Steel slag secondary processing treatment system

Abstract

The utility model discloses a secondary processing system for steel slag, which is sequentially provided with a raw material plant, a feeding station, a first magnetic separation screening station, a purification station, a second magnetic separation screening station and a finished product station according to a process sequence, and low-temperature solid steel slag subjected to primary treatment is conveyed into the closed raw material plant by a belt conveyor or a dumper; after the low-temperature solid steel slag is pretreated, materials are conveyed by the belt conveyor in the closed belt vestibule in the whole process from the feeding station, the first magnetic separation screening station, the purification station and the second magnetic separation screening station to the finished product station in sequence, so that centralized dust collection and point type dust collection are combined, and secondary pollution cannot be generated in the whole processing process. A multi-stage iron separation process is adopted, it is ensured that magnetic powder and slag steel of steel-making of return ironmaking are higher than current national or industrial related standard requirements, the granularity of the steel slag tailings is small, the content of metal iron and f-CaO (free calcium oxide) is greatly reduced, and a foundation is laid for large-scale application of the steel slag tailings to the building material industry.

Description

Technical Field

[0001] The utility model belongs to the technical field of resource utilization of metallurgical solid waste, relates to a secondary processing technology of steel slag, and particularly relates to a secondary processing system of steel slag. Background Art

[0002] Steel slag is a solid waste generated during the steelmaking process, accounting for a large proportion of metallurgical solid waste, and its utilization rate is only about 40%. According to different types of steelmaking, steel slag is divided into desulfurization slag, converter slag, electric furnace slag and refined slag. The process of cooling, solidifying and pre-crushing steel slag from high-temperature liquid is called the primary treatment of steel slag. Steel slag contains about 10% of metallic iron. The low-temperature solid steel slag after primary treatment is finely crushed, graded and magnetically separated to remove ferromagnetic materials in order to fully recover the metallic iron therein and create conditions for the resource utilization of steel slag tailings. This is called the secondary treatment of steel slag.

[0003] At present, after the steel slag is processed once, it is transported to the secondary processing site for secondary processing. The existing steel slag secondary processing methods mainly have the following problems:

[0004] (1) The existing secondary processing lines have extensive production processes and simple equipment, and cannot effectively recover the metal resources in the steel slag;

[0005] (2) The existing secondary processing lines are operated outdoors, which creates dust during the processing process, creates a poor production environment, and causes atmospheric pollution;

[0006] (III) The particle size composition, MFe (metallic iron) content and free calcium oxide (f-CaO) content of the steel slag tailings discharged from the existing secondary processing lines are all relatively high, and cannot be used on a large scale in the building materials industry. This is the main reason for the low utilization rate of steel slag.

[0007] Therefore, there is an urgent need to propose a new type of steel slag secondary processing solution with low environmental pollution, high metal recovery rate, and the particle size composition, metallic iron (MFe) content and free calcium oxide (f-CaO) content of the produced steel slag tailings all meet the current national or industry standards and specifications. This is extremely urgent at a time when steel slag cannot be used as a mixed material in the production of general-purpose silicate cement. Utility Model Content

[0008] The purpose of the utility model is to provide a novel secondary processing system for steel slag, which has reasonable and excellent equipment configuration, pollution-free production, high metal recovery rate, and the particle size composition, MFe (metallic iron) content and f-CaO (free calcium oxide) content of the produced steel slag tailings all meet the current national or industry standards and specifications, so as to solve the problems existing in the above-mentioned existing secondary processing lines and greatly improve the utilization rate of steel slag.

[0009] To achieve the above object, the present utility model provides the following solutions:

[0010] The present utility model provides a secondary processing system for steel slag, including a feeding station, a first magnetic separation and screening station, a purification station, a second magnetic separation and screening station, and a finished product station, which are sequentially arranged according to the process sequence. Among them:

[0011] The feeding station includes a first-stage particle size classifier, a first feeder, and a belt conveyor I, which are sequentially connected according to the process sequence.

[0012] The first magnetic separation and screening station includes a first belt-type electromagnetic separator, a second-stage particle size classifier, a third-stage particle size classifier, and a magnetic separator, which are sequentially connected according to the process sequence. The first belt-type electromagnetic separator is arranged on the belt conveyor I.

[0013] The purification station includes a belt conveyor III, a three-way distributor, a second feeder, an intermediate bin, and a steel slag fine crusher, which are sequentially connected according to the process sequence.

