Desulfurizing smelting method for ultra low sulfur pure iron

Abstract

The present invention provides a desulfurizing smelting method for ultra low sulfur pure iron, and the method comprises the following steps: smelting a raw material in an electric furnace, and controlling complete deslagging is performed after Si content reaches 0-0.50% and P content reaches 0-0.005% in an oxygen melting period step; after the deslagging is complete, tapping in the manner of eccentric bottom tapping, and adding an aluminum ingot into a steel ladle along a steel flow according to the dosage of 3.0-4.5kg / t; performing LF smelting, in the LF refining process, using a CaO + CaF2 + Al2O3 slag system for desulfurization; and casting after composition and temperature of molten steel meet requirements. Aluminum as a desulfurizing agent and the CaO + CaF2 + Al2O3 slag system as a refining slag system are used for the desulfurization, and special safety and protective measures are not needed in processing, transportation, storage and use processes.

Description

technical field [0001] The invention relates to a desulfurization smelting method of ultra-low sulfur pure iron, in particular to the technical field of iron and steel smelting. Background technique [0002] Ultra-low sulfur pure iron has high resistance to hydrogen-induced cracks and sulfur stress cracks, and it is required to control the sulfur content in steel to ≤10×10 -6 . Thereby ensuring that pure iron reaches the level of ultra-low impurity elements to meet the production needs of secondary hardened steel, precision alloys with high purity requirements, advanced blade steel and stainless steel. [0003] The steps of the existing commonly used production method are: (1) carrying out EAF (electric furnace) smelting of raw materials; (2) LF (ladle furnace) smelting; (3) VD (vacuum degassing furnace) furnace vacuum degassing; (4) Tapping and casting. In this manufacturing method, complete slag removal is carried out after the silicon and phosphorus content reaches the...

AI Technical Summary

Problems solved by technology

[0007] One is due to the fine particles of CaC 2 (Carbide) particle diameter is 0.1 ~ 1.0mm, it is very easy to react with water and moisture in the air, and its product C 2 h 2 (Acetylene gas) is flammable and explosive, endangering safety;

[0008] Second, calcium carbide is easy to weather, and there will be a certain loss during storage and transportation, especially in the southern region where our company is located, where the air humidity is high, and there will be greater loss;

[0009] Third, calcium carbide can only remove the oxygen in the slag for indirect desulfurization, while the dissolved oxygen and oxides in the steel can only diffuse into the slag to react with the calcium carbide

Moreover, BaO is a highly toxic toxic substance, which is harmful to human health if inhaled or ingested, and is not conducive to on-site production

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