A high-efficiency treatment method for converter slag

Abstract

The invention relates to the technical field of converter slag treatment, and specifically discloses a converter slag high-efficiency treatment method, comprising the following steps: A01: loading the slag into a hot stewing device, spraying water on the slag, laying room-temperature slag powder on the surface of the slag, and closing the hot stewing device; A02: hot stewing the slag in step A01, the hot stewing treatment cycle is 16-20 hours, water is pumped five times, and the slag is cooled to 30-60 DEG C; A03: saturated steam is generated in the hot stewing device in step A02, the slag is hot-stemmed and self-decomposed into powder by the residual heat of the slag, and free calcium oxide and free magnesium oxide are hydrolyzed and eliminated; A04: the slag obtained in step A03 is transferred out, and after screening, magnetic separation and crushing, tailings, magnetic separation powder and slag steel products are obtained, so that the problem that the free calcium oxide and free magnesium oxide contained in the traditional converter slag are slowly hydrated and gradually expand in volume, resulting in structural instability and hindering the application of the slag in construction and road engineering is solved.

Description

Technical Field

[0001] The present application relates to the technical field of converter slag treatment, and specifically discloses a method for efficiently treating converter slag. Background Art

[0002] Steel slag is an inevitable product of the converter steelmaking process, with a production rate of 10% to 15%. Steel slag contains a large amount of alkaline oxides of Ca and Mg substances, and steel slag contains a lot of iron elements with poor grindability, resulting in low steel slag utilization. Due to the low steel slag utilization rate, the current steel slag stockpile is as high as hundreds of millions of tons. During the storage process, there are dust diffusion pollution, leakage pollution to groundwater, etc.

[0003] Domestic and foreign steel enterprises mainly use steel slag in the field of building materials through research, such as for paving roads, building dams, etc. However, the utilization of steel slag in this field is small and its value is low. The tailings after smelting reduction and iron removal of steel slag are mainly metal substances such as calcium oxide and magnesium oxide, which are resources with great development and utilization potential. However, converter steel slag also contains a small amount of free calcium oxide and free magnesium oxide, which have the characteristics of slow hydration and gradual volume expansion, which can easily lead to structural instability, seriously restricting and hindering the application of steel slag in construction and road engineering. Therefore, in view of this, the inventor provides a method for efficient treatment of converter steel slag to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the free calcium oxide and free magnesium oxide contained in the traditional converter steel slag have the characteristics of slow hydration and gradual volume expansion, resulting in structural instability and hindering the application of steel slag in construction and road engineering.

[0005] In order to achieve the above object, the basic scheme of the present invention provides a method for efficiently treating converter slag, comprising the following steps:

[0006] A01: Load hot-melt slag into the hot stewing device in quantitative quantities for multiple times. Spray water on the surface of the slag after each loading. After the hot stewing device is filled with slag, lay 300mm-400mm thick normal temperature slag powder on the surface of the slag, and then close the hot stewing device.

[0007] A02: The steel slag sealed in the hot stewing device in step A01 is hot stewed. The hot stewing treatment cycle is 16-20 hours including the slag loading treatment time. Water is pumped into the hot stewing device five times. The single water pumping amount is 70-120 t / h. The single water pumping duration is 45-180 minutes. The water pumping amount increases gradually. The single water pumping duration t1 of the first four times is equal. The fifth water pumping duration t2 is in a ratio range of 2.5-4 to the water pumping duration t1 of any of the first four times. The steel slag in the hot stewing device is cooled to 30-60°C.

[0008] A03: During the hot stewing treatment of the steel slag in step A02, saturated steam is generated in the hot stewing device, and the residual heat of the steel slag causes the steel slag to be self-decomposed and powdered, the slag and iron are separated, and the free calcium oxide and free magnesium oxide in the steel slag are hydrolyzed and eliminated;

[0009] A04: The cooled steel slag obtained through the water hot stewing treatment in step A03 is transferred out from the hot stewing device, and then subjected to four screening treatments, two magnetic separation treatments and one crushing treatment to obtain three slag steel products with different particle sizes, including tailings with an iron content of more than 80%, magnetic separation powder with an iron content of more than 35% and slag steel with an iron content of more than 80%.

