Iron-containing and zinc-containing dust resource recycling treatment process and system

Abstract

The invention relates to an iron-containing and zinc-containing dust resource recycling treatment process and system. The process comprises the following steps: (1) raw material pretreatment; (2) calcining the iron-containing and zinc-containing material at high temperature; (3) iron element recovery; (4) zinc element recovery; (5) environment-friendly treatment; the system comprises a raw material pretreatment unit, a rotary kiln, an iron recovery unit, a zinc recovery unit, a flue gas treatment unit and a fly ash treatment unit. On the basis of the rotary kiln reduction technology, the raw material pretreatment process adopting the cold briquetting technology and the iron element recovery process adopting the hot briquetting technology are coupled, the iron-containing and zinc-containing dust is treated, the iron element and the zinc element are efficiently recovered, and meanwhile the purposes of low consumption and environmental protection are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a resource recovery and treatment process and system for iron-containing and zinc-containing dust in a steel enterprise. Background Art

[0002] Iron-containing and zinc-containing dust generated in the production process of the steel industry is a solid waste with many types, large production volume and complex composition. It contains harmful elements such as K, Na, Zn and Cl, which greatly limits its recycling. At present, iron-containing and zinc-containing dust are mainly added to the mixture of the sintering process and enter the blast furnace with the sintered ore. During the production process of the blast furnace, iron-containing and zinc-containing dust will be generated again. This cycle repeats and accumulates in the blast furnace, resulting in nodules on the upper part of the blast furnace, affecting the normal production of the blast furnace.

[0003] Another conventional method for treating iron-containing and zinc-containing dust is to use the reduction method to increase the iron content and reduce the zinc content, so as to obtain zinc oxide dust products and solid iron materials. The rotary kiln is a widely used iron-reducing and zinc-reducing equipment. The iron-containing material is reduced in the high-temperature atmosphere of the rotary kiln; the zinc-containing material enters from the high-end of the rotary kiln. After entering the kiln, the material is preheated, dried, calcined and reduced in sequence under the action of high-temperature flue gas. Zinc vapor volatilizes into the gas phase under the action of flue gas flow, and the iron element is discharged from the low end of the rotary kiln with the solid phase. The process of pretreatment of iron-containing and zinc-containing dust to generate solid iron-containing material products is long and complicated, and consumes a lot of energy media. The solid material in the rotary kiln is in reverse contact with the high-temperature flue gas. The disc pelletizer is usually used to pretreat the iron-containing and zinc-containing materials to give them a certain particle size to prevent the powdered materials from being discharged out of the system with the high-temperature flue gas. However, the process of the disc pelletizer requires continuous addition of process water, and the system process is complicated and the cost is high.

[0004] After the slag of the rotary kiln is discharged from the lower end of the rotary kiln, it can be cooled by water cooling or air cooling. When water cooling is used, the hot iron-containing slag discharged from the lower end of the rotary kiln is directly discharged into the cold slag pool, and the cooling water is used for cooling and recycling. The use of water cooling, on the one hand, causes a waste of water resources. On the other hand, a large amount of steam will overflow instantly when the high-temperature slag contacts with cold water, resulting in a poor on-site operating environment. In addition, the iron in the solid phase slag is oxidized by water, which will reduce the metallization rate of the solid phase slag. When air cooling (the cooling medium is nitrogen at room temperature) is used, due to the high temperature of the slag (generally 500-600°C), a large amount of nitrogen is required, resulting in a large consumption of energy media. Summary of the invention

[0005] The present invention provides a resource recovery and treatment process and system for iron-containing and zinc-containing dust. The process and system are based on rotary kiln reduction technology, coupled with a raw material pretreatment process using cold briquetting technology and an iron recovery process using hot briquetting technology, to treat iron-containing and zinc-containing dust, thereby achieving the goal of low consumption and environmental protection while efficiently recovering iron and zinc elements.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A resource recovery and treatment process for iron-containing and zinc-containing dust includes the following steps:

[0008] (1) Raw material pretreatment: the iron-containing and zinc-containing dust raw material, binder, coal powder, and iron ore powder are mixed according to a set ratio, and the mixed material is conveyed to a cold pressing machine to be pressed into agglomerates to obtain iron-containing and zinc-containing materials;

[0009] (2) High-temperature calcination of the iron-containing and zinc-containing materials: The iron-containing and zinc-containing materials pressed into agglomerates in process (1) are transported from the tail of the rotary kiln to the inside of the rotary kiln. The iron-containing and zinc-containing materials undergo a reduction reaction in the rotary kiln. The iron element therein is discharged from the head of the rotary kiln along with the slag phase, and the zinc element is discharged from the tail of the rotary kiln along with the flue gas.

