While the use of nanoparticles to accelerate the densification process of ceramic materials has been utilized for several decades22,25 and have recently also been exploited for pressure assisted sintering at milder temperatures down to 150–200℃ (refs 26–28) or for binding at room temperature29, no evidence was shown thus far that this effect can also be harnessed to densify a sparsely soluble ceramic material into strong bulk compacts with water at ambient temperature.