Stainless steel smelting tailing treatment method and system

Abstract

The invention relates to a stainless steel smelting tailing treatment method and system, and the treatment method comprises the following steps: 1) crushing the slag surface of tailings: crushing the surface of crusting tailings to ensure the fluidity of slag charge; (2) water quenching is conducted, specifically, tailings in the slag tank are poured into a first chute and then enter a water quenching pool through a second chute; a nozzle is arranged at the inlet end of the second chute, high-pressure water flow is sprayed into the second chute, and the water pressure is 0.3-1 MPa; the tailings poured into the first chute are poured from the position above the high-pressure water flow and collide with the high-pressure water flow, primary water quenching is completed, and the primary water quenching temperature is 80-90 DEG C; the tailings obtained after primary water quenching enter a water quenching pool through a second chute and make full contact with water in the water quenching pool, secondary water quenching is conducted, and the temperature of secondary water quenching is 80-95 DEG C; rapidly cooling and quenching the slag charge to finally form tailings with the granularity of less than or equal to 3mm; and (3) dewatering: storing the tailings subjected to secondary water quenching in a dewatering slag bin, and draining and drying.

Description

Technical Field

[0001] The invention belongs to the technical field of stainless steel production, and in particular relates to a method and system for treating stainless steel smelting tailings. Background Art

[0002] 304 and 316 stainless steel are the most common stainless steel types, widely used in metal materials in the fields of construction, home furnishing, catering, etc., and are favored by people for their excellent corrosion resistance, aesthetics and practicality. It has good corrosion resistance, high temperature resistance, oxidation resistance, aesthetics and other characteristics, and is a high-quality surface material. During the production process of 304 / 316 stainless steel, a large amount of steel slag will be produced. Steel slag is formed by the cooling and crystallization of molten steel. Its main components are iron oxide and calcium oxide, including: SiO 2 27~37%, CaO 40~65%, MgO 3~6%, MnO 0.5~10%, and the balance is Fe and unavoidable impurities.

[0003] At present, with the diversified development of steelmaking processes and technologies at home and abroad, steel slag treatment processes mainly include air quenching, water quenching, hot pouring, hot stuffing, drum method and other methods.

[0004] Wind quenching method: tilt the slag pot, the molten slag is blown away by the ejected air and broken into particles, and the heat dissipated by the high-temperature air and the particle slag is recovered in the bell-type boiler and the slag particles are captured. The advantages of this method include safety and reliability, simple process, low investment, large processing capacity, complete one-time granulation, and low water consumption. However, the disadvantage is that it has great requirements on the fluidity of steel slag. Due to the high basicity and viscosity of steel slag, the steel slag that can be treated with wind quenching generally does not exceed 50% of the total steel slag, and the rest of the steel slag must be treated by other methods.

[0005] Water quenching method: high-temperature molten slag flows out slowly, and is cut and crushed by high-pressure water when falling, and is quenched and contracted to form stress concentration and break. The advantages of this method include fast slag discharge, simple process, small footprint, low investment cost, small particle size of treated slag, and stable performance. The disadvantages are that improper operation during slag water quenching is prone to explosion, the uniformity of slag particle size is relatively poor, and only liquid slag can be processed.

[0006] Hot pouring method: When the slag exceeds the quenchable temperature, a large amount of water is sprayed on the slag. The resulting temperature stress causes the slag to break, and the hydration of free calcium oxide will further break the slag. The advantages include fast slag discharge, short cooling time, conducive to mechanized production, large processing capacity, high slag activity, and high production efficiency. The disadvantages are large equipment loss, large floor space, large amount of dust from crushing and processing, and large amount of steam, which is not good for both the environment and energy saving.

[0007] Hot stuffing method: using the sensible heat of high-temperature molten slag, the temperature stress generated when it meets water and the hydrolysis of free calcium oxide to break the slag. The advantages include simple process operation, ability to process high-basicity slag, good slag-iron separation effect, high slag activity and good stability. The disadvantages are uneven particle size, long processing cycle and large subsequent crushing and processing volume.

[0008] Drum method: The slag enters the drum at a suitable flow rate. Under the action of centrifugal force and spray water, the slag is dispersed by water and condensed into small pieces for collection. The advantages include fine slag particle size, complete separation of scrap steel and slag, very favorable scrap steel recycling, short production process, small footprint, high production efficiency, less dust, steam is discharged through the chimney for good environmental performance, high degree of automation and low labor intensity. The disadvantages are complex equipment, difficult maintenance, requirement for good fluidity of slag, inability to handle solid slag and slag with poor fluidity, and high operating costs.