[0010] (3) Iron recovery: The slag material discharged from the rotary kiln head in process (2) is transported to a hot press briquetting machine and directly pressed into briquettes to complete the iron recovery process;

[0011] (4) Recovery of zinc element: The zinc-containing flue gas discharged from the rotary kiln tail in process (2) is sent to a waste heat recovery device to recover sensible heat, then cooled by a surface cooler and fly ash is recovered, and finally collected by a bag filter to obtain secondary zinc oxide;

[0012] (5) Environmental protection treatment: The fly ash discharged from the waste heat recovery device and the surface cooler in process (4) is transported to the water washing device, and the solid phase after water washing is returned to process (1) to be mixed with the iron-containing and zinc-containing materials. The liquid phase after water washing enters the high-salt wastewater zero discharge device to obtain crystallized salt and recycled water after treatment, wherein the recycled water is sent to process (1) to participate in mixing and batching; the flue gas after bag dust removal in process (4) is introduced into the flue gas purification device by the induced draft fan for purification treatment.

[0013] In the process (3), nitrogen gas sealing is adopted in the process of conveying the slag phase material discharged from the kiln head of the rotary kiln to the hot pressing machine and in the hot pressing process; the high-temperature nitrogen generated by the gas sealing nitrogen after the hot pressing process is conveyed to the kiln head of the rotary kiln for heating the combustion-supporting air and auxiliary fuel gas, and then discharged with the smoke of the rotary kiln.

[0014] In the process (1), the binder is one or more of starch, sugar, crude fiber and bentonite.

[0015] In the process (1), the iron-containing and zinc-containing materials are formulated in the following proportions by weight: 68-90 parts of iron-containing and zinc-containing dust raw materials, 0-8 parts of coal powder, 3-10 parts of starch, 2-6 parts of bentonite, and 4-15 parts of iron ore concentrate powder.

[0016] In the process (1), the iron content of the iron-containing and zinc-containing material is 50% to 60% by weight, and the carbon content is 5% to 8% by weight.

[0017] In the process (1), the size of the cold-pressed iron- and zinc-containing material lumps is 5 to 30 mm, the water content is 9% to 11%, the drop strength of the lumps is greater than 10 times / 0.5 m, and the average compressive strength of the lumps is 200 to 300 N / lump.

[0018] A resource recovery and treatment system for iron-containing and zinc-containing dust, comprising a raw material pretreatment unit, a rotary kiln, an iron recovery unit, a zinc recovery unit, a flue gas treatment unit and a fly ash treatment unit; the raw material pretreatment unit is composed of a raw material storage bin, a raw material conveying device, a strong mixer and a cold briquetting machine connected in sequence; the cold briquetting machine is connected to the material inlet of the rotary kiln through a material conveying device; the iron recovery unit is composed of a nitrogen-sealed chute and a hot briquetting machine; the slag phase outlet of the rotary kiln is connected to the material inlet of the hot briquetting machine through a nitrogen-sealed chute; the zinc recovery unit is composed of a waste heat boiler, a surface cooler, a bag dust collector and a recovered zinc storage bin, a waste heat boiler is provided at the kiln tail of the rotary kiln, and the waste heat boiler is connected to the surface cooler and the bag dust collector through a flue gas pipeline The ash discharge port at the bottom of the bag filter is connected to the recovered zinc storage bin through a pneumatic conveying pump; the flue gas treatment unit is composed of an induced draft fan, a flue gas purification device and a chimney, and the purified flue gas outlet of the bag filter is connected to the flue gas purification device and the chimney through an induced draft fan; the fly ash treatment unit is composed of a water washing tank, a filter press and a wastewater treatment system; an ash discharge hopper is provided at the kiln tail of the rotary kiln, and the bottom outlet of the ash discharge hopper is connected to the water washing tank through a screw conveyor; the ash discharge port at the bottom of the surface cooler is connected to the water washing tank through a screw conveyor; the water washing tank is connected to the filter press and the wastewater treatment system in turn through a sewage pipe, the solid phase outlet of the filter press is connected to the raw material conveying device through a material conveying device, and the recycled water outlet of the wastewater treatment system is connected to the water inlet of the high-power mixer.

