Recycling method and equipment for one-stage smelting of waste steel secondary material in refining furnace

Abstract

The invention provides a recovery processing method and equipment for one-stage smelting of a waste steel secondary material in a refining furnace, and the method comprises the following steps: adding the waste steel secondary material with the weight ratio of more than 50% into the refining furnace, and then melting the waste steel secondary material in the refining furnace; a reducing agent is added into the refining furnace, the waste steel secondary material is subjected to reduction deoxygenation in the refining furnace to become molten steel for the manufacturing process, and the waste steel secondary material subjected to recycling treatment is selected from any steel type. According to the method, the closed dust collection cover is arranged above the refining furnace, and the refining furnace with a dust collection structure is arranged above the dust collection cover, so that material damage caused by splashing of molten steel formed by melting of the waste steel secondary material can be prevented, and air pollution caused by scattering of flying dust formed at high temperature can be prevented. According to the method, continuous feeding can be achieved, the feeding position of the waste steel secondary material can be adjusted to ensure the feeding effect, and ingredients such as chromium and manganese can be added according to the requirements of the required molten steel to adjust the materials.

Description

Technical Field

[0001] The present invention relates to a method and equipment for recycling secondary steel scrap by one-stage smelting in a refining furnace, and more particularly to a method and equipment for recycling secondary steel scrap such as wood shavings, turnings, slag (ball mill water washing material), rust scale, flame cuttings, grinding chips, peeling materials, CNC wood shavings and similar waste materials after metal processing by one-stage smelting in a refining furnace. The weight proportion of the secondary steel scrap added in the refining furnace can be more than 50% to 100%. Background Art

[0002] Traditionally, raw iron ore (iron ore sand) is smelted in an electric arc furnace. In addition to raw iron ore, steel mills also use a large amount of scrap steel generated by construction to obtain high-quality steel using a double furnace smelting operation of an electric furnace (or converter) and a refining furnace. The scrap steel is put into an electric furnace to melt into liquid high-temperature molten steel. After the steel is tapped into a steel ladle, it is sent to a refining furnace for further refining. Usually, the molten steel is kept warm in the refining furnace and the composition and casting temperature are adjusted to achieve the effect of improving the quality of the steel embryo. For example, JP7266938B, CN113652523B, CN117587186A and other previous cases disclose double furnace smelting technology. Among them, scrap steel is classified into high-quality high-grade scrap materials if it is thick, high-density, less oxidized, clean and less dirty (grease, paint, water, sand, organic matter, etc.) and impurities (galvanized tin, etc.). Otherwise, it is secondary scrap steel, such as the shavings, turning chips, slag iron (ball mill water washing material), rust, flame cuttings, grinding chips, peeling materials, CNC shavings and similar processed waste materials mentioned in this article later, which contain a large amount of non-metallic, grease and fine particles. The greater the grade difference, the greater the price difference.

[0003] In the double furnace smelting, in order to improve the utilization rate of scrap steel, scrap steel is further added to the refining furnace, such as CN108660287A, CN117431365A, CN117778670A, CN114015836B, CN221094200U, etc. The scrap steel put into the refining furnace in the above-mentioned previous cases, for example, CN108660287A discloses the use of steel bar cut ends (secondary waste after non-mechanical processing) with a length of ≤100mm and a diameter of ≤40mm, CN117431365A discloses the use of large-tonnage scrap steel (secondary waste after non-mechanical processing) such as steel plate edge wire cut ends and tails, billets and middle package surplus steel, and CN114015836B discloses that the amount of scrap steel put into the refining furnace is 100kg / ton steel to 120kg / ton steel.

[0004] The finished steel enters the processing plant for subsequent processing. Among them, the waste (scrap steel) generated in the process of metal processing, such as shavings, turning chips, slag iron (ball mill water washing material), rust, flame cuttings, grinding chips, peeling materials, CNC shavings and similar waste materials after processing, although their composition is the same as the raw materials, they will be attached to lubricants such as turning oil during the processing, or they are easily oxidized due to poor storage environment after processing. They have the characteristics of fine fragmentation, high oxygen content, and high impurities. Therefore, these scrap steels are different from the primary materials such as simple recycled scrap steel or large pieces of scrap steel cut off. They belong to the secondary waste materials (or called secondary materials) in scrap steel. There is a significant price difference between secondary scrap steel and high-grade scrap steel, but because of the unstable recovery rate of adding water or poor recovery rate in the electric furnace (or converter), they can only be added in limited quantities. Even due to the characteristics of furnace operation such as blowing or dust collection, secondary materials cannot be used.

