Hydrothermal synthesis of pollucite, analcime and their solid solutions and analysis of their properties

Pollucite, as a perfect long-term potential host for radioactive Cs immobilization, barely exists in pure form naturally but in an isomorphism form between pollucite and analcime due to coexistence of Cs and Na. Pollucite could be hydrothermally synthesized with Cs-polluted soil or clay minerals which contain Cs and Na, and it is necessary to study the properties of the synthesis if Cs and Na contained. Pure pollucite, analcime and their solid solutions were hydrothermally synthesized with chemicals, and it was found that the most formed pollucite analcime solid solutions with Cs/(Cs + Na) ratios of 2/6–5/6 had very similar properties in mineral composition, morphology and size, structural water (Cs cations) and coordination environment to pollucite. This also suggests that even coexistence of Cs and Na in nature, pollucite favors to form due to site preference for Cs over Na, which leads to the property and the structure of the most solid solutions similar to that of pollucite. •Pure pollucite barely exists in nature due to coexistence of Cs and Na.•Pollucite, analcime and their solid solutions could be hydrothermally synthesized.•Most formed solid solutions were found to have similar properties to pollucite.•Even coexistence in nature, pollucite favors to form due to site preference for Cs over Na.