MANUFACTURE OF CHROMIUM STEEL BY USING HIGHLY REDUCED CHROMITITE

摘要

PURPOSE:To effectively use inexpensive chromium raw material, by charging chromitite reduced so that metallization ratio is regulated to a specific value or above into a refining furnace and then adding a flux so that sum total of Al2O3 and MgO and the ratio of CaO to SiO2 are regulated to specific values, respectively. CONSTITUTION:A highly reduced product of chromitite reduced so that metallization ratio of chromium is regulated to =70% is charged, without completely separating gangue minerals in advance, into a top and bottom blown converter- type refining vessel. At this time, a flux is added so that sum total of Al2O3 and MgO introduced from adhering gangue minerals is regulated to [(T-1,750)/10+20](%)-[(T-1,750)/10+50](%) (where T means absolute temperature) in formed slag and the ratio of CaO to SiO2 is also regulated to 0.5-2.0. By this method, stainless steel refining costs can be remarkably reduced without hindering productivity.