[0005] If we want to recycle secondary scrap steel into usable resources, the following methods are currently used:

[0006] 1. Briquetting forging method: As described in TW181997B and GB1313545A, the secondary scrap steel is ground and homogenized, then pressurized and filled into a metal container, forged into a steel embryo by heating and pressurizing, and a reducing atmosphere is introduced to reduce the metal oxides therein. CN116536535A directly uses a hydraulic press to briquette the steel embryos, and then puts them into a furnace as blocks to be melted into molten steel. The main problem of this method is the low working efficiency.

[0007] 2. Fuel furnace (electric furnace) smelting method: As described in CN208733152U, the scrap steel secondary material is added with coal and heated together in the fuel furnace to form molten steel, and the metal oxides in the secondary material can be reduced by carbon heat. The main problems of this method are: (1) The fuel furnace is the first stage of metal smelting. In order to obtain a large amount of initially smelted molten steel, the fuel furnace is large in size and wide in width. The furnace cover and the upper half of the furnace wall are equipped with a water cooling mechanism. In order to promote the melting of the incoming materials as soon as possible, a high voltage is introduced. During the smelting process, the scrap steel secondary material is easily adhered to the furnace body of the fuel furnace due to splashing, and a large amount of dust is generated during the smelting process. It is equipped with a powerful dust extraction system with strong dust collection characteristics, which causes the scrap steel secondary material to be lost in the form of slag and dust ash. , resulting in serious loss of secondary scrap steel materials, and the first stage of the smelting process in the fuel furnace will go through steps such as oxygen blowing desiliconization / dephosphorization, so the fuel furnace is an oxidizing atmosphere, which is not conducive to the effective reduction and deoxidation recovery of finely crushed highly oxidized secondary scrap steel materials. If the target yield or precious metal recovery rate is to be achieved, high-priced raw materials (high-grade high-quality scrap steel) must be used. Therefore, the maximum amount of secondary scrap steel added in the fuel furnace smelting method usually does not exceed 30% by weight; (2) The use of fossil fuels produces carbon emissions and air pollution. CN113430449B discloses the addition of 10% to 40% of low-chromium secondary materials (secondary materials) in the electric arc furnace of double furnace steelmaking.

[0008] 3. Medium frequency furnace smelting method: As described in CN111575440A and CN001040393A, the secondary scrap steel is cleaned and degreased, dried and dehydrated to remove impurities, and then a carburizer is added to the secondary scrap steel for reduction refining in a medium frequency furnace (induction furnace), and oxygen desulfurization and dephosphorization are performed before the secondary scrap steel is discharged from the furnace. The main problems of this method are: (1) the secondary scrap steel is easily lost in the form of slag due to splashing during the smelting process; (2) physical or chemical bridging can cause steel penetration and gas explosion, so impurities must be removed first, otherwise uneven heating may cause the medium frequency furnace to explode and cause industrial safety hazards. The process of removing impurities uses chemicals such as alkali, which are harmful to the environment; (3) the volume of the medium frequency furnace is small, and the amount that can be processed in one smelting is small. In addition, the narrow entrance of the medium frequency furnace makes the industrial safety risk high and the secondary scrap steel needs to be pre-treated.

[0009] In addition to the above-mentioned problems, the above-mentioned various secondary scrap steel material recycling and processing methods have limited processing capacity for secondary scrap steel materials and cannot efficiently remove and recover the precious elements contained in the secondary scrap steel materials, such as stainless steel and high-alloy steel secondary materials. Summary of the invention

[0010] In order to effectively recycle and process secondary scrap steel materials, the purpose of the present invention is to provide a method and equipment for recycling and processing secondary scrap steel materials by one-stage smelting in a refining furnace.