[0014] The second magnetic separation and screening station includes a fourth-stage particle size classifier, a third belt-type electromagnetic separator, and a magnetic separator, which are sequentially connected according to the process sequence.

[0015] The finished product station includes a magnetic powder bin and a non-magnetic tail slag bin.

[0016] Each adjacent two stations among the feeding station, the first magnetic separation and screening station, the purification station, the second magnetic separation and screening station, and the finished product station are interconnected through a closed belt corridor, and materials are conveyed by belt conveyors.

[0017] Preferably, the magnetic separators in the first magnetic separation and screening station and the second magnetic separation and screening station are both roll-type magnetic separators; the steel slag fine crusher is a rod mill or an inertial cone crusher.

[0018] Preferably, the first-stage particle size classifier is a floor screen, a bar-type vibrating feeder, or a shaftless rotary screen; the screen hole size of the first-stage particle size classifier is 120 mm - 200 mm; the third-stage particle size classifier is a single-layer vibrating screen or a double-layer vibrating screen; the second-stage particle size classifier and the fourth-stage particle size classifier are both vibrating screens or shaftless rotary screens, and the screen hole sizes are both 10 mm - 20 mm.

[0019] Preferably, the first feeder and the second feeder are both reciprocating feeders, vibrating feeders, belt feeders, or vibrating troughs.

[0020] Preferably, the magnetic powder bin is a steel plate bin or a concrete bin; the non-magnetic tail slag bin is a group of steel plate bins or a steel-concrete structure tent-shaped bin.

[0021] Preferably, the Class III particle size classifier is the double-deck vibrating screen, and a ninth belt conveyor is arranged at the oversize material outlet of the double-deck vibrating screen, and a second belt-type iron remover is arranged on the ninth belt conveyor.

[0022] Preferably, the steel slag secondary processing system further includes a raw material workshop, which is arranged in front of the feeding station and is used for temporarily storing the steel slag to be secondarily processed; a lifting device is configured in the raw material workshop for transporting the materials in the raw material workshop; and the feeding station is arranged in the raw material workshop.

[0023] Preferably, the raw material workshop is an enclosed raw material workshop.

[0024] Preferably, a fog cannon is further arranged in the raw material workshop, and the fog cannon is used for spraying and dust reduction in the raw material workshop; the feeding station, the first magnetic separation and screening station to the purification station share a set of HDC wet dust removal system for centralized wet dust collection at each dust-producing point; a set of pulse bag type dust removal system is provided for dry dust collection at each belt transfer point from the second magnetic separation and screening station to the finished product station; a bag filter on the top of the bin is arranged in the finished product station for dust collection or a fog cannon is arranged for dust reduction.

[0025] Preferably, a bag filter on the top of the bin is used for dust collection in the magnetic powder bin of the finished product station, and a fog cannon is used for dust reduction in the non-magnetic tailing slag bin.

[0026] Preferably, the steel slag secondary processing system further includes a PLC control system, and the PLC control system is communicatively connected to the feeding station, the first magnetic separation and screening station, the purification station, the second magnetic separation and screening station and the finished product station.

[0027] The utility model has achieved the following technical effects compared with the prior art:

[0028] The steel slag secondary processing system proposed by the utility model has a reasonable structural design. By successively arranging a raw material workshop, a feeding station, a first magnetic separation and screening station, a purification station, a second magnetic separation and screening station and a finished product station in the technological order, a new steel slag secondary processing production line is formed. The low-temperature solid steel slag after the first treatment is transported into the enclosed raw material workshop by a belt conveyor or a dump truck. After the pretreatment of the low-temperature solid steel slag, the whole process from the feeding station, the first magnetic separation and screening station, the purification station and the second magnetic separation and screening station to the finished product station is carried out by a belt conveyor in an enclosed belt corridor, realizing the combination of centralized dust collection and point dust collection, which is beneficial to achieving up-to-standard discharge, can fundamentally improve the problem of dust flying in the process of steel slag secondary processing, and ensure that no secondary pollution will be generated in the whole process of processing.

[0029] The above-mentioned secondary processing system for steel slag can adopt a multi-stage iron separation process during the secondary processing of steel slag by setting up the first magnetic separation and screening station and the second magnetic separation and screening station, ensuring that the magnetic powder and steel slag for returning iron to steelmaking are higher than the current national or industry-related standard requirements. The particle size of the steel slag tailings is fine, and the contents of MFe (metallic iron) and f-CaO (free calcium oxide) are greatly reduced, laying a foundation for the large-scale application of steel slag tailings in the building materials industry.

