Saturday, December 18, 2010

Rare, But Not Unusual

Rare Earth Elements

Rare Earth Elements in oxide form
News stories about rare earth elements (REE) are becoming more frequent as greater attention focuses on the rise of the cleantech and renewable energy industries, the growing economic competition between the US and China, and issues of natural resource scarcity and security.

REE are under increasing control by China, which dominates world production and supply. The Chinese have used their effective monopoly to further their industrialization, but also as part of a broader effort to establish their position in the global economic and political order.

The physical properties, commercial uses, economic factors, and political considerations of REE are not widely known or appreciated by the public, yet their importance is real and growing. An examination of the different aspects of REE will illuminate not just their future significance, but also serve as an example of the broader economic and political trends of the next few decades.

What are rare earth elements (REE)? Sometimes referred to as "rare earths" they are the 16 (or 17) elements with atomic numbers 57 through 71, from lanthanum to lutetium (the “lanthanides”), as well as yttrium (and sometimes scandium) which are included due to their chemical similarity. REE are commonly found together as minerals in the Earth’s crust because of their atomic similarity and a shared set of behaviors under formative geological processes.

Compared to the better-known basic industrial elements (iron, tin, copper, zinc, aluminum, nickel, lead, etc.) the production and use of REE is relatively small. Their importance, however, is greater than their tonnage would indicate. REE have many uses, including in glasses, for glass polishing, in batteries, to make super magnets, for metal alloying, for TV phosphors and in catalytic converters. REE enable generators for wind and other turbines, lighter weight components that improve vehicle mileage, energy-efficient lighting, lower emissions, denser computer hard drives as well as many defense-related uses.

Why are they called "rare earths"?
Most of the REE are not as rare as the group’s name suggests. They were named rare earth elements because most were identified during the 18th and 19th centuries as oxide components within seemingly rare minerals. Cerium is the most abundant REE, and it is actually more common in the Earth’s crust than is copper or lead. All of the REE except promethium are more abundant than silver or mercury.
While relatively more abundant, and 2-3 times more concentrated than such industrial metals as copper and zine, REE are rarely concentrated into deposits that are economic to recover. Even when they are, the geology defies standardization.
The complex metallurgy of rare earth elements is compounded by the fact that no two REE ores are truly alike. As a result, there is no standard process for extracting the REE-bearing minerals and refining them into marketable rare earth compounds. To develop a new rare earth elements mine, the ores must be extensively tested by using a variety of known extraction methods and a unique sequence of optimized processing steps. Compared with a new zinc mine, process development for rare earth elements costs substantially more time and money.
The result of the process of mineral extraction is generally a mixture of REE, so a further separation, both costly and complicated is required. At California's Mountain Pass mine a single ore, bastnasite, would yield 12 different rare earth oxides (REOs) in a system of 34 separate processing steps. Finally, impurities must be removed, chief among them thorium, which, due to its radioactivity, creates an additional regulatory and cost burden. Some deposits, such Olympic Dam in Australia, are contaminated with uranium.

The United States has had only one domestic source of REE--the Mountain Pass mine in California owned by Molycorp (formerly Molybdenum Corporation of America). The deposits there were discovered in 1949 and production commenced in in 1953. Prior to 1998 the United States produced most of the REE required for its domestic industry, entirely from Mountain Pass. In 1998 production started decreasing, and China started supplying an increasing share. In 2002 operations ceased because the permit expired (although Molycorp continues to produce REE from previously mined ores.) Global production shifted to the handful of countries with commercially viable concentrations of REE: Austria, Canada, France, Malaysia, and the BRIC countries, especially China. It has been widely reported that China is now the dominant producer of REE--as much as 96% of global production in 2010.

Until the last two years there has been little concerted effort to identify, explore and develop REE resources outside of China. That is now changing, with about 150 projects underway globally in the past 2 years according to the USGS. Of those, 10 are in the US.
In the case of REE, very little exploration has ever been done and the most intense period ever of direct exploration for REE is currently underway (2010). Many important past discoveries have been serendipitous—the world’s largest REE mine, Bayan Obo in China, was first mined for iron ore. The “funny” steel produced from this ore was investigated and found to be contaminated with REE. Mountain Pass, California, was found in the course of a U.S. Geological Survey radioactivity reconnaissance project that expected to find uranium.
Once found, the pre-production process until mining operations commence can be time-consuming, litigious, and thus expensive. Mining efforts of comparable ore complexity, operational size, environmental disruption, infrastructure requirements and financing challenges, e.g. for nickel laterite, can take 7-10 years, or longer if significant opposition arises or the due diligence of any party identifies troublesome issues.

US reserves and inferred resources are thought to amount to some 1.5M tonnes, which is large compared to the peak production at Mountain Pass, in 1990, of 20,000 tonnes per year. However, the USGS cautions:
The lack of mining industry exploration of REE deposits in the last few decades is paralleled by a low level of geological research. The U.S. Geological Survey has demonstrated in related studies that the first step in improving our understanding of REE resources and prospects for further discoveries is to conduct national and global mineral resource assessments. Rare earth elements are one of the commodities under consideration for the next National Resource Assessment, scheduled to begin in 2012.
Last year Molycorp announced it would re-open production at Mountain Pass by 2012. With the decade-plus long lead times to actually start producing in other locations, the need to begin developing REE production capability in the US is immediate.

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