[0011] The present invention provides a method for recycling and treating secondary scrap steel by one-stage smelting in a refining furnace, the steps comprising:

[0012] Adding secondary scrap steel materials with a weight ratio of between 50% and 100% in a refining furnace, and then melting the secondary scrap steel materials in the refining furnace. Adding a reducing agent in the refining furnace, the secondary scrap steel materials are reduced and deoxidized in the refining furnace to become molten steel for the process. The secondary scrap steel materials to be recycled and processed are selected from any type of steel.

[0013] Furthermore, the secondary scrap steel material is secondary scrap steel material of alloy steel.

[0014] Furthermore, the reducing agent includes coke added to the refining furnace or silicon and lime added during the smelting process.

[0015] Furthermore, a dust collecting hood is arranged above the refining furnace, and the dust collecting hood prevents the splashing of molten steel from the secondary scrap steel material, causing material damage, and prevents the scattering of flying dust formed by high temperature, causing air pollution. Furthermore, a dust collecting structure is arranged above the dust collecting hood, thereby raising the setting position of the dust collecting structure, and the flying dust is cooled quickly without the need for a water cooling mechanism. The dust collecting structure can avoid inhaling excessive and high-temperature flying dust, and extend the service life of the dust collecting structure. Generally, the height of the dust collecting hood is close to the height of the electrode rod. The present invention achieves the above-mentioned effect by arranging the dust collecting structure above the dust collecting hood, for example, the dust collecting structure can be controlled to be higher than the electrode rod by about 1.5 to 3 times, or at least higher than the electrode rod by about 2 to 6 meters. Therefore, as long as the setting height of the dust collecting structure can be raised, it is within the protection scope of the present invention even if it is not arranged above the dust collecting hood.

[0016] Furthermore, a scrap steel secondary material silo is provided, a feeding piece is connected to the scrap steel secondary material silo, and a movable feeding pipe is connected to the feeding piece and the refining furnace, and the movable feeding pipe can reciprocate between the feeding piece and the refining furnace, wherein the feeding piece can be provided with one of a vibration mechanism, a rolling mechanism, a disturbance mechanism or a stirring mechanism, and the feeding position of the scrap steel secondary material can be adjusted by vibration, rolling or stirring / disturbance by external objects, thereby achieving continuous feeding of the scrap steel secondary material and adjusting the feeding position of the scrap steel secondary material to ensure the feeding effect.

[0017] Furthermore, a scrap steel secondary material silo and a component adjustment silo are provided, the scrap steel secondary material silo and the component adjustment silo are connected to the refining furnace, the scrap steel secondary material is fed into the scrap steel secondary material silo, and the component adjustment material is fed into the component adjustment silo.

[0018] Furthermore, a slag discharge port is provided at a selected height of the refining furnace to discharge molten steel with more impurities above the selected height in the refining furnace.

[0019] Furthermore, a steel tapping port is arranged at the bottom of the refining furnace, so as to achieve slag-free steel tapping through the steel tapping port.

[0020] Furthermore, the furnace body of the refining furnace is made of air-permeable bricks, and the convection air can oxidatively remove impurities in the refining furnace, such as oxidatively removing phosphorus.

[0021] Furthermore, molten steel with different compositions can be added into the refining furnace to produce alloy steels with different compositions.

[0022] The present invention further provides a refining furnace device for carrying out the recovery and treatment method of the aforementioned secondary scrap steel material by one-stage smelting in a refining furnace, the refining furnace device comprising:

[0023] A refining furnace, with a steel outlet at the bottom of the refining furnace, a slag outlet at a selected height of the refining furnace, and an electrode rod at a high position of the refining furnace. A dust collecting hood, arranged above the refining furnace. A dust collecting structure, arranged above the refining furnace, the dust collecting structure is arranged at a height between about 1.5 and 3 times higher than the height of the electrode rod, or at least between about 2 meters and 6 meters higher than the height of the electrode rod. A scrap steel secondary material silo, with a feeding piece connected to the scrap steel secondary material silo, and a movable feeding pipe connected to the feeding piece and the refining furnace, the feeding piece is provided with one of a vibration mechanism, a rolling mechanism, a disturbance mechanism or a stirring mechanism, and the movable feeding pipe can reciprocate between the feeding piece and the refining furnace. A component adjustment silo, connected to the refining furnace.

