Preparation and application method of alumin-barium-Ca2C refining slag

Abstract

The invention relates to the field of iron and steel smelting, and provides a preparation and application method of aluminum-barium-Ca2C refining slag, the method comprises the following steps: S1, obtaining low-nitrogen aluminum ash, cryolite powder, a binder, metal aluminum, metal barium and Ca2C, and uniformly mixing the low-nitrogen aluminum ash, the cryolite powder and the binder to obtain a mixture; s2, the mixture serves as an outer layer material, metal aluminum, metal barium and Ca2C serve as inner layer materials, and refining slag balls are obtained through dry pressing; s3, lime is mixed and added during tapping of the calcium aluminate pre-molten slag converter, molten steel is obtained after tapping is finished, the refining slag balls are added into the molten steel to the surface of the molten steel, soft blowing is carried out, and a steel ladle slag surface is formed; and S4, the refining slag balls and lime are added to the surface of the steel ladle slag again, heating, slagging and desulfurization are conducted, and the alumin-barium-Ca2C refining slag is obtained. The raw materials are simple and extremely easy to obtain, and meanwhile, the adopted low-nitrogen aluminum ash and industrial cryolite are solid wastes of an aluminum factory, so that the pressure of recycling of metallurgical solid wastes is relieved.

Description

Technical Field

[0001] The present invention relates to the field of steel smelting, and more specifically to a preparation and application method of aluminum-barium-Ca2C refined slag. Background Art

[0002] At present, there are many types of slag agents used for steel refining in actual production. In response to the needs of different varieties, steel smelting workers continue to develop and try various types of refining slag. Generally speaking, there are several categories: The first category is synthetic slag made from lime, bauxite, wollastonite, fluorite and other raw materials. This type of slag is made by simply mechanically mixing the above raw materials after appropriate processing. Since the raw materials of this type of slag are almost all "raw materials", it has a slow slag formation rate, high impurity content, high slag consumption, and high energy consumption. At the same time, the fluorine content also aggravates the erosion of the furnace lining and the pollution to the environment. It cannot achieve the purpose of LF refining and slag making, especially when smelting high-grade varieties, the quality pass rate is low and the cost is high.

[0003] The second type is pre-melted synthetic slag, which is obtained by high-temperature melting of limestone, dolomite, wollastonite, fluorite, bauxite, etc. Its main components are calcium aluminate series. This type of slag has a low melting point and strong desulfurization and removal capabilities, but the cost is extremely high. At the same time, the slag acquisition process puts great pressure on the environmental protection.

[0004] The third category is recycled synthetic slag that is treated with waste slag from steel smelting as raw materials. For example, after desulfurization, the CaO, SiO2, Al2O3 and MgO components contained in LF refined slag are reused in the refining process. However, the multiple recycling of harmful elements such as P and S in the slag will lead to enrichment and increase, and the mineral structure of components such as CaO, SiO2, Al2O3 and MgO tends to be stable, and the activity is reduced, which seriously affects the refining effect and makes it difficult to meet the production needs of high-cleanliness steel. In addition, the high energy consumption and serious environmental pollution in the recovery and treatment process of waste steel smelting slag also limit its large-scale application.

[0005] The fourth category is a refined slag powder composed of ultrafine powder of calcium carbonate, magnesium carbonate or a mixture of calcium carbonate and magnesium carbonate as the main raw material, and a mixture of calcium oxide and magnesium oxide + low melting point pre-melted slag + fluorite. Calcium carbonate and magnesium carbonate are used as in-situ generators of tiny bubbles to induce ultrafine bubbles in molten steel to remove inclusions. In addition, this slag agent can quickly melt in molten steel to form slag droplets and form low melting point calcium aluminate with Al2O3 inclusions in the molten steel, which is easy to float to the ladle slag, thereby reducing the number and size of Al2O3 inclusions produced by refining. However, after the surface of calcium oxide or magnesium oxide reacts with sulfur or Al2O3, its product is wrapped on the surface of calcium oxide or magnesium oxide particles, hindering its further reaction, resulting in high slag material consumption and low efficiency; at the same time, the slag material is ultrafine powder material, which will cause dust pollution and a large amount of slag waste during storage, transportation and use; the added CaO and MgO are ultrafine powders, which are very easy to absorb water and deteriorate, seriously affecting their performance.

