阅读说明：本技术 一种用于对钢液直接进行铬合金化的产品及方法 (Product and method for directly performing chromium alloying on molten steel ) 是由 乌力平 李国安 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种用于对钢液直接进行铬合金化的产品及方法,属于冶金技术领域。本发明将铬化合物细粉与部分金属和/或碳质还原剂细粉混匀,在结合剂的辅助下压制成块状单体产品,以方式1)加入等待出钢的热钢包中,先利用钢包余热部分碳化还原铬化合物中的铬,随后出钢时借助钢液脱氧合金化条件完全还原铬化合物中铬,或2)直接加入出钢钢液中,在出钢过程中借助钢液脱氧合金化条件完成铬化合物中铬的完全还原,从而实现采用铬化合物对钢液进行即时直接铬合金化,无需任何额外的相关辅助设施或额外辅助操作。同时,在特定钢种条件下,根据还原剂中碳素与金属配比和加入方式的变化,实现从高碳到微碳成品铬铁合金替代。(The invention discloses a product and a method for directly performing chromium alloying on molten steel, belonging to the technical field of metallurgy. The method comprises the steps of uniformly mixing chromium compound fine powder and partial metal and/or carbonaceous reducing agent fine powder, pressing the mixture into a massive monomer product under the assistance of a binding agent, adding the massive monomer product into a hot steel ladle waiting for steel tapping in a way 1), firstly, partially carbonizing and reducing chromium in the chromium compound by using the waste heat of the steel ladle, and then completely reducing chromium in the chromium compound by using molten steel deoxidation alloying conditions during steel tapping, or 2) directly adding the massive monomer product into molten steel, and completing the complete reduction of chromium in the chromium compound by using the molten steel deoxidation alloying conditions during the steel tapping, so that the chromium compound is adopted to carry out immediate direct chromium alloying on the molten steel, and no additional related auxiliary facility or additional auxiliary operation is needed. Meanwhile, under the condition of a specific steel grade, the substitution of the finished ferrochrome alloy from high carbon to micro carbon is realized according to the change of the ratio of carbon to metal in the reducing agent and the addition mode.)

1. A product for directly carrying out chromium alloying on molten steel is characterized in that: the method adopts a chromium compound as a metal chromium source, and the chromium compound, a reducing agent and binding agent fine powder are uniformly mixed and then pressed into a blocky monomer.

2. A product for direct chromium alloying of molten steel according to claim 1, characterized in that: the chromium compound is one or more of chromium oxide, chromate and chromium silicate in combination, and is converted into Cr₂O₃The content is more than 30 percent.

3. A product for direct chromium alloying of molten steel according to claim 1, characterized in that: the reducing agent is one or the combination of two of a carbon reducing agent and a metal reducing agent.

4. A product for direct chromium alloying of molten steel according to claim 3 wherein: the metal reducing agent comprises one or more of metals or alloys containing silicon, calcium, aluminum.

5. A product for direct chromium alloying of molten steel according to any of claims 1-4, characterized in that: the total amount of the reducing agent exceeds the sum of the total balance required by the reduction of the iron element combined with oxygen and the reduction of the chromium element combined with oxygen in the chromium compound.

6. A product for direct chromium alloying of molten steel according to claim 5 wherein: when the reducing agent contains at least one of carbon, calcium, silicon and aluminum, M ═ n (n)_C+n_Ca+1/2n_Si+2/3n_Al)/n₀The value range of M is 1.05-1.5; wherein n is_C、n_Ca、n_Si、n_SiRespectively represents the mole numbers of carbon, calcium, silicon and aluminum elements in the reducing agent, n₀Represents the sum of the total number of moles of reducing elements required for reduction of iron-bonded oxygen and reduction of chromium-bonded oxygen in the chromium compound.

7. The product and method for direct chromium alloying of molten steel according to claim 6, wherein: the range of the M value is preferably 1.1-1.3.

8. A product for direct chromium alloying of molten steel according to any of claims 1-4, characterized in that: the thickness of the blocky monomer is 20-60 mm; the particle size of the filled reaction mass is not more than 400 μm.

