Americium co-precipitation with calcium oxalate

Abstract

Relevance. The fact that the literature does not contain any data not only on crystallization coefficients, but also on the nature of the co-precipitation of americium (III) with calcium oxalate. The co-precipitation reaction of americium with calcium oxalate is used to concentrate trace amounts of americium due to calcium oxalate low solubility and adsorption capacity. In this relation, the study of co-precipitation of trace amounts of americium with calcium oxalate, as well as the study of the isolation of trace amounts of americium using a calcium carrier and its subsequent separation from the carrier, is of unconditional interest. Aim. Investigation of americium co-precipitation with the solid sorbent – calcium oxalate, description of the equilibrium of the sorption isotherm using Langmuir and Freundlich models. Methods. When studying the establishment of co-precipitation of americium with a carrier – calcium oxalate, the qualification of the chemical reagents used met the requirements of the grade not lower than r.g. The isotope americium-241 was used in the work, the composition of the solid phase of the carrier – calcium oxalate – corresponded to the formula CaC2O4·H2O. The concentration of americium (III) cations in the initial solution and in the filtrate was determined by gamma-spectrometric method using the SCS-07P spectrometric complex, the amount of calcium – by complexometric titration with murexide as an indicator, and the concentration of oxalate ion – by permanganatometric method. Results. It was found that the co-precipitation of americium (III) nitrate solutions with calcium oxalate is largely due to adsorption of the micro-component – americium (III) – on the surface of the existing or newly formed precipitate of the macro-component calcium oxalate. It is determined that the Langmuir equation model adequately describes sorption, since the processing of experimental data by the least squares method showed that in coordinates C/A=f(C) the sorption isotherm is described by the equation of a straight line with a high correlation coefficient of more than 0.95.