OUT-OF-FURNACE DESULFURIZATION OF HOT METAL AT UKRAINIAN METALLURGICAL PLANTS

摘要

Expansion of steel continuous casting is accompanied by stricter constraints on sulfur content. At present, most specialists regard out-of-furnace desulfurization of hot metal as an essential element in the production of low-sulfur steel in converter and open-hearth shops. The need for out-of-furnace desulfurization capacity is especially pressing when blast furnaces operate on high-sulfur coke, which is typical of Ukraine. Nevertheless, in recent years, the number of departments for out-of-furnace desulfurization of hot metal (DODHM) at Ukrainian enterprises has significantly declined. Currently, the only facilities with this capacity are Metallurgicheskii Kombinat Azovstal Joint Stock Company, Mariupol'skii Metallurgicheskii Kombinat im. Il'icha Joint Stock Company, and Krivorozhstal Metallurgical Works. Therefore, we may expect many plants to prioritize the construction or reconstruction of DODHM in the near future. We know that DODHM are usually employed for two purposes. The first applies to enterprises where the blast furnaces run on highly basic slag. In this case, only the part of the hot metal for smelting high-stress steel is treated, with reduction in sulfur content from 0.02-0.04 to 0.005-0.010 percent or less. In addition, with disruption of blast-furnace operation, unconditioned steel is processed in the DODHM, to obtain a residual sulfur content of 0.025-0.035 percent. For furnaces operating on slags of low basicity, the DODHM removes the sulfur from all the smelted hot metal, with reduction in sulfur content from 0.06-0.12 to 0.025-0.035 percent, or less if necessary.