Modeling of the Chemical and Energy Technological Process of Roasting Ore Phosphate Raw Materials in a Dynamic Dense Layer of a Roasting Conveyor Machine

Physical and mathematical models of the complex energy-intensive chemical-energy technological process of roasting of ore phosphate raw materials in a moving dense layer with cross-feeding of a heat-carrier gas on the conveyor of the roasting machine are presented. Research is carried out in the temperature ranges of the thermal and aerodynamic modes of functioning of the operating roasting conveyor and sintering machines taking into account the macrokinetics of the thermally activated chemical–energy–technological processes of decarbonization. The reason for the influence of the conditions of internal heat exchange in grains of ore material in the reacting dense layer on the macrokinetics of the carbonate dissociation reaction is scientifically substantiated. The proposed model is characterized by complex consideration of a wide range of changes in the parameters of the kinetic equations of the chemical–energy–technological process of carbonate dissociation. An adequacy analysis of the proposed model is presented. A series of computational experiments aimed at revealing the dependence between the heating conditions of ore samples and the degree of decarbonization is carried out. The influence of the temperature dependences of the thermophysical characteristics of raw and burnt ore material and the thermophysical characteristics of the heating gas is established. The influence of the conditions of roasting of ore phosphate raw material on the flow rate and temperature of heating gas on time is found. The temperature distributions of the heating gas and ore material along the layer height at any moment of time and temperature distribution in the elementary measuring unit are determined.