Abstract
This study proposes physical and mathematical models of the chemical–power technological process of roasting of a dispersed ore phosphate material in a moving dense multilayer mass on a conveyor of a roasting machine with a cross-supply of the heat-carrier gas. A computational model is developed on the basis of the constructed models, on which computational experiments are performed to study the influence of the thermophysical characteristics of ore raw materials on the efficiency of roasting. The extent of the influence of the thermal conductivity coefficient of ore phosphate materials on the energy efficiency and completeness of thermally activated endothermic reactions of carbonate dissociation is established. The method based on using the multilayer polyfractional charge of ore dispersed raw materials on the grate of the roasting machine conveyor for vigorously influencing the efficiency of the chemical–power technological process of roasting is scientifically substantiated and confirmed in computational experiments. It is established that the changes in the temperature of the heat-carrier gas in the dense layer and at the outlet from it, the roasting efficiency, and the uneven decarbonization along the height of the dense layer of the thermally processed ore raw materials depend substantially on the thermophysical characteristics. As found from the results of computational experiments, the use of polyfractional filling of ore phosphate raw materials on the conveyor of the roasting machine under the prescribed roasting conditions leads to a decrease in the temperature of the exhaust gases, and to an increase of average degree of decarbonization of the layers in raw materials. It is found that the use of polyfractional filling changes the dependence of the heat-carrier-gas temperature on the layer height coordinate.