THERMODYNAMIC STUDY OF UTILIZATION OF SAWDUST FROM PINE-WOOD IN THE IRON-ORE SINTERING PROCESS

The aim of this study was to evaluate, from thermodynamic point of view, the possibilities of sawdust from pine-wood utilization in iron-ore sintering process. Sawdust from pine-wood with standard coke breeze were studied as sintering fuels. Materials used in this study were subjected to chemical and physical analyses typically used for coal and coke characterisation. Sawdust from pine-wood has lower content of fixed carbon and higher volatile matter content. Sawdust from pine-wood has relatively low calorific values (17,39 MJ/kg) compared with coke breeze (28,16 MJ/kg). It can be observed from the chemical analyses that sawdust from pine-wood has lower sulphur level and much lower ash content, in comparison with the coke breeze. In order to visualize feasibility of individual reactions depending on temperature, Gibbs equilibrium diagrams were calculated by thermodynamic modeling program HSC Chemistry 5.11. From analysis of fuels burning reactions follows, that the highest temperatures in the sintering bed (experimental about 1200 - 1260 degrees C) are achieved with the coke breeze. Combustion of higher amount of volatile matter in sawdust from pine-wood leading to the lower maximum temperatures in the sintering bed (experimental about 900 - 1150 degrees C). It was found that less of this energy would be available in sinter making due to the evaporation of some of the volatile matter ahead of the flame front. Overall the results suggest that it is realistic to substitute maximum 10% of coke breeze with sawdust from pine-wood in the iron ore sintering process.