Dr. Marcos de Campos

Abstract:

The present situation of the market and applications of rare-earths is reviewed. It is given special attention for discussing the possibility of substitution of  rare-earth magnets by other families of magnets.

Three are the main commercial applications of rare-earths: i) luminescent phosphors, ii) magnets, and iii) catalysis.

For catalysis, the cheap rare-earths as cerium and lanthanum are employed.  Luminescent phosphors are essential in many applications, as lasers and, for example, erbium is used in optical fibers. However, in spite of its relevance, erbium is not expensive as Tb and Dy. 

In LED applications, the rare-earths are used as thin films, and , thus the demand in volume  is not very significant when compared with the demand for magnets. The use of white LED (light emission diode) significantly reduced the demand for europium after 2015, but this application is still relevant. In the 1960s and up the 1980s, Europium was the most expensive rare-earth, due to extreme demand.

The rare-earth market is nowadays driven by Tb, Dy, Nd and Pr, which are employed in rare-earth iron permanent magnets of the RE2Fe14B family (RE=rare earth). For applications in high temperature, dysprosium and terbium are added, and this made the demand and price of Dy and Tb be skyrocketing.

SmCo magnets have the problem of using the expensive element cobalt. Nowadays the demand and price of cobalt increased conbseiderably due to application in rechargeable battteries, and thus, SmCo use in large scale is avoided, but they remain relevant for high temperature applications (above 150oC).

Possible alternatives for rare-earth  permanents magnets are discussed. Among the few options for replacement are the ferrite magnets (BaFe12O19 or SrFe12O19), the Alnico magnes based on shape anisotropy and maybe iron nitrogen. Economic and technical feasibility of these families of magnets are discussed.

Its is given a brief overview about recent mining projects in Brazil, which are focusing on ionic clays, with the objective of extracting the scarce and expensive elements terbium and dysprosium.