[0030] In some technical solutions disclosed by the present utility model, the non-magnetic tailings bin of the finished product station adopts a large-capacity steel-concrete structure tent-shaped bin with the function of decomposing f-CaO in the non-magnetic tailings, which can reduce the f-CaO content to less than 3%. After particle size classification according to relevant standard specifications, it meets the technical requirements of GB / T 24765-2009 "Steel Slag for Wear-Resistant Asphalt Pavement" and JC / T 2735-2023 "Steel Slag Asphalt Mixture", and can replace some natural aggregates (such as basalt) for paving high-grade highways.

[0031] In some technical solutions disclosed by the present utility model, considering that the steel slag is stacked outdoors in the existing secondary processing yard, causing dust in sunny days and leakage in rainy days, which is likely to cause environmental pollution and groundwater pollution, this embodiment preferably sets the raw material workshop as a closed reinforced concrete workshop. Brief Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is the overall process flow chart of the secondary processing system for steel slag disclosed in the embodiments of the present utility model;

[0034] Figure 2 It is the plane layout diagram of the secondary processing system for steel slag disclosed in the embodiments of the present utility model;

[0035] Figure 3 It is Figure 1 the I-I sectional view of

[0036] Figure 4 It is Figure 1 the II-II sectional view of

[0037] Figure 5 It is Figure 1 the III-III sectional view of

[0038] Figure 6 It is Figure 1Cross-sectional view of IV-IV;

[0039] Figure 7 is Figure 1 Cross-sectional view of V-V;

[0040] Figure 8 is Figure 1 Cross-sectional view of VI-VI.

[0041] In the figure, the reference numerals are:

[0042] 100, Steel slag secondary processing system; 101, Raw material workshop; 102, Loading station; 103, First magnetic separation and screening station; 104, Purification station; 105, Second magnetic separation and screening station; 106, Finished product station;

[0043] 1, Electric double-girder crane; 2, Grade I particle size classifier; 3, Belt conveyor 1; 4, First belt-type iron remover; 5, Grade II particle size classifier; 6, Grade III particle size classifier; 7, First roll-type magnetic separator; 8, Belt conveyor 2; 9, Belt conveyor 3; 10, Belt conveyor 4; 11, Vibrating feeder; 12, Steel slag fine crusher; 13, Belt conveyor 5; 14, Belt conveyor 6; 15, Second roll-type magnetic separator; 16, Grade IV particle size classifier; 17, Belt conveyor 7; 18, Belt conveyor 8; 19, Fog cannon; 20, Belt conveyor 9; 21, Second belt-type iron remover; 22, Reciprocating feeder; 23, Third belt-type iron remover; 24, Belt conveyor 10; 25, Belt conveyor 11; 26, Three-way distributor. Specific implementation mode

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] The purpose of the present invention is to provide a new type of steel slag secondary processing system, which has reasonable and excellent equipment configuration, pollution-free production, high metal recovery rate, and the particle size composition, MFe (metallic iron) content, and f-CaO (free calcium oxide) content of the produced steel slag tailings all meet the current national or industry standard specifications, and can solve the problems existing in the existing secondary processing lines, such as simple equipment, serious environmental pollution, low metal recovery rate, and the particle size composition, MFe content, and f-CaO content of the produced steel slag tailings all failing to meet the requirements of the current national or industry-related standard specifications.

[0046] To make the above objects, features, and advantages of the present utility model more apparent and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Embodiment 1