9. A method for direct chromium alloying of molten steel is characterized in that: the direct chromium alloying of molten steel is achieved by pre-feeding the product of any one of claims 1-8 into a ladle waiting for tapping before tapping or by feeding said product into a ladle that is tapping.

10. The method of molten steel direct chrome alloying of claim 9, wherein: when the product is added into a steel ladle waiting for steel tapping in advance, the reaction material filled in the product performs partial chromium reduction and carbonization reaction in advance by utilizing the heat accumulated by the steel ladle, and then realizes the whole chromium reduction condition by means of molten steel deoxidation alloying in the subsequent steel tapping process, and the molten steel direct chromium alloying is completed while the steel is tapped;

when the product is added into a steel ladle which is tapping when tapping is started, reaction materials filled in the product are subjected to reduction reaction by utilizing the heat of molten steel, and the molten steel is directly subjected to chromium alloying while tapping by means of the condition that the molten steel is deoxidized and alloyed to realize the reduction of all chromium in the tapping process.

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a product and a method for directly performing chromium alloying on molten steel.

Background

In the field of metallurgy, chromium alloying of steel is an important means necessary for improving the strength, corrosion resistance, wear resistance, high temperature resistance, oxidation resistance and other properties of steel, and is widely applied to the production of special steel materials for various purposes such as stainless steel, acid-resistant steel, heat-resistant steel, ball bearing steel, spring steel, tool steel and the like, and the specific treatment mode is mainly realized by chromium alloying of molten steel.

However, the preparation of the selected chromium-enriched compound for the chromium alloying of molten steel into the currently common finished ferrochromium alloy is a metallurgical and chemical process with high energy consumption, high pollution and low efficiency. In recent years, steelmaking workers have been dedicated to theoretical research and experiments for direct chromium alloying of molten steel using chromium compounds rich in chromium, and have conducted research and trials for decades. Although there are many advantages of using chromium compounds to directly perform molten steel chromium alloying, in actual industrial production, except that a single steel mill (such as a thousand leaf factory and a western factory of japan JFE) uses chromite to perform furnace alloying and steel smelting furnace duplex industrial production of stainless steel with high chromium content (this method is equivalent to moving and synthesizing the smelting furnace of an iron alloy production plant beside the steel smelting furnace or combining the smelting furnace together), only reports of semi-industrial tests of using chromium minerals to reduce in the furnace in an electric furnace of an ukrandon nisk metallurgical plant, a research and development center of the english-steel duplex (1997), a royal institute of technology (2012-2016) of sweden, and the like are reported, and there is no other industrial application and popularization, and the main processes of these attempts are mostly: the chromium compound is dissolved in the slag to form slag, and then the slag is melted and reduced to form metallic chromium, and finally the metallic chromium enters the reduction process in the molten steel furnace. The methods for attempting to alloy the molten steel by adopting the chromium minerals have the problems that the direct alloying of the molten steel is realized by reducing through the process of providing energy and substances by an online smelting auxiliary device and creating thermodynamic or kinetic conditions, the alloying operation is complicated, the process time is long, particularly, the chromium element steel slag balance existing after slag dissolution causes low and unstable chromium yield, the reduction process cost is high, and the like.

Disclosure of Invention

1. Problems to be solved

Aiming at the problems that special equipment and facilities are required, the process operation is complex and tedious, the alloying process time is long, the microalloying degree is difficult to ensure, the yield is low and the yield is unstable when the direct chromium microalloying is attempted to be carried out on molten steel in the prior art, the invention provides a product and a method for directly carrying out chromium alloying on the molten steel. The product is directly added into the steel ladle waiting for steel tapping or the steel ladle discharging steel, so that the method realizes the immediate direct chromium alloying of the molten steel by adopting the chromium compound without any additional related auxiliary facilities or additional auxiliary operation. Meanwhile, under the condition of a specific steel grade, the replacement of the finished ferrochrome alloy from high carbon to micro carbon can be realized according to the change of the ratio of carbon to metal in the reducing agent and the addition mode.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the invention relates to a product for directly carrying out chromium alloying on molten steel, which adopts a chromium compound as a metal chromium source, and is pressed into a blocky monomer after being uniformly mixed with a reducing agent and binding agent fine powder.