[0019] The raw material storage bins include iron-containing and zinc-containing dust storage bins, coal powder storage bins, iron ore concentrate powder storage bins and binder storage bins, among which the iron-containing and zinc-containing dust storage bins include ash bins and mud bins; the tops of the ash bins, coal powder storage bins, iron ore concentrate powder storage bins and binder storage bins are all equipped with bag dust collectors, and the bottom discharge ports are all equipped with manual unloading valves and electric unloading valves; the bottom discharge port of the mud bin is equipped with a screw conveyor and a manual unloading valve.

[0020] The rotary kiln has a low kiln head and a high kiln tail. The kiln head is provided with an auxiliary gas inlet and a combustion-supporting air inlet. The auxiliary gas inlet is connected to a fuel conveyor, and the combustion-supporting air inlet is connected to a combustion-supporting fan.

[0021] The wastewater treatment system consists of a filtrate tank, a filtrate pump and a high-salt wastewater zero discharge device which are connected in sequence.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) Based on the rotary kiln reduction technology, the raw material pretreatment process using cold pressing technology and the iron recovery process using hot pressing technology are coupled to treat the iron-containing and zinc-containing dust, with a simple process flow and low energy consumption;

[0024] 2) The slag phase material discharged from the rotary kiln head is transported to the hot pressing machine, and nitrogen gas sealing is used during the transportation and hot pressing process. The iron-containing slag is pressed into a pellet under a nitrogen atmosphere, and then the surface is oxidized in an air atmosphere to form a protective film, which is beneficial to the stability of the iron element inside the hot pressing pellet and ensures the metallization rate of the solid phase slag;

[0025] 3) The high-temperature nitrogen generated by the hot-pressing process of the gas-sealed nitrogen is transported to the kiln head of the rotary kiln to heat the combustion air and auxiliary fuel gas, and then discharged to the flue gas treatment unit with the rotary kiln flue gas for purification to achieve standard emission;

[0026] 4) The fly ash discharged from the rotary kiln, waste heat boiler and surface cooler is transported to the water washing device (including water washing tank and filter press), the separated solid phase is returned to the mixing and batching section, and the liquid phase is returned to the mixing and batching section after being treated by the high-salt wastewater zero discharge device. There is no solid waste and liquid waste discharged, and the environmental protection effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention discloses a flow chart of a process for recycling and treating iron- and zinc-containing dust resources.

[0028] Figure 2 It is a structural schematic diagram of a resource recovery and treatment system for iron-containing and zinc-containing dust according to the present invention.

[0029] In the figure: 1. Bag filter on the top of the silo 2. Raw material storage silo 3. Manual discharge valve 4. Electric discharge valve 5. Raw material conveying device 6. Mud silo 7. Screw conveyor 8. Powerful mixer 9. Cold briquetting machine 10. Waste heat boiler 11. Rotary kiln 12. Combustion fan 13. Fuel conveyor 14. Nitrogen sealing chute 15. Hot briquetting machine 16. Surface cooler 17. Bag filter 18. Pneumatic conveying pump 19. Zinc recovery silo 20. Ton bag packaging machine 21. Induced draft fan 22. Flue gas purification device 23. Chimney 24. Washing tank 25. Filter press 26. Filtrate tank 27. Filtrate pump 28. High-salt wastewater zero discharge device DETAILED DESCRIPTION

[0030] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0031] like Figure 1 , Figure 2 As shown, the iron-containing and zinc-containing dust resource recovery and treatment process of the present invention includes the following process:

[0032] (1) Raw material pretreatment: The iron-containing and zinc-containing dust raw material, binder, coal powder, and iron ore powder are mixed according to a set ratio, and the mixed material is conveyed to a cold pressing machine 9 to be pressed into agglomerates to obtain an iron-containing and zinc-containing material;

[0033] (2) High-temperature calcination of the iron-containing and zinc-containing materials: The iron-containing and zinc-containing materials pressed into agglomerates in process (1) are transported from the tail of the rotary kiln 11 to the inside of the rotary kiln 11. The iron-containing and zinc-containing materials undergo a reduction reaction in the rotary kiln 11. The iron element therein is discharged from the head of the rotary kiln 11 along with the slag phase, and the zinc element is discharged from the tail of the rotary kiln 11 along with the flue gas.