[0024] The following effects can be achieved according to the above technical features:

[0025] 1. The present invention uses a refining furnace for one-stage smelting to recycle and process secondary scrap steel. The refining furnace for one-stage smelting directly puts the secondary scrap steel into the refining furnace for smelting. After smelting in the refining furnace, a high proportion of precious metals can be recovered and it can directly become molten steel that meets the quality requirements. The secondary scrap steel put into the refining furnace can be as high as 50% by weight, and even 100% of the secondary scrap steel can be put into the refining furnace for smelting and recycling. Therefore, the present invention can effectively remove the secondary scrap steel derived from the production of products in the city, and can use low-cost secondary scrap steel to produce high-value steel, which has the characteristics of urban steelmaking.

[0026] 2. The fuel furnace (electric furnace) is relatively large in size and has a relatively wide horizontal width. The furnace cover and the upper half of the furnace wall are equipped with a water cooling mechanism. In order to promote the melting of the incoming materials as quickly as possible, it has the characteristics of high voltage and an oxidizing atmosphere inside. Therefore, the smelting process has obvious splashing and will produce a large amount of dust. It is equipped with a powerful dust extraction system, and the finely divided scrap steel secondary materials are easily sucked away and lost. Compared with the smelting method using a fuel furnace (electric furnace), the refining furnace is relatively small in size and is slender. It can be sealed to achieve a reducing atmosphere (+reducing raw materials) environment. There is no water cooling in the production process, and the splashing is relatively weak, so generally no strong dust extraction is required (and the dust collection structure of the present invention is set higher). Therefore, the present invention smelts the scrap steel secondary materials in a refining furnace in a single stage, and adds coke or silicon and lime and other reducing agents during the smelting process for reduction and deoxidation. The refining furnace is a reducing environment with a reducing atmosphere, and a high recovery rate can be obtained for precious metals.

[0027] 3. Compared with the medium frequency furnace smelting method, the present invention smelts the secondary scrap steel in a refining furnace in a one-stage process, and adds coke or silicon and lime and other reducing agents during the smelting process for a reduction process. A larger amount can be recovered and processed at one time, and there is no need for a process to remove oil / impurities.

[0028] 4. The secondary scrap steel materials put into the refining furnace for one-stage smelting and recycling treatment in the present invention are not limited to steel types, such as carbon steel or alloy steel secondary scrap steel materials, and are particularly suitable for the recycling of high-value alloy steels such as 304 and 316 stainless steels.

[0029] 5. The present invention sets a closed dust collecting hood above the refining furnace, which can prevent the molten steel of the scrap secondary material from splashing and causing material damage, and prevent the flying dust formed by high temperature from scattering and causing air pollution. By raising the setting position of the dust collecting structure, for example, setting the dust collecting structure above the dust collecting hood, the flying dust cools quickly without the need for a water cooling mechanism, so the dust collecting structure can avoid inhaling excessive and high-temperature flying dust, and the service life of the dust collecting structure can be extended.

[0030] 6. Since the refining furnace is generally used for the second stage of smelting in the metal smelting process, it is intended to keep the molten steel melted in the first stage of the fuel furnace warm or refine it to obtain the required steel grade. The volume is small and the feed port is smaller than that of the fuel furnace. The scrap steel secondary material with uneven shapes may get stuck in the feed port. The present invention uses a feeding piece and a mobile feeding pipe to vibrate / roll / stir / disturb, and move the feeding, which can achieve the purpose of continuous feeding of the scrap steel secondary material, and can also adjust the feeding position of the scrap steel secondary material to ensure accurate feeding.

[0031] 7. The types of steel used for metal processing to produce cuttings are limited, and the composition of molten steel is affected by the input materials. The present invention sets up a double silo of a scrap steel secondary material silo and a composition adjustment silo. Through the composition adjustment silo, composition adjustment materials such as chromium and manganese can be added according to the required composition requirements of the molten steel, thereby increasing the flexibility of the molten steel composition.

[0032] 8. The present invention sets a steel tapping port at the bottom of the refining furnace, so as to tap steel from the bottom of the refining furnace, thereby achieving the effect of slag-free steel tapping, and sets a slag discharge port at a selected height of the refining furnace, so as to discharge molten steel with more impurities.

[0033] 9. The body of the refining furnace is made of air-permeable bricks, and the convection air can oxidize and remove impurities in the refining furnace, such as oxidative dephosphorization.

