Lanthanum (La) is element number 57 and gives the lanthanide series its name. Along with cerium, it is among the most abundant rare earths in the Earth’s crust. It rarely appears in the news because it is not used in permanent magnets. Even so, lanthanum is at work in many places: oil refineries, hybrid car batteries, camera lenses, and foundries.
Basic Properties
Lanthanum is a soft, silvery-white metal that oxidizes quickly in air. It is a light rare earth element (LREE), in the same group as cerium, praseodymium, and neodymium. Lanthanum has no 4f electrons, so it is not strongly magnetic like neodymium. Its uses rely mostly on its chemical and optical behavior instead.
Sources and Production
Lanthanum is not mined on its own. It comes out of the same minerals as other rare earths, mainly bastnaesite and monazite. In both minerals, lanthanum and cerium usually make up the largest share. Separating it from the other elements requires multi-stage solvent extraction, as explained in rare earth extraction and refining.
Main Uses
Refinery cracking catalysts. This is one of the largest uses of lanthanum. In fluid catalytic cracking (FCC) units, lanthanum is added to zeolite catalysts to make them more stable at high temperature and more active in breaking heavy oil fractions into gasoline and other light products.
Nickel-metal hydride (NiMH) batteries. The negative electrode uses a hydrogen-storage alloy based on lanthanum and nickel. NiMH batteries are still used in many hybrid cars, so a single vehicle can contain several kilograms of lanthanum.
Optical glass. Lanthanum oxide raises the refractive index of glass without adding much color dispersion. This glass is used in camera lenses, telescopes, and microscopes.
Mischmetal and metallurgy. Mischmetal is an alloy of light rare earths, mostly cerium and lanthanum. It is used in lighter flints, as an addition in steelmaking to control the shape of sulfide inclusions, and in small amounts in nodularizing alloys for ductile iron . Lanthanum is also added to some magnesium and aluminum alloys to improve heat resistance.
Welding electrodes and cathodes. Lanthanated tungsten electrodes are used in TIG welding as a replacement for radioactive thoriated electrodes. Lanthanum hexaboride (LaB6) serves as the electron source in electron microscopes.
Medicine and water treatment. Lanthanum carbonate is used as a phosphate binder for patients with kidney failure. Lanthanum compounds are also used to bind phosphate in ponds and lakes to limit algae growth.
The Balance Problem: Abundant but Less Wanted
Rare earth demand today is driven by magnets, so neodymium and praseodymium are the elements producers chase. But every tonne of ore processed also yields larger amounts of lanthanum and cerium. As a result, supply of these two elements tends to exceed demand, and their prices are far below those of the magnet elements. Analysts call this the balance problem.
For a mining project, this means its economic value depends on a small share of the elements in the ore, while lanthanum and cerium still have to be separated, stored, or sold. For that reason, research into new uses for lanthanum and cerium, such as heat-resistant aluminum alloys, also affects project viability. A similar dynamic is covered in our comparison of light and heavy rare earths.
Relevance for Indonesia
Monazite, a by-product mineral of tin mining in Bangka Belitung, contains light rare earths, with cerium, lanthanum, and neodymium as the main constituents. If rare earth downstream processing in Indonesia moves ahead, lanthanum will be one of the high-volume products. The challenge is finding a market for it. Domestic oil refining, glass, and foundry industries are potential users, but the scale needs to be worked out carefully from the feasibility study stage.
A Supporting Element That Should Not Be Ignored
Lanthanum does not set rare earth market prices, but it is present in every project and every production balance. Understanding its uses and market helps in assessing a rare earth project as a whole, and not only through the magnet elements covered in our article on neodymium magnets .
Related Articles
- Light vs Heavy Rare Earth Elements: LREE vs HREE
- Neodymium and Praseodymium: The Key Elements of Permanent Magnets
- Rare Earth Extraction and Refining Process
- Rare Earth Downstream Processing in Indonesia