Further, the chromium compound is one or more of chromium oxide, chromate and chromium silicate in combination, and the amount of chromium is reduced to Cr₂O₃The content is more than 30 percent.

Furthermore, the reducing agent adopts one or two combinations of a carbon reducing agent or a metal reducing agent.

Still further, the metal reducing agent comprises one or more combinations of metals or alloys containing silicon, calcium, aluminum.

Further, the total amount of reducing agent used exceeds the sum of the total balance required for the reduction of iron-bound oxygen and the reduction of chromium-bound oxygen in the chromium compound.

Further, when the reducing agent contains at least one of carbon, calcium, silicon, and aluminum, M ═ n (n)_C+n_Ca+1/2n_Si+2/3n_Al)/n₀The value range of M is 1.05-1.5; wherein n is_C、n_Ca、n_Si、n_SiRespectively represents the mole numbers of carbon, calcium, silicon and aluminum elements in the reducing agent, n₀Represents the sum of the total number of moles of reducing elements required for reduction of iron-bonded oxygen and reduction of chromium-bonded oxygen in the chromium compound.

Further, said N is₁、N₂And N₃The preferable ranges are 1.1-1.3.

Furthermore, the thickness of the blocky monomer is 20-60 mm; the particle size of the filled reaction mass is not more than 400 μm.

The method for direct chromium alloying of the molten steel realizes direct chromium alloying of the molten steel by adding the product into a steel ladle waiting for steel tapping in advance or adding the product into the steel ladle which is tapping before the steel tapping.

Furthermore, when the product is added into a steel ladle waiting for tapping in advance, the reaction material filled in the product performs partial chromium reduction and carbonization reaction in advance by utilizing the heat accumulated in the steel ladle, and then realizes the whole chromium reduction condition by means of molten steel deoxidation alloying in the subsequent tapping process, and the molten steel direct chromium alloying is completed while tapping;

when the product is added into a steel ladle which is tapping when tapping is started, reaction materials filled in the product are subjected to reduction reaction by utilizing the heat of molten steel, and the molten steel is directly subjected to chromium alloying while tapping by means of the condition that the molten steel is deoxidized and alloyed to realize the reduction of all chromium in the tapping process.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention relates to a product and a method for directly carrying out chromium alloying on molten steel, wherein a chromium compound is used as a metal chromium source, is uniformly mixed with a reducing agent and binding agent fine powder and then is pressed into a blocky monomer, when in use, the product is directly added into a steel ladle to be tapped or a steel ladle which is tapping, and the heat of the steel ladle is utilized to carry out reaction, so that the direct chromium alloying on the molten steel can be finished, the operation is simple and convenient, the alloying process is short, the time consumption is less, the chromium metallization degree is higher, and the metal yield is higher and stable. Meanwhile, the carbon and metal ratio in the reaction materials in the product and the product adding mode can be adjusted according to specific steel grades, so that the substitution of the finished ferrochrome alloy from high carbon to micro carbon is effectively realized.

(2) The invention relates to a method for directly carrying out chromium alloying on molten steel, which is characterized in that after the product is added at one time, floating substances on the surface of the molten steel and the molten steel are circularly mixed by the molten steel by utilizing the characteristic that the early stage of the tapping process basically has no slag and the molten steel is well stirred by the strong kinetic energy of the flowing force of the tapping steel, the reduction of a chromium compound is carried out in the basically slag-free molten steel by virtue of the conditions of molten steel deoxidation, silicon-aluminum-carbon alloying and the like, the thermodynamics and the kinetic conditions of the reduction reaction are good, the problems of slow slag melting and dissolution of the high-melting point chromium compound, poor thermodynamics conditions of melting reduction, poor reduction kinetic conditions on the whole and the like in all previous attempts are solved, the purpose of directly carrying out the chromium alloying on the molten steel by adopting a vanadium compound is effectively realized, and the chromium yield is higher and stable.

