2015 Volume 55 Issue 7 Pages 1390-1397
In order to increase the heat efficiency of the chromium ore smelting reduction furnace, a heated ore addition technology using a burner in the converter was developed. 5 ton scale pilot converter tests were conducted. Based on the results of the pilot converter tests, this technology has been applied to the actual process. The results are summarized as follows:
1) Compared with the conventional process (without burner), the amount of effective heat transfer increased by 18% with addition of heated ore using the burner in 5 ton converter.
2) A decrease in the off-gas temperature and reduction of the thermal load on the refractory were also confirmed in 5 ton converter.
3) The heat transfer ratio of burner combustion with addition of heated ore increased up to about 90%, depending on the increase of the ore feeding rate in 5 ton converter.
4) From the results of a numerical simulation, it was revealed that the total sensible heat of all particles increases as the ore feeding rate increases. As a result, the ore particles heated by the flame function as a medium of heat transfer from the flame to the molten metal and slag.
5) This technology was applied to an actual smelting reduction furnace at JFE Steel East Japan Works (Chiba). As in the tests with 5 ton converter, the heat transfer ratio of burner combustion with addition of heated ore was about 90%. The supplied energy per unit of chromium ore added to the furnace decreased by 17%.