A slag-making method and application for the smelting of all scrap electric arc furnaces based on the high-voltage block ratio

Abstract

The present invention provides a slag-making method and application for all scrap electric arc furnace smelting based on high-pressure block ratio, including S1: setting slag in the smelting furnace before smelting; S2: adding the first batch of slag materials into the furnace through a high-position bin at the start of smelting; S3: adding mixed scrap with a high-pressure block ratio charge structure into the furnace through a continuously preheated horizontal channel at the start of smelting, while supplying power and oxygen to the furnace; S4: injecting carbon powder into the furnace during the period from 5 minutes of smelting to the stage of stopping adding mixed scrap, and keeping the carbon powder injection rate constant; S5: adding electric furnace tail slag and the second batch of slag materials at 8-12 minutes of smelting; S6: adding the third batch of slag materials into the furnace at 18-20 minutes of smelting; S7: keeping the carbon powder injection rate constant during the period from stopping adding scrap to the tapping stage; S8: discharging slag within 3-5 minutes after stopping adding scrap. The present invention can optimize the slag-making system of the entire smelting process, improve the arc thermal efficiency, and reduce the occurrence of splashing caused by the arc impacting the slag layer due to excessive slag viscosity.

Description

Technical Field

[0001] The present invention relates to the technical field of arc furnace steelmaking smelting control, and particularly relates to a slag-making method and application for all-scrap arc furnace smelting based on the high-pressure block ratio.

Background Art

[0002] Currently, due to the low price of steel, the competitiveness of all-scrap arc furnace smelting is relatively low. Generally, the raw material structure used in all-scrap electric furnace steelmaking is poor, with a relatively large proportion of briquettes and light and thin shavings, which has a certain negative impact on smelting. In the all-scrap arc furnace smelting process, there is usually remaining slag in the furnace before smelting. To make the slag generate bubbles as soon as possible to form foamed slag for submerged arc and to increase the carbon content of the molten steel, carbon balls with a relatively large density are added to the furnace when starting to supply power. At the same time, to make foamed slag as soon as possible, 1 / 2 - 2 / 3 of the slag materials are added within 10 minutes before power-on smelting. During this process, as FeO in the slag is reduced and diluted, and scrap is continuously added with low power utilization efficiency, the temperature of the molten pool continuously drops to 1520 - 1530 °C. At this time, the viscosity of the foamed slag is too large, the effect of the foamed slag becomes poor, and the height of the buffer area of the foamed slag where the briquettes fall into the molten pool shrinks, resulting in a severe impact effect of the briquettes, causing the slag and steel to be splashed and adhered to the furnace lid and furnace wall, resulting in the melting oxidation of the furnace lid and furnace wall and the deterioration of the heat transfer effect, increasing the hidden danger of furnace lid and furnace wall leakage; at the same time, it is extremely easy to have arc impact on the molten pool, resulting in splashing, increasing the consumption of metal materials, and also increasing the formation of nodules on the furnace lid and furnace wall to a certain extent.

[0003] In the all-scrap arc furnace smelting process, the slag-making system is crucial. It is necessary to carry out submerged arc smelting with foamed slag throughout the process. Therefore, it is necessary to adopt oxygen supply operation throughout the process. In order to maintain the foamed slag in a good state throughout the smelting process, it is necessary to control the oxygen supply to maintain an appropriate FeO content to achieve an efficient and reasonable slag-making system. If the slag-making system is unreasonable, it will prolong the smelting time, increase power consumption, reduce the furnace lining life, especially cause the occurrence of nodule formation on the furnace lid and furnace wall, leading to the occurrence of furnace lid leakage accidents, and at the same time, it is easy to have splashing, resulting in an increase in metal material consumption.

[0004] Therefore, it is necessary to study a slag-making method and application for all-scrap arc furnace smelting based on the high-pressure block ratio to address the deficiencies of the existing technology and solve or alleviate one or more of the above problems.