[0010] Furthermore, steps A01-A04 specifically involve a hot stewing device, including a hot stewing pool for containing steel slag and a movable cover for closing the hot stewing pool. The steel slag holding capacity of the hot stewing pool is 200-230t, and a safety air release valve is provided on the movable cover.

[0011] Further, in step A01, after each water spraying, the slag is loosened using an excavator.

[0012] Furthermore, in step A01, the particle size of the room temperature steel slag powder is 1-10 mm. Before laying the room temperature steel slag powder, an excavator is used to level the surface of the steel slag in the hot stewing device.

[0013] Furthermore, in step A02, the total amount of water pumped five times during the hot stewing treatment cycle is 550-570t.

[0014] Furthermore, in step A01, the slag loading treatment time is 8-12 hours.

[0015] Furthermore, in step A04, the screening particle size of the screening machine used in the four screening processes is gradually reduced.

[0016] Further, in step A04, the crushing process is performed after the second screening process is completed, and the oversize material obtained by the second screening is successively sent to the hydraulic jaw crusher and the rod mill for crushing via a belt conveyor.

[0017] Further, in step A04, the first magnetic separation treatment is performed after the first screening treatment is completed, and the screened material obtained by the first screening is magnetically separated by a self-unloading electromagnetic iron remover, and the magnetic field strength range of the self-unloading electromagnetic iron remover is 1000-1200Gs.

[0018] Further, in step A04, the second magnetic separation treatment is performed after the third screening treatment is completed, and the undersize obtained from the third screening is magnetically separated by a roller magnetic separator, and the magnetic field strength range of the roller magnetic separator is 1300-1500Gs.

[0019] The principles and effects of this basic solution are:

[0020] 1. Compared with the prior art, the present invention treats converter slag through the process of hot stewing, screening, magnetic separation and crushing to achieve efficient treatment of slag. At the same time, by utilizing the saturated steam generated by the hot stewing of slag, the free calcium oxide and free magnesium oxide contained in the slag are fully hydrolyzed and eliminated, which not only eliminates the instability of the slag and improves the activity of the slag steel product finally obtained, but also makes the stability of the slag meet the standards, so that the hot stewed slag can be used in the fields of building materials, building materials products, road aggregates, etc., and the slag is turned into treasure and completely recycled and reused, which solves the problem that the free calcium oxide and free magnesium oxide contained in the traditional converter slag are slowly hydrated and gradually expand in volume, resulting in structural instability and hindering the application of slag in construction and road engineering.

[0021] 2. Compared with the prior art, the present invention provides a safety air release valve on the movable cover to prevent excessive air pressure in the hot stewing pool from affecting the hot stewing effect, thereby improving the safety and reliability of the hot stewing device.

[0022] 3. Compared with the prior art, the present invention lays room-temperature steel slag powder on the surface of high-temperature steel slag, which can not only prevent the high-temperature steel slag from exploding and splashing when it meets water, but also has a heat-insulating effect on the steel slag, thereby achieving a better slag stewing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A schematic structural diagram of a hot stewing device involved in a method for efficiently treating converter slag proposed in an embodiment of the present application is shown;

[0025] Figure 2 The overall flow chart of a method for efficiently treating converter slag proposed in an embodiment of the present application is shown;

[0026] Figure 3 A data graph showing the iron content of a product obtained by processing slag according to an efficient method for processing converter slag proposed in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0028] The reference numerals in the drawings of the specification include: a hot stewing pool 1, a movable cover 2, a safety air release valve 3, and a track 4.

[0029] A method for efficiently treating converter slag, embodiment 1 Figure 1 As shown, it relates to a hot stewing device, including a hot stewing pool 1 for containing steel slag and a mobile cover 2 for closing the hot stewing pool 1. The hot stewing pool 1 is 7m long, 5m wide and 5m deep. The hot stewing pool 1 uses steel billets to directly contact the hot slag. The steel billets are fixed to the concrete wall with bolts. Heat-resistant castables are used to fill the space between the concrete wall and the steel billets to play a role of heat insulation and auxiliary fixation. The steel slag holding capacity of the hot stewing pool 1 is 200t. The mobile cover 2 covers the hot stewing pool 1 through a sliding adjustment on a track 4. The mobile cover 2 has a deadweight of 22t. A safety relief valve 3 is installed on the mobile cover 2 through a flange connection. The safety relief valve 3 is used to automatically open its valve to release steam when the air pressure in the hot stewing pool 1 is too high. Figure 2 As shown, the specific steps include:

