Hard-baking of pellets containing iron oxide - with successive utilisation of exhaust heat of the process

摘要

Pellets contg. iron oxide are baked hard by flow of hot gases through the pellet bed, with subsequent cooling by means of cooling gases. The method includes the following characteristic features: (a) cooling air is introduced into the rear of the cooling section (K) through the line (1); (b) a part of the heated cooling gas extracted via the line (2b) is mixed with a part of the exhaust gas arriving from the thermal treatment section via the line (4); (c) the resulting mixture is supplied to the drying section (D) via the line (2a); (d) the exhaust gas from the drying section is mixed with exhaust gas from the thermal treatment section via the lines (6, 7) and supplied to the front of the cooling section via the line (5a); (e) the exhaust gas from the front of the cooling section is directed into the thermal treatment section; (f) a part of the exhaust gas exiting the thermal treatment section is supplied to the suction drying section after the pressure drying section and into the heating zone; and (g) the exhaust gas of the pellet combustion machine are removed from the suction drying section or the suction drying section and at least the beginning of the heating zone. USE/ADVANTAGE - For pelletisation of iron ores. The process is carried out with low heat consumption, with economical removal of harmful constituents from the exhaust gases.