CN-122012869-A - LF furnace smelting method suitable for recycling casting residue of RH process path steel ladle

Abstract

The invention discloses an LF furnace smelting method suitable for recycling casting residues of RH process path steel ladles, and belongs to the technical field of ferrous metallurgy. The method comprises the steps of calculating the weight of slag according to a formula, determining the FeO of slag according to a steel grade C, als, calculating the first aluminum adding amount of an LF furnace, heating for the first time, determining the strong stirring time after heating according to a desulfurization rate, sampling after aluminum supplementing according to the color of slag, adjusting the composition and the temperature, and discharging molten steel after calcium treatment. According to the method, the ladle casting residue of the RH process path steel is poured into the empty ladle before tapping, and the adaptive LF deoxidization system and the operation method are designed, so that the safe and efficient recycling of the ladle casting residue of the RH process path steel is realized, the casting residue is effectively recycled, the metal yield is improved, the smelting period of the LF furnace is shortened, the desulfurization effect is improved, the nitrogen content of the molten steel discharged from the LF furnace is reduced, the molten steel quality is improved, the production efficiency is improved, the production cost is reduced, and the multiple production requirements of a steel mill are met.

Inventors

• LI YINGJIANG
• MAO MING
• HAN BAO
• HU XIAOGUANG
• ZANG HONGCHEN
• PENG CHENGSONG
• LI BAOQING
• ZUO CONGHUA

Assignees

• 马鞍山钢铁有限公司

Dates

Publication Date

20260512

Application Date

20260204

Claims (5)

1. 1. The LF furnace smelting method suitable for recovering the casting residue of the steel ladle in the RH process path is characterized in that the RH process path refers to the smelting process path of the steel ladle from converter to RH to continuous casting, slag TFe is more than or equal to 3% when the RH is out of a station, and the balance is CaO and SiO 2 、MnO、Al 2 O 3 , and the method comprises the following steps: S1, primary molten steel in a LF process path is smelted in a converter; S2, before tapping of the converter, placing a ladle which is ready for receiving molten steel of the converter on a ladle car track, and weighing to obtain WB1, directly overturning ladle casting residues containing RH process path steel types to an empty ladle through a crane, and weighing to obtain WB2; W Weight of slag =(WB2-WB1)/4; S3, classifying slag FeO by C, ALs of RH process path steel types based on specific steel types: s4, tapping the converter, wherein the tapping process controls the slag discharging amount of the converter to avoid a large amount of slag discharging; s5, after tapping, taking a steel sample 1 after the tapping, checking components, and then lifting a ladle to enter an LF furnace for smelting; S6, after molten steel enters an LF furnace, opening a ladle, blowing argon at the bottom, stirring for 1-2 minutes, adding aluminum particles for strong deoxidization, wherein the aluminum particle quantity=the aluminum consumption of removing slag oxygen in casting residue and the aluminum consumption of alloying, stirring for 1-2 minutes after adding aluminum particles, stirring in a turning way, and then starting heating; The aluminum consumption amount calculation method for removing slag oxygen in casting residue comprises the following steps: 2Al+3FeO=Al 2 O 3 +3Fe; From the chemical equation, M Al =54*W Weight of slag x 1000 x slag FeO/(3 x 72); The method for calculating the aluminum consumption of alloying comprises the following steps: Alloying aluminum consumption = molten steel amount (LF outbound target als+loss of Als-post-furnace Als during LF smelting); s7, during the heating period, the heating is stopped when the temperature of molten steel is predicted to reach the LF outlet target temperature of +20 ℃, and after the heating is stopped, the bottom blowing argon flow is regulated to perform strong stirring desulfurization on the molten steel, wherein the strong stirring time is determined according to the desulfurization rate; s8, dipping a slag sample after the strong stirring is finished, observing the color of the slag, namely taking a steel sample 2 if the slag is white, taking the steel sample 2 after the strong stirring for 5 minutes after adding 0.5kg/t of aluminum particles into the slag if the slag is black, taking the steel sample 2 after the strong stirring for 3 minutes after adding 0.2kg/t of aluminum particles into the slag if the slag is gray, and measuring the temperature after taking the steel sample 2; s9, adjusting the temperature according to the temperature measurement result, adjusting the components according to the analysis result of the steel sample 2, performing calcium treatment according to the steel grade process, and taking the steel sample 3 for temperature measurement before the molten steel comes out of the station.
2. 2. The LF furnace smelting method suitable for recycling the casting residue of the RH process path steel ladle, as set forth in claim 1, wherein in S9, the components, the temperature and the calcium treatment process are adjusted to conform to the conventional operation standard of the LF furnace in the metallurgical industry.
3. 3. The LF furnace smelting method suitable for recycling the casting residue of the RH process path steel ladle, which is disclosed in claim 1, is characterized in that in S7, the strong stirring time is as follows: desulfurization rate= (S content after furnace-steel grade LF furnace target S content)/S content after furnace.
4. 4. The LF furnace smelting method suitable for recycling the casting residue of the RH process path steel ladle, as set forth in claim 1, wherein in S4, the tapping process controls the slag amount of the converter to be not more than 2 kg/ton of steel.
5. 5. The LF furnace smelting method suitable for recycling the casting residues of the steel grade ladles of the RH process path according to claim 1, wherein in the step S4, the deoxidizer is added to hit the molten steel Als content after the furnace is between 0.010 and 0.040 percent under the condition of not casting residues of the same steel grade.

