Preparation of analogs of minerals pollucite and sphene by metallothermal self-propagating high-temperature synthesis (SHS) was studied with model systems. These analogs are intended for immobilizing silica gel fixed cesium and strontium radionuclides, respectively. The optimal conditions for SHS were found, and the phase compositions of the reaction products were studied. In synthesis of pollucite, the energy-forming components are Al and Fe2O3, and in synthesis of sphene, Ti and MoO3. The mineral analogs synthesized are distinguished by high hardness and chemical stability. Virtually no cesium is lost by evaporation.