EFFECTIVE USE OF HYDROGEN WITHIN COAL IN PRE-REDUCTION OF IRON OXIDE FOR MINIMIZING THE AMOUNTS OF COAL USED AND CO_2 EXHAUSTED IN AN IRON BATH SMELTING REDUCTION PROCESS

摘要

To minimize the amounts of coal used and CO_2 exhausted in an iron bath smelting reduction process, conditions for effective use of volatile matter (VM) in the pre-reduction of iron oxide were examined; 1 kg coal having 36.5 mass% VM was carbonized under rising temperature conditions up to a maximum temperature ranging from 873 to 1273 K and 2 kg iron oxide pellets packed in a separate reactor were reduced with this gas except tar at a constant temperature equal to the maximum carbonization temperature (called here "processing temperature" T_P). The results are (1) In the cases of T_P=873 and 973 K, VM does not release enough, but in the cases of Tp=1073 K and more, VM releases up to about the amount of proximate analysis: (2) Hydrocarbons are considered to decompose into hydrogen and carbon or carbon monoxide through cracking or reforming reactions in the reduction reactor at higher temperatures and to contribute to the reduction reactions: (3) Fractional reduction F increases linearly with Tp as F=0.00091T_P-0.73: (4) As T)P rises, contribution of hydrogen to the reduction reactions increases from 40% to 60%.