[0034] (3) Iron recovery: The slag phase material discharged from the kiln head of the rotary kiln 11 in process (2) is transported to the hot briquetting machine 15 and directly pressed into briquette to complete the iron recovery process;

[0035] (4) Recovery of zinc element: The zinc-containing flue gas discharged from the kiln tail of the rotary kiln 11 in process (2) is sent to a waste heat recovery device to recover sensible heat, then cooled by a surface cooler 16 and fly ash is recovered, and finally collected by a bag filter 17 to obtain secondary zinc oxide;

[0036] (5) Environmental protection treatment: The fly ash discharged from the waste heat recovery device and the surface cooler 16 in process (4) is transported to the water washing device, and the solid phase after water washing is returned to process (1) to be mixed with the iron-containing and zinc-containing materials. The liquid phase after water washing enters the high-salt wastewater zero discharge device 28, and after treatment, crystallized salt and recycled water are obtained, wherein the recycled water is sent to process (1) to participate in mixing and batching; the flue gas after bag dust removal in process (4) is introduced into the flue gas purification device (such as a desulfurization device) by the induced draft fan 21 for purification treatment.

[0037] In the process (3), nitrogen gas sealing is adopted in the process of conveying the slag phase material discharged from the kiln head of the rotary kiln 11 to the hot pressing machine 15 and in the hot pressing process; the high-temperature nitrogen generated by the gas sealing nitrogen after the hot pressing process is conveyed to the kiln head of the rotary kiln 11 for heating the combustion-supporting air and auxiliary fuel gas, and then discharged with the smoke of the rotary kiln.

[0038] In the process (1), the binder is one or more of starch, sugar, crude fiber and bentonite.

[0039] In the process (1), the iron-containing and zinc-containing materials are formulated in the following proportions by weight: 68-90 parts of iron-containing and zinc-containing dust raw materials, 0-8 parts of coal powder, 3-10 parts of starch, 2-6 parts of bentonite, and 4-15 parts of iron ore concentrate powder.

[0040] In the process (1), the iron content of the iron-containing and zinc-containing material is 50% to 60% by weight, and the carbon content is 5% to 8% by weight.

[0041] In the process (1), the size of the cold-pressed iron- and zinc-containing material lumps is 5 to 30 mm, the water content is 9% to 11%, the drop strength of the lumps is greater than 10 times / 0.5 m, and the average compressive strength of the lumps is 200 to 300 N / lump.

[0042] like Figure 2 As shown, the iron-containing and zinc-containing dust resource recovery and treatment system of the present invention comprises a raw material pretreatment unit, a rotary kiln 11, an iron recovery unit, a zinc recovery unit, a flue gas treatment unit and a fly ash treatment unit; the raw material pretreatment unit is composed of a raw material storage bin 2, a raw material conveying device 5, a strong mixer 8 and a cold briquetting machine 9 connected in sequence; the cold briquetting machine 9 is connected to the material inlet of the rotary kiln 11 through a material conveying device; the iron recovery unit is composed of a nitrogen-sealed chute 14 and a hot briquetting machine 15; the slag phase outlet of the rotary kiln 11 is connected to the material inlet of the hot briquetting machine 15 through a nitrogen-sealed chute 14; the zinc recovery unit is composed of a waste heat boiler 10, a surface cooler 16, a bag dust collector 17 and a recovered zinc storage bin 19, a waste heat boiler 10 is arranged at the kiln tail of the rotary kiln 11, the waste heat boiler 10 is connected to the surface cooler 16 and the bag dust collector 17 through a flue gas duct, and the bottom of the bag dust collector 17 The ash discharge port is connected to the recovery zinc storage bin 19 through a pneumatic conveying pump 18 (a ton bag packaging machine 20 can be provided at the discharge port of the recovery zinc storage bin 19); the flue gas treatment unit is composed of an induced draft fan 21, a flue gas purification device 22 and a chimney 23, and the purified flue gas outlet of the bag filter 17 is connected to the flue gas purification device 22 and the chimney 23 through the induced draft fan 21; the fly ash treatment unit is composed of a water washing tank 24, a filter press 25 and a wastewater treatment system; an ash discharge hopper is provided at the kiln tail of the rotary kiln 11, and the bottom outlet of the ash discharge hopper is connected to the water washing tank 24 through a screw conveyor 7; the ash discharge port at the bottom of the surface cooler 16 is connected to the water washing tank 24 through a screw conveyor 7; the water washing tank 24 is connected to the filter press 25 and the wastewater treatment system in sequence through a sewage pipe, the solid phase outlet of the filter press 25 is connected to the raw material conveying device 5 through a material conveying device, and the recycled water outlet of the wastewater treatment system is connected to the water inlet of the strong mixer 8.

