Pre-molten synthetic slag and converter tapping reverse wash-heat method using same

Abstract

The invention discloses pre-molten synthetic slag and a method for carrying out reverse wash-heat on molten steel from converter tapping by using the pre-molten synthetic slag. The pre-molten synthetic slag comprises the following components in percentage by mass: 5-10% of Al, 16-20% of Al2O3, 28-32% of CaO, 11-15% of MgO, 8-12% of CaF2 and 3-7% of SiO2, and the remnants are inevitable impurities. According to the method for carrying out reverse wash-heat on the molten steel from converter tapping by using the pre-molten synthetic slag, ferro-aluminum is adopted for deoxygenation, the whole ferro-aluminum and a half of the pre-molten synthetic slag are flatly paved and fed to the bottom of steel ladles before tapping, the rest pre-molten synthetic slag is uniformly added through a chute along with the steel flow in the 0-1/4 process of tapping, then the pre-molten synthetic slag captures the Al2O3 impurity in the floating process so as to wash and heat the molten steel.

Description

technical field [0001] The invention belongs to the technical field of converter steelmaking. Specifically, the invention relates to a method for washing molten steel with slag during the tapping process of the converter. Background technique [0002] At the end of converter smelting, molten steel contains about 200-1000ppm of dissolved oxygen. Usually, deoxidation and removal of inclusions are carried out by deoxidizing steel in converter + LF / RH refining. The specific process is: put 1 / 4 to 3 / 3 of steel in converter 4 Add aluminum, silicon and other deoxidizers for deoxidation during the process. When the steel is nearing the end, some high-oxidizing converter slag is put into the ladle with the steel flow, and then after the ladle enters the refining station, according to the oxidation of molten steel and steel slag , add lime, deoxidizer and other slagging materials, electrify the slag, and use the method of blowing argon at the bottom of the ladle during the refining pr...

AI Technical Summary

Problems solved by technology

However, due to the use of refining stations for final deoxidation and removal of inclusions in this process, the equipment cost, power consumption, and electrode loss increase the production cost by about 20-50 yuan/ton of steel, and due to the carbon increase of the electrode, it is impossible to produce ultra-low carbon steel

[0003] In order to reduce the cost increase caused by refining molten steel, a series of slag washing materials and slag washing technologies have been developed in recent years, which can partially replace LF refining furnaces. For example, Chinese invention patents with patent numbers ZL200910096625.1 and ZL200910096624.7 Disclosed is a heating common steel slag washing material and heating direct slag washing material used in converter steelmaking and its preparation method and use method.

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