secondary refining cycle, the time required for slag feeding, gas strong stirring and intensified desulfurization accounts for about 1 / 4 ~ 1 / 2 of the refining cycle. Therefore, how to shorten the slag forming time and accelerate the interfacial reaction between slag and steel is of great significance to shorten the refining cycle of ladle furnace. The premelted refining slag has the advantages of uniform composition, low melting point and fast melting speed, which can shorten the smelting time,
Compared with the sintering refining slag, the premelted refining slag has the following characteristics: 1. For the same slag composition, the average melting temperature of the premelted refining slag is obviously lower than that of the sintering refining slag, which can be reduced by about 40 ℃. 2. The composition of premelted refining slag is uniform, the fluidity of molten slag is good, the comprehensive metallurgical effect of deoxidization, desulfurization and adsorption of impurities is better than that of sintering refining slag, and the desulfurization rate of premelted refining slag is obviously higher than that of sintering refining slag (for example, after the application of premelted refining slag in the furnace of Tianjin steel pipe plant, the average desulfurization rate increases from 71% to 89% of the original sintering refining slag). 3. The melting point of premelted refining slag is low and melting speed is fast, which greatly shortens the secondary refining time, thus shortening the whole smelting time, improving the quality of molten steel, reducing slag consumption, refining power consumption and ladle refractory consumption. 4. The premelted refining slag can be pre melted to form uniform compound in advance, which makes it have strong homogeneity of composition, stable performance, no moisture absorption, and is convenient for storage and long-distance transportation. 5. The premelted refining slag can be broken into slag with certain particle size after remelting treatment. It is not easy to produce dust in the process of use and transportation, which greatly improves the production environment of refining workshop.