**Section 4**

**Bulk Crystallization from Aqueous Solutions** 

380 Advances in Crystallization Processes

[53] Aslibeiki, B., H. Salamati, P. K., Eshraghi, M., and Tahmasebi, T. (2010). Superspin glass

[54] Morales,M.P., Veintemillas-Verdaguer, S., Montero, M.I., and Serna, C.J. (1999). Surface

[58] Hanh, N., Quy, O. K., Thuy, N.P., Tung, L.D., and Spinu, L. (2003). Synthesis of cobalt

[60] Smit, J., and Wijn, H. P. J. (1959). Ferrites-physical properties of ferromagnetic oxides in

[61] Naseri, M. G., Saion, E. B., Ahangar, H. A., Shaari, A. H. and Hashim, M.(2010). Simple

[62] Berkowitz, A.E., Lahut, J. A., and VanBuren, C.E. (1980). Properties of Magnetic Fluid

[63] Berkowitz, A.E., Lahut, J. A., Jacobs, I.S., Levinson, L.M., and Forester, D.W. (1975). Spin pinning at ferrite-organic interfaces. Physical Review Letters, 34(10): 594-597. [64] Coey, J. M. D. (1971). Noncollinear spin arrangement in ultrafine ferrimagnetic

[65] Jacob, J., and Khadar., M. A. (2010). Investigation of mixed spinel structure of nanostructured nickel ferrite. Journal of. Applied. Physics 107(11): 114310-114320. [66] Hadjipanayis, G.C., and Siegel, R.W. (1994). Nanophase Materials-Synthesis-Properties-

[68] Ammar, S., Jouini, N., Fiévet, F., Beji, Z., Smiri, L., Moliné,P., Danot, M., and Grenèche,

[69] George, M., John, A.M., Nair, S.S., Joy, P.A., and Anantharaman, M.R.(2006). Finite size

[70] Sepelak, V., Menzel, M., Bergmann, I. Wiebcke, M., Krumeich, F., and Becker, K.D.

J.M. (2006). Magnetic properties of zinc ferrite nanoparticles synthesized by hydrolysis in a polyol medium. *Journal of Physics: Condensed Matter, 18*(39): 9055-9069.

effects on the structural and magnetic properties of sol–gel synthesized NiFe2O4

(2004). Structural and magnetic properties of nanosize mechanosynthesized nickel ferrite. Journal of Magnetism and Magnetic Materials, 272-276(2): 1616-1618. [71] Zhao, D., Wu, X., Guan, H., and Han, E. (2007). Study on supercritical hydrothermal synthesis of CoFe2O4 nanoparticles. Journal of Supercritical Fluids, 42(2): 226-233. [72] Chaoquan, H., Zhenghong, G., and Xiaorui, Y. (2008). One-pot low temperature

synthesis of MFe2O4 (M = Co, Ni, Zn) superparamagnetic nanocrystals. Journal of

magnetic properties. Physica B:Condensed Matter, 327(2-4): 382-384. [59] Maensiri, S., Masingboon, C., Boonchom, B., and Seraphin, S. (2007). A simple route to

[55] Brabers, V. A. M. (1995). In Handbook of Magnetic Materials (Vol. 8). New York. [56] Nogues, J., Sort, J., Langlias, V., Skumryev, V., Suriñach, S., Muñoz, J.S., and Baró, M.D. (2005). Exchange bias in nanostructures. Physics Reports, 422(3): 65-117. [57] Maaz, K., Mumtaz, A., Hasanain, S.K., and Ceylan, A. (2007). Synthesis and magnetic

Journal of Magnetism and Magnetic Materials, 308(2): 289-295.

relation to their technical applications. New York: Wiley.

TreatmentMethod Journal of Nanomaterials (2010) 1-8.

crystallites. Physical. Review. Letters, 27(17): 1140-1142.

Applications. Kluwer Academic Publishers, Drodrecht. [67] Chikazumi, S. (1959). Physics of Magnetism. New York: John Wiley.

powders J. Magn. Magn.Mater. (302) 190–195.

Magnetism and Magnetic Materials, 320(8): L70-L73.

Particles. IEEE Transactions on Magnetics, MAG-16(2): 184-190.

322(19): 2929-2934.

Materialia, 56(9): 797-800.

11(11): 3058.

state in MnFe2O4 nanoparticles. Journal of Magnetism and Magnetic Materials,

and Internal Spin Canting in γ-Fe2O3 Nanoparticles. Chemistry of. Materials,

properties of cobalt ferrite (CoFe2O4) nanoparticles prepared by wet chemical route.

ferrite nanocrystallites by the forced hydrolysis method and investigation of their

synthesize nickel ferrite (NiFe2O4) nanoparticles using egg white. Scripta

Synthesis and Characterization of Cobalt Ferrite Nanoparticles by a Thermal

**15** 

*Japan* 

Masaumi Nakahara

**Separation of Uranyl Nitrate** 

**Hexahydrate Crystal from Dissolver Solution** 

Batch crystallization is widely used for the separation and high purification of organic and inorganic materials in the fine chemical, food, pharmaceutical and biochemical industries. In the atomic power industry, application of crystallization to U purification of the Plutonium Uranium Reduction Extraction (PUREX) first cycle product was attempted in Kernforschungszentrum Karlsruhe (KfK), Germany (Ebert et al., 1989). The feed solution had 240−480 g/dm3 U concentration and 0.1 g/dm3 fission products (FPs) concentration in 5−6 mol/dm3 HNO3 solution. Reducing conditions were achieved with 2.4 g/dm3 of U(IV) which was added to change the Pu valence to Pu(IV) which was required for good separation of Pu from U. In a six-stage cascade crystallizer, the feed solution was cooled down in steps from 30 to −30°C in the course of about 30 min. More than 90% of U was recovered in form of uranyl nitrate hexahydrate (UNH) crystals with an average diameter of 0.2 mm, while a much greater proportion of the transuranium (TRU) elements and FPs remained in the mother liquor. The decontamination factors (DFs) of several of the FPs were determined for one crystal step plus several crystal washing operations. The measured DFs

An advanced aqueous reprocessing for a fast neutron reactor fuel cycle named "New Extraction System for TRU Recovery (NEXT)" has been proposed as one fast neutron reactor fuel reprocessing method (Koyama et al., 2009) and is being developed in Japan Atomic Energy Agency (JAEA). On the advanced aqueous reprocessing for fast neutron reactor fuel cycle, it is supposed to recover not only U and Pu but also minor actinides (MAs; Np, Am and Cm) for the efficient utilization of resources. It will be also effective in decreasing the environmental impact because of their long half-life and high radiotoxicity. These elements are loaded in a fast neutron reactor and are burned as core fuel. Figure 1 shows schematic diagram of NEXT process for fast neutron fuel reprocessing. The NEXT consists of highly efficient dissolution of fuel with HNO3 solution (Katsurai et al., 2009), U crystallization for partial U recovery (Shibata et al., 2009), simplified solvent extraction for U, Pu and Np co-recovery using tri-*n*-butyl phosphate (TBP) as an extractant (Sano et al., 2009), and extraction chromatography for mutual separation of actinide elements and lanthanide elements from a raffinate (Koma et al., 2009). The powdered fuel was dissolved

**1. Introduction** 

of Pu and Cs were 102 and 103, respectively.

**of Irradiated Fast Neutron Reactor Fuel** 

*Japan Atomic Energy Agency, Nuclear Fuel Cycle Engineering Laboratories* 