Summary of the Invention

[0005] In view of this, the present invention provides a slag-making method and application for smelting all scrap electric arc furnace based on high-pressure block ratio. By optimizing the slag-making system of the entire smelting process, controlling the oxygen supply intensity in the early stage, increasing the FeO content in the early slag, promoting the rapid melting of slag materials, quickly forming a foamed slag for submerged arc smelting, improving the arc thermal efficiency, increasing the height of the buffer area where scrap materials fall into the molten pool, reducing the probability of slag-steel splashing and sticking to the furnace cover and furnace wall due to the violent impact of large-sized blocks on the molten pool, and at the same time reducing the occurrence of splashing caused by the arc impacting the slag layer due to excessive slag viscosity.

[0006] On the one hand, the present invention provides a slag-making method for smelting all scrap electric arc furnace based on high-pressure block ratio. The slag-making method for smelting all scrap electric arc furnace is completed by a horizontally charged electric furnace, and the steel grade to be smelted is plain carbon steel. The slag-making method for smelting all scrap electric arc furnace includes the following steps:

[0007] A slag-making method for smelting all scrap electric arc furnace based on high-pressure block ratio. The slag-making method for smelting all scrap electric arc furnace is completed by a horizontally charged electric furnace, and the steel grade to be smelted is plain carbon steel. It is characterized in that the slag-making method for smelting all scrap electric arc furnace includes the following steps:

[0008] S1: Set slag in the smelting furnace before smelting;

[0009] S2: Add the first batch of slag materials into the furnace through a high-position bin at the beginning of smelting;

[0010] S3: Add the mixed scrap with a high-pressure block ratio furnace charge structure into the furnace through a continuously preheated horizontal channel at the beginning of smelting, and at the same time supply power and oxygen to the furnace;

[0011] S4: During the period from 5 minutes of smelting to the stage of stopping adding the mixed scrap, inject carbon powder into the furnace, and maintain the carbon powder injection rate at a certain value and keep it constant;

[0012] S5: At 8 - 12 minutes of smelting, add electric furnace tail slag and the second batch of slag materials into the furnace through the horizontal feeding channel and the high-position bin respectively;

[0013] S6: At 18 - 20 minutes of smelting, add the third batch of slag materials into the furnace;

[0014] S7: From the stage of stopping adding scrap to the tapping stage, maintain the carbon powder injection rate at a certain value and keep it constant;

[0015] S8: Discharge slag within 3 - 5 minutes after stopping adding scrap.

[0016] For the aspects and any possible implementation described above, a further implementation is provided. The horizontal feeding electric furnace is equipped with a lance oxygen lance at the furnace door, two wall oxygen lances, and three wall carbon lances. The lance oxygen lance is arranged at the furnace door of the horizontal feeding electric furnace. The two wall oxygen lances include a first wall oxygen lance and a second wall oxygen lance. The central angle formed by the first wall oxygen lance and the lance oxygen lance is 44° - 46°, and the central angle formed by the second wall oxygen lance and the first wall oxygen lance is 89° - 91°. The three wall carbon lances include a first wall carbon lance, a second wall carbon lance, and a third wall carbon lance. The first wall carbon lance is arranged above the furnace door of the horizontal feeding electric furnace. The second wall carbon lance is arranged above the second wall oxygen lance. The central angle formed by the second wall carbon lance and the first wall carbon lance is 134° - 136°, the central angle formed by the third wall carbon lance and the first wall carbon lance is 134° - 136°, and the central angle formed by the second wall carbon lance and the third wall carbon lance is 89° - 91°.

[0017] For the aspects and any possible implementation described above, a further implementation is provided. In step S3, the oxygen supply time is from the start of smelting to the tapping stage. During the smelting process, the total oxygen supply flow rate is controlled within 53 Nm 3 ·h -1 ·t -1 ~59 Nm 3 ·h -1 ·t -1 , and the oxygen supply flow rate is kept constant. The oxygen supply flow rate of the lance oxygen lance is 40 Nm 3 ·h -1 ·t -1 , where the oxygen supply flow rate of the first wall oxygen lance is 13 Nm 3 ·h -1 ·t -1 ~19 Nm 3 ·h -1 ·t -1 . The oxygen supply flow rate of the second wall oxygen lance is fine-tuned according to the slag overflow situation at the furnace door, and the adjustment range is ±3 Nm 3 ·h -1 ·t -1 . When adjusting, the total oxygen supply flow rate of the two wall oxygen lances remains unchanged.

