Metal solid waste reduction cooling system

Abstract

The utility model belongs to the technical field of solid waste treatment, and particularly discloses a metal solid waste reduction cooling system which is characterized in that a reduction device, a cooling pyrolysis device and a screening device which are sequentially connected in series are designed, biomass is pyrolyzed by utilizing waste heat of high-temperature kiln slag generated by pyrogenic treatment of metal solid waste, and the high-temperature kiln slag is cooled while the high-temperature kiln slag is cooled. Biomass coke and pyrolysis gas are produced, the coke and the pyrolysis gas can be circularly used for heat supply of pyrogenic process treatment of zinc-containing dust and sludge, fossil fuel in the original technological process is replaced or partially replaced, the kiln slag waste heat utilization rate is increased, and meanwhile the carbon emission of fossil energy of the whole technology is reduced; the device has the advantages of simple overall structure, convenience in operation, sustainable production, low equipment investment cost, simplicity in maintenance, wide application range, high practicability, environmental friendliness and the like.

Description

Technical Field

[0001] The utility model relates to the treatment of metal solid waste, in particular to a reduction cooling system for treating metal solid waste generated in the steel industry, belonging to the technical field of solid waste treatment in the steel industry. Background Art

[0002] Generally speaking, the metal solid waste in the steel process mainly refers to the zinc-containing dust and mud in the steel process, which mainly comes from blast furnace ash, converter ash, electric furnace ash, etc., containing 20%~40% iron and 2%~10% zinc. It is one of the difficult-to-treat solid wastes of steel enterprises and an important resource for steel enterprises. If it is directly returned to the sintering cycle, a large amount of zinc will enter the blast furnace, corrode the blast furnace lining, form nodules on the blast furnace, and affect the longevity and smooth operation of the blast furnace equipment. Therefore, the zinc component in these solid wastes must be removed before the iron-containing component is returned to the metallurgical process.

[0003] There are two main methods for removing zinc from metal solid waste: wet method and pyrolysis method. The wet method has higher requirements on the grade of zinc, so the pyrolysis method is generally used in China. The main process flow is to mix zinc-containing dust with fuel and binder to form balls and enter the heat treatment equipment (rotary hearth furnace or rotary kiln). The fuel is generally coke powder, and the rotary hearth furnace uses bentonite as a binder, while the rotary kiln generally does not use a binder. Under high temperature conditions of 1100~1300℃, the zinc and iron in the solid waste are reduced, and the zinc is reduced to zinc element to form zinc vapor which enters the flue gas and is re-oxidized to zinc oxide in the flue gas, and then captured by the dust collector to become a secondary zinc oxide product. The remaining bottom slag is mainly iron-containing pellets after reduction, and after cooling, it returns to the metallurgical process to recover iron resources. Regardless of whether a rotary hearth furnace or a rotary kiln is used, the iron-containing pellets still have a high temperature of 800~1000℃ when they come out of the kiln. Currently, some cooling methods include directly entering a cold water pool, and some use cylinder cooling and continuously spraying cooling water on the outer surface of the cylinder. These cooling methods can achieve the cooling effect, but the heat energy contained in the kiln slag is not effectively utilized, and water resources are wasted. The water vapor generated causes water mist to fill the working area, resulting in a worse production environment.

[0004] In addition, current pyrometallurgical reduction equipment has high energy consumption and uses fossil fuels such as coke as the main energy source. The rotary hearth furnace also uses surplus metallurgical gas in the steel plant as fuel, which is essentially a fossil fuel derived from coal and has high carbon emissions. Biomass is considered a "zero-carbon" energy source, but if biomass is used to directly replace part of the coke, it is difficult to directly mix the biomass and zinc-containing dust due to the large density difference between biomass and zinc-containing dust, and the biomass will be rapidly pyrolyzed when entering the furnace, and a large amount of combustible gas produced will enter the flue gas and be lost, causing heat loss. Utility Model Content

