CN-121992165-A - Molten iron dephosphorizing agent prepared from hot-pressed iron blocks and preparation method thereof

Abstract

The invention relates to the technical field of molten iron pretreatment, in particular to a molten iron dephosphorizing agent prepared by taking hot-pressed iron blocks as raw materials and a preparation method thereof, wherein the molten iron dephosphorizing agent comprises, by weight, 50-60% of the hot-pressed iron blocks and 40-50% of desulfurizing agents, the metallization rate in the hot-pressed iron blocks is more than or equal to 85%, the desulfurizing agents are KR desulfurizing agents, the components in percentage by mass are more than or equal to 80% of CaO, 3-8% of SiO 2 ≤2.5%,CaF 2 , less than or equal to 0.02% of Al 2 O 3 , less than or equal to 0.015% of P+S, the balance of unavoidable impurities, and the activity is more than or equal to 280ml. The dephosphorization agent has the beneficial effects of high utilization rate, short deslagging time, good dephosphorization effect, higher dephosphorization rate, and the invention lays a foundation for reducing dephosphorization burden of the converter and reducing slag consumption.

Inventors

• LUO HONGYAN
• HUANG LAIRONG
• MIAO QIANG
• WANG XU
• ZHANG YANLONG
• QIU WEN
• LIU YANQING
• Gao Zhenchong
• TIAN YU
• XIA JI
• ZHANG YINGPENG
• JIN ZHAODONG

Assignees

• 本溪北营钢铁（集团）股份有限公司

Dates

Publication Date

20260508

Application Date

20260119

Claims (7)

1. 1. The dephosphorizing agent for the molten iron prepared by taking the hot-pressed iron block as a raw material is characterized by comprising, by weight, 50-60% of the hot-pressed iron block, 40-50% of a desulfurizing agent, wherein the metallization rate of the hot-pressed iron block is more than or equal to 85%, the desulfurizing agent is KR desulfurizing agent, and the desulfurizing agent comprises, by mass, more than or equal to 80% of CaO, 3-8% of SiO 2 ≤2.5%,CaF 2 , less than or equal to 0.02% of Al 2 O 3 , less than or equal to 0.015% of P+S, the balance of unavoidable impurities, and the activity is more than or equal to 280ml.
2. 2. The dephosphorizing agent for molten iron prepared by taking hot-pressed iron blocks as raw materials according to claim 1, wherein the adding amount of the dephosphorizing agent for molten iron is 15-20 kg/t when KR molten iron pretreatment is carried out on molten iron.
3. 3. The dephosphorizing agent for molten iron prepared by using hot-pressed iron blocks as raw materials according to claim 2, wherein the dephosphorizing reaction is carried out by generating [ CaO.P 2 O 5 ] under the condition of rich [ O ] through [ CaO ] during the pretreatment of the KR molten iron, so that [ P ] in the molten iron is removed to generate stable [ CaO.P 2 O 5 ]: 2[P]+5[O]+[CaO]=[CaO·P 2 O 5 ]。
4. 4. the dephosphorizing agent for molten iron prepared by taking hot-pressed iron blocks as raw materials according to claim 1, wherein the dephosphorizing rate of the dephosphorizing agent for molten iron in KR molten iron pretreatment is more than or equal to 70 percent.
5. 5. A method for preparing the dephosphorizing agent for molten iron prepared by taking hot-pressed iron blocks as raw materials according to claim 1, which is characterized in that the specific preparation method comprises the following steps: S1, crushing and grinding hot-pressed iron blocks, feeding the crushed and ground powder into a heating device, heating to 1050-1100 ℃, preserving heat for 45-60 min, fully oxidizing metal Fe into Fe 2 O 3 and Fe 3 O 4 ,Fe 2 O 3 +Fe 3 O 4 which are more than or equal to 95%, and cooling to room temperature; s2, mixing the cooled powder of the hot-pressed iron block with a desulfurizing agent to form a mixture, and pressing the mixture into 5-10 mm particles by using a high-pressure ball press to obtain molten iron dephosphorizing agent particles.
6. 6. The method for preparing a dephosphorizing agent for molten iron by using hot-pressed iron blocks as a raw material according to claim 5, wherein the air-fuel ratio of the heating device in the step S1 is controlled to be 0.6-0.7.
7. 7. The method for preparing the dephosphorizing agent for molten iron by taking hot-pressed iron blocks as raw materials according to claim 5, wherein the content of Fe 2 O 3 +Fe 3 O 4 , the content of CaO, the content of CaF 2 and the content of SiO 2 in the mixture in S2 are more than or equal to 55%, more than or equal to 40%, 1-4% respectively.

