Molten iron ladle and scrap steel desulfurization process method

Abstract

The embodiment of the invention provides a molten iron ladle waste steel adding desulfurization process method which comprises the following steps: before molten iron is added, waste steel with the weight being 10-15% of that of the molten iron is added into a molten iron ladle, and the molten iron ladle is baked until the temperature of the inner wall of the molten iron ladle is 700-900 DEG C; after baking is finished, molten iron is added into the ladle; adding a steel melting agent into the ladle, wherein the steel melting agent comprises a carbonaceous material; conveying the ladle to a molten iron pretreatment desulfurization station; a composite desulfurizer is added into the ladle, and pretreatment desulfurization operation is conducted on the molten iron in the ladle through a KR desulfurization stirring technology; the composite desulfurizer comprises lime, fluorite and waste steel particles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel smelting, and particularly relates to a molten iron ladle waste steel desulfurization process method. BACKGROUND

[0002] In modern steel production, molten iron pretreatment desulfurization is a key link to ensure the quality of molten steel. The traditional molten iron pretreatment desulfurization process mainly operates on pure molten iron, but as the proportion of waste steel used in the steelmaking process continues to increase, more and more enterprises begin to try to add waste steel to the molten iron ladle before pretreatment desulfurization. However, in this case, the addition of more waste steel will change the composition and temperature of the molten iron, and have more adverse effects on the desulfurization effect.

[0003] In the process of realizing the present application, the applicant found that at least the following problems exist in the prior art:

[0004] After adding more waste steel to the molten iron, the waste steel does not melt, the molten iron has poor fluidity, and further causes problems such as reduced desulfurization efficiency and increased consumption of desulfurizing agent. SUMMARY

[0005] The embodiments of the present application provide a molten iron ladle waste steel desulfurization process method to at least solve the problems of waste steel not melting, poor fluidity of molten iron, and further causing problems such as reduced desulfurization efficiency and increased consumption of desulfurizing agent after adding more waste steel to the molten iron.

[0006] To achieve the above purpose, on the one hand, the embodiments of the present application provide a molten iron ladle waste steel desulfurization process method, comprising:

[0007] Before the molten iron is poured in, 10% to 15% of waste steel by weight of the molten iron is added to the molten iron ladle, and the molten iron ladle is roasted to an inner wall temperature of 700 to 900 degrees Celsius;

[0008] After the roasting is completed, the molten iron is poured into the molten iron ladle;

[0009] A steel-making agent is added to the molten iron ladle, and the steel-making agent comprises carbonaceous material;

[0010] The molten iron ladle is transported to a molten iron pretreatment desulfurization station;

[0011] A composite desulfurizing agent is added to the molten iron ladle, and a KR desulfurization stirring process is used to pretreatment desulfurize the molten iron in the molten iron ladle; the composite desulfurizing agent comprises lime, fluorite and waste steel particles.

[0012] Further, the molten iron is poured into the molten iron ladle after the roasting is completed, comprising:

[0013] After the end of the roasting, the molten iron is poured into the ladle, and the molten iron tapping temperature of the ladle is 1400-1500 degrees Celsius.

[0014] Further, the steel-making agent is added to the ladle, including:

[0015] During the pouring of the molten iron into the ladle or before the molten iron pretreatment desulfurization after the pouring, the steel-making agent is added to the ladle at a ratio of 30-60 kg per ton of scrap steel according to the amount of the added scrap steel.

[0016] Further, in the composite desulfurizer, the mass percentage of lime is 15-20%, the mass percentage of fluorite is 15-20%, and the mass percentage of scrap steel particles is 60-70%; the added amount of the composite desulfurizer is 3-5% of the weight of the molten iron in the ladle.

[0017] Further, after the end of the roasting, the molten iron is poured into the ladle, and during the pouring of the molten iron, the steel-making agent is added, and then the ladle is covered and kept warm.

[0018] Further, the carbonaceous material in the steel-making agent includes rice straw ash, carbon powder, coke, or graphite.

[0019] Further, the total scrap steel added to the ladle includes the scrap steel added to the ladle before the pouring of the molten iron and the scrap steel particles in the composite desulfurizer added to the ladle; wherein the total scrap steel added to the ladle accounts for 12-18% of the weight of the ladle; the scrap steel added to the ladle before the pouring of the molten iron accounts for 10-15% of the weight of the ladle.

