2006 Volume 92 Issue 12 Pages 825-832
A new DRI process named SMIMET (Sheet Material Insertion Metallization Method), which a wet and dense sheet material of coal and iron ore mixture is reduced in RHF (rotary hearth furnace), was proposed. Binder addition and pelletizing process were omitted in this process. The fundamental and bench scale tests of it were carried out. In these tests, the raw materials were formed into the sheet shape samples by hand or sheet forming machine. Then, sheets were reduced at 1573K in air atmosphere. The produced DRI formed into briquettes at 1273K in Ar atmosphere or at room temperature. After that, the softening-melting down tests were carried out. As a result, sheets contained higher F.C. coal smashed when they were heated rapidly. Sheet smash was controlled by decrease of the apparent density of the sample. Also, higher metallization degree DRI were produced when hematite are and/or higher F.C. coal was used. The influence of sheet thickness on the productivity was greater than that of apparent density of it. Therefore, the sheet thickness should be decreased when the higher F.C. coal was used to increase the productivity. In addition, the permeability of the softening-melting down tests was affected by the porosities of briquettes. It is believed that the strength of DRI increased when it was formed into briquette so that the temperature, which DRI began to soften and melted, was raised.