[0048] As Figures 1 to 8 shown, this embodiment proposes a steel slag secondary processing system 100. In the steel slag secondary processing system 100, a raw material workshop 101, a feeding station 102, a first magnetic separation and screening station 103, a purification station 104, a second magnetic separation and screening station 105, and a finished product station 106 are sequentially arranged in the technological order. Among them: The raw material workshop 101 is used to temporarily store the steel slag to be secondary processed. Considering that the steel slag in the existing secondary processing yard is stacked outdoors, there is dust in sunny days and leakage in rainy days, which is likely to cause environmental and groundwater pollution. In this embodiment, it is preferably to set the raw material workshop 101 as a closed reinforced concrete workshop. There is a lifting device with an electromagnetic chuck in the workshop, and the lifting device preferably adopts an electric double-girder crane 1. The feeding station 102 is arranged in the raw material workshop 101. The feeding station 102 specifically includes a first-stage particle size classifier 2, a first feeder, and a belt conveyor 3. The first magnetic separation and screening station 103 specifically includes a first belt-type iron remover 4, a second-stage particle size classifier 5, a third-stage particle size classifier 6, and a magnetic separator. The purification station 104 specifically includes a three-way distributor 26, a second feeder, an intermediate bin, a vibrating feeder 11, and a steel slag fine crusher 12. The second magnetic separation and screening station 105 specifically includes a fourth-stage particle size classifier 16, a third belt-type iron remover 23, and a magnetic separator. The finished product station 106 specifically includes a magnetic powder bin and a non-magnetic tail slag bin. Among the above-mentioned feeding station 102, first magnetic separation and screening station 103, purification station 104, second magnetic separation and screening station 105, and finished product station 106, every two adjacent ones are interconnected through a closed belt corridor, and materials are conveyed by belt conveyors.

[0049] Specifically, in this embodiment, the raw material workshop 101 preferably includes 1 to 3 closed reinforced concrete workshops. Different closed reinforced concrete workshops can be used to temporarily store the steel slag to be secondary processed from different sources, and the above-mentioned lifting device and feeding station 102 are provided in each workshop. The screened materials of the feeding station 102 in each workshop are transported to the same belt conveyor through the corresponding belt conveyor 3 for collection, and finally conveyed into the first magnetic separation and screening station 103 for iron separation and particle size classification.

[0050] Specifically, in this embodiment, the function of the first-stage particle size classifier 2 is to pre-classify the particle size of the pretreated raw materials. It can be a flat screen (a fixed grid screen with a screen surface flush with the ground), a bar vibrating feeder with particle size classification function, or a shaftless rotary screen with self-cleaning screen holes. Among them, the bar vibrating feeder is preferred, and the shaftless rotary screen is more preferred. And the screen hole size of the first-stage particle size classifier 2 can be 120 mm to 200 mm, preferably 160 mm, and more preferably 200 mm.

[0051] Specifically, in this embodiment, the third-stage particle size classifier 6 is preferably a vibrating screen. When it is a single-layer vibrating screen, its screen hole size is 10 mm to 60 mm, preferably 12 mm; when it is a double-layer vibrating screen, the screen hole size of its lower layer is 10 mm to 20 mm, and the screen hole size of its upper layer is 35 mm to 60 mm, preferably the screen hole size of the lower layer is 12 mm and the screen hole size of the upper layer is 50 mm. The main function of the third-stage particle size classifier 6 is to further divide the raw materials pre-classified by the first-stage particle size classifier 2 into 2 to 3 particle grades, and the steel slag raw materials of different particle grades enter different processing or utilization links.

[0052] Furthermore, in this embodiment, both the second-stage particle size classifier 5 and the fourth-stage particle size classifier 16 are preferably vibrating screens or shaftless rotary screens, and their screen hole sizes are 10 mm to 20 mm, preferably 12 mm. The functions of the second-stage particle size classifier 5 and the fourth-stage particle size classifier 16 are to classify the ferromagnetic slag steel into two particle grades, and the slag steel of different particle grades enters different processing or utilization links.

[0053] Furthermore, in this embodiment, both the first feeder and the second feeder can be reciprocating feeders 22, vibrating feeders, belt feeders or vibrating conveying troughs, and different types of feeders can be selected for the steel slag raw materials in different sections of the production line.

[0054] Furthermore, in this embodiment, the three-way diverter 26 of the purification station 104 can be an electro-hydraulic three-way diverter or a tray-type flap double-door three-way valve. The tray-type flap double-door three-way valve can specifically adopt the "a tray-type flap double-door three-way valve" disclosed in the Chinese patent with the application number 202321303401.5. In this solution, the three-way diverter 26 is preferably a tray-type flap double-door three-way valve.

[0055] It should be noted that the aforementioned vibrating screens, bar vibrating feeders, shaftless rotary screens, belt-type electromagnetic separators, magnetic separators, belt conveyors, vibrating conveying troughs, vibrating feeders and reciprocating feeders, etc. are all commercially available and mature and reliable conventional equipment, and their specific structures and working principles will not be elaborated here.