(3) The method for directly carrying out chromium alloying on the molten steel has the advantages that the recarburization control in the direct alloying process is combined, the recarburization control comprises the control of the proportion of carbon and a metal reducing agent for adjusting the amount of slag additionally generated during reduction, the consideration of the adding mode of a direct reduction material pressed block body and the like, and the influences on recarburization of the molten steel, the original slag system of a factory and the like are reduced as much as possible. In addition, after the product is added at one time, no additional related auxiliary facility or additional auxiliary operation is needed, the operation of directly alloying the molten steel is simple and convenient, the application and popularization of the direct alloying of the chromium compound molten steel become possible, compared with the common method of finished product ferroalloy adopted in the industry at present, the direct chromium alloying of the chromium compound shortens the reduction path to a great extent, protects resources, reduces pollution and energy consumption, and has great economic benefit and social benefit.

Detailed Description

The chromium in chromium oxide, chromate or chromium silicate is relatively easy to reduce from a thermodynamic point of view, since chromium in various natural chromium compounds only binds slightly stronger to oxygen than iron and even less than manganese in manganese ores in terms of its binding capacity to oxygen. However, because the chromium has high melting point, poor reduction kinetics conditions such as poor wettability with various liquid phases and the like, and the condition of reducing agent with enough high concentration is difficult to exist under the general working condition, the prior art of directly carrying out chromium alloying on the molten steel by adopting the chromium compound is a furnace method by virtue of a smelting process, special equipment and facilities are required to be used, the operation of the related process is complex and tedious, the process time of dissolving and slagging, melting reduction and alloying of the chromium compound is long, the problems of large reducing agent loss, low chromium yield, large fluctuation and the like cannot be solved, and therefore, except that the stainless steel which uses a large amount of chromium is produced by special equipment and facilities, even chromium minerals are directly used in a special process, the direct alloying of the chromium compound molten steel by the prior art is not possible to be carried out simply, quickly and efficiently.

In view of the above, the invention provides a product and a method for directly carrying out immediate chromium alloying on molten steel in a steel ladle in the tapping process by adopting a selected enriched natural chromium compound, such as chromium oxide, chromate, chromium silicate and other bulk commercial chromium compounds, the basic principle is that the floating materials on the surface of the molten steel and the molten steel are circularly mixed by the molten steel by utilizing the characteristic that the early stage of the tapping process is basically free from slag and the molten steel is well stirred by the strong kinetic energy of the steel-tapping flow, the reduction of the chromium compound fine powder is carried out in the molten steel under the conditions of molten steel deoxidation, carbon-silicon-aluminum alloying and the like, the thermodynamic and kinetic conditions of the reduction reaction are good, the reduction process is simple and easy to implement, the direct chromium alloying of the molten steel can be rapidly completed while tapping, and subsequent other processes are not needed, so that finished products of high-carbon, medium-carbon and even micro-carbon ferrochrome are replaced by one step, and the immediate direct chromium alloying of the molten steel by the chromium compound is realized.

Specifically, the product of the invention is in a monomer block shape, and the thickness dimension of the monomer is 20About 60mm, and the convenience of block making and the storage, transportation and use of materials are both considered. The product of the invention is prepared by uniformly mixing chromium compound fine powder as an alloying metal chromium source, reducing agent fine powder and a bonding agent and then pressing, and the particle size of the filled reaction materials is not more than 400 mu m, so that the contact specific surface area among the reaction materials can be effectively improved, and the integral strength of the product can be ensured. Wherein the chromium compound filled in the product adopts one or more of chromium oxide, chromate and chromium silicate, and is converted into Cr₂O₃The content is more than 30 percent. The reducing agent adopts one or two combinations of carbon reducing agent or metal reducing agent, and the metal reducing agent comprises one or more combinations of metal or alloy containing silicon, calcium and aluminum, and can be fully or partially mixed in the chromium compound.

