with 13 Mt (15.4%). Australia accounts for 1.98% of world EDR with 1.65 Mt REO.
The main types of REE deposits make up the largest REO resources in the world with the Bayan Obo deposit in China, which is predominantly REE-iron ores with bastnasite and monazite as the main REE bearing minerals, totalling at least 48 Mt REO (EDR + Inferred + Subeconomic Resources) at a grade of 6%. The only production of REOs from a carbonatite has been from the Mountain Pass deposit in California, which has total resources of 1.8 Mt REO at an average grade of about 9% REO. Deposits associated with carbonatite laterites include Araxa in Brazil with 8.1 Mt REO at 1.8% and Mount Weld in WA with 1.74 Mt REO. Other deposit categories include a vein type at Nolans Bore in the Northern Territory (NT) and an alkaline trachyte deposit at Toongi in NSW, along with a peralkaline syenite deposit at Lovozero in Russia.
Industry Developments
Lynas Corporation Ltd: The Mount Weld deposit in WA is within the lateritic profile over an alkaline carbonatite complex a Measured (2.21 Mt at 14.7% REO), Indicated (3.84 Mt at 11.5% REO) and Inferred Resources (6.19 Mt at 6.8% REO) totalling 12.2 Mt at 9.7% REO with an REO content of 1.18 Mt. In another part of the carbonatite complex there are Indicated (1.5 Mt) and Inferred (36.2 Mt) Resources totalling 37.7 Mt, which include total lanthanides at 1.16% and 0.09% Y2O3. The company completed the first stage of mining activities in 2008 and commenced construction of a concentration plant at Mount Weld and an advanced materials plant in Malaysia. Both of these activities were suspended in the first quarter of 2009 because of uncertainty concerning the financing arrangements for the project. In September 2009, Lynas announced a fully underwritten share issue in Lynas to raise $450 million, which will be used to complete phase 1 of the Lynas rare earths project. Lynas reported in its 2009 annual report that it had signed long term contracts with four customers to supply rare earths and signed letters of intent with another two customers.
Arafura Resources Ltd: Nolans Bore rare earth-phosphate-uranium-thorium deposit is located 135 km northwest of Alice Springs in the NT. It has Measured, Indicated and Inferred Resources totalling 30.3 Mt to a depth of 130 metres which grades at 2.8% REO, 12.9% P2O5, 0.44 pounds per tonne U3O8, and 0.27% Th. According to Arafura, the distribution of the LREE currently being considered for extraction, (La, Ce, Pr, and Nd) amount to 95% whereas the HREE (Sm, Eu, Gd, Tb, Dy) amount to 4.23%. In February 2009, Arafura announced it had executed a letter of intent with the Jiangsu Eastern China Non-Ferrous Metals Investment Holding Co Ltd (JEC) a subsidiary of the East China Mineral Exploration and Development Bureau (ECE) for ECE to acquire up to 25% for the issued capital of Arafura through two share placements. The proposal was approved by the Foreign Investment Review Board in May 2009 and accepted by the shareholders in September 2009. The company is conducting a definitive feasibility study on the Nolans Bore project.
Alkane Resources Ltd: The company's Dubbo Zirconia Project located 30 km south of Dubbo in NSW has a reported Measured Resource of 35.7 Mt and 37.5 Mt of Inferred Resources grading 1.96% ZrO2, 0.04% HfO2, 0.46% Nb2O5, 0.03% Ta2O5, 0.14% Y2O3, 0.745% total REO, 0.014% U3O8, and 0.0478% Th.
A Demonstration Pilot Plant (DPP) was constructed and commissioned in May 2008 at the Australian Nuclear Science and Technology Organisation (ANSTO) facility at Lucas Heights in NSW. Alkane reported that the DPP completed two trial runs in 2008 and one more in the first quarter of 2009, producing high quality zirconium and niobium products. In November 2009, Alkane reported that the plant had produced the first LREE and Y-HREE products, and stressed the importance of the rare earths as a revenue earner, particularly the HREE. The current plans are to make a decision on development during the second half of 2010 with production to commence in 2011-12 if development goes ahead.
Navigator Resources Ltd: The company's Cummins Range carbonatite deposit occurs in the south east part of the Kimberley region in WA. In September 2009, it reported Inferred Resources of 4.17 Mt at 1.72% Total REO (TREO), 11.0% P2O5, 187 ppm U3O8 and 41 ppm Th at a cut-off grade of 1% TREO. The TREO was subdivided into 95.6% Light REO (La, Ce, Pr, Nd), 4.1% Middle REO (Sm, Eu, Gd, Tb, Dy) and 0.3% Heavy REO (Ho, Er, Tm, Yb, Lu).
Historic exploration records reported that the Yangibana ferrocarbonatite-magnetite-rare earth-bearing dykes (ironstones) form part of the Gifford Creek Complex in WA. The dykes occur as lenses and pods, are typically the last stage of carbonatite fractionation and are enriched in REE fluorite and U-Th mineralisation. The Yangibana prospect has a recorded resource of 3.5 Mt at 1.7% REO. The rare earths are in coarse grained monazite containing up to 20% Nd2O5 and 1600 ppm Eu2O3.
Other deposits of possible significance for rare earth resources in the future include the BHP Billiton's Olympic Dam iron oxide-copper-gold deposit and the Mount Gee Marathon Resources uranium rare-earth deposit in SA.
Notes
- Kingsnorth, K., The rare-earths market: can supply meet demand in 2014? PDAC, Toronto March 2009
- ABS, 2009b, International trade, Cat. No.5465.0, Canberra.
- Cooper W., 1990 Queensland mineral commodity report. Queensland Government Mining Journal, September 1990. Department of Resource Industries. 383-389
- Barrie, J., 1965 - Rare Earths. In Mcleod, I. R. (Editor), Australian Mineral Industry: The Mineral Deposits. Bureau of Mineral Resources, Australia, Bulletin 72, 515-521.