[0056] Furthermore, in this embodiment, the steel slag fine crusher 12 can be a rod mill or an inertial cone crusher, and the rod mill is preferred.

[0057] Furthermore, in this embodiment, the functions of the belt-type electromagnetic separators in the aforementioned first magnetic separation and screening station 103 and the second magnetic separation and screening station 105 are to magnetically separate the magnetic slag in the undersize material of the first-stage particle size classifier 2 and the oversize material of the fourth-stage particle size classifier 16 respectively. The obtained magnetic slag is large slag steel and medium slag steel respectively, and its MFe > 85%.

[0058] Furthermore, in this embodiment, the magnetic powder silo of the finished product station 106 can be a steel plate silo or a concrete silo, preferably a steel plate silo.

[0059] Furthermore, in this embodiment, the non-magnetic tail slag silo of the finished product station 106 can be a group of steel plate silos or a steel-concrete structure tent silo with a large capacity (single silo volume > 3000m 3 ) and having the function of decomposing f-CaO in the non-magnetic tail slag, preferably a steel-concrete structure tent silo.

[0060] Furthermore, a dust removal facility is also provided in this embodiment. The dust removal facility specifically includes a spray dust removal device, an HDC wet dust removal system, a pulse bag dust removal system, a dust collector on the top of the silo, and a fog cannon, etc. Specifically: a fog cannon is set in the raw material workshop 101 to spray and reduce dust in the raw material workshop; the feeding station 102, the first magnetic separation and screening station 103 to the purification station 104 share a set of HDC wet dust removal system to centrally wet dust collect at each dust-producing point; a set of pulse bag dust removal system is provided for dry dust collection at each belt transfer point from the second magnetic separation and screening station 105 to the finished product station 106; if the magnetic powder silo of the finished product station 106 is a steel plate silo, a dust collector on the top of the silo is set above the magnetic powder silo, and if the non-magnetic tail slag silo of the finished product station 106 is a steel-concrete structure tent silo, a fog cannon 19 is set inside the non-magnetic tail slag silo to reduce dust. The above dust removal facilities are all mature technologies and are not shown in the figure.

[0061] When the above-mentioned steel slag secondary processing system 100 is used for steel slag secondary processing, the process is as follows:

[0062] As Figure 1 and Figure 2 shown, the low-temperature solid-state steel slag after primary treatment is transported into the raw material workshop 101 by a dump truck (or a belt conveyor), and after pretreatment, it is sent to the feeding station 102 by a forklift or an electric double-girder crane 1 (the other feeding station 102 and its transfer belt conveyor are not shown in the figure). The feeding station 102 is used for feeding and pre-screening the steel slag transported by the dump truck on the secondary treatment production line. A floor screen with a screen hole size of 200×200mm is used as the first-stage particle size classifier 2. The steel slag with a particle size > 200mm on the screen is short-transported to the open space near the first-stage particle size classifier 2 (floor screen) by tools such as an electric double-girder crane 1 for temporary storage. The steel slag with a particle size ≤ 200mm under the screen is temporarily stored through the undersize transition hopper and then fed into the belt conveyor 3 by the reciprocating feeder 22 and enters the first magnetic separation and screening station 103.

[0063] The first magnetic separation and screening station 103 is a centralized disposal facility for the first magnetic separation and screening in the secondary processing technological process of steel slag (before the fine crushing process). It is equipped with technological equipment such as a first belt-type iron remover 4, a grade-II particle size classifier 5, a grade-III particle size classifier 6, a first roll-type magnetic separator 7, and a belt conveyor. Specifically: The first belt-type iron remover 4 extracts magnetic slag steel from the material layer continuously passing on the belt conveyor 1-3 and sends it into the grade-II particle size classifier 5 (vibrating screen). The oversize material with a particle size > 12 mm, which is large slag steel with MFe > 85%, automatically falls into the large slag steel storage tank and is regularly returned to the steelmaking process as scrap steel. The undersize material with a particle size ≤ 12 mm automatically falls into the belt conveyor 3-9. The steel slag in the continuous material layer on the belt conveyor 1-3 after being magnetically separated by the first belt-type iron remover 4 is sent into the grade-III particle size classifier 6 (vibrating screen). The oversize material with a particle size > 12 mm automatically falls into the belt conveyor 3-9. The undersize material with a particle size ≤ 12 mm is sent into the first roll-type magnetic separator 7 by a feeder. The magnetic slag discharged from the first roll-type magnetic separator 7 automatically falls into the belt conveyor 3-9, while the non-magnetic slag successively passes through the belt conveyor 2-8, the belt conveyor 5-13, and the belt conveyor 7-17 and enters the non-magnetic slag steel plate silo group (in the figure, the non-magnetic slag tail slag silo is a steel-concrete structure tent-shaped silo, rather than a steel plate silo group) for external sales.