Description

Molten iron dephosphorizing agent prepared from hot-pressed iron blocks and preparation method thereof Technical Field The invention relates to the technical field of molten iron pretreatment, in particular to a molten iron dephosphorizing agent prepared by taking hot-pressed iron blocks as raw materials and a preparation method thereof. Background The KR method, which is totally called a mechanical stirring desulfurization method, is the most widely used molten iron pre-desulfurization technology in the current iron and steel smelting production, and is inserted into a molten iron tank by a stirrer wrapped by refractory materials in a high-speed rotating way, so that a strong vortex stirring area is formed inside the molten iron. Then adding desulfurizing agent into the vortex to make it fully mixed and reacted with molten iron so as to attain the goal of deep desulfurization. Most steelworks have KR pretreatment equipment. The KR method has the advantages of small equipment occupation, less investment and high desulfurization efficiency, and is valued. But the dephosphorization efficiency is very poor when the KR method is adopted for sulfur removal, oxygen in the dephosphorization process is required to be as high as possible according to dephosphorization thermodynamic conditions, but the KR method molten iron pretreatment process is free of a spray gun and auxiliary oxygen blowing equipment, oxygen cannot be blown additionally, efficient dephosphorization is required on the basis of the KR method, and the oxygen source in the dephosphorization agent is required to be ensured to be enough to provide dephosphorization requirements, so that a high oxygen source dephosphorization agent used in the KR method is needed. The Chinese patent of patent publication No. CN100526480C discloses a dephosphorizing agent for molten iron pretreatment by a KR stirring method, which basically comprises 35-50wt% of T.Fe which is more than or equal to 66.5%, less than or equal to 10.0% of (FeO) concentrate powder, 30-45wt% of active lime, 3-8wt% of fluorite, 0.5-5wt% of fluorite powder and 0.5-8wt% of BaCO 3, and is pressed into a block. Compared with the existing dephosphorizing agent, the dephosphorizing agent has high self oxygen content, and can meet the requirement of KR process dephosphorization without auxiliary oxygen supply on oxygen source. However, the basic composition does not mention hot-pressed iron blocks and desulfurizing agents, and the total iron content of the hot-pressed iron blocks is higher than that of the concentrate powder. The Chinese patent publication No. CN1372009A discloses a dephosphorizing agent for molten iron and molten steel, which is used for reducing the phosphorus content in steel in the production of iron making and steel making. The dephosphorizing agent consists of ferric oxide, active lime and fluorine-free calcium. Pulverizing the above materials, stirring, and granulating to obtain the final product. The dephosphorization method has the advantages of good dephosphorization effect, convenient use, low cost, less environmental pollution and the like. The dephosphorizing agent has small particles, is easy to be pumped away by dust removing equipment, and has a spray gun and an auxiliary oxygen blowing equipment, and has sufficient oxygen source. The method does not need to blow oxygen additionally, and has high oxygen source per se, thereby achieving the purpose of high-efficiency dephosphorization. A dephosphorizing agent prepared by taking decarburization furnace slag as a raw material and a molten iron dephosphorizing method are disclosed in Chinese patent publication No. CN103498016B, and belong to the technical field of molten iron desulfurization. The dephosphorization agent consists of 40-60% of decarbonization furnace slag, 10-30% of dust, 10-30% of lime powder and 5-10% of slag melting agent by weight. The prepared materials are uniformly mixed and pressed into dephosphorizing agents through a high-pressure ball press. 10-20 kg/t of steel, 10-20 kg/t of lime and 10-20 kg/t of magnesium balls or light burned dolomite are added into the converter to form initial slag of dephosphorization of molten iron in the earlier stage of the converter, the dephosphorization rate of the molten iron in the earlier stage of the converter can be more than 60%, and conditions are created for realizing a clean steel platform for converter smelting. The invention does not mention hot-pressed iron blocks and desulfurizing agents, also requires external oxygen supply, and is carried out in a converter, and is not suitable for pre-dephosphorization in the KR process. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides the molten iron dephosphorizing agent prepared by taking the hot-pressed iron blocks as raw materials and the preparation method thereof, wherein the hot-pressed iron blocks are crushed and ground, then are sent to a heating device to be