HYDROLYSIS OF UREA NITRATE CONCENTRATED SOLUTIONS

Abstract

The relevance of the research is the rationale for utilization of urea nitrate formed in the previously developed process of urea denitration of uranium nitrate refined raffinates for nuclear fuel fabrication enterprises. In this paper, we consider the results of the quantitative hydrolysis of urea nitrate into ammonium nitrate used in the hydrometallurgy of uranium. Objects: model solutions of carbamide nitrate with a concentration of 100–500 g/l with the addition of various reagents: nitric acid, ammonium nitrate. Methods: IR spectroscopy, pH meter, spectrophotometry, gas chromatography. Results. IR spectroscopy, pH metry, spectrophotography. The authors have studied urea nitrate hydrolysis at atmospheric pressure, at temperatures of 70–105 °С, concentrations of the initial solution of 100–500 g/l and with the addition of various reagents – nitric acid and ammonium nitrate. It was found that increasing temperature contributes to hydrolysis intensification; the addition of nitric acid at a concentration of 100 g/l slows down the process, and the addition of ammonium nitrate practically does not affect the hydrolysis of urea nitrate. IR spectroscopic studies suggest that heating solutions with initial concentrations of 100 and 200 g/l at 90 °С for 20 hours with the discharge of evolved gases leads to the complete hydrolysis of urea nitrate. The degree of hydrolysis of urea nitrate and the degree of its conversion to ammonium nitrate coincide at acidic and neutral pH values. A spectroscopic study together with chemical analysis data confirmed the presence of urea nitrate bicarbonate and ammonium nitrate in the hydrolysis products. No intermediate hydrolysis products were detected.

Keywords

• urea nitrate
• hydrolysis
• activation energy
• ir spectra
• nitric acid
• ammonium bicarbonate
• ammonium nitrate