[0020] Further, the carbon content in the scrap steel particles is ≥0.18%, and the external size is a cylindrical particle with a diameter less than 10 mm and a length less than 80 mm.

[0021] Further, the method includes: adding 10 tons of scrap steel to the ladle, and then roasting to a temperature of 700 degrees Celsius on the inner wall of the ladle;

[0022] After the end of the roasting, 100 tons of molten iron are poured into the ladle, and the temperature of the molten iron before the pouring is 1400 degrees Celsius;

[0023] The steel-making agent is added to the ladle when the pouring of the molten iron reaches 1 / 4 of the total amount of the molten iron to be poured, and the added amount of the steel-making agent is about 300 kg;

[0024] The ladle is transported to the molten iron pretreatment desulfurization station;

[0025] The composite desulfurizing agent is added into the ladle, wherein the mass percentage of lime in the composite desulfurizing agent is 20%, the mass percentage of fluorite is 20%, and the mass percentage of scrap steel particles is 60%; the adding amount of the composite desulfurizing agent is 3 tons; wherein the limestone and fluorite are 600 kg;

[0026] The molten iron is pretreated and desulfurized by using the KR desulfurizing stirring process to obtain desulfurized molten iron.

[0027] Further, the method comprises: adding 15 tons of scrap steel into the ladle, and then baking the ladle to 900 DEG C of the inner wall temperature of the ladle;

[0028] After the baking is completed, 100 tons of molten iron is quantitatively added into the ladle, and the temperature of the molten iron before being added into the ladle is 1550 DEG C;

[0029] When the molten iron to be added is 1 / 4 of the total amount of the molten iron to be added, the steel melting agent is added into the ladle, and the adding amount of the steel melting agent is about 900 kg;

[0030] The ladle is transported to the molten iron pretreatment desulfurization station;

[0031] The composite desulfurizing agent is added into the ladle, wherein the mass percentage of lime in the composite desulfurizing agent is 15%, the mass percentage of fluorite is 15%, and the mass percentage of scrap steel particles is 70%; the adding amount of the composite desulfurizing agent is 5 tons; wherein the limestone and fluorite are 750 kg;

[0032] The molten iron is pretreated and desulfurized by using the KR desulfurizing stirring process to obtain desulfurized molten iron.

[0033] The above technical solution has the following beneficial effects: the scrap steel to be added is added into the ladle twice, the first time is before the molten iron is added, the scrap steel is melted by baking and the molten iron, and the steel melting agent containing carbonaceous material is added to promote the melting of the scrap steel, the second time is when the desulfurizing agent is added, the scrap steel particles are added into the ladle as a component of the composite desulfurizing agent, and the scrap steel particles fall into the molten iron, so that the other components of the composite desulfurizing agent enter the molten iron, and the problem that the other components of the desulfurizing agent float on the surface of the molten iron and do not mix with the molten iron is solved to a certain extent, the desulfurization effect is improved, and the amount of the desulfurizing agent is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0035] Figure 1 is a flow chart of a molten iron ladle plus scrap steel desulfurization process method according to an embodiment of the present application;

[0036] Figure 2 is another flow chart of a molten iron ladle plus scrap steel desulfurization process method according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0038] In one aspect, as shown in Figure 1 , the present application provides a molten iron ladle plus scrap steel desulfurization process method, comprising:

[0039] Step S10, before the molten iron is poured in, scrap steel with a weight of 10% to 15% of the weight of the molten iron is added to the molten iron ladle, and the molten iron ladle is roasted to a temperature of 700 to 900 degrees Celsius on the inner wall of the molten iron ladle;

[0040] Step S11, after the roasting is completed, the molten iron is poured into the molten iron ladle;

[0041] Step S12, a steel-making agent is added to the molten iron ladle, and the steel-making agent comprises carbonaceous material;

[0042] Step S13, the molten iron ladle is transported to a molten iron pretreatment desulfurization station;

[0043] Step S14, a composite desulfurizer is added to the molten iron ladle, and a KR desulfurization stirring process is used to perform a pretreatment desulfurization operation on the molten iron in the molten iron ladle; the composite desulfurizer comprises lime, fluorite, and scrap steel particles.