[0064] The belt conveyor 3-9 sends the steel slag with a particle size of 0 - 200 mm into the three-way distributor 26. The steel slag material flow is divided into two paths by the three-way distributor 26: One path directly flows into the feed bin of the first steel slag fine crusher 12, and the other path passes through the belt conveyor 4-10 and enters the feed bin of the second steel slag fine crusher 12. The steel slag in the two feed bins is evenly fed into the steel slag fine crusher (rod mill) 12 below by the vibrating feeders 11 located below them for fine crushing. The finely crushed steel slag discharged from the two steel slag fine crushers 12 is sent into the grade-IV particle size classifier 16 (vibrating screen) by the belt conveyor 6-14. The oversize material with a particle size > 12 mm automatically falls into the belt conveyor 10-24, and the magnetic slag among it is sucked out by the third belt-type iron remover 23 suspended above it to obtain medium slag steel with MFe > 85%. The medium slag steel automatically falls into the medium slag steel storage tank and is regularly returned to the steelmaking process as scrap steel. The non-magnetized steel slag is sent into the feed bins of the two steel slag fine crushers 12 by a belt conveyor (not shown in the figure), thus forming a closed-loop fine crushing. The undersize material with a particle size ≤ 12 mm is sent into the second roll-type magnetic separator 15 by a reciprocating feeder 22. The magnetic slag (TFe > 50%) discharged from the second roll-type magnetic separator 15 is directly sent into the magnetic powder silo by the belt conveyor 8-18 and is regularly sent to the sintering or pellet production line by a self-unloading truck. The non-magnetic slag (particle size ≤ 12 mm, MFe < 2%) discharged from the second roll-type magnetic separator 15 is directly sent into the non-magnetic steel plate silo group (not shown in the figure) for external sales.

[0065] The above-mentioned secondary steel slag processing system 100 forms a new secondary steel slag processing production line by sequentially arranging a raw material plant 101, a feeding station 102, a first magnetic separation and screening station 103, a purification station 104, a second magnetic separation and screening station 105, and a finished product station 106 in the technological order. The low-temperature solid steel slag after primary treatment is transported into the enclosed raw material plant 101 by a belt conveyor or a tipper truck. After the pretreatment of the low-temperature solid steel slag, the whole process from the feeding station 102, the first magnetic separation and screening station 103, the purification station 104, and the second magnetic separation and screening station 105 to the finished product station 106 is carried out by a belt conveyor in an enclosed belt corridor, realizing centralized dust collection and the combination of point-type and dry-wet dust collection, collecting and treating the dust generated during the operation, achieving up-to-standard discharge, fundamentally improving the problem of dust flying during the secondary steel slag processing, and ensuring that no secondary pollution will be generated during the whole process of processing.

[0066] The above-mentioned secondary steel slag processing system 100 respectively uses a special belt-type electromagnetic separator to continuously and automatically extract the magnetic iron in the screen undersize of the grade I particle size classifier 2 and the screen oversize of the grade IV particle size classifier 16, ensuring that the metallic iron (MFe) in the slag steel returned to steelmaking is not less than 85%.

[0067] The particle size of the non-magnetic tail slag is ≤ 12 mm, and the metallic iron (MFe) is < 2%, which is conducive to selling it to a patented chemical plant for producing "Steel Slag Powder for Cement and Concrete" according to GB / T 20491-2017 or "Steel Slag Powder" according to GB / T 28293-2012 for use as a mineral admixture in a commercial concrete mixing station.

[0068] The whole secondary steel slag processing system 100 realizes the centralized and enclosed disposal of low-temperature solid steel slag, adopts a reduction and cleaning production line with preliminary rough selection followed by fine selection, not only has a stable operation during the production process without technological accidents such as material blockage and machine jamming, but also has stable and controllable product quality. The whole system can be centrally controlled by a PLC control system, manage the whole line in zones according to the actual production situation, start and stop the associated equipment with one key, and realize intelligent early warning, switching, and control according to the technological logic, and can be operated with few or no operators.

