| 摘要 |
PURPOSE:To perform appropriate thermal control and obtain the aimed denitrified substance of excellent purity by providinga color brightness meter classifying the change in form of a chemical material by color in a device wherein the chemical material is denitrified by heating. CONSTITUTION:The color brightness meter 21 is provided in a container 11 wherein a vessel 12 filled with uranyl nitrate solution 13 is heated by a heater 22 to dissolve nitric acid as as to remove NOx then produced and produce UO3. For heating on said occasion, the microwave heating by a microwave waveguide 23 may also be applied. The temperature of the solution 13 first rises up to a point A, evaporation continues up to a point B, and the condensate is yellow from the point B to C. In the sphere from the point C to D, NOx is produced through dissolution of the nitric acid and then the aimed material UO3 is produced. After the point D, however, black U3O8 is produced. Therefore, so as to reduce U3O8 and increase UO3 in the solution as much as possible, the color change after the point B is monitored 32 by the color brightness meter 21, and, when the black part is detected in the brown, the thermal control 31 and then the control by heating 33 are applied immediately by a controller 30 provided. |
