ŚLĘZAK Wojciech AGH-University of Science and Technology


The cohesive zone is amongst the most important areas within the blast furnace. It is limited by isotherms of the beginning and the end of softening of the burden materials. Both the oxide phase and the metallic phase melting processes start within this particular area. The gas flow, and effectively the efficiency of the blast furnace process, depends on the location and shape of the cohesive zone. A number of tests that are described in the subject literature has been performed in order to determine the temperatures of the beginning of softening and melting of iron ores and agglomerates. The authors of this paper used an FRS 1600 high-temperature aparatus. This allows to precisely measure the force applied, the temperature, and the sample height changes. The applied device is intended mainly for tests of rheological parameters. However, its measuring capabilities allow it to be used also for material softening tests. Iron ore in the form of pellets, and agglomerate, were used for the measurements. The samples were placed in a graphite crucible shielded with argon. The sample material was subjected to the pressure of a spindle with a normal force of 19.6 N, while at the same time changes in the sample height as a function of temperature were recorded. Immediately after the softening measurement, the burden material viscosity changes, along with the temperature growth, were measured.