[0018] For the aspects and any possible implementation described above, a further implementation is provided. In step S4, a certain value is 45 kg·min -1 ·t -1 ~50 kg·min -1 ·t -1 , the carbon injection rate of the first carbon lance is 25 kg·min -1 ·t -1 , and the carbon injection rate of the second carbon lance is 15 kg·min-1 ·t -1 The carbon injection rate of the third carbon lance is 5 kg·min -1 ·t -1 -10 kg·min -1 ·t -1 The carbon injection rate of the third carbon lance can be fine-tuned according to the slag overflow situation at the furnace door, and the adjustment range is ±2 kg·min -1 ·t -1 During adjustment, the total carbon injection rate of the three wall-mounted carbon lances remains unchanged, and a certain value in S7 is 60 - 65 kg / min

[0019] In the aspects and any possible implementation manners as described above, a further implementation manner is provided. The first batch of slag materials is 3 - 3.5 kg / t carbon balls, 16 - 17.6 kg / t lime, and 4 - 4.5 kg / t magnesium balls. The second batch of slag materials is 11.8 - 13 kg / t lime and 4 - 4.5 kg / t magnesium balls. The third batch of slag materials is 10 - 11.8 kg / t lime

[0020] In the aspects and any possible implementation manners as described above, a further implementation manner is provided. In S3, the proportion of briquettes in the mixed scrap steel of the high-pressure briquette ratio to furnace charge structure is 20% - 25%, and the average size of the briquettes is 700 mm × 500 mm × 500 mm

[0021] In the aspects and any possible implementation manners as described above, a further implementation manner is provided. In S3, the oxygen supply method is a constant oxygen supply flow rate, the FeO content in the slag increases to 23% ± 2%, and in S7, the tapping stage is the end point of smelting. The control target of the FeO content in the slag at the end point of smelting is 20% ± 2%

[0022] In the aspects and any possible implementation manners as described above, a further implementation manner is provided. In S5, the composition of the electric furnace tail slag is FeO: 17 - 19%, MgO: 8 - 9%, and the basicity is 2 - 2.2

[0023] In the aspects and any possible implementation manners as described above, a further implementation manner is provided. The slag set in S1 is the remaining slag in the furnace at the end of the previous furnace smelting. Among them, the composition of the remaining slag is the composition of the slag at the end point of the previous furnace smelting. The slag composition is FeO: 20 - 25%, MgO: 8 - 9%, and the basicity is 2 - 2.2. The purpose of slag discharging in S8 is to prevent the accumulation of continuous smelting amount, which may lead to excessive slag amount and affect the heating effect

[0024] In the aspects and any possible implementation manners as described above, a further application of the slag-making method for all-scrap electric arc furnace smelting based on the high-pressure briquette ratio is provided, and the electric furnace tail slag solid waste is treated by the slag-making method for all-scrap electric arc furnace smelting

[0025] Compared with the prior art, the present invention can achieve the following technical effects:

[0026] The slag-making method proposed by the present invention optimizes the oxygen supply operation in the smelting process, increases the FeO content in the slag in the early stage of all-scrap steel smelting, thereby promoting the rapid melting of the slag material and shortening the formation time of the foamy slag. At the same time, taking advantage of the characteristics of high FeO content, low melting point, and less endothermic for pre-melting of the electric arc furnace tail slag, the electric arc furnace tail slag is added at an opportune time in the early stage of smelting to improve the slag composition and state, enhance the quality of the foamy slag, reduce the power consumption per ton of steel, and reduce the probability of slag and steel splashing and adhering to the furnace lid and furnace wall caused by the severe impact of large-sized compacts on the molten pool, which in turn increases the probability of water leakage in the furnace lid and furnace wall. At the same time, it reduces the occurrence of splashing caused by the arc impacting the slag layer due to excessive slag viscosity. It reduces the possibility of safety hazards of water leakage in the furnace lid and furnace wall of the all-scrap steel electric arc furnace and the labor intensity of the furnace front workers. At the same time, it also treats the solid waste of the electric arc furnace tail slag, turning waste into treasure, which has certain environmental protection significance.