[0006] Iron and steel smelting work is based on the cleanliness requirements of different varieties, and LF refining slag and its refining technology are constantly developed to meet the production needs of high-cleanliness or ultra-cleanliness steel. In order to maintain and give full play to the advantages of existing LF refining slag, suppress its adverse effects, and overcome the problems of high energy consumption, high inclusion content in steel products, poor shape or large size of inclusions, slow slag formation speed or insufficient foaming and short duration, slow desulfurization rate, weak inclusion adsorption capacity, and environmental pollution of slag during the refining process or after refining. Developing efficient and environmentally friendly LF refining slag to make it suitable for secondary refining slag system of molten steel, especially to meet the LF production of clean steel or ultra-clean steel refining slag, further improve the efficiency of removing desulfurization and adsorbing inclusions, reduce consumption and increase efficiency, and be more environmentally friendly has become an urgent problem to be solved by practitioners in the industry.

[0007] The existing technology uses a modifier, and the raw materials are composed of 50-70% active lime, 10-30% fluorite, and 10-30% calcium aluminate by weight percentage. The chemical composition should meet the following requirements: active lime: CaO≥90%, MgO<8%, activity ≥300ml; fluorite: CaF2≥80%, SiO2<15%; calcium aluminate: 40%<CaO<60%, 25%<Al2O3≤45%, SiO2<5%, MgO<5%; the three raw materials are crushed to a particle size of ≤20mm, and then mixed with a mixer for 15-30 minutes. After being evenly mixed, the finished product is packaged. The modifier is added to the ladle with the steel flow during the converter steelmaking process, and the addition amount is 3-7kg / t steel. Advantages: After adding the modifier, liquid slag can be quickly generated, fully mixed with the ladle top slag, and the chemical composition of the ladle top slag can be changed, so that the composition of the ladle top slag is within the composition range that is conducive to desulfurization, thereby improving the refining desulfurization rate, reducing the refining cycle, improving production efficiency, and facilitating production continuity; at the same time, after adding the modifier, it will promote the floating removal of inclusions during the slag mixing process, and has a desulfurization rate of 30% to 60%, which is easy to operate and low in cost. Disadvantages: Different materials have different specific gravities, and there is an uneven phenomenon in the mixing process, which affects the control accuracy of the slag composition in the subsequent use process. In addition, the powder loss in the crushing and material preparation process is too much, which has a certain adverse effect on environmental protection.

[0008] The existing technology improves the properties of steel slag during the refining treatment of pure steel and ultra-pure steel, which is conducive to the adsorption and removal of inclusions, reduces the total oxygen in the finished product, and produces steel slag modified aluminum slag balls with extremely low harmful impurity content. It contains metallic aluminum, aluminum oxide, calcium carbonate, calcium oxide and inevitable impurities. Advantages: ordinary and easy-to-obtain raw materials, simple and reliable balling process, no component segregation fluctuation, simple addition process, and excellent surface spreading and heat preservation performance of molten steel. Adding steel slag modified aluminum slag balls during refining treatment can improve the fluidity of slag in the furnace; reduce the total iron content in the slag, reduce the aluminum-calcium ratio, improve the adsorption performance of Al2O3 in the refined slag, reduce the total oxygen in the finished product in the molten steel, and greatly reduce the inclusion of oxides in the molten steel. The product does not contain fluorine, which is beneficial to protecting the environment and equipment. Disadvantages: The materials are all "raw materials", the smelting process is slow to melt, and the energy consumption is high.

[0009] The prior art prepares the refining slag agent by using waste lining bricks and aluminum ash from aluminum electrolysis. When silicon carbide in the waste lining bricks and aluminum in the aluminum ash are added to the LF furnace, heat is released to create a reducing atmosphere, which is beneficial to reduce the oxygen in the steel slag and achieve the purpose of steel slag modification. Advantages: Compared with other LF furnace deoxidation slag agents, waste lining bricks and aluminum ash from aluminum electrolysis are cheap, which reduces the production cost of LF furnace slag making, and the quality of LF furnace refining slag is stable, thereby achieving the recycling of waste lining bricks and aluminum ash from aluminum electrolysis and increasing the added value of solid waste. Disadvantages: The nitrogen content of aluminum ash containing metal aluminum electrolysis is extremely high, basically above 5%, which is extremely unfavorable for controlling the nitrogen content of liquid steel, especially high-quality low-nitrogen steel, which seriously restricts the application of the invention; in addition, the invention uses waste refractory materials, which have low activity and are difficult to melt, resulting in greatly weakened steel smelting effect, and is not suitable for the development of high-quality steel.