[0043] The raw material storage bin 2 includes an iron-containing zinc dust storage bin, a coal powder storage bin, an iron ore powder storage bin and a binder storage bin, wherein the iron-containing zinc dust storage bin includes an ash bin and a mud bin 6; the tops of the ash bin, the coal powder storage bin, the iron ore powder storage bin and the binder storage bin are all provided with a bin top bag dust collector 1, and the bottom discharge ports are all provided with a manual discharge valve 3 and an electric discharge valve 4; the bottom discharge port of the mud bin 6 is provided with a screw conveyor 7 and a manual discharge valve 3.

[0044] The rotary kiln 11 has a low kiln head and a high kiln tail. An auxiliary gas inlet and a combustion-supporting air inlet are provided at the kiln head. The auxiliary gas inlet is connected to a fuel conveyor 13 , and the combustion-supporting air inlet is connected to a combustion-supporting fan 12 .

[0045] The wastewater treatment system is composed of a filtrate tank 26, a filtrate pump 27 and a high-salt wastewater zero discharge device 28 which are connected in sequence.

[0046] The iron-containing zinc dust raw material of the present invention includes dry dust generated by various processes of the steel plant, and wet sludge with a certain moisture content. Among them, the iron-containing zinc dust raw material with low moisture content is stored in the ash bin, and the iron-containing zinc dust raw material with high moisture content is stored in the mud bin 6; the iron-containing zinc dust raw material in the ash bin is unloaded to the raw material conveying device 5 through the manual unloading valve 3 and the electric unloading valve 4, and the iron-containing zinc dust raw material in the mud bin 6 is unloaded to the raw material conveying device 5 through the screw conveyor 7 and the manual unloading valve 3; the raw material conveying device 5 quantitatively conveys the iron-containing zinc dust, coal powder (if any), iron ore concentrate powder and binder to the strong mixer 8 for uniform mixing, and then under the action of the cold pressing machine 9, the mixed powder material is pressed into agglomerates and sent to the rotary kiln 11. The slag phase material discharged from the kiln head of the rotary kiln 11 is transported to the hot pressing machine 15, and under the action of the hot pressing machine 15, the slag phase material is directly pressed into agglomerates to complete the recovery of iron elements.

[0047] By adjusting the addition ratio of coal powder, the weight percentage content of C in the cold-pressed agglomerates is ensured to be 5% to 8%. No solid fuel needs to be added during high-temperature calcination in the rotary kiln 11, thereby ensuring that the cold-pressed agglomerates are fully reduced.

[0048] The following examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0049] [Example 1]

[0050] This embodiment uses the iron-containing zinc dust resource recovery and treatment process of the present invention to treat the iron-containing zinc dust. First, the cold pressing technology is used to pre-treat the iron-containing zinc dust raw material, and then the rotary kiln reduction technology is used to reduce the iron-containing zinc material, and then the hot pressing technology is used to directly press the solid phase kiln slag discharged from the rotary kiln head, and finally the efficient recovery of iron and zinc elements is achieved. The specific process is as follows:

[0051] 1. Raw material pretreatment process based on cold pressing technology: iron-containing and zinc-containing dust raw materials, binder, coal powder, and iron ore powder are mixed according to the set ratio, and the mixed materials are transported to the cold pressing machine, under the action of the cold pressing machine, the powdered materials are pressed into agglomerates. The pretreatment process is as follows:

[0052] 1. Raw material preparation: In this embodiment, the iron-containing and zinc-containing dust raw materials include steel mill converter mud, steel mill blast furnace material yard ash, blast furnace dry ash collected by steel mill bag dust collector, steel mill blast furnace gas ash, and steelmaking secondary dust, a total of 5 types of iron-containing and zinc-containing dust. Starch and bentonite are used as binders, and coal powder and iron ore concentrate powder are added.