[0044] The scrap steel is added into the molten iron to realize resource recycling, reduce the dependence on primary iron ore, and adjust the composition of the molten iron (such as carbon content and alloy element ratio), so as to provide a more suitable raw material basis for subsequent smelting. The scrap steel is controlled at 10%-15% of the weight of the molten iron. If the proportion is too low, the expected temperature adjustment or composition adjustment effect may not be achieved. If the proportion is too high, the temperature of the molten iron may be excessively reduced, affecting the subsequent smelting rhythm. The iron ladle is baked to 700-900 DEG C, which can reduce the temperature loss when the molten iron is poured into the ladle, and maintain the heat stability of the molten iron. Baking the iron ladle to a higher temperature in advance can avoid the thermal stress caused by the sharp temperature difference when the cold ladle body contacts the high-temperature molten iron, reduce damage such as ladle body cracking and peeling, and prolong the service life of the equipment. When the temperature is lower than 700 DEG C, the ladle body absorbs too much heat, which may cause the molten iron to be cooled down too much. When the temperature is higher than 900 DEG C, the ladle lining material (such as refractory bricks) may be overheated and aged, which shortens its service life and even causes safety hazards.

[0045] The embodiment of the present application has the following technical effects: The scrap steel to be added is added into the iron ladle twice, the first time is to add the scrap steel before pouring the molten iron, and the second time is to add the scrap steel particles as a component of the composite desulfurizer together with other components in the composite desulfurizer when adding the desulfurizer. When the scrap steel particles fall into the iron ladle, they will fall into the molten iron, so as to promote other components in the composite desulfurizer to enter the molten iron, to a certain extent, solve the problem that other components of the desulfurizer float on the surface of the molten iron and mix with the molten iron insufficiently, improve the desulfurization effect, and reduce the amount of desulfurizer.

[0046] Further, the pouring of the molten iron into the iron ladle after the baking is completed comprises:

[0047] After the baking is completed, the molten iron is poured into the iron ladle, and the molten iron temperature of the iron ladle is 1400 DEG C to 1500 DEG C.

[0048] When the temperature is lower than 1400℃, the fluidity of the molten iron is poor, which easily leads to the formation of a crust in the ladle, and the molten iron needs to consume more energy (such as oxygen and fuel) to increase the temperature after entering the converter, which prolongs the smelting time, and even causes difficulties in slagging and incomplete reaction due to insufficient temperature, which affects the uniformity of the molten iron composition. When the temperature is higher than 1500℃, the molten iron intensively erodes the refractory material inside the ladle, which shortens the service life of the ladle lining; the high-temperature molten iron also easily leads to an excessively violent reaction in the converter, which increases the risk of splashing, and may cause excessive burning loss of alloy elements (such as manganese and silicon) in the molten iron, which increases the cost of alloy consumption. The temperature of the molten iron in the temperature range of 1400-1500℃ can not only ensure that the molten iron has good fluidity, avoids the formation of a crust or difficulty in transportation, but also provides sufficient initial heat for the blowing of the converter, meets the temperature requirements of the reactions such as slagging, decarburization, and deoxidization, and reduces the excessive damage to the equipment.

[0049] Further, the steel-making agent is added to the ladle, including:

[0050] During the process of pouring the molten iron into the ladle or after pouring the molten iron and before the pretreatment of the molten iron, the steel-making agent is added to the ladle according to the amount of the scrap steel, and the proportion of the steel-making agent is 30-60 kg per ton of scrap steel.

[0051] After the carbonaceous material in the steel-making agent is dissolved in the molten iron, the interfacial tension between the molten iron and the surface of the scrap steel is reduced, the high-temperature molten iron is more easily wetted on the surface of the scrap steel, and the heat transfer and the melting of the scrap steel are accelerated.

[0052] Further, in the composite desulfurizing agent, the mass percentage of lime is 15-20%, the mass percentage of fluorite is 15-20%, and the mass percentage of scrap steel particles is 60-70%; the added amount of the composite desulfurizing agent is 3-5% of the weight of the molten iron in the ladle.

