The literature reports the mechanochemical synthesis of hydroxyapatite (Ca10(PO4)6(OH)2) from different precursors to those reported in this study , and even if from eggshell, the method uses phosphoric acid solution instead of powder phosphate salts . Thus, as far as the authors know, no mechanochemical process has been reported for the production of calcium and potassium hydrogen phosphate (K3CaH(PO4)2) and potassium calcium phosphate (CaKPO4) from calcite provide by eggshell and KH2PO4, i.e. different structures from hydroxyapatite including potassium as one of the main components. It is in this sense that new technologies of ecological fertilizer production have been prioritizing environmental care using industrial and other potential wastes in the formulation of new products , avoiding unnecessary economic losses, are primarily relevant in the current socio-environmental scenario.