[0053] 2. Raw material ratio: The ratio of iron-containing and zinc-containing dust raw materials, binders and additives (by weight) is as follows: 33.7 parts of steel plant converter mud, 22.1 parts of steel plant blast furnace material yard ash, 13.2 parts of blast furnace dry ash, 11.3 parts of steel plant blast furnace gas ash, 3.5 parts of steelmaking secondary dust, 5.2 parts of coal powder, 3.7 parts of starch, 2.5 parts of bentonite, and 4.8 parts of iron ore concentrate powder.

[0054] 3. Performance test: The performance of the mixed materials was tested. The iron content of the mixed material was 56.7% (weight percentage), and the carbon content of the mixed material was 5.7% (weight percentage).

[0055] 4. Cold pressing process: The mixed materials are transported to the cold pressing machine, under which the powder materials are pressed into agglomerates. The size of the agglomerates after cold pressing is 13-15 mm, the moisture content of the agglomerates (weight percentage) is 10.2%, the falling strength of the agglomerates is >10 times / 0.5m, and the average compressive strength of the agglomerates is 266N / piece.

[0056] 2. High-temperature calcination process of iron-containing and zinc-containing materials: The iron-containing and zinc-containing materials pressed into agglomerates are transported from the tail of the rotary kiln to the inside of the rotary kiln. The agglomerated materials are reduced in the rotary kiln, and the iron element in the materials is discharged from the head of the rotary kiln with the slag phase, and the zinc element in the materials is discharged from the tail of the rotary kiln with the flue gas.

[0057] 3. Iron recovery process based on hot pressing technology: The slag phase material discharged from the rotary kiln head is transported to the hot pressing machine, under the action of the hot pressing machine, the slag phase material is directly pressed into balls to complete the iron recovery.

[0058] 4. Zinc recovery process based on multi-stage cooling technology: The zinc-containing flue gas discharged from the tail of the rotary kiln is recovered through a waste heat boiler to recover sensible heat, and then the flue gas is further cooled by a surface cooler and fly ash is recovered, and then the zinc element is recovered through a bag dust collector.

[0059] 5. Environmental protection treatment process: The fly ash discharged from the rotary kiln, waste heat boiler and surface cooler is transported to the water washing device (consisting of a water washing tank and a filter press), the separated solid phase is returned to the mixing and batching section, and the separated liquid phase enters the high-salt wastewater zero discharge device. The flue gas after the bag filter is introduced into the desulfurization device through the induced draft fan, and is discharged after purification and meets the standards.

[0060] In this embodiment, the iron-containing solid phase material is directly placed in the ambient air after being hot-pressed into a ball by a hot-pressing machine. The oxygen in the ambient air is used to oxidize the iron elements on the surface of the hot-pressed ball to form a protective film, which is beneficial to the stability of the iron elements inside the hot-pressed ball and ensures the metallization rate of the solid phase slag.

[0061] [Example 2]

[0062] This embodiment uses the iron-containing zinc-containing dust resource recovery and treatment process of the present invention to treat the iron-containing zinc-containing dust. The process is the same as that of Example 1, except that the raw material pretreatment process is as follows:

[0063] 1. Raw material preparation: In this embodiment, the iron-containing and zinc-containing dust raw materials include comprehensive water treatment sludge, activated coke flue gas purification system dust, converter dust, blast furnace primary bag dust, steelmaking secondary dust, a total of 5 kinds of iron-containing and zinc-containing dust, starch and bentonite are used as binders, and iron ore concentrate powder is added.

[0064] 2. Raw material ratio: The ratio of various iron-containing and zinc-containing dust raw materials, binders and additives (by weight) is as follows: 22.2 parts of comprehensive water treatment sludge, 8.2 parts of dust removal ash from activated coke flue gas purification system, 17.4 parts of converter dust removal ash, 24.7 parts of blast furnace primary bag ash, 3.5 parts of steelmaking secondary dust, 5.7 parts of starch, 3.5 parts of bentonite, and 14.8 parts of iron ore concentrate powder.

[0065] 3. Performance test: The performance of the mixed materials was tested. The iron content in the mixed material was 51.7% (weight percentage), and the carbon content in the mixed material was 7.4% (weight percentage).

[0066] 4. Cold pressing process: The mixed materials are conveyed to the cold pressing machine, under which the powder materials are pressed into lumps. The lumps are 20-25 mm in size, 10.2% in water content (weight percentage), 10 times / 0.5 m in drop strength, and 203 N / lumps in average compressive strength.