[0030] A01. Slag loading: The steel slag is transported and loaded into the hot stewing pool 1. Specifically, in this embodiment, after the converter is slaged, a plurality of slag pots loaded with steel slag are transported into the steel slag hot stewing treatment room by a straddle carrier, and the slag pots are lifted one by one by a 100 / 30t bridge crane, and the hot molten steel slag in the slag pots is tipped into the hot stewing pool 1. After tipping a pot of steel slag, a small amount of water is sprayed on the surface of the steel slag, and the steel slag is loosened by an excavator to ensure that there is no water on the surface of the steel slag in the hot stewing pool 1 before the next slag dumping. After pouring 5 cans of steel slag with a total volume of 200t into the hot stewing pool 1, use an excavator to level the surface of the steel slag in the hot stewing pool 1. At this time, the steel slag has not cooled down and its surface is a red slag surface. A layer of 300mm thick processed room temperature steel slag powder with a particle size of 1mm is laid on the red slag surface. The laying of room temperature steel slag powder can prevent the red slag surface from exploding and splashing when it encounters water, and at the same time plays a role in thermal insulation. Then the sliding movable cover 2 closes the port of the hot stewing pool 1.

[0031] A02, hot stewing with water: The steel slag sealed in the hot stewing device in step A01 is hot stewed, and then five water-brewing operations are performed. Specifically, in this embodiment, the first water-brewing is 70 t / h, the second water-brewing is 80 t / h, the third water-brewing is 100 t / h, and the fourth water-brewing is 110 t / h. The duration t1 of each of the first four water-brewing is 45 min. The fifth water-brewing is 120 t / h, and the duration t2 of the fifth water-brewing is 180 min. The water-brewing amount of the five times increases gradually, and the ratio of the duration t2 of the fifth water-brewing to the duration t1 of any of the first four water-brewing times is 4. The initial water-brewing amount is small in order to prevent the water from reacting with the carbon contained in the high-temperature steel slag to generate water gas and avoid explosion caused by rapid reaction. When the reaction is stable, the water-brewing amount is gradually increased, and the water-brewing time is controlled. When the temperature in the hot stewing device drops to 30°C, the stewing operation is completed. At this time, the valve of the safety relief valve 3 on the movable cover 2 automatically opens to discharge the residual steam in the hot stewing device.

[0032] A03. Self-decomposition of slag: During the process of hot stewing of slag in step A02, saturated steam is generated in the stewing device. The residual heat of the slag stews the slag until it self-decomposes and powderizes, thereby separating the slag and iron, and at the same time, hydrolyzing and eliminating the free calcium oxide and free magnesium oxide in the slag.

[0033] A04, slag removal and screening: The cooled steel slag obtained by hot braising treatment in step A03 is transferred from the hot braising tank 1, such as Figure 3 As shown in FIG. 1 , after four screening processes, two magnetic separation processes and one crushing process, three slag steel products with different particle sizes are obtained, namely tailings with an iron content of more than 80%, magnetic separation powder with an iron content of more than 35%, and slag steel products with an iron content of more than 80%. The product conditions of the three slag steel products are shown in FIG. Figure 3 shown.

[0034] Specifically, in this embodiment, the steel slag after the heat stewing treatment is discharged by a crawler excavator, and the steel slag enters a screening machine with a sieve hole diameter of 200mm, and the screened material is a No. 1 slag steel product for storage, and the screened material enters a screening machine with a sieve hole diameter of 40mm through a belt conveyor; wherein, before entering the screening machine with a sieve hole diameter of 40mm, the steel slag first passes through a self-unloading electromagnetic iron remover with a magnetic field strength of 1000Gs for electromagnetic iron removal, and the belt conveyor runs at a speed of 1.5m / s, and the No. 2 slag steel product is magnetically selected for storage; after the steel slag is screened by a screening machine with a sieve hole diameter of 200mm, the screened material with a particle size between 40mm and 200mm is obtained by a belt conveyor and enters a 500mm×750mm hydraulic jaw crusher through a belt conveyor, and then enters a rod mill for processing through a belt conveyor; the processed material has a particle size less than 4 After the materials with a particle size of 0mm are collected, they enter a screening machine with a sieve hole diameter of 10mm through a belt conveyor. The lower screen materials with a particle size less than 10mm under the sieve are magnetically separated by a roller magnetic separator. The magnetic field strength of the roller magnetic separator is 1300Gs. The magnetic separation powder products are selected and stored, and the tailings are sent to the tailings warehouse by a belt for storage; and the materials with a particle size between 10mm and 40mm on the sieve of the screening machine with a sieve hole diameter of 10mm enter another rod mill for processing through a belt conveyor. The materials after processing in the rod mill enter the next screening machine with a sieve hole diameter of 10mm through a belt conveyor, and the screened materials are stored as No. 3 slag steel products. At the same time, the underscreen materials also enter the roller magnetic separator with a magnetic field strength of 1300Gs, and the magnetic separation powder obtained by sorting is mixed with the magnetic separation powder of the previous level for storage, and the obtained tailings are stored in the tailings yard through a belt conveyor.