[0034] 10. Adding molten steel of different compositions into the refining furnace can produce alloy steels of different compositions and also reduce the use of alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the refining furnace equipment of the present invention.

[0036] Figure 2 is a flow chart of the method of the present invention.

[0037] Explanation of the accompanying numbers: 1-refining furnace; 11-steel outlet; 12-slag outlet; 13-electrode rod; 2-dust collecting hood; 3-dust collecting structure; 4-scrap secondary material silo; 5-feeding piece; 6-mobile feeding pipe; 7-composition adjustment silo; 8-trolley; A-molten steel. DETAILED DESCRIPTION

[0038] The following embodiments are only used to assist in explaining the method and equipment for recycling and treating secondary steel scrap by one-stage smelting in a refining furnace of the present invention, and are not intended to limit the present invention. Secondary steel scrap refers to waste materials after metal processing, such as wood shavings, turnings, slag (ball mill water washing materials), rust scale, flame cuttings, grinding chips, peeling materials, CNC wood shavings, etc.

[0039] See also Figure 1 As shown, the refining furnace equipment of this embodiment includes: a refining furnace 1, a steel outlet 11 with a sliding door is arranged at the bottom of the refining furnace 1, a slag outlet 12 is arranged at a selected height of the refining furnace 1, and an electrode rod 13 for heating is arranged at the upper half of the refining furnace 1. A dust collecting hood 2 is arranged above the refining furnace 1. A dust collecting structure 3 is arranged above the dust collecting hood 2, specifically, the setting position of the dust collecting structure 3 is raised, for example, the dust collecting structure 3 can be controlled to be higher than the height of the electrode rod 13 by about 1.5 to 3 times, or at least higher than the height of the electrode rod 13 by about 2 meters to 6 meters. A scrap steel secondary material bin 4, a feeding member 5 connected to the scrap steel secondary material bin 4, and a movable feeding pipe 6 connected to the feeding member 5 and the refining furnace 1, the feeding member 5 is provided with a vibration mechanism, a rolling mechanism, a disturbance mechanism or a stirring mechanism, and the movable feeding pipe 6 can reciprocate between the feeding member 5 and the refining furnace 1. A component adjustment bin 7, connected to the refining furnace 1. A trolley 8, used to carry the refining furnace 1, and the trolley 8 can easily carry and change the setting position of the refining furnace 1.

[0040] See also Figure 2 As shown, when performing the one-stage smelting and recycling of the secondary scrap steel material, the secondary scrap steel material with a weight ratio between 50% and 100% is added to the refining furnace 1, and then the secondary scrap steel material is melted in the refining furnace 1. A reducing agent is added to the refining furnace 1, so that the secondary scrap steel material is reduced and deoxidized in the refining furnace 1 to become molten steel A for the process. The secondary scrap steel material for recycling is not limited to the type of steel, for example, carbon steel or alloy steel secondary scrap steel material can be used, and is particularly suitable for the recycling of high-value alloy steels such as 304 and 316 stainless steel.

[0041] In this embodiment, the scrap steel secondary material is directly fed from the scrap steel secondary material bin 4, and there is no need to perform a process of removing oil / impurities from the scrap steel secondary material in advance. Vibration / rolling / stirring / disturbance and mobile feeding can be performed through the vibration mechanism, rolling mechanism, disturbance mechanism or stirring mechanism of the feeding member 5 and the mobile feeding pipe 6, so as to achieve the purpose of continuous feeding of the scrap steel secondary material, and the feeding position of the scrap steel secondary material can also be adjusted to ensure that the material is actually fed into the refining furnace 1, and the scrap steel secondary material will not be stuck at the feeding port of the refining furnace 1. After the scrap steel secondary material is completely fed, the electrode rod 13 is used to heat the scrap steel secondary material to melt it into molten steel A. During the smelting process, coke is added to the refining furnace 1, or silicon and lime are added as reducing agents. The molten steel A splashed during the smelting process can be blocked by the dust collecting cover 2 to prevent the molten steel A of the scrap steel secondary material from splashing and causing material damage. The dust collecting cover 2 can also prevent the flying dust formed at high temperature from scattering and causing air pollution. The dust collecting structure 3 is arranged above the dust collecting cover 2 to raise the setting position. Therefore, due to the fast cooling characteristic of the fly ash, it is not necessary to use a water cooling mechanism. The dust collecting structure 3 also avoids the inhalation of excessive and high-temperature fly ash, thereby extending the service life of the dust collecting structure 3. The furnace body of the refining furnace 1 is made of air-permeable bricks. The convection air can oxidize and remove impurities in the molten steel A in the refining furnace 1, such as oxidative dephosphorization. However, the types of steel used for metal processing to produce cuttings are limited, and the composition of the molten steel A is affected by the input material. Through the component adjustment silo 7, materials such as chromium and manganese can be added according to the composition requirements of the required molten steel A to increase the flexibility of the composition of the molten steel A. The scrap steel secondary material smelting process can also add molten steel A with different components in the refining furnace 1 to produce alloy steels with different components. After the secondary scrap steel material is melted into molten steel A, the molten steel A with a large amount of impurities such as floating solid oxides above a selected height in the refining furnace 1 can be discharged through the slag discharge port 12 after smelting, thereby shortening the operation schedule. Then, the steel can be tapped from the steel tapping port 11 at the bottom of the refining furnace 1 to achieve the effect of slag-free tapping.