[0005] In view of the problems of unutilized waste heat, poor cooling effect and high fossil energy consumption in the existing pyrolysis process for treating metal solid waste, the utility model provides a metal solid waste reduction and cooling system, which can continuously achieve the reduction and cooling treatment of metal solid waste through a reduction device, a cooling pyrolysis device and a screening device arranged in series. It should be noted that the system adopts dry heat exchange cooling pyrolysis, which can achieve dry cooling of the hot reduction slag of metal solid waste while utilizing the sensible heat of the hot reduction slag to achieve pyrolysis of biomass, and return the pyrolysis gas and pyrolysis carbon generated by pyrolysis to participate in the reduction and disposal of metal solid waste, thereby significantly reducing the consumption of fossil energy while improving the efficiency of waste heat utilization.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the present utility model are as follows:

[0007] A metal solid waste reduction and cooling system, the system includes a reduction device, a cooling pyrolysis device and a screening device. The feed port of the reduction device is connected to a metal solid waste conveying mechanism, the slag discharge port of the reduction device is connected to a hot material inlet of the cooling pyrolysis device through a kiln slag conveying mechanism, and the exhaust port of the reduction device is connected to a flue gas exhaust pipe. The cold material inlet of the cooling pyrolysis device is connected to a biomass powder conveying pipeline, the exhaust port of the cooling pyrolysis device is connected to an air inlet of the reduction device through a pyrolysis gas conveying pipeline, and the slag discharge port of the cooling pyrolysis device is connected to a feed port of the screening device through a mixed slag conveying mechanism. The first slag discharge port of the screening device is connected to a reduction slag conveying mechanism, and the second slag discharge port of the screening device is connected to the feed port of the reduction device through a pyrolytic carbon conveying mechanism.

[0008] Preferably, the cooling pyrolysis device comprises a kiln head, a rotating kiln body, a kiln tail and a powder barrel. The kiln head and the kiln tail are respectively arranged at the two ends of the rotating kiln body. The powder barrel passes through the kiln head, the rotating kiln body and the kiln tail in sequence and is arranged axially, and a powder drop hole is provided at the lower part of the tube body of the powder barrel located in the rotating kiln body. Both end openings of the powder barrel are connected to a biomass powder conveying pipeline. A hot material inlet connected to a kiln slag conveying mechanism is provided at the lower part of the kiln head. An exhaust port connected to a pyrolysis gas conveying pipeline is provided at the upper part of the kiln tail; a slag discharge port connected to a mixed slag conveying mechanism is provided at the lower part of the kiln tail.

[0009] Preferably, in the rotary kiln body, a plurality of powder dropping holes are provided at the lower part of the tube body of the powder tube near the kiln head, and the length of the tube body with the powder dropping holes is not less than 1 / 4 of the total length of the powder tube, preferably 1 / 2 to 3 / 4 of the total length of the powder tube.

[0010] Preferably, a blind plate is provided inside the tube body of the powder tube with the powder drop hole, and the tube cavity of the powder tube is divided into a front tube cavity and a rear tube cavity which are not connected to each other by the blind plate. In the rear tube cavity, the length of the tube cavity with the powder drop hole is 1 / 10 to 1 / 2 of the total length of the rear tube cavity, preferably 1 / 4 to 1 / 2 of the total length of the rear tube cavity.

[0011] Preferably, the powder falling hole is a round hole, a square hole or a strip hole.

[0012] Preferably, the diameter of the powder falling hole is 0.5-5 mm, preferably 1-4 mm.

[0013] Preferably, the cooling pyrolysis device is of an inclined design with a higher head and a lower tail, and the inclination angle between the cooling pyrolysis device and the horizontal plane is 3 to 8°, preferably 4 to 6°.

[0014] Preferably, a pyrolysis gas delivery branch pipe connected to the biomass powder delivery pipe is led out from the pyrolysis gas delivery pipe. A booster fan may or may not be provided on the pyrolysis gas delivery branch pipe.

[0015] Preferably, the reduction device is a rotary kiln or a rotary hearth furnace. The screening device is an air screen. The hot air outlet of the screening device is also connected to the air inlet of the reduction device through a hot air delivery pipeline.

[0016] Preferably, the system further comprises an extrusion molding device. The second slag outlet of the screening device is connected to the feed port of the extrusion molding device through the pyrolytic carbon conveying mechanism, and the discharge port of the extrusion molding device is connected to the feed port of the reduction device through the biomass carbon conveying mechanism.

