The equilibrium compositions of multi-component heterogeneouse systems N-Al-O-Ca-Mg. Cu-Zn-Al-O and Fe-Al-K-Ca-Si-O in gaseous and condensed state are established. Further, we have developed a three-dimentional model dealing with the motion, heating, melting and evaporation (thermal destruction) of micron-size particles-(5-60 mum-Fe, Fe2O3, Fe3O4, FeO, Ni, NiO, Cu, Al, Al2O3, CaO, Mg, MgO) in an axial-symmetric plasma-chemical reactor (PCR). Based on the model calculations, we have designed and build plasma-chemical installations and used them to study the mechanisms of preparation of catalysts (and regeneration of spents of deactivated catalysts) for reforming of natural gas (steam conversion of CH4), for low-temperature steam conversion of CO and for synthesis of NH3. A physical-chemical analysis of plasma-chemically synthesised (PCS) and/or regenerated ultra-dispersed catalysts in electric-arc low-temperature plasma conditions has been performed by X-ray structural and phase analysis, electron microscopy, Mossbauer spectroscopy, derivatographic, thermal-magnetic, chemical and analytical methods, by studing the dynamics and kinetics of formation of the active surface due to the reduction (the "plasma" catalysts undergo reduction 2-5 times faster than their respective commercial analoges and show activity by 15-20% higher than that of the conventional catalysts).