[0027] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned technical effects simultaneously.

Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is the layout diagram of the oxygen and carbon guns provided by an embodiment of the present invention;

[0030] Figure 2 It is the flow chart of the slag-making method for all-scrap steel electric arc furnace smelting provided by an embodiment of the present invention.

Detailed Embodiments

[0031] In order to better understand the technical solutions of the present invention, the embodiments of the present invention will be described in detail below with reference to the drawings.

[0032] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0033] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "a", "the" and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise.

[0034] As Figure 2 shown, the present invention provides a slag-making method for melting all scrap in an electric arc furnace based on a high-pressure block ratio. The slag-making method for melting all scrap in an electric arc furnace is completed by a horizontally charged electric furnace. The steel grade to be smelted is plain carbon steel. The slag-making method for melting all scrap in an electric arc furnace includes the following steps:

[0035] S1: Set slag in the smelting furnace before smelting;

[0036] S2: At the start of smelting, add the first batch of slag materials into the furnace through a high-position storage bin;

[0037] S3: At the start of smelting, add mixed scrap with a high-pressure block ratio furnace charge structure into the furnace through a continuously preheated horizontal channel, and at the same time, supply power and oxygen to the furnace;

[0038] S4: From 5 minutes after the start of smelting until the stage of stopping adding mixed scrap, inject carbon powder into the furnace, and maintain the injection rate of carbon powder at a certain value and keep it constant;

[0039] S5: At 8 - 12 minutes of smelting, add electric furnace tail slag and the second batch of slag materials into the furnace through the horizontal charging channel and the high-position storage bin respectively;

[0040] S6: At 18 - 20 minutes of smelting, add the third batch of slag materials into the furnace;

[0041] S7: From the stage of stopping adding scrap to the tapping stage, maintain the injection rate of carbon powder at a certain value and keep it constant;

[0042] S8: Discharge slag within 3 - 5 minutes after stopping adding scrap.

[0043] The horizontal feeding type electric furnace is equipped with one lance at the furnace door, two lances on the furnace wall and three carbon lances on the furnace wall. The lance at the furnace door is arranged at the furnace door of the horizontal feeding type electric furnace. The two lances on the furnace wall include a first lance on the furnace wall and a second lance on the furnace wall. The central angle formed by the first lance on the furnace wall and the lance at the furnace door is 44°-46°. The central angle formed by the second lance on the furnace wall and the first lance on the furnace wall is 89°-91°. The three carbon lances on the furnace wall include a first carbon lance on the furnace wall, a second carbon lance on the furnace wall and a third carbon lance on the furnace wall. The first carbon lance on the furnace wall is arranged above the furnace door of the horizontal feeding type electric furnace. The second carbon lance on the furnace wall is arranged above the second lance on the furnace wall. The central angle formed by the second carbon lance on the furnace wall and the first carbon lance on the furnace wall is 134°-136°. The central angle formed by the third carbon lance on the furnace wall and the first carbon lance on the furnace wall is 134°-136°. The central angle formed by the second carbon lance on the furnace wall and the third carbon lance on the furnace wall is 89°-91°. In step S3, the oxygen supply time is from the start of smelting to the tapping stage. During the smelting process, the total oxygen supply flow rate is controlled at 53 Nm 3 ·h -1 ·t -1 ~59 Nm 3 ·h -1 ·t -1 , and the oxygen supply flow rate is kept constant. The oxygen supply flow rate of the lance at the furnace door is 40 Nm 3 ·h -1 ·t -1 , of which the oxygen supply flow rate of the first lance on the furnace wall is 13 Nm 3 ·h -1 ·t -1 ~19 Nm 3 ·h -1 ·t -1 , and the oxygen supply flow rate of the second lance on the furnace wall is fine-tuned according to the slag overflow situation at the furnace door, and the adjustment range is ±3 Nm 3 ·h -1 ·t -1 , and the total oxygen supply flow rate of the two lances on the furnace wall remains unchanged during the adjustment.