The total dosage of the reducing agent exceeds the total balance required by the reduction of the iron element combined with oxygen and the reduction of the chromium element combined with oxygen in the chromium compound, so as to ensure the full reduction of chromium in chromium oxide or chromate and prevent the excessive reducing agent element from being oxidized into molten steel and influencing the economy of direct alloying. When the reducing agent contains at least one of carbon, calcium, silicon and aluminum, M ═ n (n)_C+n_Ca+1/2n_Si+2/3n_Al)/n₀And the value range of M is 1.05-1.5. Wherein n is_C、n_Ca、n_Si、n_SiRespectively represents the mole numbers of carbon, calcium, silicon and aluminum elements in the reducing agent, n₀Represents the sum of the total number of moles of reducing elements required for reduction of iron-bonded oxygen and reduction of chromium-bonded oxygen in the chromium compound. When the reducing agent does not contain any element, the mole number is 0, that is:

when the reducing agent is only one of a carbon reducing agent and a calcium-containing metal or alloy, the ratio of the total number of moles of the carbon element or the calcium element to the sum of the total number of moles of the iron element combined with oxygen reduction and the chromium element combined with oxygen reduction in the chromium compound satisfies 1.05-1.5. When the carbon reducing agent and the metal or the alloy containing the calcium element are adopted, the ratio of the sum of the molar total number of the carbon element and the calcium element to the sum of the molar total number of the iron element combined oxygen reduction and the chromium element combined oxygen reduction in the chromium compound satisfies 1.05-1.5.

When the reducing agent comprises a metal (or alloy) containing an aluminum element, the ratio of 2/3 moles of the aluminum element to the sum of the total number of moles of the iron element combined with oxygen reduction and the chromium element combined with oxygen reduction in the chromium compound satisfies 1.05-1.5.

When the reducing agent comprises a metal or an alloy containing silicon, the ratio of the mole number of 1/2 silicon to the sum of the mole total number of the iron element combined oxygen reduction and the chromium element combined oxygen reduction in the chromium compound satisfies 1.05-1.5.

When the reducing agent is a combination of a carbon reducing agent and a metal or an alloy containing calcium, silicon and aluminum, the ratio of the sum of the mole numbers of the carbon element, the calcium element, the 1/2 silicon element and the 2/3 aluminum element to the sum of the mole numbers required for reduction of iron-combined oxygen and reduction of chromium-combined oxygen in the chromium compound satisfies 1.05-1.5.

More preferably, in order to ensure the completeness and sufficiency of the reduction of chromium and the economy of direct alloying, in the reducing agent, the value of M is preferably 1.1 to 1.3.

The method for directly carrying out chromium alloying on molten steel can be selected into two modes of formula design and steel ladle adding according to the alloying carbon-containing target, the economical efficiency and the amount of the generated additional reducing slag.

Further, the first method is as follows: the reducing agent mainly uses carbon element, the material pressing block is added into a steel ladle waiting for steel tapping in advance before steel tapping, partial chromium carbon thermal reduction and carbonization are carried out on the reaction material in advance under the action of heat accumulated in the steel ladle, partial heat emitted by the steel ladle is absorbed and utilized to carry out some thermal compensation, and then the condition of complete chromium reduction is realized by means of molten steel deoxidation alloying in the subsequent steel tapping process, and the immediate molten steel direct chromium alloying of chromium compounds is completed while steel tapping. The method generates less additional reducing slag relatively, can also utilize more carbon heat for reduction, but has certain molten steel recarburization and is used for replacing finished high and medium carbon ferrochrome.

Further, the second method is as follows: the reducing agent mainly adopts metal elements or completely adopts metal or alloy thereof, a material pressing block is added into a steel ladle before or when tapping is started, and the instant molten steel direct chromium alloying of chromium compounds is completed while tapping by virtue of the condition that the molten steel deoxidization alloying realizes the complete chromium reduction in the tapping process through the excitation reduction reaction of the heat of the molten steel. The method relatively generates more additional reduction slag (depending on the chromium grade of the chromium compound), and can control little or no recarburization in the direct alloying process according to the proportion of carbon element in the reducing agent, so that the method is used for substituting finished low-carbon ferrochrome alloy to carry out micro-chromium or low-chromium alloying treatment on molten steel.

The invention is further described with reference to specific examples.

