Sodium sulfate mixed with rare earth

Sodium Sulfate Mixed with Rare Earth Sulfates and Silicon Dioxide... 

In conclusion, the sodium sulfate mixed with rare earth sulfates (Ln=Y and Gd) and silicon dioxide exhibits high electrical conductivity and is more durable than the pure sodium sulfate. Furthermore, the Na-SO, -Y (S0, -SiO solid electrolyte ipaintains a similar phase to Na-oO -I, whicn is excellent in Na+ cation conduction. The measured EMf was in excellent accordance with the calculated EMF, at SO2 gas concentration in the range of 30 ppm to 1 %. In fact, the solid reference electrode method could be applicable as a practical SO2 gas detector. 

Shiokawa, 1985b, J. Electrochan. Soc. 132,2519. Imanaka, N., G. Adachi and J. Shiokawa, 1986a, A solid electrolyte for sulfur dioxide detection, sodium sulfate mixed with rare earth sulfates and silicon dioxide, ACS Symposium on Chemical Sensors -Fundamentals and Applications (American Chemical Society) p. 121. 

Figure 48 (Imanaka et al. 1985a) shows one of the representative aT-T relationships for sodium sulfate and sodium sulfate doped with various amounts of yttrium sulfate with silicon dioxide. The Si02 addition prevents the sodium sulfate from becoming ductile. By doping a rare earth in the form of yttrium sulfate into sodium sulfate, the conductivity is greatly enhanced and the phase transition which causes the decline in the oT-T curve disappears except at the lowest 2(804)3 mixing of 4.9 mol%. This result indicates that the rare-earth mixing in sulfate with silicon dioxide contributes greatly to suppressing the phase transition in sodium sulfate as well as increasing the ionic conductivity.

An alternative process for opening bastnasite is used ia Chiaa high temperature roastiag with sulfuric acid followed by an aqueous leach produces a solution containing the Ln elements. Ln is then precipitated by addition of sodium chloride as a mixed sulfate. Controlled precipitation of hydroxide can remove impurities and the Ln content is eventually taken up ia HCl. The initial cerium-containing product, oace the heavy metals Sm and beyond have been removed, is a light lanthanide (La, Ce, Pr, and Nd) rare-earth chloride. 

Separation. — The separation of thorium from the rare earth metals with which it is still mixed may be accomplished by three methods (1) the carbonate separation depends on the fact that thorium carbonate is much more soluble in sodium carbonate than the carbonates of the rare earth metals (2) by the fractional crystallization of the mixed sulfates at 15°-20°, crystals of Th(S04)2 8 H20 are obtained at the insoluble end of the series (3) thorium oxalate forms a soluble double salt with ammonium oxalate, while the rare earth oxalates are almost insoluble in this reagent. Some other methods which have been suggested are fractionation of the chromates,4 of the hydrogen alkyl sulfates,5 of the acetates, by the use of sebacic add 6 and hydrogen peroxide. 

---