[0044] In step S4, a certain value is 45 kg·min -1 ·t -1 ~50 kg·min -1 ·t -1 , the carbon injection rate of the first carbon lance is 25 kg·min -1 ·t -1 , the carbon injection rate of the second carbon lance is 15 kg·min -1 ·t -1 , the carbon injection rate of the third carbon lance is 5 kg·min -1 ·t -1 -10 kg·min -1 ·t -1, the carbon injection rate of the third carbon lance can be finely adjusted according to the slag overflow situation at the furnace door, and the adjustment range is ±2 kg·min -1 ·t -1 , when adjusting, the total carbon injection rate of the three wall carbon lances remains unchanged, and a certain value in S7 is 60 - 65 kg / min. The first batch of slag materials is 3 - 3.5 kg / t carbon balls, 16 - 17.6 kg / t lime, and 4 - 4.5 kg / t magnesium balls. The second batch of slag materials is 11.8 - 13 kg / t lime and 4 - 4.5 kg / t magnesium balls. The third batch of slag materials is 10 - 11.8 kg / t lime. The proportion of briquettes in the mixed scrap steel of the high-pressure briquette ratio furnace charge structure in S3 is 20% - 25%, and the average size of the briquettes is 700 mm × 500 mm × 500 mm. The oxygen supply method in S3 is a constant oxygen supply flow rate, and the FeO content in the slag increases to 23% ± 2%. The tapping stage in S7 is the end of smelting, and the target FeO content of the end slag of smelting is controlled at 20% ± 2%. The composition of the electric furnace tail slag in S5 is FeO: 17 - 19%, MgO: 8 - 9%, and the basicity is 2 - 2.2. The slag set in S1 is the remaining slag in the furnace at the end of the previous furnace smelting. Among them, the composition of the remaining slag is the composition of the end slag of the previous furnace smelting, and the slag composition is FeO: 20 - 25%, MgO: 8 - 9%, and the basicity is 2 - 2.2. The purpose of slag discharging in S8 is to prevent the cumulative amount of continuous smelting from causing excessive slag volume and affecting the heating effect.

[0045] The present invention also provides an application of a slag-making method for all-scrap electric arc furnace smelting based on the high-pressure briquette ratio, and the electric furnace tail slag solid waste is treated by the slag-making method for all-scrap electric arc furnace smelting.

[0046] Example 1:

[0047] The present invention discloses a slag-making method and application for all-scrap electric arc furnace smelting based on the high-pressure briquette ratio. The all-scrap electric arc furnace is a Consteel horizontal charging type electric furnace, equipped with one furnace door oxygen lance, two wall oxygen lances, and three wall carbon lances. The layout diagram is as Figure 1 shown. The steel grade to be smelted is plain carbon steel. The method specifically includes the following steps:

[0048] Step 1: There is remaining slag in the furnace at the end of the previous furnace smelting. The composition of the remaining slag is the composition of the end slag of the previous furnace smelting, FeO: 20 - 25%, MgO: 8 - 9%, and the basicity is 2 - 2.2;

[0049] Step 2: At the beginning of smelting, 3 - 3.5 kg / t carbon balls, 16 - 17.6 kg / t lime, and 4 - 4.5 kg / t magnesium balls are added to the furnace through the high-level bunker; Adding carbon balls instead of injecting carbon powder is because the carbon balls have a greater density, which can promote better bubble effect in the slag in the early stage and have a better carbon addition effect for the molten steel.

[0050] Step 3: At the start of smelting, power is supplied and oxygen is blown. The mixed scrap steel with a high-pressure briquette ratio furnace charge structure is added into the furnace through a continuously preheated horizontal channel. The proportion of the briquette is 20% - 25%, and the average size of the briquette is 700mm×500mm×500mm;