[0042] Please refer to Table 1 below. This embodiment further tests the secondary scrap steel materials of 304, 310, 316, T91 and other steel grades. The secondary scrap steel materials are fed in the form of wood chips, and the input ratio is 100% of the secondary scrap steel materials. After the one-stage smelting and recycling treatment in the refining furnace, it can be found that the yield of molten steel reaches 91.7% to 99.3%, and the high yield of more than 90% can be achieved regardless of the steel grade.

[0043] Table 1

[0044]

[0045]

[0046] Please refer to Table 2 and Table 3 below, which further compare (1) the molten steel yield of the first-grade material of scrap steel smelted by a conventional steel mill using a fuel furnace (electric furnace), (2) the molten steel yield of the scrap steel smelting method described in the prior art by adding secondary materials to the fuel furnace (electric furnace), (3) the estimated molten steel yield of the scrap steel smelting method described in the prior art by adding secondary materials to 100%, and (4) the molten steel yield of the scrap steel smelting method of the present invention by the refining furnace in one stage. YS and YT in Table 3 are the plant numbers of the applicant. It can be seen from Table 2 and Table 3 that the molten steel yield of the scrap steel smelting method described in the prior art by adding secondary materials to the fuel furnace (electric furnace) is lower than the molten steel yield of the first-grade material of the scrap steel smelted by the conventional steel mill using the fuel furnace (electric furnace), and the molten steel yield estimated by adding secondary materials to 100% based on the addition ratio is even lower. Therefore, as described in the prior art, when the secondary scrap steel is recycled and processed by the fuel furnace (electric furnace) smelting method, the input rate of the secondary scrap steel is usually no more than 30% by weight; but when the secondary scrap steel is recycled and processed by the refining furnace of the present invention, the molten steel yield can be even higher than the molten steel yield of the primary scrap steel smelted by the fuel furnace (electric furnace) in the traditional steelmaking plant. In this way, in addition to being able to effectively remove the secondary scrap steel, the production cost of the molten steel is also significantly lower than the production cost of the traditional production method using raw ore or primary material due to the large amount of secondary scrap steel.

[0047] Table 2

[0048]

[0049] Table 3

[0050]

[0051] The recycling method of the secondary steel scrap material of the present invention through one-stage smelting in a refining furnace has not been disclosed by the prior art. Compared with the prior art, which can only recycle and process the secondary steel scrap material below 30% by weight per smelting, the recycling treatment of the secondary steel scrap material in the refining furnace of the present invention can add a high proportion of the secondary steel scrap material to the refining furnace (higher than 50% by weight, or even 100% completely added), and obtain a high recovery rate of precious metals after recycling and processing, which has unexpected effects. Therefore, the present invention is progressive. Furthermore, the method of recycling and processing a high proportion of secondary steel scrap material by one-stage smelting in a refining furnace has not been used by the steelmaking industry, so it also overcomes technical prejudice and solves the long-standing problem of the difficulty in processing secondary steel scrap material, which meets the auxiliary judgment of progressive factors.