Example 1

In the embodiment, the medium carbon steel liquid is directly subjected to chromium alloying to replace high carbon ferrochrome. Adopting south African chromite with the Cr2O3 content of 45%, wherein the FeO content and the Fe2O3 content of the iron oxide are respectively 21% and 6%, adopting anthracite powder with the fixed carbon of 88% and ferrosilicon with the silicon content of 72% as material oxygen balance reducing agents, and considering that the weight ratio of thermal compensation to economy is 1: 1; since the high-carbon ferrochrome contains 5.8% of carbon, the ratio of the total number of moles of the elemental carbon and 1/2 silicon metal in the reducing agent to the total number of moles of the iron and chromium-bonded oxygen elements in the chromium compound is 1.3. 8.4kg of chromite (2.64 kg of pure chromium element, 1.76kg of iron and chromium combined oxygen element) is taken, 1.13kg of ferrosilicon and 1.13kg of anthracite are calculated to be uniformly mixed, 1.0kg of sodium silicate binding agent diluted solution is added to be uniformly mixed, the mixture is pressed into a rectangular block with the size of about 40 x 50mm, 11.7kg of total alloying material is added into a casting hot ladle with the capacity of 1 ton and the lining surface temperature of 900 ℃, and the steel is discharged after being baked for 10 minutes. The total tapping amount of the intermediate frequency furnace is 800kg, 1kg of pure aluminum for molten steel deoxidation alloying and 2kg of ferrosilicon containing 75 percent of silicon are added into a steel ladle before tapping, the components of the molten steel in the steel ladle and the intermediate frequency furnace are C0.35 percent, Si 0.18 percent and chromium 0.04 percent, and finally, the analysis shows that the content of C0.38 percent, Si 0.43 percent and Cr 0.34 percent in a steel sample of the steel ladle are reduced, the yield of chromium alloy elements in direct alloying materials added by chromium is 90.9 percent, and the level of the chromium alloy elements is equivalent to that of the finished ferrochrome alloy.

Example 2

In the embodiment, the low-carbon structural steel liquid is directly subjected to chromium alloying to replace low-carbon ferrochrome. The method is characterized in that the south African chromite with the Cr2O3 content of 45% is adopted, the iron oxide FeO content and the Fe2O3 content are respectively 21% and 6%, anthracite powder with the fixed carbon content of 88% and calcium and silicon-calcium alloy with the silicon content of 30% and 50% are respectively adopted as a material oxygen balance reducing agent, and the ratio of the total mole number of elemental carbon, elemental calcium and 1/2 silicon metal in the reducing agent to the total mole number of iron and chromium combined oxygen elements in a chromium compound is 1.1. The low-carbon ferrochrome only contains 0.5 percent of carbon, and the economical efficiency is also considered, and a small amount of anthracite is contained in the material. 8.4kg of chromite (2.64 kg of pure chromium element, and 1.76kg of iron and chromium combined oxygen element) is taken, and 2.4kg of silicon-calcium alloy and 0.25kg of anthracite are calculated as corresponding reducing agents. Mixing the fine powder of each material uniformly, adding 0.8kg of sodium silicate binder diluted solution, pressing into rectangular blocks with the size of about 40 × 50mm, adding 10.45kg of total alloying material into a casting hot ladle with the capacity of 1 ton and the lining surface temperature of 800 ℃, and tapping after waiting for 15 minutes. The total tapping amount of the intermediate frequency furnace is 900kg, and 1kg of pure aluminum for molten steel deoxidation alloying and 2kg of ferrosilicon containing 75% of silicon are added into a steel ladle before tapping. The compositions of the molten steel sampled in the steel ladle and the intermediate frequency furnace are C0.04%, Si 0.05% and Cr 0.03%, and finally C0.06%, Si 0.20% and Cr 0.29% in the steel sample of the steel ladle are analyzed, and the yield of the chromium alloy element in the direct alloying material added by the reduced amount of the chromium is 88.7%, which is equivalent to the level of the finished ferrochrome alloy.