[0051] Step 4: The total oxygen supply flow rate during the entire smelting process is controlled within 53 Nm 3 ·h -1 ·t -1 ~59 Nm 3 ·h -1 ·t -1 and the oxygen supply flow rate is kept constant. Among them, the oxygen supply flow rate of the lance at the furnace door is 40 Nm 3 ·h -1 ·t -1 ; the oxygen supply flow rate of the No. 2 lance on the furnace wall is 13 Nm 3 ·h -1 ·t -1 ~19 Nm 3 ·h -1 ·t -1 ; the oxygen supply flow rate of the lance can be finely adjusted according to the slag overflow situation at the furnace door, and the adjustment range is ±3 Nm 3 ·h -1 ·t -1 . When adjusting, it is necessary to ensure that the total oxygen supply flow rate of the two lances remains unchanged;

[0052] Step 5: No pulverized carbon is sprayed into the furnace within 5 minutes after power is supplied at the start of smelting, and the FeO content in the slag is increased to 23% ± 2%;

[0053] Step 6: From 5 minutes of smelting to the stage of stopping adding scrap steel, the pulverized carbon spraying rate is kept constant at 45 kg·min-1·t -1 ~50 kg·min -1 ·t -1 . The pulverized carbon spraying rate of the No. 1 carbon lance is 25 kg·min -1 ·t -1 , the pulverized carbon spraying rate of the No. 2 carbon lance is 15 kg·min -1 ·t -1 , the pulverized carbon spraying rate of the No. 3 carbon lance is 5 kg·min -1 ·t -1 -10 kg·min -1 ·t -1 . The pulverized carbon spraying rate of the carbon lance can be finely adjusted according to the slag overflow situation at the furnace door, and the adjustment range is ±2 kg·min -1 ·t -1 . When adjusting, it is necessary to ensure that the total pulverized carbon spraying rate of the carbon lances remains unchanged;

[0054] Step 7: When smelting for 8-12 minutes, add 9.4-11.8kg / t of electric furnace tailings and the second batch of slag 11.8-13kg / t of lime and 4-4.5kg / t of magnesium balls into the furnace through the horizontal feeding channel and the high-level silo respectively;

[0055] Step 8: After smelting for 18-20 minutes, add the third batch of slag 10-11.8kg / t lime into the furnace, and all slag addition is completed;

[0056] Step 9: Stop adding scrap steel until the steel is tapped. There is no fixed time to stop adding scrap steel. It varies according to the capacity of the electric arc furnace and the scrap steel adding rate. The carbon powder spraying rate is maintained at 60-65kg / min and remains constant, and the carbon spraying rate of the 1# carbon gun is 30kg·min -1 ·t -1 , the carbon spraying rate of No. 2 carbon gun is 20kg·min -1 ·t -1 , the carbon spraying rate of 3# carbon gun is 10kg·min -1 ·t -1 -15kg·min -1 ·t -1 ;

[0057] The oxygen blowing method for all-scrap steel electric arc furnace smelting does not adopt the low-medium-high oxygen flow mode, but adopts a constant oxygen flow rate. The purpose is to increase the oxygen supply in the early stage, appropriately increase the FeO content in the slag, promote the melting of slag, reduce the viscosity of slag, create good conditions for the formation of foam slag, and shorten the formation time of foam slag. Reduce the possibility of slag steel sticking to the furnace cover due to the violent impact of scrap steel on the molten pool, thereby increasing the probability of leakage of the furnace cover, and reduce the occurrence of splashing caused by arc impact on the slag layer due to excessive slag viscosity. The purpose of reducing the oxygen flow rate in the later stage is to prevent the overoxidation of molten steel; the control of oxygen blowing volume in the whole process is basically the same as the low-medium-high oxygen blowing flow rate mode, and the purpose is to control the FeO content of the final slag.

[0058] The purpose of adding electric furnace tailings at the early stage of smelting is to maintain the state of foamy slag and quickly slag. The composition of electric furnace tailings is FeO: 17-19%, MgO: 8-9%, and the basicity is 2-2.2.

[0059] After the addition of scrap steel is stopped, the slag volume reaches the maximum value. The increase in the carbon injection volume per unit time is conducive to the C reduction reaction of FeO, so as to maintain the slag in a good foamy slag state and use the electrical energy to heat the molten steel with maximum efficiency; increasing the carbon injection rate reduces the FeO in the slag and improves the metal recovery rate. The target FeO content of the terminal slag is controlled at 20%±2%.

