Method for refining size of free magnesium oxide in ladle furnace slag

Abstract

The invention discloses a method for refining the size of free magnesium oxide in ladle furnace slag. The method comprises the steps of adding an appropriate amount of grain growth inhibitors into theladle furnace slag, and raising temperature to enable the ladle furnace slag to be in a molten state; in the process of slag liquid flowing out through a chute, conducting air quenching and rapid cooling treatment for the ladle furnace slag with high-pressure high-speed air; collecting ladle furnace slag particles treated by air quenching by a rotary cooling drum, and conducting secondary outer-drum water circulating cooling; and finally, collecting the treated ladle furnace slag. The method conducts primary air quenching cooling and secondary outer-drum water circulating cooling for the molten ladle furnace slag and is supplemented by the effect of the grain growth inhibitors, so that the average size of free magnesium oxide in the treated ladle furnace slag is reduced by one order of magnitude, and small size and high activity are maintained. The method is very helpful to improve the volume stability of the ladle furnace slag used as a gelling material for building materials, and promote the efficient resource utilization of the building materials.

Description

technical field [0001] The invention relates to the technical field of resource utilization of ladle furnace refining slag, and more specifically relates to a method for refining the size of free magnesium oxide in ladle furnace steel slag. Background technique [0002] Ladle furnace refining slag is a smelting by-product produced by using a ladle refining furnace to refine scrap steel or crude steel. According to statistics, for every 1 ton of molten steel refined, 20-50kg of ladle furnace slag needs to be discharged. As my country's steel is accelerating into the depreciation era and my country's huge demand for special steel / high-quality steel, the demand for scrap steel and crude steel refining has grown rapidly year by year (in 2017, my country's scrap steel depreciation volume and crude steel output reached 200 million tons and 830 million tons respectively tons <China Iron and Steel Association, National Bureau of Statistics data>), also produces a large amount o...

AI Technical Summary

Problems solved by technology

[0005] At present, since scrap steel and crude steel refining enterprises have not specially treated the discharged ladle furnace slag, natural cooling is generally used to cool it down and then discharge and accumulate, resulting in dense crystallization of f-MgO and coarse grains; for converter steel slag, currently Generally, heat braising treatment process is used to digest part of f-CaO and f-MgO in converter steel slag in advance to reduce its content, but the water in this method will undergo hydration reaction with part of the cementitious minerals in advance, which will reduce the steel slag to a certain extent. activity, especially C in ladle furnace slag 12 A 7 Minerals and water react rapidly, and if this method is adopted, the gelling activity of ladle furnace slag will be significantly reduced, so it is not suitable for the ladle furnace steel slag targeted by the present invention

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