[0053] The lime, fluorite, and scrap steel particles in the composite desulfurizing agent can be processed by mixing in proportion offline and then poured into the ladle, or weighed and collected in a total bin according to the proportion and then added to the ladle, which has the beneficial effect of further increasing the amount of scrap steel in the ladle, and the scrap steel particles falling into the molten iron during the adding process impact the molten iron and enter the molten iron, so that the effective desulfurizing components such as lime can fully contact the molten iron in the ladle to improve the desulfurizing effect.

[0054] Further, after the roasting is completed, the molten iron is poured into the ladle, and the ladle is covered and kept warm after the steel-making agent is added during the process of pouring the molten iron.

[0055] Further, the carbonaceous material in the steel-making agent includes rice straw ash, carbon powder, coke, or graphite.

[0056] Further, the total scrap steel added to the ladle includes scrap steel added to the ladle before the molten iron is poured and scrap steel particles in the composite desulfurizer added to the ladle; wherein the total scrap steel added to the ladle accounts for 12% to 18% of the weight of the ladle; and the scrap steel added to the ladle before the molten iron is poured accounts for 10% to 15% of the weight of the ladle.

[0057] The amount of scrap steel added to the ladle can be increased to 12-18%, and the scrap steel is added in two times, wherein 10-15% of the scrap steel is added before the molten iron is poured, and the rest is added in the form of small scrap steel particles (scrap steel particles) with the desulfurizer during the pretreatment desulfurization of the molten iron.

[0058] Further, the carbon content in the scrap steel particles is ≥0.18%, and the shape size is a cylindrical particle with a diameter less than 10 mm and a length less than 80 mm.

[0059] If the carbon content of the scrap steel is too low (such as low-carbon cold-rolled scrap steel with a carbon content ≤0.05%), a large amount of addition (for example, accounting for 10% to 15% or even 12% to 18%) will significantly reduce the carbon concentration of the molten iron. By limiting the carbon content to ≥0.18%, the dilution range of the carbon in the molten iron can be reduced, the carbon material supplementing pressure in the flux can be reduced, and the amount of carbon material used can be saved. Carbon is an austenite-forming element in iron, which can reduce the melting point of the scrap steel. The melting point of the scrap steel with a carbon content ≥0.18% is 5-10℃ lower than that of low-carbon scrap steel, which is more easily melted at the same molten iron temperature (1400-1500℃), shortens the melting time, and reduces the heat consumption. The cylindrical particle with a diameter less than 10 mm and a length less than 80 mm can achieve rapid sinking of the desulfurizer into the molten pool, increase the contact with the molten iron, improve the desulfurization effect of the desulfurizer, and also avoid the problem of being too large to be quickly melted.

[0060] Further, the method comprises: adding 10 tons of scrap steel to the ladle, and then baking the ladle until the inner wall temperature of the ladle reaches 700℃;

[0061] After the baking is completed, 100 tons of molten iron is poured into the ladle, and the temperature of the molten iron before being poured into the ladle is 1400℃;

[0062] When the molten iron to be poured reaches 1 / 4 of the total amount of the molten iron to be poured, the flux is added to the ladle, and the amount of the flux added is about 300 kg;

[0063] The ladle is transported to a molten iron pretreatment desulfurization station;

[0064] The composite desulfurizer is added to the ladle, wherein the mass percentage of lime in the composite desulfurizer is 20%, the mass percentage of fluorite is 20%, and the mass percentage of scrap steel particles is 60%; the amount of the composite desulfurizer added is 3 tons; and the amount of the lime and the fluorite is 600 kg.

[0065] The molten iron is pretreated and desulfurized by a KR desulfurization stirring process.

[0066] Further, the method comprises: adding 15 tons of scrap steel into the ladle, and then baking to 900 DEG C of the inner wall temperature of the ladle;

[0067] After the baking is completed, 100 tons of molten iron is quantitatively added into the ladle, and the temperature of the molten iron before being added into the ladle is 1550 DEG C;

[0068] When the molten iron to be added is 1 / 4 of the total amount of the molten iron to be added, the steel-making agent is added into the ladle, and the amount of the steel-making agent is about 900 kg;

[0069] The ladle is transported to a molten iron pretreatment desulfurization station;

[0070] The composite desulfurizing agent is added into the ladle, wherein the mass percentage of lime in the composite desulfurizing agent is 15%, the mass percentage of fluorite is 15%, and the mass percentage of scrap steel particles is 70%; the amount of the composite desulfurizing agent is 5 tons; wherein the limestone and the fluorite are 750 kg;

[0071] The molten iron is pretreated and desulfurized by a KR desulfurization stirring process.