[0017] Preferably, the metal solid waste conveying mechanism, mixed slag conveying mechanism, reduced slag conveying mechanism, pyrolytic carbon conveying mechanism, and biomass carbon conveying mechanism are each independently a chain conveyor, a belt conveyor, or a trolley. The kiln slag conveying mechanism is a chain conveyor or a trolley.

[0018] In the present invention, generally, when metal solid waste (such as zinc dust mud) is disposed by pyrolysis, the high-temperature slag still has a high temperature of 800-1000°C after being discharged from the reduction device. The present invention utilizes the waste heat of the high-temperature slag generated by the pyrolysis of metal solid waste (such as zinc dust mud) by designing a reduction device, a cooling pyrolysis device and a screening device connected in series, and pyrolyzes the biomass. While the high-temperature slag is cooled, the biomass is pyrolyzed to obtain pyrolysis carbon and pyrolysis gas. Compared with the existing process, the high-temperature slag no longer directly enters the cooling water pool, but enters a pyrolysis cooling reactor. Biomass powder (in order to ensure the reaction efficiency, the particle size of the biomass powder is not more than 1mm, preferably not more than 0.5mm) is fed into the pyrolysis cooling reactor as a cooling medium to absorb the sensible heat of the high-temperature slag. The mass ratio of biomass powder to high-temperature slag is generally 1-3:1 (preferably 1.2-2:1). Biomass and high-temperature slag are fully mixed in the pyrolysis cooling reactor. Since biomass can generally undergo pyrolysis reaction at a temperature above 300°C, it can absorb the sensible heat of the high-temperature slag and be pyrolyzed. Generally, the residence time of the pyrolysis cooling reaction is not less than 20 minutes. The generated pyrolysis gas is separated from the equipment, and the pyrolytic charcoal and slag form an iron-carbon mixture and are discharged from the pyrolysis cooling equipment. At the same time, they are cooled to 200~320°C and then separated by a screening device.

[0019] In the present invention, the cooling pyrolysis device can have various forms, with the main purpose of ensuring sufficient pyrolysis of biomass and effective cooling of hot slag. The cooling pyrolysis device of the present invention is a structure of a horizontal rotary cooling pyrolysis reactor (such as Figure 2 As shown in the figure), it includes a kiln head, a rotating kiln body, a kiln tail and a powder barrel. The kiln head and the kiln tail are both static structures. The rotating kiln body rotates under the drive of rollers (not shown in the figure). The powder barrel is fixed by the kiln head and the kiln tail (it is a static structure and does not rotate with the kiln body). A blind plate is installed on the powder barrel to divide the powder barrel into two areas (the front tube cavity and the rear tube cavity). The front tube cavity (as shown in the left side of the figure, zone I) is a high-temperature zone, and the lower side of the high-temperature zone is evenly opened for the transportation of biomass powder from the left. The rear tube cavity opening area (as shown in the right side of the figure near the blind plate zone II) is a medium-temperature zone, and its lower side is also opened with holes for the transportation of biomass from the right. The right side of the rear tube cavity (as shown in the right side of the figure near the kiln tail zone III is a low-temperature zone) has no holes on the axis. The length distribution ratio of zones I, II, and III is generally 1:1:1.

[0020] In the utility model, the cooling pyrolysis device is designed to be tilted as a whole, with a high kiln head and a low kiln tail, and the tilt angle is generally 3~8° (preferably 4~6°). The reduced hot slag enters the kiln from the hot material inlet through a push rod or a chute, and moves forward under the rotation and tilting of the kiln body. The biomass powder is pneumatically conveyed, with pyrolysis gas as the carrier gas, and is fed into the powder barrel from both ends of the powder barrel, and enters the kiln from the powder falling holes on the lower side of zone I and zone II respectively, and covers the hot slag, and is fully mixed, heat exchanged, and pyrolyzed with the hot slag. Some biomass charcoal can also undergo a small amount of reduction reaction with the iron oxide in the hot slag, which can improve the metallization rate of the slag to a certain extent. After the biomass pyrolysis absorbs heat, it is cooled together with the slag, and the mixture of pyrolysis charcoal and slag is discharged from the slag discharge port at the kiln tail, and the pyrolysis gas is discharged from the exhaust port and sucked out of the kiln body by negative pressure. A part of the pyrolysis gas is returned to the kiln as a carrier gas for biomass powder, and the other part of the pyrolysis gas is transported to the outside as fuel, such as being used as fuel for the reduction of zinc-containing dust and mud, and is fed into the rotary hearth furnace burner or the rotary kiln head to replace part of the coke powder.

