In this paper, the possibility of introducing slag in the fiery-liquid state into the metallurgical cycle with the production of different products depending on the processing technology (binders, slag, pumice, etc.) is considered. The scientific substantiation of the processing of slag melts by crushing a slag stream in order to obtain granules of a certain size is considered, and the process of deformation and crushing (decay) of a slag stream during interaction with the energy-carrying phase - high-speed gas (air) stream is analyzed. It has been established that under conditions of dynamic interaction with an air high-speed flow, the slag jet in the deformable section behaves like a quasi-elastic body, exhibiting properties characteristic of a solid, which explains the destruction of the jet under the action of a longitudinal tensile and deforming slag stream due to the pressure of the gas stream. Taking into account it the sizes of destroying pressure and corresponding for this purpose speed of current of air are set depending on a temperature and diameter of stream of slag fusion. It was found that the pressure and air flow rate increase with increasing diameter of the slag stream and decrease with increasing temperature of the slag. The got performances hired can be used for the choice of optimal parameters of slag fusion and energy-carrying phase at development of technological processes of processing of metallurgical slags with the forecast receipt of friction composition of eventual products. Mathematical models are neat for the got dependences with approximation of dependence of maximum pressure of current of air from the physical parameters of slag fusion and the quadratic is got and sedate to dependence with the high coefficient of determination, exceeding 0,98