Production of direct reduced iron by a sheet material inserting metallization method

Abstract

A new process for producing DRI called SMIMET (Sheet Material Inserting Metallization method), in which a sheet of material consisting of a coal and iron ore mixture is inserted in a rotary hearth furnace, is proposed here and basic experiments were operated. 4 types of iron ore and of coal were used in these experiments. One type of iron ore and one type of coal were mixed with water, and were formed into a sheet of material on a tray. The sheet was inserted into an electric furnace and reduced at 1373-1573K. Obtained results are summarized as follows:1) Over 90% metallization was achieved by increasing the coal ratio to over 20%.2) Temperature doesn't affect reduction very much at 1473K or more, but CO2 had great influence on it.3) Metallization of the sheet material is the same as that for green pellet made of the same material.4) A higher degree of metallization was achieved by using smaller particles of coal and iron ore.5) Metallization of the sheet was not affected by the various characteristics of the different type of ore. A higher degree of metallization was accomplished by using coal with less volatile matter.6) DRI (metallization degree=93%, fragment size=5-20mm) was produced from a sheet of material (1910dry-kg/m3, moisture=10.6%, thickness=10mm) reduced by 12.5min at 1273-1573K.