[0021] In the present invention, the density of the pyrolytic carbon produced by biomass pyrolysis is only 0.25~0.35t / m 3 , and the slag density can reach 1.5~2.2t / m 3 The density difference between the two is huge, so the screening device of the utility model is selected as an air screen machine, which is used to separate the two. The wind blown by the air screen machine can perform secondary cooling on the kiln slag to reduce its temperature to below 100°C. At this time, the kiln slag (i.e., reduced slag) can be sold as an iron-containing raw material and returned to the metallurgical process. The cold air used by the air screen machine becomes hot air at 150~200°C after being discharged. This part of the hot air can be recycled as the combustion air of the reduction equipment, thereby further improving the waste heat utilization efficiency of the system. In a preferred embodiment, the volatile matter V of biomass pyrolysis carbon powder is less than 10%, and the volume is fluffy. It can be made into charcoal with a particle size of 3~5mm by extrusion molding (for example, at a pressure of 30~50MPa, extrusion is not less than 1min), and its density is increased to 0.9~1.1t / m 3 It can be used as a reducing agent for metal solid waste, replacing the coal in the original process. After being mixed with metal solid waste to form balls, it enters the reduction equipment for high-temperature reduction treatment, thereby significantly reducing the consumption of fossil energy.

[0022] In the utility model, the pyrolysis gas produced after pyrolysis of biomass powder mainly consists of CO: 25%~40%, H2: 30%~45%, and CH4: 5%~10%. It is a combustible gas with high calorific value and can be fed into the reduction equipment as fuel to provide heat for the reduction equipment. In a rotary hearth furnace, the pyrolysis gas can be directly sprayed into the burner above the trolley for combustion; in a rotary kiln, the pyrolysis gas can be fed into the kiln together with hot air through the kiln head nozzle for combustion. Generally, the biomass used in the utility model mainly refers to plant waste derived from agricultural and forestry waste and energy crops, including but not limited to straw, bagasse, pine wood, sawdust, etc., which are sheared and ground into powder for use in the utility model. Through the layout design among the various devices of the utility model, the circulation interaction of gas, solid, heat, etc. among the various devices is realized, the effective cooling of high-temperature kiln slag and the step-by-step utilization of the remaining heat are realized, and at the same time, biomass powder can effectively replace the original fossil fuel to reduce zinc-containing materials, the energy efficiency of the system is greatly improved, and the unit disposal energy consumption and the CO2 emission level from fossil energy are greatly reduced.

[0023] In the utility model, the reduction device can adopt a rotary kiln or a rotary hearth furnace, and its main function is to separate the iron and zinc in the zinc-containing dust and mud, and reduce the iron oxide to metallic iron. The zinc in the solid waste is discharged with the airflow in the reduction device, and the iron in the solid waste remains in the kiln slag. The function of the cooling pyrolysis device is to pyrolyze the biomass and cool the kiln slag. The biomass uses the high temperature conditions of the kiln slag to achieve pyrolysis, and obtains pyrolysis gas (used to provide a reducing atmosphere and heat source for the reduction device) and pyrolytic carbon (with metal solid waste ingredients to provide the heat source required for reduction). The function of the screening device is to screen the slag discharged from the cooling pyrolysis device to obtain the reduced material and the biomass carbon powder after pyrolysis. The reduced material enters the metallurgical process for resource recycling, and the biomass carbon powder is used to provide a heat source and reducing material for the reduction device.