Description

LF furnace smelting method suitable for recycling casting residue of RH process path steel ladle Technical Field The invention relates to the technical field of ferrous metallurgy, in particular to an LF furnace smelting method suitable for recycling casting residues of steel ladles of RH process paths. Background The common steelmaking process flow in China is converter-LF-continuous casting or converter-RH-continuous casting. The converter belongs to a primary refining furnace, and LF and RH are secondary refining furnaces. The LF furnace has the functions of heating, alloying, desulfurizing reducing slag and the like, and the RH furnace has the functions of deep decarburization, deoxidization, alloying and the like. The continuous casting is to cast liquid molten steel contained in a ladle into a continuous casting blank. The top of the liquid steel contained in the ladle is covered with slag, and the properties of the slag are related to smelting steel types and smelting processes. When the smelting process route is converter-LF-continuous casting, the slag is required to have strong reducibility (slag feo+mno is generally less than 1%) because the LF furnace needs to be desulphurised. When the smelting process path is converter-RH-continuous casting, particularly when the process is adopted to produce ultralow carbon steel such as automobile plates, non-oriented silicon steel and the like, slag has stronger oxidizing property (slag FeO+MnO is generally more than 5%). Recovery of ladle casting residue from continuous casting processes is a common steelmaking technique. Since the molten steel and the slag are mixed with each other in the later stage of pouring, it is difficult to distinguish accurately, so the ladle casting residue is composed of the molten steel and the slag. The recovery of the molten steel from the casting residue is a significant benefit, and recovery of this portion of the molten steel is a goal that is actively pursued by the steelworks, while the slag from the casting residue does not necessarily have recovery value. When the slag has reducibility, if the part of casting residue is returned to the ladle of the converter-LF-continuous casting process path, not only molten steel in the casting residue can be recovered, but also the part of slag can be practically used as a slag forming material, and good metallurgical effect can be produced, and when the slag has oxidizability, if the part of casting residue is returned to the ladle of the converter-LF-continuous casting process path, due to the oxidizability of the slag, deoxidizing agent needs to be added to remove oxygen in the slag in the casting residue during LF smelting, which can lead to the adverse effects of prolonged LF smelting time, reduced desulfurization effect and the like. Chinese patent (publication No. CN 113102712B) discloses a ladle casting residue recycling method suitable for ultra-low carbon steel, which is characterized in that ladle casting residues containing oxidizing slag of the ultra-low carbon steel can be recycled by using a ladle containing molten iron to recycle the ladle casting residues for a plurality of times and then adding the recycled casting residues and the molten iron in the ladle into a converter after deoxidization, and Chinese patent (publication No. CN 112899433A) discloses a ladle casting residue recycling method for the ladle casting residues and the molten slag, which is characterized in that (1) bedding molten iron is pre-filled into a molten iron tank, (2) the casting residues and the molten iron tank are filled into the molten iron tank and uniformly stirred, and (3) the molten iron tank is filled with residual molten iron and then the casting residues are removed by using a slag remover and then added into the converter. The Chinese patent (issued publication number: CN 111349743B) discloses an energy-saving and emission-reduction method for recycling hot casting residues, and a set of feasible hot casting residue recycling method is prepared by comprehensively carding and summarizing feasibility analysis, flow design, point and cheating analysis of recycling procedures, process standard formulation, process operation formulation, effect analysis after recycling and the like of the hot casting residues. After the casting residue is recycled, the molten steel receiving rate is improved, the auxiliary material consumption is reduced, the rapid slag formation of refining is promoted, the refining treatment time is shortened, and the refining efficiency is improved. However, it is known from the specification [0003] (after the casting of molten steel is completed, steel slag in a molten steel tank, namely, casting slag, has good fluidity, and slag is subjected to modification treatment when molten steel is refined, and a part of ladle casting slag which has high CaO content, high alkalinity and strong reducibility has strong refining ability, and at the same time, a certain amount o