Rare Earths in Some Niobate-Tantalates

J. R. Butler
Imperial College, South Kensington, London, S.W. 7.

Summary: Rare-earth distribution has been determined for fourteen niobatetantalates containing essential rare earths. Those minerals with more than about 15 % TiO2 (and corresponding to either priorites or members of the euxenite-polycrase series) have Yt as the dominant rare earth with the heavier lanthanons1 in excess of the lighter lanthanons. Those minerals with less than about 4 % TiO2 and less than about 30 % (Yt,Ln)2O3 (and corresponding to samarskites) also have Yt as the dominant rare earth but they show a marked concentration of Gd + Tb + Dy over the other lanthanons. It is tentatively suggested that this power of selective lanthanon enrichment may be characteristic of samarskite among the niobate-tantalates examined.

Mineralogical Magazine; March 1958 v. 31; no. 240; p. 763-780; DOI: 10.1180/minmag.1958.031.240.05
© 1958, The Mineralogical Society
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