[0035] Specifically, the amount of water pumped during the entire slag stewing period of the hot stewing device in this embodiment is 550t, and the entire hot stewing treatment cycle of the steel slag is 16h, including 8h of slag loading time, 6h of slag stewing time and 2h of slag discharge time.

[0036] The equipment used in Example 2 and Example 1, the connection between the equipment and the method for treating converter slag are the same. The difference between Example 2 and Example 1 is that the slag holding capacity of the hot stewing pool 1 is 220t. In the hot stewing pool 1, the thickness of the room temperature slag powder laid on the surface of the slag in a high temperature state is 350mm, and the particle size of the laid room temperature slag powder is 5mm. During the hot stewing treatment of the slag, the duration t1 of each of the first four water pumpings is 50min, and the duration t2 of the fifth water pumping is 150min. The ratio of the duration t2 of the fifth water pumping to the duration t1 of any of the first four water pumpings is 3. When the stewing operation is completed, the temperature in the hot stewing device drops to 50°C; when the slag passes through the self-unloading electromagnetic iron remover for electromagnetic iron removal, the magnetic field strength of the self-unloading electromagnetic iron remover is 1100Gs, and when the slag is magnetically separated by a roller magnetic separator, the magnetic field strength of the roller magnetic separator is 1400Gs.

[0037] In this embodiment, the amount of water pumped during the entire slag stewing period of the hot stewing device is 560t, and the hot stewing treatment cycle of the slag is 18h, including slag loading time of 10h, slag stewing time of 6h and slag discharge time of 2h.

[0038] The equipment used in Example 3 and Example 1, the connection between the equipment and the method for treating converter slag are the same. The difference between Example 3 and Example 1 is that the slag holding capacity of the hot stewing pool 1 is 230t. In the hot stewing pool 1, the thickness of the room temperature slag powder laid on the surface of the slag in a high temperature state is 400mm, and the particle size of the laid room temperature slag powder is 10mm. During the hot stewing treatment of the slag, the duration t1 of each of the first four water pumpings is 68min, and the duration t2 of the fifth water pumping is 170min. The ratio of the duration t2 of the fifth water pumping to the duration t1 of any of the first four water pumpings is 2.5. At the end of the slag stewing operation, the temperature in the hot stewing device drops to 60°C. When the slag passes through the self-unloading electromagnetic iron remover for electromagnetic iron removal, the magnetic field strength of the self-unloading electromagnetic iron remover is 1200Gs. When the slag is magnetically separated by a roller magnetic separator, the magnetic field strength of the roller magnetic separator is 1500Gs.

[0039] In this embodiment, the amount of water pumped during the entire slag stewing period of the hot stewing device is 570t, and the hot stewing treatment cycle of the slag is 20h, including slag loading time of 12h, slag stewing time of 6h and slag discharge time of 2h.

[0040] The setting of the water pumping rule and water pumping duration during slag stewing is the best treatment method for obtaining the best slag stewing effect obtained by the enterprise after long-term research and exploration. By adopting the slag treatment method provided by the present invention, the pulverization rate of converter slag stewing can reach 90%-95%.

