Separation and purification of uranium from the alkaline leaching solution obtained from the dissolution of the evaporation pool scrap (C36) of the uranium processing plant using alkaline precipitation

In the current research work, the alkaline precipitation method was used for the primary separation and purification of uranium in the solution which obtained from the dissolution of the evaporation pool scrap (C36) of the uranium processing plant. In this method, the effect of various parameters such as pH, temperature, stirring speed, aging time and seeding on the uranium precipitation yield as a sodium diuranate and the amount of impurities such as sodium and fluoride in the precipitate were evaluated. The results show that by increasing the pH of the solution up to 14, the separation yield increases up to 98.1%. Nonetheless, using the seeding method, the pH value is reduced to 12  and the separation efficiency increases to 99 %. Also, the results show that increasing the aging time and stirring speed increases the separation percentage and decreases the amount of sodium and fluoride impurities in the precipitation, while increasing the temperature leads to an increase in the separation percentage of uranium and impurities, too. In general, by applying the seeding process, pH adjustment up to 12, aging time of 12 hours, temperature of 50°C and stirring speed of 250 rpm, the best conditions for the primary uranium separation as a sodium diuranate with the minimum amount of major impurities in the precipitation were obtained.