Neodymium sesquioxide

Several other useful modifications of calciothermic reduction have been successfully developed for the preparation of this neodymium-bearing magnetic alloy. One of these is reduction-extraction which involves the reduction of neodymium sesquioxide (Nd203) with calcium in a molten calcium chloride-sodium chloride salt bath at 750 °C and the simultaneous extraction of the reduced metal into a molten neodymium-zinc or neodymium-iron alloy pool. The neodymium-zinc alloy product is treated in vacuum to remove zinc and produce neodymium metal, while the neodymium-iron alloy is itself the end product of... 

Calcium is generated in situ for effecting reduction in another process in which elemental sodium is introduced in the charge mixture. The production of neodymium metal or of its alloys by the reduction of neodymium sesquioxide with sodium in the presence of calcium chloride is known as the NEOCHEM process. This process was developed at the General Motors Research Laboratories in the 1980s. The overall reaction pertinent to the process can be written as... 

SYNS DINEODYMIUM TRIOXIDE NEODYMIA NEODYMIUM(III) OXIDE NEODYMIUM(3+) OXIDE NEODYMIUM SESQUIOXIDE NEODYMIUM TRIOXIDE... 

Following is an example for the preparation of NdCoOs perovskite by freeze-drying method [30] 0.005 mol neodymium sesquioxide was first dissolved in 5 rrrl of concentrated nitric acid, and then added to a solution of 0.01 mol of cobalt (II) acetate in 25 ml of water. The pH of the resulting solution was adjusted to 4.5 by addition of dilute ammorria. Finally, the resulting reddish solution were frozen in liquid N2 and transferred into a freeze-dryer operated at a pressure of 7.6 torr. The resulting blue-pink powder was placed into an alurttina boat and pretreated at 400 °C for 2 h under vacuum. The "ashes" were finally groimd and treated for 24 h under a dynamic oxygen atmosphere at 700 and 900 °C. 

Rare-earth sesquioxides are of interest as laser host materials in addition to other practical applications. Neodymium is known to exhibit laser action in several rare-earth oxides including La203 (Hoskins and Softer, 1965) and Gd203 (Softer and Hoskins, 1964). Laser action in crystals of the form R R203 has also been observed, particularly Ho Er203 (Softer and Hoskins, 1966) and Tm Er203 (Softer and Hoskins, 1965). The possibility of obtaining stimulated emission from crystals of the latter form has spurred much of the fundamental spectroscopic research on the sesquioxides. 

Self-Diffusion of Oxygen in Neodymium and Samarium Sesquioxide, G.D. Stone, G.R. Weber and L. Eyring, Proceedings of a Conference on Mass Transport in Oxides, pp. 179-186, 1968. 

Pankratz, L.B., E.G. King and K.K. Kelley, 1962, High-Temperature Heat Contents and Entropies of the Sesquioxides of Europium, Gadolinium, Neodymium, Samarium and Yttrium Jn Bur. Mines Ryjort. of Inv. 6033. Panlei( er, R.J., R.N. Blumenthal and J.E. Gamier, 1975, J. Phys. Chem. Solids, 36, 1213. 

Stecura, S., 1965, Crystallographic Modifications and Phase Transformation Rates of Five Rare Earth Sesquioxides Lanthanum Oxide, Neodymium Oxide, Samarium Oxide, Europium Oxide and Gadolinium Oxide, in Bur. of Mines Rept. of Inv. 6616. 

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