Sulfur fixing agent without slag accretion agent for magnesium spraying and deep desulphurizing for molten iron , and desulphurization process thereof

Abstract

Disclosed is a slag conglomeration agent-free sulfur-fixing agent for magnesium-spraying deep desulfurization in the hot metal pretreatment as well as a desulfurization process thereof, belonging to the technique field of hot metal pretreatment in the steelmaking process. The materials of the sulfur-fixing agent include quicklime, light-burned dolomite and fluorite; and are present in weight percentage: quicklime: 57 to 80 percent, light-burned dolomite: 15 to 35 percent, and fluorite: 0 to 8 percent; and chemical constituents of the sulfur-fixing agent comprise, in weight percentage: CaO: 55to 80 percent, MgO: 5 to 25 percent, SiO2: 0 to 9 percent, CaF2: 0 to 8 percent, Al2O3: 0 to 3 percent, MnO: 0 to 2 percent, K2O: <0.30 percent, Na2O: <0.01 percent, S: <0.025 percent, and P2O5: <0.1percent. The materials are added before hot metal charging or in the hot metal charging process of the hot metal pretreatment. Slag of the sulfur-fixing agent added with molten iron for magnesium-spraying pretreatment has strong capacities of sulfur adsorption and fixation, and has rather high viscosity and melting point, is easy in accumulation and agglomeration, the direct slag skimming can be implemented without adding slag conglomeration agent, meanwhile, the resulfurization caused by adding generally adopted acid slag conglomeration agent can be prevented.

Description

technical field [0001] The invention relates to the technical field of molten iron pretreatment in the steelmaking process, and in particular provides a slag-free sulfur-fixing agent and a desulfurization process for molten iron pretreatment of magnesium spraying deep desulfurization, which is suitable for molten iron spraying magnesium desulfurization, especially for deep desulfurization Process optimization for desulfurization. Background technique [0002] At present, the pretreatment desulfurization of molten iron mainly includes the input method, the method of rotating and stirring the molten iron container, the method of mechanical stirring with a stirrer, and the injection method. Especially in recent years, injection has been widely used. It is a desulfurization method that sprays into the deep part of molten iron to stir the molten iron and desulfurizer fully. Commonly used desulfurizers include lime powder, calcium carbide powder, soda powder, metal magnesium, an...

AI Technical Summary

Problems solved by technology

At present, the use of passivated metal magnesium particles is the trend of desulfurization agent. It has the advantages of small dosage, small amount of slag, high desulfurization efficiency, and lower temperature. At present, it is widely used to increase the viscosity of slag by adding an acidic slag accumulator after the injection, but this will change the composition of the slag system, easily cause sulfur reversion and deteriorate the desulfurization effect, so it is necessary to improve the existing technology