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The lanthanides that dissolved as a result of the acid treatment were subjected to solvent extraction, to capture the europium, and purify the other individual components of the ore. A further product included a lanthanide mix, depleted of much of the cerium, and essentially all of samarium and heavier lanthanides.
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%.
Lanthanum is rarely the dominant lanthanide found in the rare earth minerals, and in their chemical formulas 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+
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 ...
Thulium is principally extracted from monazite ores (~0.007% thulium) found in river sands, through ion exchange. Newer ion-exchange and solvent-extraction techniques have led to easier separation of the rare earths, which has yielded much lower costs for thulium production. The principal sources today are the ion adsorption clays of southern ...
Of the above yttrium minerals, most played a part in providing research quantities of lanthanides during the discovery days. Xenotime is occasionally recovered as a byproduct of heavy-sand processing, but is not as abundant as the similarly recovered monazite (which typically contains a few percent of yttrium). Uranium ores from Ontario have ...
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-(La) is a relatively rare representative of the monazite group, with lanthanum being the dominant rare earth element in its structure. As such, it is the lanthanum analogue of monazite-(Ce) , monazite-(Nd) , and monazite-(Sm) .