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Monazite sand deposits are prevalently of the monazite- composition. Typically, the lanthanides in such monazites contain about 45–48% cerium, about 24% lanthanum, about 17% neodymium, about 5% praseodymium, and minor quantities of samarium, gadolinium, and yttrium. Europium concentrations tend to be low, about 0.05%.
The composition of the lanthanides was about 49% cerium, 33% lanthanum, 12% neodymium, and 5% praseodymium, with some samarium and gadolinium, or distinctly more lanthanum and less neodymium and heavies as compared to commercial monazite. The europium content was at least double that of a typical monazite.
Lanthanum is rarely the dominant lanthanide found in the rare earth minerals, and in their chemical formulae it is usually preceded by cerium. Rare examples of La-dominant minerals are monazite-(La) and lanthanite-(La). [50] Production of Lanthanum from Monazite sand. The La 3+
Dysprosium is obtained primarily from monazite sand, a mixture of various phosphates. The metal is obtained as a by-product in the commercial extraction of yttrium. In isolating dysprosium, most of the unwanted metals can be removed magnetically or by a flotation process.
Lanthanites are frequently found as secondary minerals formed by the weathering of other minerals and occur as scales or tabular crystals. Originally identified at Bastnäs, Sweden, [9] they have subsequently been found in New Zealand, [10] Japan, [11] Madagascar, [12] Wales, [13] China, [14] France, [15] Germany, [16] Greenland, [17] Finland, [18] Canada, [19] Austria, [20] Romania, [21 ...
The lanthanides obey the Oddo–Harkins rule – odd-numbered elements are less abundant than their even-numbered neighbors. Three of the lanthanide elements have radioactive isotopes with long half-lives (138 La, 147 Sm and 176 Lu) that can be used to date minerals and rocks from Earth, the Moon and meteorites. [88]
Lanthanide metals react exothermically with hydrogen to form LnH 2, dihydrides. [1] With the exception of Eu and Yb, which resemble the Ba and Ca hydrides (non-conducting, transparent salt-like compounds),they form black pyrophoric, conducting compounds [6] where the metal sub-lattice is face centred cubic and the H atoms occupy tetrahedral sites. [1]
Monazite-derived mischmetal typically was about 48% cerium, 25% lanthanum, 17% neodymium, and 5% praseodymium, with the balance being the other lanthanides. When bastnäsite started being processed for rare-earth content in about 1965, it too was converted to a version of rare-earth chloride and on to mischmetal. This version was higher in ...