Crystal structure of Mongolian phosphorite minerals and mechanochemistry

We have carried out crystal structure investigations of natural and mechanochemically activated samples of Burenkhan, Tsakhir uul and Aldarkhan phosphorite deposits (The Nord Mongolia) by X-ray, neutron and synchrotron powder diffraction techniquies. We have determined the exact mineral contents of the phosphorite ore and crystallochemical formula of each mineral. It was established that natural samples of Tsakhir uul and Aldarkhan phosphorite deposits contain flourite (CaF₂) among the main ore minerals (Ca₅(PO₄)₃F and SiO₂). However, in the sample of Tsakhir uul amount of CaF₂ is more than in the Aldarkhan sample. It was shown that as a result of mechanochemical activations any new crystal phases formed. However, occured strong distortion in the crystal lattice of flourapatite, especially, in the PO₄ -tetrahedrons that possibly lead to increasing of the lattice energy and to better solubility of apatite after mechanochemical activation.