![]() ![]() When the smelting temperature is 1873 K, the slag quantity is 5 wt%, the initial Sb content of the liquid steel is 0.06 wt%, the initial C content is 0.05 wt%, and the slag basicity ( w CaO/ w SiO2) is 5 the effect of CaC 2 content on Sb removal from molten steel is shown in Figure 1. However, the reaction mechanism between CaC 2 and residual element Sb needs to be revealed. Moreover, the cost of CaC 2 treatment is cheaper than other calcium treatment methods. CaC 2 as a refining agent in the steelmaking process can decompose to Ca and C at steelmaking temperatures, and Ca could react with the residual elements in the molten steel. Nevertheless, the elimination of residual element Sb in molten steel is rarely studied. Typically, the Sb contents in ordinary steel grades need to be controlled under 0.05 wt%, and for some special steel grades, the Sb content restriction is lower than 0.01 wt%. Sb can be employed as an alloying element in free-cutting steel, weathering steel, and non-oriented silicon steel however, it is an unfavorable element for most steel grades. Current research concentrates on the residual elements Cu and Sn since they are particularly prevalent in scrap steel. Several studies have found effective techniques for removing residual elements from iron-based melts, including melt filtration, the electric field method, lead solvent method, calcium reaction method (including calcium flux or calcium alloy), sulfide flux method, and vacuum evaporation method. The removal reaction of Sb from molten steel by CaC 2 is a reversible reaction, and the diffusion of the products from the interface is the limiting factor of the overall reaction. An increased initial Sb content in molten steel and slag quantity are beneficial to improving the removal ratio of Sb, but an increased initial C content in molten steel is detrimental to the progress of the Sb removal reaction. ![]() In molten steel, CaC 2 will preferentially react with O and S, and as the smelting temperature decreases, the distribution ratio of Sb, L Sb, improves. ![]() The ”Sb-reversion” phenomenon will appear in the molten steel when the smelting period is progressively extended. When the smelting time is 5~10 min, the removal ratio of Sb from molten steel is at its peak and can reach 45.8%. To remove the residual element Sb in molten steel, the CaO-SiO 2-Al 2O 3 refining slag system containing CaC 2 was used, and the effect of the CaC 2 content in the molten slag, slag quantity, smelting temperature, and initial Sb and C contents in molten steel on the Sb removal ratio in the steel was investigated, and the mechanism of Sb removal by the aforementioned refining slag system was discussed in order to provide some experimental and theoretical basis for industrialization practice. Currently, there are few studies on Sb removal from molten steel. As a result, the above elements are recycled and accumulate in the scrap, which will eventually have a negative impact on the properties of steel. However, the current steelmaking processes cannot efficiently remove the residual elements in the scrap, such as Cu, Sn, As, and Sb. Increasing the use of steel scrap and enhancing its recycling utilization are important strategies for fostering the low-carbon and environmental-friendly growth of the iron and steel industry in China.
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