[0010] The prior art discloses a method of using calcium aluminate refining slag produced in the secondary refining process of aluminum-killed steel as the main raw material, and forming calcium aluminate synthetic slag with stable chemical composition and performance by crushing and mechanically mixing a small amount of lime and bauxite. Advantages: The secondary utilization of aluminum-killed steel refining slag is realized, which not only greatly reduces the production cost of calcium aluminate synthetic slag, but also reduces the discharge of refining waste slag in steel plants. The calcium aluminate synthetic slag is creatively used for the refining and slag making of silicon-killed steel hard steel strands. By designing a low-melting-point CaO-Al2O3-SiO2-MgO quaternary refining slag system and its slag forming method, the use of refined fluorite is reduced, and the problems of high production cost of traditional synthetic slag, high fluorite consumption in the process of high-carbon steel smelting, high smelting cost and large pollution are solved. Disadvantages: The multiple recycling of harmful elements such as P and S will increase the enrichment and cause pollution to the molten steel; the mineral phase structure of components such as CaO, SiO2, Al2O3 and MgO tends to be stable, and the activity is reduced, which seriously affects the refining effect, and it is difficult to meet the production requirements of high-cleanliness steel. Summary of the invention

[0011] Based on the above purpose, the present invention proposes a preparation and application method of aluminum-barium-Ca2C refined slag, comprising the following steps: S1: obtaining low-nitrogen aluminum ash, cryolite powder, a binder, metal aluminum, metal barium and Ca2C, and uniformly mixing the low-nitrogen aluminum ash, cryolite powder and the binder to obtain a mixture; S2: The mixed material is used as the outer layer material, and the metal aluminum, metal barium and Ca2C are used as the inner layer material, and dry-pressed into refined slag balls; S3: adding lime to the mixed flushing when the calcium aluminate pre-melted slag converter is tapped, and molten steel is obtained after the tapping is completed, and the refined slag balls are added to the molten steel to the surface of the molten steel, and soft blowing is performed to form a ladle slag surface; S4: adding the refined slag balls and lime to the surface of the ladle slag again, heating the slag for desulfurization to obtain aluminum-barium-Ca2C refined slag.

[0012] In some embodiments, in step S1, the ratio of low-nitrogen aluminum ash, cryolite powder, binder, metal aluminum, metal barium and Ca2C is obtained as follows: Low-nitrogen aluminum ash accounts for 30-40%, cryolite accounts for 10-20%, binder accounts for 1-2%, metallic aluminum accounts for 10-20%, metallic barium accounts for 10-20%, and Ca2C accounts for 20-30%.

[0013] In some embodiments, in step S1, the calcium aluminate pre-slag, low-nitrogen aluminum ash, cryolite powder, and binder are mixed evenly to obtain a mixture with a moisture content of less than 0.5%.

[0014] In some embodiments, the mass fraction of each substance in the low nitrogen aluminum ash is in the range of nitrogen ≤ 1.0%, Al2O3 is 60-70%, and the rest is impurities; The mass fractions of various substances in cryolite range from 38 to 42% for F, 36 to 40% for Al2O3, 14 to 18% for Na2O, and the rest are impurities.

[0015] In some embodiments, the mass fraction of metallic aluminum is in the range of aluminum ≥ 99%, and the rest is impurities; The mass fraction of metallic barium is in the range of barium ≥ 98%, and the rest is impurities; The mass fraction range of Ca2C is Ca2C ≥ 90%, and the rest is impurities.

[0016] In some embodiments, in step S3, The amount of lime added is 3kg / t steel for ordinary varieties, 4kg / t steel for general varieties, and 5kg / t steel for high-grade varieties.

[0017] In some embodiments, the amount of refined slag balls added is 1 kg / t steel for ordinary varieties, 2 kg / t steel for general varieties, and 3 kg / t steel for high-grade varieties.

[0018] In some embodiments, in step S3, When the ladle slag surface is disturbed and the diameter of the molten steel turning over is ≤20cm, soft blowing is completed.

