• Resources Recycling
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• v.16 no.2 s.76
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• pp.23-31
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• 2007

In this study, the crystallization of neodymium carbonate from neodymium chloride solution by addition of ammonium bicarbonate was investigated. The concentration of reactants such as neodymium chloride and ammonium bicarbonate, and reaction temperature play an important part in order to obtain the crystal of neodymium carbonate. It seemed that amorphous neodymium carbonate was prepared by aggregation of primary particles formed through nucleation. If reaction rate was increased by increasing the concentration of reactants and reaction temperature, then neodymium carbonate crystal could be obtained. Lanthanite-type neodymium carbonate[$Nd_2(CO_3)_3{\cdot}8H_2O$] and tengerite-type neodymium carbonate[$Nd_2(CO_3)_3{\cdot}2.5H_2O$] could be obtained with reaction renditions. Lanthanite-type neodymium carbonate was sensitive to temperature. The thermal decomposition of neodymium carbonate contained the processes or dehydration, decarbonation and crystalization of $Nd_2O_3$. The shape of lanthanite-type neodymium carbonate was irregular lump type, and tengerite-type neodymium carbonate had the shape of needle type. The shape of $Nd_2O_3$ was affected by the shape of neodymium carbonate.

• Resources Recycling
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• v.13 no.5
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• pp.37-44
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• 2004

In this study, neodymium oxalate powders were prepared by injecting oxalic acid to the neodymium chloride solution resulted from the acid leaching solution of NdFeB magnet scrap. The effect of experimental conditions on the characteristics of neodymium oxalate powders were investigated. Neodymium oxalate was aggregated by primary particles formed by nucleation, and average size of aggregates was affected by experimental conditions. In a constant volume, increase of reactants affected the average size of aggregate formed by collision of primary particles. In a constant concentration of reactants, agitation speed decreased the size of aggregate due to breakage of particles attached on the surface of aggregate. The number of primary particles decreased with increasing reaction temperature, and the size of aggregates decreased due to the decrease of collision probability. From the results of decomposition behavior of neodymium oxalate, oxalate decomposed from $400^{\circ}C$, and neodymium oxide began to crystallize at above $620^{\circ}C$.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.512-515
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• 2008

The removal of iron from neodymium chloride solution was carried out by solvent extraction using Alamine 336 in kerosine. The effect of Alamine 336, hydrochloric acid and chloride ion concentrations on the extraction of Fe were studied. The results showed that Alamine 336 as an extractant for removal of iron was effective and the extraction percentage of iron was increased with increasing hydrochloric acid and chloride ion concentration in aqueous solution. The extraction of 99% of iron is attained at a ratio of A/O = 4 by distilled water. The stripping yield of iron from loaded Alamine 336 decreased with decreasing hydrochloric acid concentration in stripping solution.

• Resources Recycling
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• v.26 no.5
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• pp.39-47
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• 2017

In this study, the precipitation of rare earth-sodium sulfate with sodium sulfate was conducted in order to separate rare earth from Fe in rare earth sulfate solution. Neodymium (Nd) was easily precipitated as Nd-sulfate salt with sodium sulfate, on the other hand, excessive sodium sulfate was needed for the precipitation of Dy-sulfate salt. Also neodymium not only promoted the precipitation of dysprosium sulfate salt but also increased recovery of dysprosium sulfate salt in sulfuric acid solution. At the condition of $60^{\circ}C$ precipitation temperature, 3 h reaction time, 7 equivalents sodium sulfate, the recovery of neodymium and dysprosium sulfate salt was 99.7% and 94.3% respectively from the sulfuric acid solution containing Nd of 23.39 mg/ml and Dy of 8.67 mg/ml. Lastly, from the results of separation of Dy to Nd by the method of sulfate double salt, the effect of salting out with NaCl is important to increase the grade of Dy, and 98.7% of Dy grade could be obtained in this study.