[0024] In the utility model, the kiln head and kiln tail of the cooling pyrolysis device are respectively connected to the rotating kiln body by a dynamic and static combination device (such as a bearing), that is, the kiln head and the kiln tail remain stationary, and the rotating kiln body rotates under the action of an external driving force (such as a roller, a roller, etc.). The kiln slag discharged from the reduction device is constantly rolling in the cooling pyrolysis device, which is convenient for releasing heat (cooling) and fully contacting with the biomass. The powder barrel can be a stationary device or a rotating device; when the powder barrel is a stationary device, the powder barrel is fixedly connected to the kiln head and / or the kiln tail; when the powder barrel is a rotating device, the powder barrel is connected to the kiln head and / or the kiln tail through a bearing, and the powder barrel rotates under the action of an external driving device. The biomass charcoal can flow in the powder barrel by its own gravity, and can flow in the powder barrel under the action of gas (such as pyrolysis gas).

[0025] In the utility model, the flow direction of solid materials is: the reduction device produces kiln slag, the kiln slag and biomass enter the cooling pyrolysis device, and then are discharged into the screening device, the reduced coarse-grained materials enter the next metallurgical resource utilization process, and the fine-grained materials discharged from the screening device are transported to the reduction device. The airflow direction in the reduction device is: entering from one end of the reduction device, reducing the metal solid waste, and then discharged from the other end of the reduction device; wherein, the discharged waste gas is collected by the dust removal device. The cooling pyrolysis device produces pyrolysis gas, which is discharged from the exhaust port of the cooling pyrolysis device; preferably, a part of the pyrolysis gas enters the cooling pyrolysis device again as a flow carrier of biomass, and then is discharged from the exhaust port of the cooling pyrolysis device. The screening device can be a vibrating screen or a wind screen device. When the wind screen device is used, air or pyrolysis gas can be used as a fluid; preferably, the gas discharged from the screening device is used as a reducing gas, fuel gas, combustion-supporting gas or preheating gas of the reduction device.

[0026] In the utility model, a blind plate is arranged in the powder barrel to divide the entire powder barrel into two sections, thereby improving the processing capacity of the cooling pyrolysis device for biomass. The temperature is higher at the upstream of the powder barrel (the end close to the hot material inlet), and the biomass enters the powder barrel and is directly pyrolyzed, and a powder drop hole can be directly opened at the bottom of the powder barrel. At the downstream of the powder barrel (the end close to the discharge of the cooling pyrolysis device), since the slag is cooled, the heat provided is relatively small. In the rear section tube cavity, a powder drop hole is opened at the bottom of the powder barrel close to the front section tube cavity, and no powder drop hole is opened at the bottom of the powder barrel close to the discharge port. The biomass is preheated and heat stored by the powder barrel without a powder drop hole, and then enters the front end of the rear section tube cavity under the action of the gas carrier. The biomass is fully pyrolyzed at the front end of the rear section tube cavity, enters the chamber of the cooling pyrolysis device from the powder drop hole at the bottom of the front end of the rear section tube cavity, and then mixes with the slag in the cooling pyrolysis device.

[0027] Compared with the prior art, the beneficial technical effects of the utility model are as follows:

[0028] 1: The utility model designs a reduction device, a cooling pyrolysis device and a screening device which are connected in series in sequence, utilizes the waste heat of high-temperature slag produced by the pyrolysis of metal solid waste, and pyrolyzes biomass. While the high-temperature slag is cooled, biomass coke and pyrolysis gas are produced. The coke and pyrolysis gas can be recycled for heating of the pyrolysis of zinc-containing dust sludge, replacing or partially replacing the fossil fuels in the original process flow, thereby improving the utilization rate of the slag waste heat and reducing the carbon emissions of the fossil energy of the entire process.

[0029] 2: The utility model has a simple overall structure, convenient operation, sustainable production, low equipment investment cost, simple maintenance, wide application range, strong practicality, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a simplified structural diagram of the system of the utility model.

[0031] Figure 2 It is a schematic structural diagram of the cooling pyrolysis device of the utility model.

[0032] Figure 3 It is a schematic diagram of the AA section of the powder barrel of the utility model.

[0033] Figure 4 It is a schematic diagram of the BB section of the powder barrel of the utility model.

[0034] Figure 5 This is an overall structural view of the system described in the utility model.