[0009] These methods have their own advantages and disadvantages and are suitable for different treatment needs and conditions. Choosing a suitable treatment method requires considering factors such as the characteristics of slag, treatment costs, environmental protection requirements, and production efficiency.

[0010] Chinese patent publication number CN102140561B discloses a slag water quenching system, including a tilting device, on which an intermediate tank is installed; a granulator is installed at the front of the intermediate tank tilting device; an explosion-proof water quenching pool is installed in the spray direction of the granulator, and the explosion-proof water quenching pool is connected to a dehydration and slag discharge device through a slag flushing ditch. A conveyor belt is provided below the slag discharge device of the dehydration and slag discharge device, and one end of the conveyor belt is connected to a silo; a drainage ditch is provided below the dehydration and slag discharge device, and the drainage ditch is connected to a circulating water pool.

[0011] Chinese patent publication number CN103710479B discloses a steel slag water quenching treatment system, which mainly provides a steel slag water quenching treatment system with high safety and low pollution. The steel slag water quenching treatment system of the present invention includes a slag pot, a steel slag separation device arranged outside the slag outlet of the slag pot, the steel slag separation device includes an intermediate container with a slope structure and a filter arranged at the bottom of the container platform, the system also includes a secondary water quenching tank, an elevated steam extraction hood arranged above the secondary water quenching tank, and the steam extraction hood is connected to a steam extraction centrifugal fan through a steam extraction pipeline.

[0012] Chinese patent publication number CN212713599U discloses an electric furnace liquid slag water quenching device, comprising a slag pot for holding molten steel and a tilting device for placing the slag pot, the slag pot is hoisted above the tilting device by a hoisting mechanism, a slag flushing trough located below the ground is arranged below the output end of the tilting device, a granulator for cooling and crushing the slag in the molten steel by a high-pressure water flow is arranged at the input end of the slag flushing trough, a slag receiving pool is arranged below the output end of the slag flushing trough, and a slag scooping mechanism for scooping out the slag after water crushing is arranged above the slag receiving pool. Summary of the invention

[0013] The purpose of the present invention is to provide a stainless steel smelting tailings treatment method and system, reduce environmental pollution, adopt slag surface crushing + two water quenching treatments, the water quenching treatment speed is fast, the water quenching output is high, and the slag does not fall to the ground. Clean and efficient production is achieved; and the recycling rate of resources is improved, and the tailings can be converted into a form that is easier to handle and utilize. The smelting waste slag is in a high-temperature molten liquid state before treatment, and is sand and gravel-like particles (particle size 1-3mm) after treatment, which can be used as road and building construction materials.

[0014] To achieve the above object, the technical solution of the present invention is: A method for treating stainless steel smelting tailings comprises the following steps: 1) Crushing of tailings slag surface The surface of the crusted tailings in the slag pot is crushed to ensure the fluidity of the slag; 2) Water quenching The tailings in the slag tank are poured into the first chute and then into the water quenching pool through the second chute; a nozzle is set at the inlet end of the second chute, and a high-pressure water flow is sprayed into the second chute, and the water pressure of the high-pressure water flow is 0.3~1MPa; the tailings poured into the first chute are poured from above the high-pressure water flow, collide with the high-pressure water flow, and complete the first water quenching, and the first water quenching temperature is 80~90℃; the tailings after the first water quenching enter the water quenching pool through the second chute, and fully contact with the water in the water quenching pool, and undergo a second water quenching, the slag is rapidly cooled and quenched, and finally forms tailings with a particle size of ≤3mm, and the second water quenching temperature is 80~95℃; 3) Dehydration The tailings after the secondary water quenching are stored in the dewatering slag bin and drained.

[0015] Preferably, in step 1), the surface of the crusted tailings is crushed by a robot.

[0016] The present invention also provides a system for the stainless steel smelting tailings treatment method, which comprises: Tipping device; A first chute, arranged at the outlet end of the tilting device; The second chute is arranged obliquely, and its inlet end corresponds to the outlet end of the first chute, and a high-pressure nozzle is arranged at the inlet end of the second chute; A water quenching tank, wherein the outlet end of the second chute is arranged in the water quenching tank.

[0017] Furthermore, there are: The sand bailer has one end set in the water quenching tank, and the bucket on the sand bailer is provided with a drain hole. Bucket elevator is installed beside the water quenching tank, and the outlet of the sand bailer corresponds to the bucket elevator; The dewatered slag bin is arranged beside the bucket elevator, and the upper outlet of the bucket elevator is connected to the dewatered slag bin through a guide groove.