[0019] In some embodiments, in step S4, The amount of refined slag balls added again is 2-3kg / t steel for ordinary varieties, 3-5kg / t steel for general varieties, and 5-7kg / t steel for high-grade varieties.

[0020] In some embodiments, the amount of lime added again is 1.0 to 1.5 times the amount of refined slag balls added.

[0021] The present invention has at least the following beneficial technical effects: The invention proposes a preparation and application method of aluminum-barium-Ca2C refined slag, which comprises the following steps: S1: obtaining low-nitrogen aluminum ash, cryolite powder, a binder, metal aluminum, metal barium and Ca2C, and uniformly mixing the low-nitrogen aluminum ash, cryolite powder and the binder to obtain a mixture; S2: using the mixture as an outer layer material, and metal aluminum, metal barium and Ca2C as an inner layer material, and dry-pressing them into refined slag balls; S3: adding lime to the mixed flow when tapping a calcium aluminate pre-melted slag converter, obtaining molten steel after tapping, and adding the refined slag balls to the surface of the molten steel, performing soft blowing to form a ladle slag surface; and S4: adding the refined slag balls and lime to the surface of the ladle slag again, heating the slag for desulfurization, and obtaining the aluminum-barium-Ca2C refined slag.

[0022] The raw materials of the present invention are simple and easy to obtain. The low-nitrogen aluminum ash and industrial cryolite used are both solid wastes from aluminum plants, which are in line with the national solid waste utilization policy and are conducive to alleviating the pressure of recycling metallurgical solid wastes. Since the low-nitrogen aluminum ash is treated at high temperature (electrode process) and is in powder form, it melts quickly in the steelmaking process, which is significantly better than the first type of refined slag made entirely of raw materials and the refined slag made of refractory waste, and can basically achieve the melting effect of the second type of fully pre-melted refined slag. By adding the steel slag modifier during the refining process, slag can be quickly formed, the slag state can be effectively improved, and the oxidizability of the steel slag can be reduced, which is conducive to desulfurization and the adsorption and removal of inclusions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 A flow chart of a method for preparing and applying aluminum-barium-Ca2C refined slag according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0025] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as in the embodiments of this application.

[0027] The present invention proposes a method for preparing and applying aluminum-barium-Ca2C refined slag. Figure 1 , including the following steps: S1: obtaining low-nitrogen aluminum ash, cryolite powder, a binder, metal aluminum, metal barium and Ca2C, and uniformly mixing the low-nitrogen aluminum ash, cryolite powder and the binder to obtain a mixture; S2: The mixed material is used as the outer layer material, and the metal aluminum, metal barium and Ca2C are used as the inner layer material, and dry-pressed into refined slag balls; S3: adding lime to the mixed flushing when the calcium aluminate pre-melted slag converter is tapped, and molten steel is obtained after the tapping is completed, and the refined slag balls are added to the molten steel to the surface of the molten steel, and soft blowing is performed to form a ladle slag surface; S4: adding the refined slag balls and lime to the surface of the ladle slag again, heating the slag for desulfurization to obtain aluminum-barium-Ca2C refined slag.

[0028] Aiming at the problems of high energy consumption in the preparation or refining process of existing refined slag, high inclusion content in steel products, poor shape or oversized inclusions, slow slag formation speed or insufficient and short foaming duration, slow desulfurization rate, weak inclusion adsorption capacity, environmental pollution of slag during the refining process or after refining, the present invention develops and invents an aluminum-barium-Ca2C high-efficiency and environmentally friendly LF refined slag, which is suitable for the secondary refining slag system of molten steel, meets the refining treatment of clean steel or ultra-clean steel produced by LF furnace, further improves the desulfurization and inclusion adsorption capacity of the refined slag, and is more environmentally friendly.

[0029] From the perspectives of cost, metallurgical effect and environmental protection, the present invention combines the advantages of the second and third types of refining slags and proposes a composite refining slag and application technology consisting of calcium aluminate pre-melted slag + low-nitrogen aluminum ash + reducing agent + flux (cryolith that cannot be reused by aluminum plants).