[0069] In summary, the secondary processing system line for steel slag proposed by the present utility model is provided with a raw material workshop, where various steel slags are pre-treated in the raw material workshop and then put on the line for processing; the process equipment is mature and reliable, the entire production line is fully enclosed, and the dust generated during operation is centrally treated by a process method combining dry and wet dust removal to achieve up-to-standard discharge; the particle size is ≤12 mm and the content of metallic iron (MFe) is <2%, which is beneficial for specialized factories to produce steel slag powder or iron and steel slag powder, thereby improving the comprehensive utilization rate of steel slag; the whole system has significant advantages such as small investment, stable operation, high automation degree, low operation cost, environmental friendliness, and high steel slag utilization rate.

[0070] Embodiment 2

[0071] The differences from Embodiment 1 are as follows:

[0072] 1. The primary particle size classifier 2 in this embodiment is a bar type vibrating feeder.

[0073] 2. The tertiary particle size classifier 6 in this embodiment is a double-layer vibrating screen. The lower screen hole size is 12 mm, and the upper screen hole size is 50 mm. The medium steel slag with a particle size >50 mm on the screen is selected by the second belt-type iron remover 21 to remove the large slag steel, and is transported by the ninth belt conveyor 20 to the medium steel slag temporary storage yard. The medium steel slag can be sold to customers with special uses (such as counterweight concrete). When the sales of medium steel slag are not good, it can also be sent into the third belt conveyor 9 together with the screen medium with a particle size of 12 mm - 50 mm and enter the purification station 104.

[0074] 3. The three-way distributor 26 in this embodiment is a tray type flap double-door three-way valve.

[0075] 4. The fourth belt conveyor 10 in this embodiment is replaced by a vibrating conveying trough.

[0076] 5. For the oversize material with a particle size >12 mm on the screen of the quaternary particle size classifier 16 in this embodiment, the slag steel is selected by the third belt-type iron remover 23, and the non-magnetic slag is transported by the tenth belt conveyor 24 to the outside of the medium steel slag temporary storage yard for sale.

[0077] 6. In this embodiment, a large-capacity steel-concrete structure tent-type silo with a volume of 3500 m 3 which has the function of decomposing f-CaO in non-magnetic tail slag is used to replace the steel plate silo group. The content of f-CaO in the non-magnetic tail slag is greatly reduced, and it can be dry-ground locally (the dry-grinding steel slag powder production process and equipment are not shown in the figure) into a specific surface area of 420 - 460 m 2Steel slag powder at / kg [[synchronously adds an admixture (which has the functions of promoting hardening of cement concrete and assisting in grinding steel slag) accounting for about 2% of the mass of the non-magnetic tailings entering the mill during dry grinding]], and then mixes 30% of steel slag powder and 70% of granulated blast furnace slag powder by mass to produce "Steel and Iron Slag Powder" with performance superior to Grade G95 of GB / T 28293-2012. Its initial setting time ratio is <160%, and the strength index is slightly lower than that of Grade S95 granulated blast furnace slag powder. And because it contains a certain amount of f-CaO, it has a micro-expansion effect, thus overcoming a series of technical problems such as the dry shrinkage of granulated blast furnace slag powder in cement concrete, the low strength of pure steel slag powder, and the serious retardation of steel slag powder to cement concrete, so as to fully utilize steel slag tailings with high value.

[0078] Example 3

[0079] The differences from Example 2 are as follows:

[0080] 1. The Class I particle size classifier 2 in this example is a shaftless rotary screen.

[0081] 2. The non-magnetic tailings bin in this example is a tent-shaped bin with a volume of 4000m 3 tent-shaped bin, and several steel slag aggregate aging bins of 5000m 3 (not shown in the figure) are set according to the patented technology (such as the steel slag aggregate aging bin disclosed in the Chinese patent with the application number 202223240899.3). The steel slag tailings after preliminary digestion (f-CaO) in the 4000m 3 tent-shaped bin are sent to the steel slag aggregate aging bin by dump truck or belt conveyor to ensure that its aging digestion time and technical indicators meet the requirements of JTG F40-2004 "Technical Specifications for Highway Asphalt Pavement Construction" and JC / T2735-2023 "Steel Slag Asphalt Mixture" (the aging time is not less than 6 months, and f-CaO < 3%). Then, after particle size classification by a probability screen, it is used as the raw material for steel slag asphalt mixture, thus greatly improving the utilization rate of steel slag.

