Reduction of mixtures of el dekheila fine pellets waste and mill scale with hydrogen and coke / Eman Mohamed Abdelhamid Ramadan ; Supervised Magdi Fouad Abadir , Hanem Abdelrahman Sibak , Shereen Kamel Amin

Thesis (Ph.D.) - Cairo University - Faculty of Engineering - Department of Chemical Engineering

Iron pellets are used in the production of steel at the El-Dekheila plant, West of Alexandria on the Northern coast of Egypt. A fraction of these pellets, reaching up to 10%, is lost by breakage on handling. The main aim of this thesis is to investigate the reduction of iron pellets waste with different percentages of mill scale in form of briquettes using hydrogen gas and coke breeze. The briquettes were sintered at temperature 1150oC to be then reduced using hydrogen. The maximum reduction was found to occur in samples containing between 20-50% mill scale. The reduction process was found to be controlled by reaction at interface between hydrogen and solid particles. The activation energies of reduction at 20, 50 and 80% mill scale were found to be 28.78 kJ.mol-1, 33.44 kJ.mol-1, and 34.02 kJ.mol-1 respectively. The second part of thesis studied the reduction of briquettes using coke breeze. The results showed that the best reduction can be reached using 2:1 stoichiometric coke, above which cementite (Fe3C) is formed as proven by XRD. The best reduction reached was 85% after 80 minutes using 20% mill scale. The reduction process was found to be controlled by nucleation and grain growth of the produced phases (Avrami- Erofeev model). The activation energies of reduction ranged from 170 kJ.mol-1 to 252 kJ.mol-1 depending on the level of mil scale used

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