Example 3

The method of the embodiment directly performs chromium alloying on the super-carbon structural steel liquid to replace micro-carbon ferrochrome. India chromite with the Cr2O3 content of 54 percent is adopted, the contents of iron oxide FeO and Fe2O3 are respectively 16.6 percent and 0 percent, and low-carbon ferrosilicon with the silicon content of 80 percent (the C percent is not more than 0.10) is adopted as a material oxygen balance reducing agent. As the carbon content of the micro-carbon ferrochrome is less than 0.03 percent, no carbon material is added. The ratio of the total number of moles of silicon metal reduced to 1/2 in the reducing agent to the total number of moles of iron and chromium combined with oxygen in the chromium compound was 1.1. 7.1kg of chromite (2.64 kg of pure chromium element, 1.47kg of iron and chromium combined oxygen element) and 1.98kg of low-carbon ferrosilicon are uniformly mixed, 0.8kg of sodium silicate binding agent solution is added and uniformly mixed, the mixture is pressed into a rectangular block with the size of about 40 x 50mm, 9.8kg of total alloyed material is added during tapping, and the rectangular block is added into a casting hot ladle with the capacity of 1 ton and the lining surface temperature of 800 ℃. The total steel output of the intermediate frequency furnace is 850kg, 1kg of pure aluminum for molten steel deoxidation alloying and 2kg of low-carbon ferrosilicon containing 78% of silicon are added into a steel ladle before steel tapping, the components of the molten steel in the steel ladle and the intermediate frequency furnace are C0.05%, Si 0.055%, and chromium 0.02%, finally, the analysis shows that the content of C0.060%, Si 0.20% and Cr0.30% in a steel sample of the steel ladle, the yield of chromium alloy elements in direct alloying material added by chromium is 90.2%, and the level of the chromium alloy elements is equivalent to that of the finished ferrochrome alloy.

Example 4

In the embodiment, the medium carbon steel liquid is directly subjected to chromium alloying to replace high carbon ferrochrome. Adopting south African chromite with the Cr2O3 content of 45%, wherein the FeO content and the Fe2O3 content of the iron oxide are respectively 21% and 6%, adopting anthracite powder with the fixed carbon of 88% and ferrosilicon with the silicon content of 72% as material oxygen balance reducing agents, and considering that the weight ratio of thermal compensation to economy is 1: 1; since the high-carbon ferrochrome contains 5.8% of carbon, the ratio of the total number of moles of the elemental carbon and 1/2 silicon metal in the reducing agent to the total number of moles of the iron and chromium-bonded oxygen elements in the chromium compound is 1.5. 8.4kg of chromite (2.64 kg of pure chromium element, 1.76kg of iron and chromium combined oxygen element) is taken, 1.4kg of ferrosilicon and 1.4kg of anthracite are calculated to be uniformly mixed, 1.0kg of sodium silicate binding agent diluted solution is added to be uniformly mixed, the mixture is pressed into a rectangular block with the size of about 40 x 50mm, 12.4kg of total alloying material is added into a casting hot ladle with the capacity of 1 ton and the lining surface temperature of 940 ℃, and steel tapping is carried out after 12 minutes of waiting. The total tapping amount of the intermediate frequency furnace is 825kg, 1kg of pure aluminum for molten steel deoxidation alloying and 2kg of ferrosilicon containing 75% of silicon are added into a steel ladle before tapping, the components of the molten steel in the steel ladle and the intermediate frequency furnace are C0.35%, Si 0.19% and chromium 0.03%, the yield of C0.39%, Si 0.44% and Cr 0.32% in a steel sample of the steel ladle is finally analyzed, and the yield of chromium alloy elements in the direct alloying material added by chromium is 91%, and the total mole number of element carbon and 1/2 silicon metal in the reduced reducing agent is equivalent to the total mole number of iron and chromium combined oxygen elements in a chromium compound when the total mole number of the finished ferrochrome alloy level and the total mole number of element carbon and 1/2 silicon metal in the reduced reducing agent is 1.3.