[0072] The above technical solutions of the embodiments of the present application are described in detail in combination with specific application examples, and the technical details not introduced in the implementation process can be referred to the related descriptions in the foregoing.

[0073] The method for adding scrap steel and pretreatment desulfurization of a ladle provided by the embodiments of the present application optimizes the ladle baking, adds scrap steel materials in batches, adds carbonaceous materials as a steel-making agent, and optimizes the proportioning of the desulfurizing agent, thereby solving the problems of non-melting of scrap steel in the ladle, low desulfurization efficiency, and large consumption of desulfurizing agent in the prior art under a high scrap steel ratio, so as to realize the effect of efficient and stable desulfurization after a high scrap steel amount (the amount of scrap steel accounts for more than 10% of the weight of molten iron) in the ladle, and simultaneously provide technical support for improving the scrap steel utilization rate of a steel enterprise and reducing carbon emissions. The main source of carbon emissions in the steelmaking process is molten iron, and the carbon emission per ton of steel can be reduced by increasing the amount of scrap steel and reducing the amount of molten iron per ton of steel produced. Therefore, the scrap steel ratio is increased from 5% to 10%, and the carbon emission per ton of steel can be reduced by 5%. Table 1 is a comparison between the embodiments of the present application and conventional (traditional) desulfurization processes. Among them, the conventional desulfurization process 1 and the conventional desulfurization process 2 first add scrap steel in the ladle according to the proportion, then add a certain amount of molten iron, and then transport to a molten iron pretreatment desulfurization station, add a conventional desulfurizing agent (fluorite + lime, the proportion of the two is between 3:6 and 5:6), and then stir and desulfurize. After desulfurization, the surface slag is usually removed. The difference between the conventional desulfurization process 1 and the conventional desulfurization process 2 is that the scrap steel ratio in the ladle is different.

[0074] Item Embodiments of the invention Conventional desulphurization process 1 Conventional desulphurization process 2 Ratio of molten iron to scrap 15％ 15％ 8％ Scrap melting ratio 98-100％ 78％ 98.5％ Scrap melting period time consumption 8-12 minutes More than 20 minutes 18 minutes Desulphurization time 12-15 minutes 25 minutes 20 minutes Desulphurization rate 92.8-93.6％ 92.5％ 92.6％ Temperature drop during desulphurization process 18.5-21.8 degrees Celsius 37.5 degrees Celsius 27.6 degrees Celsius

[0075] Table 1 Comparison of the embodiments of the present invention with conventional (traditional) desulfurization processes

[0076] To achieve the above objectives, such as Figure 2 As shown, this embodiment of the invention provides a desulfurization process for molten iron ladle with scrap steel, which is also a method for desulfurization by adding scrap steel to molten iron ladle and pretreatment, including the following steps:

[0077] Step 1: Add a portion of scrap steel to the molten iron ladle, the weight of which is 10-15% of the weight of the molten iron, and then bake it until the temperature of the inner wall of the ladle reaches 700-900℃.

[0078] Step 2: After baking, add a measured amount of molten iron to the ladle. The tapping temperature of the molten iron should be 1400-1500℃.

[0079] Step 3: During the molten iron mixing process, steelmaking agent is added to the ladle. Its main component is carbonaceous material. The amount added is calculated based on the total amount of scrap steel mentioned in Step 1, approximately 30-60 kg / ton of scrap steel.

[0080] Step four: Transport the molten iron ladle to the molten iron pretreatment desulfurization station.

[0081] Step 5: Add a composite desulfurizing agent to the molten iron ladle. Its main components are lime, fluorite, and small scrap steel particles. The mass percentages of lime, fluorite, and scrap steel particles are 15-20%, 60-70%, respectively. The amount of composite desulfurizing agent added is 3-5% of the weight of the molten iron.