[0018] Furthermore, a circulating water pool is provided, which is connected to the water quenching pool through a drainage pipe, and is connected to a water tank for supplying water to the high-pressure nozzle through a circulating water pump and a water delivery pipe.

[0019] Furthermore, a slag breaking robot is also provided, which is arranged on one side of the tilting device.

[0020] Preferably, dust collecting hoods for recovering steam and fume are respectively arranged above the second chute and / or the water quenching tank.

[0021] Preferably, the second chute has a U-shaped cross-section.

[0022] Preferably, the tilting device includes a tilting frame and a tilting cylinder; or, the tilting device is a crane.

[0023] The present invention uses the excellent impact force of high-pressure water jet technology to achieve efficient crushing of liquid steel slag. Through the high-pressure nozzle, water is accurately sprayed out under high pressure; then, the liquid steel slag is guided above the high-pressure water flow, and the high-speed kinetic energy of the water flow directly collides with the liquid steel slag to achieve the purpose of crushing and dispersing the liquid steel slag. In this process, after two water quenchings, the tailings are quickly cooled by the high-pressure water flow and finally crushed into fine particles.

[0024] In the water quenching process, the tailings are in contact with the water sprayed by the nozzle, and the tailings are quenched once and twice in sequence to obtain the final finished product of water-quenched slag, the particle size of the finished water-quenched slag is ≤3mm; the water pressure of the water quenching is 0.3~1MPa. The high-pressure nozzle can spray out pressurized water flow, which breaks the tailings into smaller particles with a strong impact force and enters the water quenching pool, where it is further cooled and refined to ensure that the tailings reach the required particle size and quality standards.

[0025] The existing water quenching water pressure is 6~8MPa. The higher the water pump pressure, the lower the water flow rate.

[0026] The water quenching water pressure of the present invention adopts a method of low pressure and large flow of 0.3-1MPa, and the amount of water when water and slag are mixed for water quenching is increased, so that a large amount of water can absorb the heat of the slag and reduce the temperature of the slag, and the water quenching reaction will be faster and more efficient; the large flow of water circulation can realize 24-hour continuous water quenching, and the water temperature can be kept stable for a long time.

[0027] In the existing water quenching process, 6~8MPa high water pressure water flow is used to break the slag flow; the present invention can break the slag flow at a water pressure of 0.3~1MPa. The reason is that because the tailings have a certain viscosity, the present invention designs the first chute and the second chute under the slag pot. Due to the height difference between the slag pot and the first chute, the power of the tailings falling on the first chute when the slag pot is overturned is increased, and it flows down with the first chute, thereby increasing the fluidity of the slag liquid, so that the tailings can be broken and diverted by a smaller water pressure in the second chute.

[0028] In addition, the water quenching water pressure of the present invention is 0.3-1 MPa, which can be achieved by a conventional water pump, and the equipment is highly economical.

[0029] In the water quenching process of the present invention, the tailings are fully contacted with water twice, the first water quenching temperature of the present invention is 80-90°C, and the second water quenching temperature is 80-95°C.

[0030] The tailings at about 1550℃ are quenched once with water at 80℃~90℃ (located in the second chute, the amount of water is slightly less than the secondary quenching in the water quenching pool), and then flow through the second chute and fall into the water quenching pool. In the second chute (equivalent to a water tank), the slag and water can be fully mixed, and the nozzle continuously sprays water to flush the slag-water mixture into the water quenching pool. In this process, the slag is continuously quenched.

[0031] The tailings are quenched twice with water at 80-95°C in a water quenching tank. The water volume in the water quenching tank is large, and the water quenching reaction is completely completed to form a finished product.

[0032] If the water temperature in the water quenching tank is greater than 95°C, the hydration reaction process of the active components in the slag (such as calcium oxide and magnesium oxide) cannot be suppressed, resulting in changes in the slag structure, which may have adverse effects such as uneven particles, pulverization, or incomplete reaction.

[0033] The water temperature in the water quenching pool is less than 80℃. Although a large amount of low-temperature water can quickly cool down the water, it is necessary to continuously add a large amount of cooling water to neutralize the water temperature, which increases water consumption. However, it has no beneficial effect on the water quenching reaction and also increases production and operation costs.

[0034] The water-quenched slag enters the slag dredger for dehydration and lifting, or enters the buffer bin for secondary dehydration, and the moisture content of the finished product is ≤5%. After the tailings flow into the water quenching pool, they are rapidly cooled, and the tailings are broken due to internal stress, cracked into smaller particles, and precipitated in the water quenching pool; then, the water-quenched slag is scooped up and lifted to the top of the dewatered slag bin, and finally enters the dewatered slag bin. In the dewatered slag bin, most of the water is separated. This water is discharged from the bottom of the dewatered slag bin and recycled. The dewatered slag particles are sent to the cement production plant by transfer vehicles.