Example 5

In the embodiment, the low-carbon structural steel liquid is directly subjected to chromium alloying to replace low-carbon ferrochrome. The method adopts south African chromite with the Cr2O3 content of 45%, the iron oxide FeO content and the Fe2O3 content of the south African chromite are respectively 21% and 6%, anthracite powder with the fixed carbon content of 88% and calcium and silicon-calcium alloy with the silicon content of 30% and 50% are respectively used as a material oxygen balance reducing agent, and the ratio of the total mole number of elemental carbon, elemental calcium and 1/2 silicon metal in the reducing agent to the total mole number of iron and chromium combined oxygen elements in a chromium compound is 1.05. The low-carbon ferrochrome only contains 0.5 percent of carbon, and the economical efficiency is also considered, and a small amount of anthracite is contained in the material. 8.4kg of chromite (2.64 kg of pure chromium element, and 1.76kg of iron and chromium combined oxygen element) is taken, and 2.3kg of silicon-calcium alloy and 0.25kg of anthracite are calculated as corresponding reducing agents. Mixing the fine powders, adding 0.8kg of sodium silicate binder diluted solution, pressing into rectangular blocks with the size of about 40 × 50mm, adding 10.3kg of total alloying materials into a casting hot ladle with the capacity of 1 ton and the lining surface temperature of 800 ℃, baking for 15 minutes, and tapping. The total tapping amount of the intermediate frequency furnace is 880kg, 1kg of pure aluminum for molten steel deoxidation alloying, 2kg of ferrosilicon containing 75% of silicon and 1.3kg of unmixed briquetted part in silicon-calcium alloy for calculating reduction chromium compounds are added into a steel ladle before tapping. The compositions of the molten steel sampled in the steel ladle and the intermediate frequency furnace are C0.04%, Si 0.05%, and chromium 0.03%, and finally C0.06%, Si 0.20%, and Cr 0.29% in the steel sample of the steel ladle are analyzed, and the yield of chromium alloy elements in the direct alloying material is 87.7% in terms of chromium, which is slightly lower than the level that the ratio of the total number of moles of element carbon, element calcium and 1/2 silicon metal in the finished ferrochrome alloy and the horizontal reduction agent to the total number of moles of iron and chromium combined with oxygen elements in the chromium compound is 1.1.

Example 6

The method of the embodiment directly performs chromium alloying on the super-carbon structural steel liquid to replace micro-carbon ferrochrome. India chromite with the Cr2O3 content of 54 percent is adopted, the contents of iron oxide FeO and Fe2O3 are respectively 16.6 percent and 0 percent, and low-carbon ferrosilicon with the silicon content of 80 percent (the C percent is not more than 0.10) is adopted as a material oxygen balance reducing agent. As the carbon content of the micro-carbon ferrochrome is less than 0.03 percent, no carbon material is added. The ratio of the total number of moles of silicon metal reduced to 1/2 in the reducing agent to the total number of moles of iron and chromium combined with oxygen in the chromium compound was 1.2. 7.1kg of chromite (2.64 kg of pure chromium element, 1.47kg of iron and chromium combined oxygen element) and 2.16kg of low-carbon ferrosilicon are uniformly mixed, 0.8kg of sodium silicate binding agent solution is added and uniformly mixed, the mixture is pressed into a rectangular block with the size of about 40 x 50mm, the total amount of alloying materials is 10.0kg, and the rectangular block is added into a casting hot ladle with the capacity of 1 ton and the lining surface temperature of 810 ℃ during tapping. The total steel output of the intermediate frequency furnace is 850kg, 1kg of pure aluminum for molten steel deoxidation alloying and 2kg of low-carbon ferrosilicon containing 78% of silicon are added into a steel ladle before steel tapping, the components of the molten steel in the steel ladle and the intermediate frequency furnace are C0.04%, Si 0.055% and chromium 0.03%, finally C0.05%, Si 0.20% and Cr0.31% in a steel sample of the steel ladle are analyzed, the yield of chromium alloy elements in the direct alloying material added with chromium is 90.5%, the level of the chromium alloy elements is equivalent to the level of finished ferrochromium alloy, and the level is slightly better than the level when the ratio of the total mole number of silicon metal of element 1/2 in a reducing agent to the total mole number of iron and chromium combined oxygen elements in a chromium compound is 1.1.