Influence of electromagnetic field on characteristics of crushed materials

Building Materials

This paper describes the findings of a study into the impact of the magnitude of induction and the frequency of rotation of an electromagnetic field on the properties of materials (Portland cement, gypsum plaster, limestone), which are treated in the vortex layer machines. The effects were assessed based on the following criteria: 1) the location of the maximum values of the specific surfaces in the factor space as determined by the Tovarov method based on the BET method and the temperature of the model powders following treatment in a vortex layer machine; 2) the symbasis of the change in the values of the specific surface as determined by the BET method and the temperature of the powders following activation. Theoretical and experimental studies have been used as a basis for putting forward the concept of treatment in vortex layer machines. The essence of the concept lies in boosting the defectiveness of particles (i.e. accumulation of defects) followed by defects emerging and particles dispersing. The maximum values of specific surfaces and of the temperature of powder upon activation can be obtained at an electromagnetic field rotation frequency of 66 Hz while the material being treated is mechanically activated at an electromagnetic field induction value of 0.21 T with Portland cement, 0.22 T with gypsum plaster and 0.23 T with limestone. A classification to define the susceptibility of the mineral component to treatment inside vortex layer machines has been proposed.