[0030] The main functions of each component are as follows: Low nitrogen aluminum ash: fast melting slag, adjusting the composition of ladle slag, mainly the proportion of Al2O3 in ladle slag, to improve its ability to absorb inclusions; Metal aluminum: reduce oxygen in steel and slag; Metallic barium: reduces oxygen in steel and slag, and also has inclusion modification treatment effect; Ca2C: reduces oxygen in steel and slag, foams slag, modifies inclusions, and adjusts CaO / Al2O3 in steel slag; Industrial cryolite: Because it has the ability to break the crystal structure of other components and reduce the melting point, it mainly plays the role of fluxing and rapid slag formation. At the same time, its structure is stable at steelmaking temperature, it will not decompose, and it will not cause environmental pollution due to its fluorine content.

[0031] In some embodiments, see Figure 1 In step S1, the ratio of low-nitrogen aluminum ash, cryolite powder, binder, metal aluminum, metal barium and Ca2C is obtained as follows: Low-nitrogen aluminum ash accounts for 30-40%, cryolite accounts for 10-20%, binder accounts for 1-2%, metallic aluminum accounts for 10-20%, metallic barium accounts for 10-20%, and Ca2C accounts for 20-30%.

[0032] In some embodiments, see Figure 1 In step S1, the calcium aluminate pre-melted slag, low-nitrogen aluminum ash, cryolite powder and binder are mixed evenly to obtain a mixture with a moisture content of less than 0.5%.

[0033] Calcium aluminate pre-melted slag has excellent high temperature resistance and corrosion resistance, and can be used as a raw material for high temperature refractory materials. Low nitrogen aluminum ash also has high temperature stability and good corrosion resistance, which can further enhance the overall performance of the material. Cryolite powder, as a flux, can reduce the melting point of the material, promote the sintering process, and improve the conductivity and chemical stability of the material. The binder plays a role in bonding the components together tightly, improving the overall strength and stability of the material.

[0034] The uniform distribution of the components in the mixture ensures the consistency of the material's performance during processing. Low moisture content can reduce water evaporation and pore formation during processing, thereby improving the density and strength of the material. The selection and amount of binder used can optimize the material's molding and processing process, improving production efficiency and product quality.

[0035] Raw materials such as calcium aluminate pre-melted slag and low-nitrogen aluminum ash usually come from industrial waste or by-products. By rationally utilizing these resources, the mining and consumption of primary resources can be reduced. At the same time, the preparation process of this mixture is relatively simple and has low energy consumption, which is conducive to reducing production costs and environmental pollution.

[0036] In some embodiments, see Figure 1 The mass fraction of each substance in low nitrogen aluminum ash is nitrogen ≤ 1.0%, Al2O3 is 60-70%, and the rest are impurities; The mass fractions of various substances in cryolite range from 38 to 42% for F, 36 to 40% for Al2O3, 14 to 18% for Na2O, and the rest are impurities.

[0037] The high alumina content in low-nitrogen aluminum ash makes it an ideal raw material for manufacturing high-temperature refractory materials such as refractory bricks and refractory castables. Refractory materials are widely used in high-temperature industries such as steel smelting and glass manufacturing, and can significantly improve production efficiency and product quality. Al2O3 has high strength and hardness, which can increase the overall strength and wear resistance of the material. Adding low-nitrogen aluminum ash to building materials such as cement and concrete can improve their compressive strength and durability.

[0038] The nitrogen content in low-nitrogen aluminum ash is low, which reduces the emission of nitrogen oxides during production and application, and is beneficial to environmental protection. In flue gas denitrification, desulfurization and other waste gas treatment technologies, low-nitrogen aluminum ash can be used as an adsorbent or catalyst to reduce the nitrogen oxide content in the waste gas.

[0039] The high fluorine content in cryolite has a fluxing effect, especially in the aluminum electrolysis process, which can reduce the melting point of the electrolyte and improve the electrolysis efficiency. The presence of fluoride ions can improve the conductivity of the electrolyte and facilitate the electrolysis process. The moderate alumina content can be used as a raw material in the aluminum electrolysis process, and can also provide an aluminum source for other chemical reactions that require aluminum elements, which helps to maintain the stable composition of the electrolyte and ensure the smooth progress of the electrolysis process. Sodium oxide plays a role in regulating the properties of the electrolyte in cryolite. By adjusting the content of sodium oxide, the physical properties of the electrolyte such as melting point, density and viscosity can be changed to adapt to different electrolysis conditions. It helps to improve the utilization rate of the electrolyte and reduce energy consumption and raw material waste in the electrolysis process.