[0082] Step 6: Pre-treatment and desulfurization of molten iron using the KR (Kambara Reactor) desulfurization stirring process.

[0083] Preferably, after the baking in step two is completed, the molten iron ladle is covered to keep it warm.

[0084] Preferably, the steelmaking agent in step three is mainly composed of carbonaceous materials, such as straw ash, carbon powder, coke, or graphite. The beneficial effect is that it can significantly improve the melting effect of scrap steel and enhance the fluidity of the molten metal in the ladle, providing good kinetic conditions for pretreatment desulfurization.

[0085] Preferably, carbonaceous materials can also be added after molten iron is added and before the molten iron is pretreated for desulfurization, but it is strictly forbidden to add them before molten iron is added, because adding them in the baking state will cause burn-off and affect the accurate control of the amount added.

[0086] Preferably, the composite desulfurizer, lime, fluorite and small steel scrap particles in step five can be mixed in proportion and processed offline before being added to the ladle, or can be weighed in proportion and collected in a total bin before being added to the ladle, which can achieve the beneficial effect of further increasing the amount of scrap steel in the ladle and allowing the effective desulfurizing components such as lime to fully contact the molten iron in the ladle during the addition process to improve the desulfurizing effect. The amount of scrap steel added to the ladle can be increased to 12-18% of the weight of the molten iron, and the scrap steel is added in two batches, of which 10-15% of the weight of the molten iron is added before the molten iron is added, and the rest is added in the form of small steel scrap particles with the desulfurizer during the pretreatment desulfurization process.

[0087] Preferably, the small steel scrap particles in step five require a carbon content of ≥0.18%, and the outer size requires a cylindrical small particle with a diameter of <10mm and a length of <80mm. The beneficial effect that can be achieved is that the secondary added scrap steel is quickly melted without affecting the fluidity of the molten iron.

[0088] The embodiment of the present application has the following technical effects: adding steel-making agent during the iron charging process, which is mainly composed of carbonaceous materials. The fluidity of the molten iron is used to continuously melt the scrap steel in the ladle during the iron charging process. The addition of the steel-making agent can significantly improve the melting effect of the scrap steel (without the steel-making agent, the scrap steel may not melt and float on the slag surface of the ladle, and after adding the steel-making agent, the scrap steel is completely melted, and there is no unmelted scrap steel on the slag surface of the ladle), and the fluidity of the molten metal in the ladle is improved (when the carbon content of the molten metal in the ladle increases from 3% to 4.3%, the melting point decreases, and the fluidity significantly improves at the same temperature) to provide good kinetic conditions for the pretreatment desulfurization. Adding 60-70% of small steel scrap particles to the traditional desulfurizer can increase the amount of scrap steel in the ladle by adding scrap steel for the second time, and can also increase the specific gravity of the desulfurizer, so that the desulfurizer can contact the molten metal in the ladle for a longer time when it is added, thereby improving the desulfurizing effect and reducing the amount of desulfurizer used. Specifically, the amount of lime and fluorite is reduced, and the amount of lime and fluorite used in the traditional process is 1000kg per furnace. In the following two embodiments of the present application, the amount of lime and fluorite is reduced to 600kg and 750kg per furnace, respectively. The scrap steel is added in two batches. A portion of the scrap steel is added to the ladle, and the weight of the scrap steel is 10-15% of the weight of the molten iron, and then the ladle is roasted to a temperature of 800-1000℃. The remaining portion is mixed with the desulfurizer and added, which can increase the amount of scrap steel added to the ladle to 12-18%.

[0089] The following is described with another specific embodiment. The embodiment of the present application provides a ladle scrap steel desulfurization process, which is also a method of adding scrap steel to the ladle and pretreatment desulfurization, including the following steps:

[0090] Step one, adding 10 tons of scrap steel to the ladle, and then roasting the ladle to a temperature of 700℃.

[0091] Step two, after the end of roasting, the ladle is quantitatively filled with 100 tons of molten iron, and the temperature of the molten iron is 1400℃.

[0092] Step three, when the molten iron is added to 1 / 4, steel-making agent is added to the ladle, and the main component is carbonaceous material, and the added amount is about 300kg.

