A new type of premelted dephosphorization agent for steelmaking and its preparation method

Abstract

The present invention is a novel premelted dephosphorization agent for steelmaking and its preparation method, the purpose of which is to provide a high-efficiency premelted dephosphorization agent suitable for steelmaking to overcome the defects of the above-mentioned various converter steelmaking dephosphorization materials . The composition and mass percentage of the pre-melted dephosphorization agent of the present invention are: CaO: 25%-40%, Fe2O3: 45%-65%, BaO: 0.1-10% Other impurities (MgO\Al2O3\SiO2)≤5.0 %. The sum of the mass percentages of the above components is 100%; the particle size of the pre-melted slag material is 1-100 mm. The composition of the pre-melted slag of the present invention is uniform and stable, has a low melting point (1210°C-1260°C), suitable viscosity (at 1400°C, 0.01-0.05Pa·S), good fluidity, and fast melting speed; creating a fluorine-free melting point Low and efficient dephosphorization and stable dephosphorization materials for steelmaking, the terminal phosphorus can reach below 0.004%.

Description

Technical field [0001] The invention belongs to the technical field of metallurgy, and is a pre-melted dephosphorizer used for removing phosphorus from steel and reducing the phosphorus content in molten steel in a steelmaking process and a preparation method thereof. Background technique [0002] Phosphorus is usually a harmful element in steel, because the high phosphorus content of steel will cause steel to produce cold brittleness and affect certain mechanical properties of steel, so it must be strictly controlled. In traditional technology, the phosphorus in steel is generally required to be controlled below 0.012%. With the improvement of the mechanical performance requirements of certain steel grades, the phosphorus in some pure steel and ultra-low phosphorus steel must be controlled at about 0.005%, or even 0.003% or less. In order to achieve this goal, most steel mills adopt the "double slag method" that is twice slagging in the converter smelting or the "two-step metho...

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Problems solved by technology

[0004] Chinese patent (patent No. 99112573.8) discloses a kind of iron scale slag agent mainly composed of FeO, which consists of: iron scale 70-90%, ironmaking sludge 5-25%, binder 1-5 %, the raw materials are crushed, configured, mixed and pressed into balls. The effect of iron scale slag removal agent is more obvious, but it has serious corrosion on the furnace lining, which makes the temperature drop of molten steel large, and the action time is short and cannot continue to remove slag, etc. question

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