[0041] Compared with the prior art, the present invention treats converter slag through the process of hot stewing, screening, magnetic separation and crushing to achieve efficient treatment of slag. At the same time, by utilizing the saturated steam generated by the self-decomposition of hot stewing of slag, the purpose of fully hydrolyzing and eliminating free calcium oxide and free magnesium oxide contained in the slag is achieved. Not only the instability of the slag is eliminated and the activity of the slag steel product finally obtained is improved, but also the stability of the slag is qualified and up to standard, which makes it convenient to apply the hot stewed slag to the fields of building materials, building materials products, road aggregates, etc., and the slag is turned into treasure and completely recycled and reused, which solves the problem that the free calcium oxide and free magnesium oxide contained in the traditional converter slag are slowly hydrated and gradually expand in volume, resulting in structural instability and hindering the application of slag in construction and road engineering.

[0042] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for efficiently treating converter slag, characterized in that: The following steps are involved: A01: Load hot-melt slag into the hot stewing device in quantitative quantities for multiple times. Spray water on the surface of the slag after each loading. After the hot stewing device is filled with slag, lay 300mm-400mm thick normal temperature slag powder on the surface of the slag, and then close the hot stewing device. A02: The steel slag sealed in the hot stewing device in step A01 is hot stewed. The hot stewing treatment cycle is 16-20 hours including the slag loading treatment time. Water is pumped into the hot stewing device five times. The single water pumping amount is 70-120 t / h. The single water pumping duration is 45-180 minutes. The water pumping amount increases gradually. The single water pumping duration t1 of the first four times is equal. The fifth water pumping duration t2 is in a ratio range of 2.5-4 to the water pumping duration t1 of any of the first four times. The steel slag in the hot stewing device is cooled to 30-60°C. A03: During the hot stewing treatment of the steel slag in step A02, saturated steam is generated in the hot stewing device, and the residual heat of the steel slag causes the steel slag to be self-decomposed and powdered, the slag and iron are separated, and the free calcium oxide and free magnesium oxide in the steel slag are hydrolyzed and eliminated; A04: The cooled steel slag obtained through the water hot stewing treatment in step A03 is transferred out from the hot stewing device, and then subjected to four screening treatments, two magnetic separation treatments and one crushing treatment to obtain three slag steel products with different particle sizes, including tailings with an iron content of more than 80%, magnetic separation powder with an iron content of more than 35% and slag steel with an iron content of more than 80%.

2. The method for efficiently treating converter slag according to claim 1, characterized in that: In the step A01, after each water spraying, the steel slag is loosened by using an excavator.

3. The method for efficiently treating converter slag according to claim 2, characterized in that: In the step A01, the particle size of the room temperature steel slag powder is 1-10 mm. Before laying the room temperature steel slag powder, an excavator is used to level the surface of the steel slag in the hot stewing device.

4. A method for efficiently treating converter slag according to any one of claims 1 to 3, characterized in that: The steps A01-A04 also specifically involve a hot stewing device, including a hot stewing pool for containing steel slag and a movable cover for closing the hot stewing pool. The steel slag holding capacity of the hot stewing pool is 200-230t, and a safety air release valve is provided on the movable cover.

5. The method for efficiently treating converter slag according to claim 4, characterized in that: In step A02, the total amount of water pumped five times during the hot stewing treatment cycle is 550-570t.

6. The method for efficiently treating converter slag according to claim 5, characterized in that: In the step A01, the slag loading treatment time is 8-12 hours.

7. A method for efficiently treating converter slag according to claim 1 or 5, characterized in that: In the step A04, the screening particle size of the screening machine used in the four screening processes is gradually reduced.

8. The method for efficiently treating converter slag according to claim 7, characterized in that: In the step A04, the crushing process is performed after the second screening process is completed, and the oversize material obtained by the second screening is successively sent to the hydraulic jaw crusher and the rod mill for crushing via a belt conveyor.

9. The method for efficiently treating converter slag according to claim 8, characterized in that: In the step A04, the first magnetic separation treatment is performed after the first screening treatment is completed, and the undersize obtained by the first screening is magnetically separated by a self-unloading electromagnetic iron remover, and the magnetic field strength range of the self-unloading electromagnetic iron remover is 1000-1200Gs.

10. The method for efficiently treating converter slag according to claim 9, characterized in that: In the step A04, the second magnetic separation treatment is performed after the third screening treatment is completed, and the undersize obtained by the third screening is magnetically separated by a roller magnetic separator, and the magnetic field strength range of the roller magnetic separator is 1300-1500Gs.

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