[0093] Step four, the ladle is transported to the molten iron pretreatment desulfurization station.

[0094] Step five, the composite desulfurizer is added to the ladle, and the main components are lime, fluorite and small steel particles. The mass percentage of lime is 20%, the mass percentage of fluorite is 20%, and the mass percentage of small steel particles is 60%. The added amount of the composite desulfurizer is 3 tons, and the limestone and fluorite are 600kg.

[0095] Step six, the KR desulfurization stirring process is used to pretreat the molten iron to obtain desulfurized molten iron.

[0096] The following is described with another specific embodiment, and the embodiment of the application provides a molten iron ladle desulfurization process method, which is also a molten iron ladle desulfurization method, comprising the following steps:

[0097] Step one, 15 tons of scrap steel are added to the ladle, and then roasting is performed until the temperature of the inner wall of the ladle is 900℃.

[0098] Step two, after the end of roasting, the ladle is quantitatively filled with 100 tons of molten iron, and the temperature of the molten iron is 1550℃.

[0099] Step three, when the molten iron is added to 1 / 4, steel-making agent is added to the ladle, and the main component is carbonaceous material, and the added amount is about 900kg.

[0100] Step four, the ladle is transported to the molten iron pretreatment desulfurization station.

[0101] Step five, the composite desulfurizer is added to the ladle, and the main components are lime, fluorite and small steel particles. The mass percentage of lime is 20%, the mass percentage of fluorite is 20%, and the mass percentage of small steel particles is 60%. The added amount of the composite desulfurizer is 3 tons, and the limestone and fluorite are 600kg.

[0102] Step six, the KR desulfurization stirring process is used to pretreat the molten iron to obtain desulfurized molten iron.

[0103] It should be understood that the particular order in which the steps of processes presented in the disclosure have been presented makes no limitation as to the scope of the disclosure. Based upon the teachings provided herein, one skilled in the art should appreciate that alternative order explanations of various steps can be implemented to be simultaneously parallel or in some cases possibly performed at different times. Also, the various steps can be reordered and / or "interleaved" with one another such that the ordering presented herein and described is an example only and should not be taken as a restriction of how the steps of the processes presented herein can be implemented. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order presented by the claims.

[0104] In the foregoing detailed description, various features are grouped together in single embodiments for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are expressly recited in each claim. Rather, as the claims below reflect, inventive subject matter lies in fewer than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate preferred embodiment.

[0105] Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed in any further embodiments. The embodiments disclosed herein will be or become patentable in the term of the patent law. It should be understood that the use of particular

[0106] The foregoing description includes example of one or more embodiments. Of course, not all possible combinations of components or method steps are described, but one of ordinary skill in the art having the benefit of this disclosure will recognize that many more combinations and permutations of the described elements are possible. It is intended that the embodiments described herein as well as those that can be apparent to one of ordinary skill in the art and are within the scope of the following claims are encompassed by the present disclosure. Furthermore, the description given herein should be considered an example only, and the intimate scope of the disclosure is intended to encompass any novel one, or independently novel combination, of the described elements or processes. In addition, any use of the term "or" in the description is meant to encompass both "and" and "or" unless otherwise indicated.

[0107] The above detailed description merely describes preferred embodiments of the application, and is not intended to limit the scope of the application. Various modifications and alterations to this description will become apparent to those of ordinary skill in the art having the benefit of this disclosure. It is intended that all such modifications and alterations be considered part of this disclosure. Therefore, the scope of the application should be determined by the following claims and their legal equivalents.

Claims

1. A desulfurization process using molten iron ladle and scrap steel, characterized in that, include: Before adding molten iron, add 10% to 15% of the weight of scrap steel to the ladle and bake it until the temperature of the inner wall of the ladle is 700 to 900 degrees Celsius. After baking, molten iron is added to the ladle; A steelmaking agent, comprising carbonaceous materials, is added to the molten iron ladle. The molten iron ladle is transported to the molten iron pretreatment desulfurization station; A composite desulfurizing agent is added to the molten iron ladle, and the molten iron in the ladle is pretreated and desulfurized using the KR desulfurization stirring process; the composite desulfurizing agent includes lime, fluorite and scrap steel particles.

