Nature-inspired Apatite Production: Steam Processing of Calcium Carbonate and Tricalcium Phosphate Nanosized Powder Blends

Green production of materials is crucial to protect the environment. In this article, a low-temperature steam synthesis strategy for apatite production is shown for limiting chemical pollution and enabling the control of crystallinity. Steam processing produced apatite from calcium carbonate and tricalcium phosphate nanosized powders. Interdiffusion between amorphous precursors gave hydroxyapatite accompanied by calcium-deficient hydroxyapatite. This study unfolds the potential of hydrothermal processing in steam as a synthesis strategy that has been forgotten since the 1950s showing where two solid nanosized powders react to form a new product without creating waste, thereby emulating the clean processing route found in nature. This research reopens the consideration of steam processing for more chemically diverse alternatives and processing of various calcium resources readily available in nature, such as eggshell waste, for greener production. Furthermore, it presents a rarely found combination of apatite forms.