[0035] Figure numerals: 1: reduction device; 101: metal solid waste conveying mechanism; 102: kiln slag conveying mechanism; 103: flue gas emission pipeline; 2: cooling pyrolysis device; 21: kiln head; 22: rotating kiln body; 23: kiln tail; 24: powder barrel; 25: powder drop hole; 26: blind plate; 201: biomass powder conveying pipeline; 202: pyrolysis gas conveying pipeline; 203: mixed slag conveying mechanism; 204: pyrolysis gas conveying branch pipe; 205: booster fan; 3: screening device; 301: reduction slag conveying mechanism; 302: pyrolysis carbon conveying mechanism; 303: hot air conveying pipeline; 4: extrusion molding device; 401: biomass charcoal conveying mechanism. DETAILED DESCRIPTION

[0036] The technical solution of the utility model is illustrated below, and the scope of protection requested for the utility model includes but is not limited to the following embodiments. Example 1

[0037] like Figure 1-5 As shown, a metal solid waste reduction and cooling system comprises a reduction device 1, a cooling pyrolysis device 2 and a screening device 3. The feed port of the reduction device 1 is connected to the metal solid waste conveying mechanism 101, the slag discharge port of the reduction device 1 is connected to the hot material inlet of the cooling pyrolysis device 2 through the kiln slag conveying mechanism 102, and the exhaust port of the reduction device 1 is connected to the flue gas exhaust pipeline 103. The cold material inlet of the cooling pyrolysis device 2 is connected to the biomass powder conveying pipeline 201, the exhaust port of the cooling pyrolysis device 2 is connected to the air inlet of the reduction device 1 through the pyrolysis gas conveying pipeline 202, and the slag discharge port of the cooling pyrolysis device 2 is connected to the feed port of the screening device 3 through the mixed slag conveying mechanism 203. The first slag discharge port of the screening device 3 is connected to the reduction slag conveying mechanism 301, and the second slag discharge port of the screening device 3 is connected to the feed port of the reduction device 1 through the pyrolysis carbon conveying mechanism 302. Example 2

[0038] Example 1 is repeated, except that the cooling pyrolysis device 2 includes a kiln head 21, a rotating kiln body 22, a kiln tail 23 and a powder barrel 24. The kiln head 21 and the kiln tail 23 are respectively arranged at the two ends of the rotating kiln body 22 and do not rotate with the rotation of the rotating kiln body 22. The powder barrel 24 sequentially penetrates the kiln head 21, the rotating kiln body 22 and the kiln tail 23 and is axially arranged, and a powder drop hole 25 is provided at the lower part of the tube body of the powder barrel 24 located in the rotating kiln body 22. Both end openings of the powder barrel 24 are connected to a biomass powder conveying pipeline 201. A hot material inlet connected to the kiln slag conveying mechanism 102 is provided at the lower part of the kiln head 21. An exhaust port connected to the pyrolysis gas conveying pipeline 202 is provided at the upper part of the kiln tail 23; a slag discharge port connected to the mixed slag conveying mechanism 203 is provided at the lower part of the kiln tail 23. Example 3

[0039] Example 2 is repeated, except that a plurality of powder dropping holes 25 are provided at the lower portion of the powder barrel 24 near the kiln head 21 in the rotary kiln body 22 , and the length of the barrel with the powder dropping holes 25 is 1 / 2 of the total length of the powder barrel 24 . Example 4

[0040] Example 3 is repeated, except that the length of the tube body with the powder dropping hole 25 is 2 / 3 of the total length of the powder barrel 24. Example 5

[0041] Example 4 is repeated, except that a blind plate 26 is further provided inside the tube body of the powder tube 24 with the powder drop hole 25, and the tube cavity of the powder tube 24 is divided into a front tube cavity and a rear tube cavity which are not connected to each other by the blind plate 26. In the rear tube cavity, the length of the tube cavity with the powder drop hole 25 is 1 / 3 of the total length of the rear tube cavity. Example 6

[0042] Example 5 is repeated, except that the length of the lumen with the powder dropping hole 25 in the rear lumen is 1 / 2 of the total length of the rear lumen. Example 7

[0043] Example 6 is repeated, except that the powder falling hole 25 is a square hole. Example 8

