Structural changes in the system natural apatite - NH 4 clinoptilolite during triboactivation

The tribochemical activation of natural phosphate-clinoptilolite mixtures facilitates the transitions of hardly assimilated by plants P2O5 forms into readily assimilated ones. Thus this approach is a solution of ecological and stuff problems, aiming to increase the transition of P2O5 into assimilated by plants form. Mixtures of Tunisian phosphorite and NH4-exchanged clinoptilolite from Beli plast deposit (Bulgaria) (in different ratio) were activated in a planetary mill. Structural changes in the mixtures during activation result in increasing of P2O5 solubility. These changes were studied by XRD and IR spectroscopy. The obtained results show ion-exchange reactions between natural apatite and NH4-clinoptilolite and deformation or rapture of Si-O-Si and Si-O-Al bonds in the clinoptilolite structure on one hand, and defectiveness and isomorphism in the apatite structure on the other.