| Abstract |
| To understand the reaction of Yttrium in water, Pourbaix diagrams were constructed at 288 K, 298 K, 318 K, and 328 K through thermodynamic calculations, and the following results were obtained: 1. At the same temperature, the equilibrium pH of the Y3+-Y(OH)3 reaction and the reduction potential of Y3+ decreased as the ionic activity decreased from 100 to 10-6.2. With increasing temperature, the reduction potential of Y3+ increased from -2.4496 V to -2.4467 V when the ionic activity was above 10-4, whereas it decreased from -2.4877V to -2.4901V when the ionic activity was below 10-6. On the other hand, the equilibrium pH of the Y3+-Y(OH)3 reaction decreased with increasing temperature regardless of ionic activity, and Y was stable at pH 5.6 and below. 3. The stable region of Y3+ is affected by the reduction of Y3+ and the Y3+-Y(OH)3 reaction. The reduction potential of Y3+ changed in different directions depending on the ionic activity with increasing temperature, but the change in the reduction potential of Y3+ was small compared to the change in the equilibrium pH of the Y3+-Y(OH)3 reaction; therefore, the stable region of Y3+ decreased with increasing temperature. 4. As the temperature increased from 288 K to 328 K, the stable area of Y and Y3+ decreased regardless of the ionic activity, withdecreasesof 85.3% and 87.4%, respectively, at an ionic activity of 100. On the other hand, the stable area of Y(OH)3 decreased by as much as 86.8% with decreasing temperature. |
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| Key Words |
| Stable Area, Pourbaix diagram, Yttrium, Y(OH)3, 안정영역, Pourbaix 다이어그램, 이트륨 |
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