Aqueous hydroxylation mediated synthesis of crystalline calcium uranate particles

作者：Ding Weixuan^*; Botha Johannes A; Hanson Bruce C; Burke Ian T

来源：Journal of Alloys and Compounds, 2016, 688: 260-269.

DOI：10.1016/j.jallcom.2016.07.140

• Uranate
• U(VI)
• Synthesis
• Precipitation
• Particles
• Crystallisation

Metal uranates(VI) are solubility limiting U(VI) phases under high pH conditions and may act as suitable long-term wasteforms. The precipitation and thermal phase development mechanisms of calcium uranate particles formed via aqueous hydroxylation reactions are studied in order to address the lack of aqueous synthesis methods currently available. Hydrous Ca-deficient uranate particles formed from aqueous solutions saturated in U(VI) oligomers were found to thermally decompose via several weight-loss steps between 100 and 800 degrees C. Crystalline calcium uranate (Ca2U3O11) is initially formed at 700 degrees C via dehydration and dehydroxylation-olation reactions under redox-neutral conditions. This initial phase decomposes to biphasic CaUO4-UO2 particles at 800 degrees C via a reductive pathway.

• 出版日期2016-12-15