The physicochemical research of ammonium fluoride processing of ash and slag waste is performed as a case-study of ash waste of Blagoveshchensk thermal station and fly ash of Amur experimental technology facility. The optimized conditions are determined for some reactions, including fluorination of feedstock in the temperature range of 50–200 °C, sublimation of ammonium hexafluorosilicate at 350–550 °C, as well as production of amorphous silica, fine-grain alumina, red iron-oxide pigment and calcium fluoride. The basic distribution patterns of rare earths, including Sc and Y, during ammonium fluoride processing are determined. The authors have developed the effective innovation technology for various ash and slag waste processing with extraction of ore microconstituents.