Method for converter steelmaking by LF (Ladle Furnace) refining furnace reducing slag

Abstract

The invention provides a method for converter steelmaking by LF (Ladle Furnace) refining furnace reducing slag. The method comprises the following steps of: cooling the reducing slag to 850 plus / minus 30 DEG C, crushing the reducing slag into slag blocks with the diameters of 50-80mm, and loading 300-360kg of slag blocks into a scrap steel hopper of a converter; during smelting, adding scrap steels and the reducing slag into the converter, and then adding 105-115 tons of molten iron, wherein the temperature of the molten iron is 1250-3500 DEG C; after feeding of the converter is finished, carrying out converting by a lower gun of the converter, controlling an oxygen flow to be 15000m<3> / h, adding 2.0 tons of limes and 2.5 tons of dolomites when converting is implemented, adding 1.0 ton of limes and 0.5-1.0 ton of dolomites after the limes and the dolomites are added for 3min, adding the oxygen flow to reach 22000m<3> / h, implementing a decarbonization and temperature rising stage, maintaining for 7-12min, and then carrying out deslagging and steel tapping to finish the once melting in the smelting process.

Description

technical field [0001] The invention relates to the utilization technology of reduced slag of LF refining furnace, which is used as a slag reducing agent in converter steelmaking, can solve the pollution problem of white slag in LF refining furnace, and reduce the usage amount of fluorite at the same time. Background technique [0002] LF refining furnace reduction slag, mainly divided into CaO-MgO-SiO for smelting silicon-killed steel 2 Slag system, CaO-MgO-SiO for smelting aluminum-killed steel 2 The slag system has the following characteristics: 1) Since one of the main components of refining furnace white slag is dicalcium silicate, when the temperature is lower than about 675°C, γ-C 2 S→β-C 2 The crystal transformation of S, accompanied by a 5% volume change, is the so-called pulverization phenomenon in the study, which seriously pollutes the environment. 2) A large amount of CaO and SiO exist in the LF furnace refining reduction slag 2 、Al 2 o 3 And MgO are the m...

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Problems solved by technology

[0003] Retrieval literature disclosure: (1): He Huanyu et al. "Research on Phase Composition and Formation Mechanism of LF Furnace Refining Waste Slag" in Wuhan University of Science and Technology Journal 2008 (No. 5) described that the composition of LF furnace refining waste slag belongs to the calcium aluminate slag system It has good desulfurization, deoxidation and adsorption inclusion capabilities, and the waste residue has high alkalinity and strong reducibility. Its free calcium oxide content is high and its sulfur capacity is large. It has the potential for recycling in metallurgical production. value, but the literature does not mention the application of refining reducing slag in the converter steelmaking process

(2) The article "Application of Solid Waste in Shaft Furnace Pellet Production" by Wu Mingli et al. Shandong Metallurgy 2010 (4) disclosed that only a small part of LF refining furnace white slag can be added in the sintering production process and cannot be used in large quantities refining white slag, the utilization rate of white slag is reduced

(3) The book "Environmental Protection and Energy Conservation of Iron and Steel Metallurgy" Metallurgical Industry Press 2006 by Li Guangqiang and others described that some of the white slag of the LF refining furnace is currently used to make special cement, but did not mention the converter treatment of the white slag of the refining furnace