[0044] Example 7 is repeated, except that the powder falling hole 25 is a round hole. Example 9

[0045] Example 8 was repeated, except that the diameter of the powder falling hole 25 was 0.8 mm. Example 10

[0046] Example 9 was repeated, except that the diameter of the powder falling hole 25 was 1 mm. Embodiment 11

[0047] Example 10 was repeated, except that the cooling pyrolysis device 2 was designed to be inclined with the head higher than the tail, and the inclination angle between the cooling pyrolysis device 2 and the horizontal plane was 5°. Example 12

[0048] Example 11 was repeated, except that the inclination angle between the cooling pyrolysis device 2 and the horizontal plane was 6°. Embodiment 13

[0049] Example 12 is repeated, except that a pyrolysis gas delivery branch pipe 204 connected to the biomass powder delivery pipe 201 is led out from the pyrolysis gas delivery pipe 202. A booster fan 205 is optionally provided on the pyrolysis gas delivery branch pipe 204. Embodiment 14

[0050] Example 13 is repeated, except that the reduction device 1 is a rotary kiln, the screening device 3 is a wind screen, and the hot air outlet of the screening device 3 is also connected to the air inlet of the reduction device 1 through a hot air delivery pipeline 303. Embodiment 15

[0051] Example 14 is repeated, except that the system further includes an extrusion molding device 4. The second slag outlet of the screening device 3 is connected to the feed port of the extrusion molding device 4 through the pyrolytic carbon conveying mechanism 302, and the discharge port of the extrusion molding device 4 is connected to the feed port of the reduction device 1 through the biomass carbon conveying mechanism 401. Example 16

[0052] Example 15 is repeated, except that the metal solid waste conveying mechanism 101, the kiln slag conveying mechanism 102, the mixed slag conveying mechanism 203, the reduced slag conveying mechanism 301, the pyrolytic carbon conveying mechanism 302, and the biomass carbon conveying mechanism 401 are all chain conveyors.

[0053] The metal solid waste reduction and cooling system of the utility model is used to heat treat zinc-containing dust mud. The zinc-containing dust mud (such as blast furnace ash, converter ash, electric furnace ash) is first sent to the reduction device 1 for reduction treatment at high temperature to obtain hot kiln slag, and then the hot kiln slag is sent to the cooling pyrolysis device 2 through the hot material inlet at the bottom of the kiln head 21. At the same time, biomass powder is sent into the powder barrel 24 and sprinkled on the hot kiln slag through the powder drop hole 25. During the rotation of the rotating kiln body 22, the hot kiln slag and the biomass powder are fully mixed for heat exchange cooling and pyrolysis. The generated pyrolysis gas is discharged through the exhaust port at the top of the kiln tail 23 and then circulated as the fuel of the reduction device 1 or as the carrier gas of the biomass powder. The mixed slag after cooling and pyrolysis is transported to the wind screen machine for wind screen treatment, wherein the pyrolysis carbon powder is separated and then processed by the extrusion molding device 4 and then used as the fuel of the reduction device 1 for reduction. Repeat the above operation to achieve the heat treatment of zinc-containing dust mud sustainably. Compared with the existing rotary kiln reduction + water cooling process, the metal solid waste reduction cooling system of the utility model reduces the unit disposal energy consumption by about 15kgce / t, reduces the unit carbon emission from fossil fuels by about 456kg / t, and increases the product metallization rate by about 6%.