2. The desulfurization process of adding scrap steel to molten iron ladle as described in claim 1, characterized in that, The step of adding molten iron to the ladle after baking includes: After baking, molten iron is added to the ladle to bring the tapping temperature of the molten iron from the ladle to between 1400 and 1500 degrees Celsius.

3. The desulfurization process using scrap steel in a molten iron ladle as described in claim 1, characterized in that, Adding a steelmaking agent to the molten iron ladle includes: During the process of adding molten iron to the ladle or before the molten iron pretreatment and desulfurization after adding molten iron, the steelmaking agent is added to the ladle at a ratio of 30 kg to 60 kg of steelmaking agent per ton of scrap steel, depending on the amount of scrap steel added.

4. The desulfurization process using scrap steel in a molten iron ladle as described in claim 1, characterized in that, In the composite desulfurizing agent, the mass percentage of lime is 15% to 20%, the mass percentage of fluorite is 15% to 20%, and the mass percentage of scrap steel particles is 60% to 70%; the amount of the composite desulfurizing agent added is 3% to 5% of the weight of the molten iron in the ladle.

5. The desulfurization process using scrap steel in a molten iron ladle as described in claim 1, characterized in that, After baking, molten iron is added to the ladle, and a steelmaking agent is added during the process of adding the molten iron. The ladle is then covered to keep it warm.

6. The desulfurization process of adding scrap steel to molten iron ladle as described in claim 1, characterized in that, The carbonaceous materials in the steelmaking agent include rice straw ash, carbon powder, coke, or graphite.

7. The desulfurization process of adding scrap steel to molten iron ladle as described in claim 1, characterized in that, The total scrap steel added to the molten iron ladle includes scrap steel added to the ladle before the molten iron is poured in and scrap steel particles from the composite desulfurizing agent added to the ladle; wherein the total scrap steel added to the ladle accounts for 12% to 18% of the weight of the molten iron ladle; and the scrap steel added to the ladle before the molten iron is poured in accounts for 10% to 15% of the weight of the molten iron ladle.

8. The desulfurization process of adding scrap steel to molten iron ladle as described in claim 1, characterized in that, The scrap steel particles have a carbon content of ≥0.18% and are cylindrical particles with a diameter of less than 10 mm and a length of less than 80 mm.

9. The desulfurization process of adding scrap steel to molten iron ladle as described in claim 1, characterized in that, 10 tons of scrap steel were added to the ladle, and then it was baked until the temperature of the inner wall of the ladle reached 700 degrees Celsius. After baking, 100 tons of molten iron are added to the ladle in a measured amount. The temperature of the molten iron before being added to the ladle is 1400 degrees Celsius. When the molten iron reaches 1 / 4 of the total amount to be added, start adding the steelmaking agent into the ladle. The amount of steelmaking agent added is about 300 kg. The molten iron ladle is transported to the molten iron pretreatment desulfurization station; A composite desulfurizing agent is added to the molten iron ladle. The composite desulfurizing agent contains 20% lime, 20% fluorite, and 60% scrap steel particles by mass. The total amount of composite desulfurizing agent added is 3 tons, of which 600 kg are limestone and fluorite. Desulfurized molten iron is obtained by pre-treating and desulfurizing molten iron using the KR desulfurization stirring process.

10. The desulfurization process of adding scrap steel to molten iron ladle as described in claim 1, characterized in that, The method includes: Add 15 tons of scrap steel to the molten iron ladle, and then bake it until the inner wall temperature of the molten iron ladle reaches 900°C; After baking, 100 tons of molten iron are added to the ladle in a measured amount. The temperature of the molten iron before being added to the ladle is 1550℃. When the molten iron reaches 1 / 4 of the total amount to be added, start adding the steelmaking agent to the ladle. The amount of steelmaking agent added is about 900 kg. The molten iron ladle is transported to the molten iron pretreatment desulfurization station; A composite desulfurizing agent is added to the molten iron ladle. The composite desulfurizing agent contains 15% lime, 15% fluorite, and 70% scrap steel particles by mass. The total amount of composite desulfurizing agent added is 5 tons, of which 750 kg are limestone and fluorite. Desulfurized molten iron is obtained by pre-treating and desulfurizing molten iron using the KR desulfurization stirring process.

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