In this work, we characterize tricalcium phosphate powders Ca9(HPO4)(PO4)5(OH) resulting from a reaction between calcium hydroxide and orthophosphoric acid at room temperature, without pH adjustment and in absence of ionic impurities. The prepared powder has an atomic ratio Ca/P of 1.512 ± 0.005. The real density is 2.68 ± 0.02 g/cm3 and the specific surface area is 80 ± 02 m2 /g. During compression, the microstructure of Cadeficient apatite powder with the presence of HPO4 groups seems to support the cohesion between particles. The transmission ratio is 90%, the transfer ratio is 41.8 and the ratio of the die-wall friction is 0.22. These results show that apatitic tricalcium powder gives a good aptitude to the compaction which leads to a good tensile strength (0.79 MPa). The heat treatment of the prepared powder shows the precise temperature for the formation of pyrophosphate, β-TCP and α-TCPa phases. The purity and aptitude to compaction of the prepared powders are very promising for pharmaceutical and medical applications.

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The objective of this work concerns the optimization of the operating conditions for the removal of heavy metals from synthetic solution by Electrocoagulation (EC). To reach this purpose, we prepared a synthetic wastewater containing certain heavy metals (Ni, Cu, Zn, Fe and Pb) to study the influence of various parameters (conductivity, pH, time of electrolysis, current density and the initial concentration of the metal) on the rate of removal of these metals. The results show that this rate of removal can reach 99.9 % in the following optimal conditions: pH included between 6 and 8 and a density of the current of 1~1.5A / dm 2 . This study shows that it is possible to remove metals in aqueous solution by the technique of electrocoagulation.