DIRECT REDUCTION OF IRON-ORE FINES IN A F LUIDIZED-BED USING HYDROGEN-RICH GAS

Objectives. During the direct reduction of ore fines in fluidized bed reactors process problems may occur. Under the presence of certain pro cess conditions the material may stick together (sticking) or will for m accretions on the reactor wall (plating). The aim of this work is to develop test equipment for the simulation and investigation of these process problems. Variating several parameters it is investigated how those factors are influencing sticking and plating in a fluidized bed. Several suggestions are given to avoid or decrease the tendency of st icking and plating. Summary. The fluidized bed technology is a process which will increase the importance for Direct Reduced Iron (DRI) prod uction in the future. The Fior plant in Venezuela is the only working plant based on this principle. Other plants are right now under constr uction like the Fior II plant (Venezuela), Finmet (Australia) and Circ ored process (Trinidad). Due to in some regions sufficiently occuring natural gas resources, the reduction with hydrogen rich gas produced b y steam-reforming offers an attractive possibility. Problems during th e process caused by swelling of the ores and the connected degradation are not expected. The sticking and plating was investigated with the help of a special electron scanning microscope with additional hot sta ge attachment and a laboratory fluidized bed. Parameters varied were t ime, temperature, grain size, type of ore, number of reduction steps, additions to the ore and choice of suitable material. After the evalua tion of the results precautions were developed to avoid or decrease th e tendency of sticking and plating in fluidized bed reactors working w ith hydrogen gas for the reduction of fine ore.