Precipitation and Hydrolysis of Uranium(VI) in Aqueous Solutions. V. The Composition of Precipitates From Uranyl Nitrate - Potassium Hydroxide - K, Ca, Sr, Ba, and Eu - Nitrate Solutions

The appearance of the solid phase in the precipitation system: uranyl nitrate -potassium hydroxide depends on the concentration of u ra nyl nitrate. The lower the concentratio n of uranyl nitrate the higher is the ratio Z = [KOH] I [U02 (N0shl (M / M) at which the precipitation of uranates occurs. In a narrow concentration range of potassium hyd roxide the decrease of the prec ipitation of uranium can be attributed to the formation of negatively charged colloid particles. The effect of various neutral electrolytes on the precipitation of uranium in the system: 10-3 M uranyl nitrate-potassium hydroxide var. has the following common characteristics : - The precipitation begins at a minimum ratio Z = 1.6; the presence of neutral electrolyte lowers the colloidal stabil ity of the system;· - A neutral electrolyte exerts the same action as the corresponding hydroxide, resulting in a formation of the corresponding uranates. The neutral electro lytes display coagulation and constitution effects