EVALUATION OF THE PRESSURIZATION ON THE HEATING AND COOLING STAGES OF METALLURGICAL TESTS IN IRON ORE PELLETS

Various gases are used in Samarco's laboratory, which are responsible for promoting the reactions during the metallurgical tests. The consumption of these gases contributes significantly to the total cost of the lab. Among these gases, there is nitrogen, used in most metallurgical testing to promote an inert atmosphere within the retort during the heating and cooling stages. In order to reduce this consumption, it was suggested that we should perform some metallurgical tests by pressuring those steps. Through a sequence of tests and statistical basis, it was evaluated that the impact of this change in the following tests: Reducibility (ISO 7215), Low Temperature Degradation (ISO 13930) and Midrex Linder Test (ISO 11257). The tests showed no statistical difference when comparing the results obtained from those using the ISO method and those obtained by pressuring the heating and cooling steps. In addition to the nitrogen, this change also allowed for a reduction to the total time of the tests, with a consequent reduction of other gases. Finally, this modification would facilitate a detection of leaks before running a test, thereby increasing the safety of the Metallurgical Laboratory activities. Depending on the results obtained, it will be proposed that the ISO committee a more detailed study of these changes, with a possible interlaboratorial test.