[0060] Table 1 shows the statistics of the total number of water leaks in the furnace lid and furnace wall for four consecutive months before and after adopting the slag-making method of the present invention. Table 2 shows the statistics of the number of splashes in the early stage of smelting for four consecutive months before and after adopting the slag-making method of the present invention. Table 3 shows the statistics of the power consumption per ton of steel for four consecutive months before and after adopting the slag-making method of the present invention.

[0061] Statistics of the total number of water leaks in the furnace lid and furnace wall before and after the implementation of the slag-making method

[0062]

[0063] Statistics of the number of splashes in the early stage of smelting before and after the optimization of the slag-making method

[0064]

[0065] Statistics of the power consumption per ton of steel before and after the optimization of the slag-making method

[0066]

[0067]

[0068] After the slag-making method of the present invention was implemented on-site, the number of water leaks in the furnace lid and furnace wall, the number of splashes in the early stage, and the power consumption per ton of steel in three consecutive months from April to June, July to September, and October to December decreased compared with before the implementation. This shows that using the optimized slag-making method of the present invention for smelting is effective in preventing the formation of nodules and water leaks in the furnace lid and furnace wall, preventing splashes in the early stage, and reducing the power consumption per ton of steel during the smelting process of a high-pressure block ratio all-scrap electric arc furnace.

[0069] The above has introduced in detail a slag-making method and application for smelting an all-scrap electric arc furnace based on a high-pressure block ratio provided by the embodiments of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

[0070] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not distinguish components by the difference in names, but by the difference in functions of the components. As used throughout the specification and claims, the terms "comprising" and "including" are open-ended terms and should be interpreted as "comprising / including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The following description in the specification is the preferred embodiment for implementing the present application, but the description is for the purpose of explaining the general principles of the present application and not for limiting the scope of the present application. The protection scope of the present application shall be subject to that defined by the appended claims.

[0071] It should also be noted that the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a commodity or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent in such commodity or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the commodity or system including the said element.