[0052] Based on the description of the above embodiments, the operation, use and effects of the present invention should be fully understood. The above embodiments are only preferred embodiments of the present invention and should not be used to limit the scope of the present invention. That is, any simple equivalent changes and modifications made according to the claims and description of the present invention are within the scope of the present invention.

Claims

1. A method for recycling and treating secondary scrap steel by one-stage smelting in a refining furnace, comprising: Adding a secondary scrap steel material in a weight proportion of between 50% and 100% in a refining furnace, and then melting the secondary scrap steel material in the refining furnace; Adding a reducing agent into the refining furnace to reduce and deoxidize the secondary scrap steel into molten steel for the process; Wherein, the secondary scrap steel material to be recycled is selected from any type of steel.

2. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: The secondary scrap steel material is secondary alloy steel scrap steel material.

3. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: Reducing agents include coke added to the refining furnace, or silicon and lime added during the smelting process.

4. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: A dust collecting hood is arranged above the refining furnace to prevent the molten steel from the secondary scrap material from splashing and causing material damage, and to prevent the flying dust formed by high temperature from scattering and causing air pollution.

5. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: An electrode rod is disposed at a high position of the refining furnace, and a dust collecting structure is disposed above the refining furnace. The dust collecting structure is disposed at a position between about 1.5 and 3 times higher than the height of the electrode rod, or at least between about 2 and 6 meters higher than the height of the electrode rod. The setting position of the dust collecting structure is thereby raised, and the flying dust is cooled quickly without the need for a water cooling mechanism. The dust collecting structure can avoid inhaling excessive and high-temperature flying dust, thereby extending the service life of the dust collecting structure.

6. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: A scrap steel secondary material bin is provided, a feeding piece is provided to connect the scrap steel secondary material bin, and a movable feeding pipe is provided to connect the feeding piece and the refining furnace. The movable feeding pipe can move back and forth between the feeding piece and the refining furnace to achieve continuous feeding of the scrap steel secondary material and adjust the feeding position of the scrap steel secondary material.

7. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace as claimed in claim 6, wherein: The feeding member is provided with one of a vibration mechanism, a rolling mechanism, a disturbance mechanism or a stirring mechanism.

8. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace as claimed in claim 1, wherein: A scrap steel secondary material bin and a component adjustment bin are provided, the scrap steel secondary material bin and the component adjustment bin are connected to the refining furnace, the scrap steel secondary material is input from the scrap steel secondary material bin, and the component adjustment material is input from the component adjustment bin.

9. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: A slag discharge port is arranged at a selected height of the refining furnace to discharge molten steel with more impurities above the selected height in the refining furnace.

10. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: A steel tapping port is arranged at the bottom of the refining furnace, so as to achieve slag-free steel tapping through the steel tapping port.

11. The method for recycling secondary steel scrap by one-stage smelting in a refining furnace according to claim 1, wherein: The furnace body of the refining furnace is made of air-permeable bricks, and convection air can oxidize and remove impurities in the refining furnace.

12. The method for recycling secondary scrap steel by one-stage smelting in a refining furnace as claimed in claim 1, further comprising adding molten steel of different compositions into the refining furnace to produce alloy steels of different compositions.

13. A refining furnace equipment, used for carrying out the one-stage smelting recovery method of secondary scrap steel in a refining furnace as claimed in any one of claims 1 to 12, comprising: A refining furnace, wherein a steel tapping port is arranged at the bottom of the refining furnace, a slag discharge port is arranged at a selected height of the refining furnace, an electrode rod is arranged at a high position of the refining furnace, and the furnace body of the refining furnace is made of air-permeable bricks; a dust collecting hood disposed above the refining furnace; A dust collecting structure is disposed above the refining furnace, wherein the dust collecting structure is disposed at a height between about 1.5 and 3 times higher than the height of the electrode rod, or at least between about 2 and 6 meters higher than the height of the electrode rod; A scrap steel secondary material bin, a feeding piece connected to the scrap steel secondary material bin, and a movable feeding pipe connected to the feeding piece and the refining furnace, the feeding piece is provided with one of a vibration mechanism, a rolling mechanism, a disturbance mechanism or a stirring mechanism, and the movable feeding pipe can reciprocate between the feeding piece and the refining furnace; A component adjustment silo is connected to the refining furnace.

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