Claims

1. A metal solid waste reduction cooling system, characterized in that: The system comprises a reduction device (1), a cooling pyrolysis device (2) and a screening device (3); the feed port of the reduction device (1) is connected to a metal solid waste conveying mechanism (101); the slag discharge port of the reduction device (1) is connected to a hot material inlet of the cooling pyrolysis device (2) via a kiln slag conveying mechanism (102); the exhaust port of the reduction device (1) is connected to a flue gas exhaust pipeline (103); the cold material inlet of the cooling pyrolysis device (2) is connected to a biomass powder conveying pipeline (201); The exhaust port of the cooling pyrolysis device (2) is connected to the air inlet of the reduction device (1) via a pyrolysis gas conveying pipeline (202); the slag discharge port of the cooling pyrolysis device (2) is connected to the feed port of the screening device (3) via a mixed slag conveying mechanism (203); the first slag discharge port of the screening device (3) is connected to the reduction slag conveying mechanism (301); the second slag discharge port of the screening device (3) is connected to the feed port of the reduction device (1) via a pyrolysis carbon conveying mechanism (302); The cooling pyrolysis device (2) comprises a kiln head (21), a rotating kiln body (22), a kiln tail (23) and a powder barrel (24); the kiln head (21) and the kiln tail (23) are respectively arranged at two ends of the rotating kiln body (22); the powder barrel (24) sequentially penetrates the kiln head (21), the rotating kiln body (22) and the kiln tail (23) in an axial arrangement, and a powder drop hole (25) is provided at the lower part of the tube body of the powder barrel (24) located in the rotating kiln body (22); both end openings of the powder barrel (24) are connected to a biomass powder conveying pipeline (201); a hot material inlet connected to a kiln slag conveying mechanism (102) is provided at the lower part of the kiln head (21); an exhaust port connected to a pyrolysis gas conveying pipeline (202) is provided at the upper part of the kiln tail (23); and a slag discharge port connected to a mixed slag conveying mechanism (203) is provided at the lower part of the kiln tail (23).

2. The metal solid waste reduction cooling system according to claim 1, characterized in that: In the rotary kiln body (22), a plurality of powder dropping holes (25) are provided at the lower portion of the powder material tube (24) near the kiln head (21), and the length of the tube with the powder dropping holes (25) is not less than 1 / 4 of the total length of the powder material tube (24).

3. The metal solid waste reduction cooling system according to claim 2, characterized in that: A blind plate (26) is further provided inside the tube body of the powder material tube (24) having the powder dropping hole (25) therein, and the tube cavity of the powder material tube (24) is divided into a front tube cavity and a rear tube cavity which are not connected to each other by the blind plate (26); in the rear tube cavity, the tube cavity having the powder dropping hole (25) has a length of 1 / 10 to 1 / 2 of the total length of the rear tube cavity.

4. The metal solid waste reduction cooling system according to any one of claims 1 to 3, characterized in that: The powder dropping hole (25) is a round hole, a square hole or a strip hole.

5. The metal solid waste reduction cooling system according to any one of claims 1 to 3, characterized in that: The diameter of the powder dropping hole (25) is 0.5-5 mm.

6. The metal solid waste reduction cooling system according to any one of claims 1 to 3, characterized in that: The cooling pyrolysis device (2) is of an inclined design with a higher head and a lower tail, and the inclination angle between the cooling pyrolysis device (2) and the horizontal plane is 3-8°.

7. The metal solid waste reduction cooling system according to claim 1, characterized in that: A pyrolysis gas delivery branch pipe (204) connected to the biomass powder delivery pipe (201) is led out from the pyrolysis gas delivery pipe (202); a booster fan (205) may or may not be optionally provided on the pyrolysis gas delivery branch pipe (204).

8. The metal solid waste reduction cooling system according to claim 1, characterized in that: The reduction device (1) is a rotary kiln or a rotary hearth furnace; the screening device (3) is an air screen; and the hot air outlet of the screening device (3) is also connected to the air inlet of the reduction device (1) via a hot air delivery pipeline (303).

9. The metal solid waste reduction cooling system according to claim 1, characterized in that: The system also includes an extrusion molding device (4); the second slag outlet of the screening device (3) is connected to the feed port of the extrusion molding device (4) via a pyrolytic carbon conveying mechanism (302); and the discharge port of the extrusion molding device (4) is connected to the feed port of the reduction device (1) via a biomass carbon conveying mechanism (401).

10. The metal solid waste reduction cooling system according to claim 9, characterized in that: The metal solid waste conveying mechanism (101), the mixed slag conveying mechanism (203), the reduced slag conveying mechanism (301), the pyrolytic carbon conveying mechanism (302), and the biomass carbon conveying mechanism (401) are each independently a chain conveyor or a belt conveyor or a trolley; the kiln slag conveying mechanism (102) is a chain conveyor or a trolley.

Images