The Separation of Ytterbium from Accompanying Rare Earths by Means of its Amalgam

Abstract

NOTES 1009rigorous purification the m. p. can be raised to 88-89'. On catalytic hydrogenation the alcohol absorbs 0.9-1.0 mole of hydrogen.' Three grams of a non-alcoholic liquid were recovered from the volatile fraction obtained during the above ethyl borate treatment. The substance polymerized very rapidly on heating and this property, together with the rotation, refractive index, and method of preparation, indicates that it was probably impure carvopinone.8 (6) Jbshel, Hall and Palkin, I n d . Eng. Chcm., Anal. E d . , 18; 447 (1941).The preparation of ytterbium amalgam by the electrolytic method described earlier1 has been repeated, using a larger amount (4 g. of oxide) of the same starting material. The electrolyses were carried to the point where no further amalgam formation took place. The rare earths from amalgams and from residual electrolytes were then extracted as chlorides called I and 11, respectively. Chloride I formed much the larger part of the material; chloride I1 amounted to about 0.1 g.From chlorides I and I1 spectrograms were made using a replica grating of 15,000 lines per inch (5906 lines per cm.) and a graphite arc source.These spectrograms for the region 2500 to 4600 k., accompanied by that of iron, were enlarged photographically to give prints with a dispersion of one k. per mm. The enlarged prints were examined with the aid of Massachusetts Institute of Technology wave length tables2 and more than 250 of the strong lines identified.The spectrogram of chloride I was that of ytterbium containing a much smaller proportion of europium. No lines of other rare earths could be found on this spectrogram. That of chloride I1 showed in addition to some remaining ytterbium and europium, the presence of gadolinium, terbium, dysprosium, yttrium, erbium, thulium and lutecium. The presence of holmium was probable but could not be established with certainty because its strong lines were masked by those of other elements present.

Observations on Rare Earths Extraction of Ytterbium from Rare Earth Mixtures with Sodium Amalgam

“…Thus, by electrolytic reduction at a mercury cathode in alkaline acetate solutions containing potassium citrate and potassium carbonate, McCoy (5,6) prepared europium, ytterbium, and samarium amalgams in yields decreasing in this order. By this method, europium was readily removed from rare earth mixtures (6) and ytterbium was extracted with somewhat less efficiency (7). While McCoy was unable to obtain amalgams of the other rare earth elements by this procedure, he did obtain europium, ytterbium, and samarium amalgams by treating acetate solutions containing citrate and potassium carbonate with potassium amalgam (5,6).…”

“…The nitrate was excluded because previous experiments had shown that nitrate solutions, or even acetate solutions containing nitrate, yield no ytterbium amalgam when treated with sodium amalgam, probably because of preferential reduction of the nitrate. In addition, alkaline citrate solutions were studied to afford a comparison of the procedure with that of McCoy (5, 6, 7).…”