title: [Coprecipitation of rare earth elements with hydroxyapatite (author's transl)].
abstract: The distribution behavior of trace rare earth elements between an aqueous phase and hydroxyapatite crystals was investigated. The apatite prepared by adding phosphate ion extremely slowly to an aqueous solution containing calcium, rare earth elements, ethylenediamine and nitrilotriacetate ion at 80 degrees C. Apparently the coprecipitation reaction seems to be anomalous, because the apparent distribution coefficient did not have a constant value through the reaction. But when the true distribution coefficient was calculated by using the thermodynamic data at 80 degrees C, it was revealed that rare earth ions were coprecipitated obeying logarithmic distribution law. The true distribution coefficient values of tervalent yttrium, scandium, europium and cerium ions were about 10(7.3), 10(9.8), 10(7.4) and 10(6.5), respectively.
mesh_terms: D002563:Cerium; D011232:Chemical Precipitation; D003460:Crystallization; D005063:Europium; D006882:Hydroxyapatites; D008674:Metals, Rare Earth; D012538:Scandium; D012996:Solutions; D015019:Yttrium
chemical_list: D006882:Hydroxyapatites; D008674:Metals, Rare Earth; D012996:Solutions; D002563:Cerium; D005063:Europium; D015019:Yttrium; D012538:Scandium