[0035] The steam and smoke generated during the primary and secondary water quenching production processes are recovered through dust collecting hoods and discharged after being treated to meet the standards.

[0036] Compared with the prior art, the present invention has the following beneficial effects: The stainless steel smelting tailings treatment method of the present invention adopts slag surface crushing + two water quenching treatments, combined with high-pressure water jets, so that the tailings are quickly cooled and finally crushed into fine particles. The water quenching treatment speed is fast and the water quenching output is high, thereby realizing clean and efficient production without slag falling to the ground.

[0037] The present invention adopts a large-flow low-pressure water process, with a water quenching water pressure of 0.3-1.0 MPa. The large flow accelerates the slag water quenching reaction, improves the water quenching speed and effect, and is safer and more reliable to use than high-pressure water; moreover, the equipment operation cost is low.

[0038] The present invention adopts two-stage chutes and two water quenching reactions. The first chute improves the fluidity of the tailings, and the second chute and the two water quenchings improve the water quenching speed and effect. The final finished product particle size is ≤3mm.

[0039] In addition, the surface of the crusted tailings is broken by a robot, which has higher efficiency and is more convenient and flexible to operate than traditional methods.

[0040] The tailings treatment system of the present invention adopts a primary chute, a secondary chute + a water quenching tank, and is combined with a high-pressure nozzle to achieve a fast water quenching treatment speed.

[0041] The tailings treatment system of the present invention adopts direct tipping of the slag pot without an intermediate tank, and has relatively high efficiency.

[0042] The existing tailings treatment technology uses hot pouring, which has low efficiency (production cycle is generally ≥24h), high water consumption, and poor environmental protection. The steel slag after hot stuffing is mostly large pieces, and the slag and iron separation is insufficient. The slag is then ground into fine particles using a ball milling process, and then processed by a shaking table magnetic separation filter to finally obtain filter dry slag (water content of about 20%). The market processing cost of each ton of slag is about 40 yuan / ton.

[0043] The tailings treatment of the present invention adopts water quenching treatment, which is highly efficient (production cycle is generally <1h) and the treated product can be used as raw material for construction. The method has a short treatment process and the slag treatment cost is reduced by about 40% compared with the hot pouring method. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the structure of the system embodiment 1 of the present invention; Figure 2 A top view of the system embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of the system embodiment 2 of the present invention; Figure 4 It is a front view of the scoop in the system embodiments 1 and 2 of the present invention; Figure 5 It is a top view of the scoop in system embodiments 1 and 2 of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with the embodiments and drawings.

[0046] The stainless steel smelting tailings treatment method of the present invention comprises the following steps: 1) Tailings crushing The surface of the crusted tailings in the slag pot is crushed to ensure the fluidity of the slag; 2) Water quenching The tailings in the slag tank are poured into the first chute and then into the water quenching pool through the second chute; a nozzle is set at the inlet end of the second chute, and a high-pressure water flow is sprayed into the second chute, and the water pressure of the high-pressure water flow is 0.3~1MPa; the tailings poured into the first chute are poured from above the high-pressure water flow, collide with the high-pressure water flow, and complete the first water quenching, and the first water quenching temperature is 80~90℃; the tailings after the first water quenching enter the water quenching pool through the second chute, and fully contact with the water in the water quenching pool, and undergo a second water quenching, the slag is rapidly cooled and quenched, and finally forms tailings with a particle size of ≤3mm, and the second water quenching temperature is 80~95℃; 3) Dehydration The tailings after the secondary water quenching are stored in the dewatering slag bin and drained.

[0047] Preferably, in step 1), the surface of the crusted tailings is crushed by a robot.

[0048] See also Figure 1~Figure 5 The system for treating the stainless steel smelting tailings provided by the present invention comprises: Tilt device 1; The first chute 2 is arranged at the outlet end of the tilting device 1; The second chute 3 is arranged obliquely, and its inlet end corresponds to the outlet end of the first chute 2. A high-pressure nozzle 4 is arranged at the inlet end of the second chute 3; The water quenching tank 5 , the outlet end of the second chute 3 is arranged in the water quenching tank 5 .

[0049] Preferably, dust collecting hoods 6, 6' for recovering steam and fume are respectively arranged above the second chute 3 and / or the water quenching tank 5.