[0072] It should be understood that the term "and / or" used herein is only an associative relationship describing associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0073] The above description shows and describes several preferred embodiments of the present application. However, as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the application concept described herein through the above teachings or the technology or knowledge in the relevant field. And the changes and variations made by those skilled in the art that do not depart from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A slag-making method for the smelting of an all-scrap electric arc furnace based on the high-voltage block ratio. The slag-making method for the smelting of the all-scrap electric arc furnace is completed by a horizontally charged electric furnace, and the steel grade to be smelted is plain carbon steel. It is characterized in that, The full scrap electric arc furnace slag-making method includes the following steps: S1: Set slag in the smelting furnace before smelting; S2: At the beginning of smelting, add the first batch of slag materials into the furnace through a high-position bin; S3: At the beginning of smelting, add mixed scrap with a high-pressure block ratio furnace charge structure into the furnace through a continuously preheated horizontal channel, and at the same time supply power and oxygen to the furnace; S4: From 5 minutes of smelting to the stage of stopping adding mixed scrap, inject carbon powder into the furnace, and the carbon powder injection rate is maintained at a certain value and remains constant; S5: At 8 - 12 minutes of smelting, add electric furnace tail slag and the second batch of slag materials into the furnace through the horizontal feeding channel and the high-position bin respectively; S6: At 18 - 20 minutes of smelting, add the third batch of slag materials into the furnace; S7: From the stage of stopping adding scrap to the tapping stage, the carbon powder injection rate is maintained at a certain value and remains constant; S8: Discharge slag within 3 - 5 minutes after stopping adding scrap; The horizontal feeding type electric furnace is equipped with one lance at the furnace door, two lances on the furnace wall and three carbon lances on the furnace wall. The lance at the furnace door is arranged at the furnace door of the horizontal feeding type electric furnace. The two lances on the furnace wall include the first lance on the furnace wall and the second lance on the furnace wall. The central angle formed by the first lance on the furnace wall and the lance at the furnace door is 44° - 46°. The central angle formed by the second lance on the furnace wall and the first lance on the furnace wall is 89° - 91°. The three carbon lances on the furnace wall include the first carbon lance on the furnace wall, the second carbon lance on the furnace wall and the third carbon lance on the furnace wall. The first carbon lance on the furnace wall is arranged above the furnace door of the horizontal feeding type electric furnace. The second carbon lance on the furnace wall is arranged above the second lance on the furnace wall. The central angle formed by the second carbon lance on the furnace wall and the first carbon lance on the furnace wall is 134° - 136°. The central angle formed by the third carbon lance on the furnace wall and the first carbon lance on the furnace wall is 134° - 136°. The central angle formed by the second carbon lance on the furnace wall and the third carbon lance on the furnace wall is 89° - 91°; In step S3, the oxygen supply time is from the start of smelting to the tapping stage. During the smelting process, the total oxygen supply flow rate is controlled within 53 Nm 3 ·h -1 ·t -1 ~59 Nm 3 ·h -1 ·t -1 , and the oxygen supply flow rate is kept constant. The oxygen supply flow rate of the lance at the furnace door is 40 Nm 3 ·h -1 ·t -1 . Among them, the oxygen supply flow rate of the first lance on the furnace wall is 13 Nm 3 ·h -1 ·t -1 ~19 Nm 3 ·h -1 ·t -1 . The oxygen supply flow rate of the second lance on the furnace wall is fine-tuned according to the slag overflow situation at the furnace door, and the adjustment range of change is ±3 Nm 3 ·h -1 ·t -1 . When adjusting, the total oxygen supply flow rate of the two lances on the furnace wall remains unchanged; The certain value in S4 is 45 kg·min -1 ·t -1 ~50 kg·min -1 ·t -1 , the carbon injection rate of the first lance is 25 kg·min -1 ·t -1 , the carbon injection rate of the second lance is 15 kg·min -1 ·t -1 , the carbon injection rate of the third lance is 5 kg·min -1 ·t -1 -10 kg·min -1 ·t -1 , the carbon injection rate of the third lance can be fine-tuned according to the slag overflow at the furnace door, and the adjustment range is ±2 kg·min -1 ·t -1 , when adjusting, the total carbon injection rate of the three wall lances remains unchanged, and the certain value in S7 is 60 - 65 kg / min; In S3, the oxygen supply method is a constant oxygen supply flow rate, and the FeO content in the slag increases to 23% ± 2%. In S7, the tapping stage is the smelting end point, and the control target FeO content of the smelting end point slag is 20% ± 2%.

2. The slag-making method for melting scrap steel in an electric arc furnace according to claim 1, characterized in that, The first batch of slag materials is 3 - 3.5 kg / t carbon balls, 16 - 17.6 kg / t lime and 4 - 4.5 kg / t magnesium balls. The second batch of slag materials is 11.8 - 13 kg / t lime, 4 - 4.5 kg / t magnesium balls. The third batch of slag materials is 10 - 11.8 kg / t lime.

3. The slag-making method for melting with an all-scrap electric arc furnace according to claim 1, characterized in that, In S3, the proportion of the pressed blocks in the mixed scrap with a high-pressure block ratio furnace charge structure is 20% - 25%, and the average size of the pressed blocks is 700 mm × 500 mm × 500 mm.

4. The slag-making method for melting with an all-scrap electric arc furnace according to claim 1, characterized in that, The composition of the electric furnace tail slag in S5 is FeO: 17 - 19%, MgO: 8 - 9%, and the basicity is 2 - 2.

2.

5. The slag-making method for smelting in an all-scrap electric arc furnace according to claim 1, characterized in that, The slag set in S1 is the remaining slag in the furnace at the end of the previous furnace smelting. Among them, the remaining slag composition is the composition of the smelting end point slag of the previous furnace. The slag composition is FeO: 20 - 25%, MgO: 8 - 9%, and the basicity is 2 - 2.

2.

6. Application of a slag-making method for smelting with all scrap in an electric arc furnace based on the high-pressure block ratio, characterized in that, Treat the electric furnace tail slag solid waste by the full scrap electric arc furnace slag-making method described in any one of claims 1 - 5 above.

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