[0040] In some embodiments, see Figure 1 , the mass fraction of metallic aluminum is in the range of aluminum ≥ 99%, and the rest is impurities; The mass fraction of metallic barium is in the range of barium ≥ 98%, and the rest is impurities; The mass fraction range of Ca2C is Ca2C ≥ 90%, and the rest is impurities.

[0041] In some embodiments, in step S3, The amount of lime added is 3kg / t steel for ordinary varieties, 4kg / t steel for general varieties, and 5kg / t steel for high-grade varieties.

[0042] Calcium oxide (CaO) in lime has extremely strong alkalinity at high temperatures and can combine with impurity elements such as phosphorus and sulfur in molten steel and slag to form corresponding stable compounds. These compounds have low solubility in slag, so they can be effectively removed from molten steel, thereby improving the purity and quality of molten steel. The addition of lime can significantly increase the alkalinity of slag. High-alkalinity slag is conducive to the dephosphorization and desulfurization reactions, and can also improve the physical properties of slag, such as reducing the melting point, viscosity and surface tension of slag, and improving the fluidity and stability of slag. This helps to reduce energy consumption and metallurgical costs in the smelting process and improve production efficiency. Lime melts quickly and can react chemically with other components in slag to form new compounds. By adding lime for dephosphorization and desulfurization treatment, the quality of molten steel can be significantly improved, and the mechanical properties and service life of steel can be improved. Lime can absorb and combine harmful gases and oxides in the molten pool to form stable slag, thereby reducing the emission of smoke and harmful gases. This helps to reduce the degree of environmental pollution caused by the smelting process, in line with the requirements of environmental protection and sustainable development.

[0043] In some embodiments, see Figure 1 The amount of refined slag balls added is 1kg / t steel for ordinary varieties, 2kg / t steel for general varieties, and 3kg / t steel for high-grade varieties.

[0044] The quality of raw materials directly affects the amount of refined slag balls added. If a purer steel grade is required, more refined slag balls need to be added to remove more impurities.

[0045] In some embodiments, see Figure 1 , in step S3, When the ladle slag surface is disturbed and the diameter of the molten steel turning over is ≤20cm, soft blowing is completed.

[0046] At the end of soft blowing, the diameter of the molten steel turning over is small, which means that the slag layer on the surface of the molten steel is relatively stable and not easily drawn into the molten steel. This helps to reduce the inclusion content in the molten steel and improve the purity of the molten steel. Molten steel with high purity is less likely to have defects such as cracks and segregation in the subsequent processing, thereby improving the quality of steel.

[0047] The soft blowing operation helps to evenly distribute the components in the molten steel. At the end of the soft blowing, the slag layer on the surface of the molten steel can better cover the molten steel, preventing the molten steel from directly contacting the oxygen in the air, thereby reducing the secondary oxidation of the molten steel. This helps to maintain a stable content of alloy elements in the molten steel and optimize the composition of the molten steel.

[0048] In some embodiments, see Figure 1 , in step S4, The amount of refined slag balls added again is 2-3kg / t steel for ordinary varieties, 3-5kg / t steel for general varieties, and 5-7kg / t steel for high-grade varieties.

[0049] Adding refined slag balls can provide more desulfurization and dephosphorization reactions and accelerate the reaction process. The re-addition of lime can significantly increase the basicity of the slag, making the slag have stronger desulfurization and dephosphorization capabilities. High-basicity slag can also reduce the melting point of the slag, improve the fluidity of the slag, and facilitate the reaction between slag and steel. The re-addition of refined slag balls and lime can stabilize the composition and properties of the slag, reduce the fluctuation and change of the slag, maintain the stability of the smelting process, and improve the smelting efficiency.

[0050] In some embodiments, the present invention is processed by the following steps.

[0051] S1: Mix low nitrogen aluminum ash, cryolite powder and binder in proportion, and the moisture content of the mixture is less than 0.5%; S2: The above mixed material is used as the outer layer material, and the metal aluminum, metal barium and Ca2C are used as the inner layer material, and dry pressed into balls with a specification of 30-50 mm; S3: During the steel tapping process of the converter, 3-5 kg / t of lime is added to the mixed flushing. After the steel tapping is completed, 1-3 kg / t of refined slag balls are added to the surface of the molten steel, and then soft blowing is performed for 3-5 minutes. S4: LF enters the station and adds the above-mentioned refined slag balls to the surface of the ladle slag at a rate of 2-5kg / t steel, and lime 3-7kg / t steel is added to the surface of the ladle slag, and then the slag is heated and desulfurization operations are performed.