[0082] In the present utility model, specific examples are used to elaborate on the principle and implementation manner of the present utility model. The description of the above examples is only used to help understand the method and its core idea of the present utility model; at the same time, for those of ordinary skill in the art, according to the idea of the present utility model, 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 utility model.

Claims

1. A secondary processing system for steel slag, characterized in that It includes a feeding station, a first magnetic separation and screening station, a purification station, a second magnetic separation and screening station, and a finished product station, which are successively arranged in the technological order. Among them: The feeding station includes a first-stage particle size classifier, a first feeder, and a first belt conveyor, which are successively connected in the technological order. The first magnetic separation and screening station includes a first belt-type electromagnetic separator, a second-stage particle size classifier, a third-stage particle size classifier, and a magnetic separator, which are successively connected in the technological order. The first belt-type electromagnetic separator is arranged on the first belt conveyor. The purification station includes a third belt conveyor, a three-way distributor, a second feeder, an intermediate bin, and a steel slag fine crusher, which are successively connected in the technological order. The second magnetic separation and screening station includes a fourth-stage particle size classifier, a third belt-type electromagnetic separator, and a magnetic separator, which are successively connected in the technological order. The finished product station includes a magnetic powder bin and a non-magnetic tail slag bin. Between every two adjacent stations among the feeding station, the first magnetic separation and screening station, the purification station, the second magnetic separation and screening station, and the finished product station, they are interconnected through a closed belt corridor, and materials are conveyed by belt conveyors.

2. The steel slag secondary processing system according to claim 1, characterized in that, The magnetic separators in the first magnetic separation and screening station and the second magnetic separation and screening station are both roll-type magnetic separators. The steel slag fine crusher is a rod mill or an inertial cone crusher.

3. The steel slag secondary processing system according to claim 1, characterized in that, The first-stage particle size classifier is a horizontal screen, a bar-type vibrating feeder, or a shaftless rotary screen. The screen hole size of the first-stage particle size classifier is 120 mm to 200 mm. The third-stage particle size classifier is a single-layer vibrating screen or a double-layer vibrating screen. The second-stage particle size classifier and the fourth-stage particle size classifier are both vibrating screens or shaftless rotary screens, and the screen hole sizes are both 10 mm to 20 mm.

4. The steel slag secondary processing system according to claim 1, wherein The first feeder and the second feeder are both reciprocating feeders, vibrating feeders, belt feeders, or vibrating conveying troughs.

5. The steel slag secondary processing system according to claim 1, wherein The magnetic powder bin is a steel plate bin or a concrete bin. The non-magnetic tail slag bin is a group of steel plate bins or a steel-concrete structure tent-type bin.

6. The steel slag secondary processing system according to claim 3, characterized in that, The third-stage particle size classifier is the double-layer vibrating screen, and a ninth belt conveyor is arranged at the oversize material outlet of the double-layer vibrating screen, and a second belt-type electromagnetic separator is arranged on the ninth belt conveyor.

7. The steel slag secondary processing system according to claim 1, characterized in that, It further includes a raw material workshop, which is arranged in front of the feeding station and is used for temporarily storing steel slag to be processed secondary. A lifting device is configured in the raw material workshop for transporting materials in the raw material workshop. The feeding station is arranged in the raw material workshop.

8. The steel slag secondary processing system according to claim 7, wherein, The raw material workshop is a closed raw material workshop.

9. The steel slag secondary processing system according to claim 7 or 8, characterized in that, A fog cannon is further arranged in the raw material workshop, and the fog cannon is used for spraying and dust reduction in the raw material workshop. A set of HDC wet dust removal system is shared by the feeding station, the first magnetic separation and screening station to the purification station for centralized wet dust collection at each dust-producing point. A set of pulse bag filter dust removal system is provided for dry dust collection at each belt transfer point from the second magnetic separation and screening station to the finished product station. A bag filter on the top of the bin is arranged in the finished product station for dust collection or a fog cannon is arranged for dust reduction.

10. The steel slag secondary processing system according to any one of claims 1 to 8, characterized in that, It further includes a PLC control system, and the PLC control system is communicatively connected to the feeding station, the first magnetic separation and screening station, the purification station, the second magnetic separation and screening station, and the finished product station.

Images