Dysprosium

Formatting of the disc is carried out by heating with a laser beam to a temperature above the Curie temperature 180°C of the magnetic layer. All information on the disc is removed when the layer has lost its ferromagnetism. At room temperature the disc is again ready for recording information. 

Dysprosium has not yet found many applications. One important use, however, is in magnetostrictive materials, which have been described in the terbium section above. Another is in the dysprosium oxide-nickel cermet ), which is used for cooling nuclear reactor rods. This makes use of dysprosium s ability to absorb neutrons. 

Dysprosium iodide Dylj, added to hahde discharge lamps, dissociates at the high temperature to dysprosium atoms, which absorb energy and emit it as a very intense, white light. 

Data reported for the solubility constant of Dy(OH)3(s) are listed in Table 8.40. There are few data and their variability is very large. There are no reported data acquired in fixed ionic strength media. Only the data of Akselrud and Spivakovskii (1960b) and derived from the Gibbs energy quoted for Dy(OH)3(s) in the TKV database (TKV, 2010) are retained. 

Data have been reported for the first hydrolysis constant of dysprosium by Klungness and Byrne (2000), Frolova, Kumok and Serebrennikov (1966) and 

Vasca et al. (2004). These data are listed in Table 8.41. Klungness and Byrne measured the stability of DyOH across the temperature range from 25 to 55 C and in 0.1 and 0.7 moll NaClO. Frolova et al. measured the stability at 25 C and in 0.3 mol 1 NaClO. Vasca et al. (2004) measured the stability at 25 C and in l-3molkg NaClO. Results from the three studies are in quite good agreement when the differences in ionic strength are considered. 

There is only a single literature source that lists data for the stability of the higher monomeric stability constants of dysprosium (Fatin-Rouge and Biinzli, 1999), where values were proposed for the stability of Dy(OH)3(aq) in two media at 0.1 moll . In both cases, the stability constant given for log 3 by Fatin-Rouge and Biinzli indicates that it is greater than 3-log These data are not retained by this review (the values have not been listed). 

Polymeric hydrolysis species of dysprosium were postulated by Vasca et al. (2004), who studied these reactions at 25 C and in 1.0-3.0molkg NaClO. These authors proposed the formation of the polymeric species Dy2(OH)2 and Dyg(OH)g +. The reported stability constants are listed in Table 8.42 including 

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The cost of dysprosium metal has dropped in recent years since the development of ion-exchange and solvent extraction techniques, and the discovery of large ore bodies. The metal costs about 300/kg in purities of 99+%. 

Parameter Gadolinium Terbium Dysprosium Holmium Erbium ThuUmn Ytterbium Lutetium... 

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach. 

The HFBR core uses fully-enriched (93%) uranium oxide-aluminum cermet curved plates dad m aluminum. The core height is 0.58 m and the diameter is 0.48 m or a volume of 103.7 Itr. The U-235 weighs 9.83 kg supported by a grid plate on the vessel bottom. The coolant flow u downward. Iience. How reversal is necessary for natural circulation. It operating temperature and pressure are 60 ( and 195 psi. There are 8 main and 8 auxiliary control rod blades made of europium oxide (Lii A)o and dysprosium oxide (DyjO,), clad in stainless steel that operate in the reflector region. The scram system is the winch-clutch release type to drop the blades into the reflector region. Actuation of scram causes a setback for the auxiliary control rods which are driven upward by drive motors,... 

Dysprosium, Dy Lutetium, Lu > L. de Boisbaudran G. Urbain 1886 Greek hvanpoaixog, dysprositos, hard to get... 

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