[0052] As shown in Table 1 and Table 2, different proportions are adjusted to obtain Example 1, Example 2 and Example 3, respectively, and the metallurgical effects of the three examples are shown in Table 3. The desulfurization rates of Examples 1-3 are between 62% and 73%, indicating that the desulfurization efficiency is high, the sulfur impurity content of the finished product is low, and the smelting cost is reduced. The rating is shown in Table 4, and the non-metallic inclusion amount is low, which means that the purity of the molten steel is increased and the production efficiency is improved. The present invention can effectively reduce the oxidizability of steel slag, optimize the composition of steel slag, quickly form slag, improve its inclusion adsorption capacity, and reduce production costs.

[0053] Table 1 Refined slag formulas of different examples, %

[0054] Table 2 Different example addition amount, kg / t 钢

[0055] Table 3 Metallurgical effects of different examples

[0056] Table 4 Metallurgical effects of different examples - non-metallic inclusion rating / grade

[0057] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0058] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0059] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing and applying aluminum-barium-Ca2C refined slag, characterized in that: The following steps are involved: S1: obtaining low-nitrogen aluminum ash, cryolite powder, a binder, metal aluminum, metal barium and Ca2C, and uniformly mixing the low-nitrogen aluminum ash, cryolite powder and the binder to obtain a mixture; S2: The mixed material is used as the outer layer material, and the metal aluminum, metal barium and Ca2C are used as the inner layer material, and dry-pressed into refined slag balls; S3: adding lime to the mixed flushing when the calcium aluminate pre-melted slag converter is tapped, and molten steel is obtained after the tapping is completed, and the refined slag balls are added to the molten steel to the surface of the molten steel, and soft blowing is performed to form a ladle slag surface; S4: adding the refined slag balls and lime to the surface of the ladle slag again, heating the slag for desulfurization to obtain aluminum-barium-Ca2C refined slag.

2. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: In step S1, the ratio of low-nitrogen aluminum ash, cryolite powder, binder, metal aluminum, metal barium and Ca2C is obtained as follows: Low-nitrogen aluminum ash accounts for 30-40%, cryolite accounts for 10-20%, binder accounts for 1-2%, metallic aluminum accounts for 10-20%, metallic barium accounts for 10-20%, and Ca2C accounts for 20-30%.

3. The method for preparing and applying the aluminum-barium-Ca2C refined slag according to claim 2, characterized in that: In step S1, the calcium aluminate pre-melted slag, low-nitrogen aluminum ash, cryolite powder and binder are mixed evenly to obtain a mixture with a moisture content of less than 0.5%.

4. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: The mass fraction range of each substance in low nitrogen aluminum ash is nitrogen ≤ 1.0%, Al2O3 is 60-70%, and the rest are impurities; The mass fractions of various substances in cryolite range from 38 to 42% for F, 36 to 40% for Al2O3, 14 to 18% for Na2O, and the rest are impurities.

5. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: The mass fraction of metallic aluminum is in the range of aluminum ≥ 99%, and the rest is impurities; The mass fraction of metallic barium is in the range of barium ≥ 98%, and the rest is impurities; The mass fraction range of Ca2C is Ca2C ≥ 90%, and the rest is impurities.

6. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: In step S3, The amount of lime added is 3kg / t steel for ordinary varieties, 4kg / t steel for general varieties, and 5kg / t steel for high-grade varieties.

7. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: The amount of refined slag balls added is 1kg / t steel for ordinary varieties, 2kg / t steel for general varieties, and 3kg / t steel for high-grade varieties.

8. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: In step S3, When the ladle slag surface is disturbed and the diameter of the molten steel turning over is ≤20cm, soft blowing is completed.

9. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: In step S4, The amount of refined slag balls added again is 2-3kg / t steel for ordinary varieties, 3-5kg / t steel for general varieties, and 5-7kg / t steel for high-grade varieties.

10. The method for preparing and applying aluminum-barium-Ca2C refined slag according to claim 1, characterized in that: The amount of lime added again is 1.0 to 1.5 times the amount of refined slag balls added.

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