Natural or synthetic hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂] has a high exchange capacity for divalent heavy metal ions and is used to treat wastewater containing such ions. The reaction mechanism of hydroxyapatite with lead salts is carried out by dissolution followed by precipitation pyromorphite. As-synthesized HAp granules were analyzed by X-ray diffraction and FTIR spectroscopy. For the study of retention of lead ions were added Ca-hydroxyapatite granules in a solution of lead nitrate. By treatment with a solution of lead nitrate in all cases the chemical reaction leading to the formation pyromorphite, which is a positive result, as it is a compound of the less soluble lead.