Improving the properties of dicalcium phosphate dihydrate (DCPD) powder by changing the morphology

Abstract

Dicalcium phosphate dihydrate (DCPD, CaHPO₄·2H₂O) has attracted attention as an environmental material recently because it reacts selectively with fluoride ions and transforms them into the highly stable, non-toxic material fluoroapatite [FAp, Ca₁₀(PO₄)₆F₂]. During this chemical reaction, the FAp particles retain their approximate shapes; in other words, DCPD particles act as templates for FAp particles. Our previous studies showed that the morphology of DCPD particles with tabular and petaloid shapes is controllable by use of a crystallization parameter under conditions of solution synthesis. DCPD has various applications, such as treatment of wastewater and polluted soil. Materials used for environmental purposes require not only appropriate chemical reactivity but also various powder properties to make them usable under various conditions. Thus, in this study, we compared the typical powder properties (bulk and tap densities, compressibility, Carr’s flowability index, sedimentation rate, and permeability) of the different morphologies of DCPD in terms of their suitability for environmental applications. The obtained results show that petaloid-shaped particles offer superior usability as compared to tabular-shaped particles.