[0050] See also Figure 1 , Figure 3~Figure 5 , the processing system of the present invention further comprises: A sand bailer 7, one end of which is disposed in the water quenching tank 5, and a scoop 71 on the sand bailer 7 is provided with a drain hole 711; A bucket elevator 8 is arranged beside the water quenching tank 5, and the outlet end of the sand bailer 7 corresponds to the bucket elevator 8; The dewatered slag bin 9 is arranged beside the bucket elevator 8 , and the upper outlet of the bucket elevator 8 is connected to the dewatered slag bin 9 through a guide groove 10 .

[0051] Furthermore, a circulating water pool 11 is provided, which is connected to the water quenching pool 5 through a drainage pipe 12 and is connected to a water tank 13 for supplying water to the high-pressure nozzle 4 through a circulating water pump and a water delivery pipeline.

[0052] In addition, a slag breaking robot 14 is provided, which is arranged on one side of the tilting device 1 .

[0053] Preferably, the second chute 3 has a U-shaped cross section.

[0054] Preferably, the tilting device 1 includes a tilting frame and a tilting cylinder; or, the tilting device 1 is a crane.

[0055] The slag pot containing steel slag is transferred to the tilting device 1 (tilting platform) where the slag pot is placed. After the surface of the crusted tailings in the slag pot is crushed, it passes through the first chute 2 and the second chute 3 in turn and enters the water quenching tank 5. The high-pressure nozzle 4 at the inlet of the second chute 3 continuously sprays high-pressure water flow with stable pressure to crush the tailings coming down from the first chute 2; the crushed tailings enter the water quenching tank 5 and merge with a large amount of water to be cooled rapidly; the sand bailer 7 then fishes out the tailings after water quenching in the water quenching tank 5; and sends it to the dewatering slag bin 9 for drainage and drying. When the moisture reaches the standard, it can be directly loaded on a truck 15 for transportation, and the next step may be cement production and processing.

Claims

1. A method for treating stainless steel smelting tailings, characterized in that: The steps include: 1) Tailings crushing The surface of the crusted tailings in the slag pot is crushed to ensure the fluidity of the slag; 2) Water quenching The tailings in the slag tank are poured into the first chute and then into the water quenching pool through the second chute; a nozzle is set at the inlet end of the second chute, and a high-pressure water flow is sprayed into the second chute, and the water pressure of the high-pressure water flow is 0.3~1MPa; the tailings poured into the first chute are poured from above the high-pressure water flow, collide with the high-pressure water flow, and complete the first water quenching, and the first water quenching temperature is 80~90℃; the tailings after the first water quenching enter the water quenching pool through the second chute, and fully contact with the water in the water quenching pool, and undergo a second water quenching, the slag is rapidly cooled and quenched, and finally forms tailings with a particle size of ≤3mm, and the second water quenching temperature is 80~95℃; 3) Dehydration The tailings after the secondary water quenching are stored in the dewatering slag bin and drained.

2. The stainless steel smelting tailings treatment method according to claim 1, characterized in that: In step 1), the surface of the crusted tailings is crushed by a robot.

3. A system for treating stainless steel smelting tailings according to claim 1 or 2, characterized in that: include, Tipping device; A first chute, arranged at the outlet end of the tilting device; The second chute is arranged obliquely, and its inlet end corresponds to the outlet end of the first chute, and a high-pressure nozzle is arranged at the inlet end of the second chute; A water quenching tank, wherein the outlet end of the second chute is arranged in the water quenching tank.

4. The system according to claim 3, characterized in that Also features: The sand bailer has one end set in the water quenching tank, and the bucket on the sand bailer is provided with a drain hole. Bucket elevator is installed beside the water quenching tank, and the outlet of the sand bailer corresponds to the bucket elevator; The dewatered slag bin is arranged beside the bucket elevator, and the upper outlet of the bucket elevator is connected to the dewatered slag bin through a guide groove.

5. The system according to claim 3 or 4, characterized in that A circulating water pool is also provided, which is connected to the water quenching pool through a drainage pipe, and is connected to a water tank supplying water to the high-pressure nozzle through a circulating water pump and a water delivery pipeline.

6. The system according to claim 3 or 4, characterized in that: A slag breaking manipulator is also provided and arranged on one side of the tilting device.

7. The system according to claim 5, characterized in that A slag breaking manipulator is also provided and arranged on one side of the tilting device.

8. The system according to claim 3, characterized in that The tilting device comprises a tilting frame and a tilting cylinder; or, the tilting device is a crane.

9. The system according to claim 3, characterized in that Dust collecting hoods for recovering steam and smoke are respectively arranged above the second chute and / or the water quenching tank.

10. The system according to claim 3 or 9, characterized in that The second chute has a U-shaped cross section.

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