ADU粉末比表面积控制工艺研究

Study on Specific Surface Area Control Technology of ADU Powder

UO_(2)粉末由ADU粉末分解还原制得,ADU粉末的比表面积会直接影响UO_(2)粉末的压烧性能,需对ADU粉末的比表面积加以控制。针对以硝酸铀酰溶液为原料制备ADU粉末的沉淀反应过程,在固定溶液铀浓度的情况下,研究了加料方式、反应温度、终点pH对ADU粉末比表面积的影响规律。结果表明:ADU粉末的比表面积随反应温度的增大而减小,随终点pH增大呈现先增大后减小的趋势;两步沉淀法制备的ADU粉末比表面积偏高,分解还原制得的UO_(2)粉末出炉易被氧化。在溶液铀质量浓度100 g/L、反应温度60℃、终点pH 8.0条件下,采用一步沉淀法制备的ADU粉末比表面积最佳,分解还原制得的UO_(2)粉末满足芯块制备要求。

UO_(2) powder is prepared by decomposition and reduction of ADU powder,the specific surface area of ADU powder directly affects the properties of UO_(2) powder.Aiming at the precipitation reaction of ADU powder prepared from uranyl nitrate,the effects of different reaction conditions on specific surface area of ADU powder were studied under the condition of fixed concentration of uranium in solution.The results show that the specific surface area of ADU powder decreases with the increase of reaction temperature;when the ending pH went up,the specific surface area of ADU powder increases first and then decreases.The specific surface area of ADU powder produced by two-step method is higher than one-step method,the UO_(2) powder prepared by decomposition and reduction is easy to be oxidized.When the concentration of solution is 100 g/L,the reaction temperature is 60℃,the pH is 8.0,the specific surface area of ADU powder prepared by one-step method is the best,the UO_(2) powder prepared by decomposition and reduction meets the requirements of preparing UO_(2) pellets.