[0067] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A process for recycling iron-containing and zinc-containing dust, characterized in that: The process includes the following: (1) Raw material pretreatment: the iron-containing and zinc-containing dust raw material, binder, coal powder, and iron ore powder are mixed according to a set ratio, and the mixed material is conveyed to a cold pressing machine to be pressed into agglomerates to obtain iron-containing and zinc-containing materials; (2) High-temperature calcination of the iron-containing and zinc-containing materials: The iron-containing and zinc-containing materials pressed into agglomerates in process (1) are transported from the tail of the rotary kiln to the inside of the rotary kiln. The iron-containing and zinc-containing materials undergo a reduction reaction in the rotary kiln. The iron element therein is discharged from the head of the rotary kiln along with the slag phase, and the zinc element is discharged from the tail of the rotary kiln along with the flue gas. (3) Iron recovery: The slag material discharged from the rotary kiln head in process (2) is transported to a hot press briquetting machine and directly pressed into briquettes to complete the iron recovery process; (4) Recovery of zinc element: The zinc-containing flue gas discharged from the rotary kiln tail in process (2) is sent to a waste heat recovery device to recover sensible heat, then cooled by a surface cooler and fly ash is recovered, and finally collected by a bag filter to obtain secondary zinc oxide; (5) Environmental protection treatment: The fly ash discharged from the waste heat recovery device and the surface cooler in process (4) is transported to the water washing device, and the solid phase after water washing is returned to process (1) to be mixed with the iron-containing and zinc-containing materials. The liquid phase after water washing enters the high-salt wastewater zero discharge device to obtain crystallized salt and recycled water after treatment, wherein the recycled water is sent to process (1) to participate in mixing and batching; the flue gas after bag dust removal in process (4) is introduced into the flue gas purification device by the induced draft fan for purification treatment.

2. The process for recycling iron-containing and zinc-containing dust according to claim 1, characterized in that: In the process (3), nitrogen gas sealing is adopted in the process of conveying the slag phase material discharged from the kiln head of the rotary kiln to the hot pressing machine and in the hot pressing process; the high-temperature nitrogen generated by the gas sealing nitrogen after the hot pressing process is conveyed to the kiln head of the rotary kiln for heating the combustion-supporting air and auxiliary fuel gas, and then discharged with the smoke of the rotary kiln.

3. The process for recycling iron-containing and zinc-containing dust according to claim 1, characterized in that: In the process (1), the binder is one or more of starch, sugar, crude fiber and bentonite.

4. The process for recycling iron-containing and zinc-containing dust according to claim 1, characterized in that: In the process (1), the iron-containing and zinc-containing materials are formulated in the following proportions by weight: 68-90 parts of iron-containing and zinc-containing dust raw materials, 0-8 parts of coal powder, 3-10 parts of starch, 2-6 parts of bentonite, and 4-15 parts of iron ore concentrate powder.

5. The process for recycling iron-containing and zinc-containing dust according to claim 1, characterized in that: In the process (1), the iron content of the iron-containing and zinc-containing material is 50% to 60% by weight, and the carbon content is 5% to 8% by weight.

6. The process for recycling iron-containing and zinc-containing dust according to claim 1, characterized in that: In the process (1), the size of the cold-pressed iron- and zinc-containing material lumps is 5 to 30 mm, the water content is 9% to 11%, the drop strength of the lumps is greater than 10 times / 0.5 m, and the average compressive strength of the lumps is 200 to 300 N / lump.

7. A system for recycling and treating iron-containing zinc dust for realizing the recycling and treating process of iron-containing zinc dust according to any one of claims 1 to 6, characterized in that: It includes a raw material pretreatment unit, a rotary kiln, an iron recovery unit, a zinc recovery unit, a flue gas treatment unit and a fly ash treatment unit; the raw material pretreatment unit is composed of a raw material storage bin, a raw material conveying device, a strong mixer and a cold briquetting machine connected in sequence; the cold briquetting machine is connected to the material inlet of the rotary kiln through a material conveying device; the iron recovery unit is composed of a nitrogen-sealed chute and a hot briquetting machine; the slag phase outlet of the rotary kiln is connected to the material inlet of the hot briquetting machine through a nitrogen-sealed chute; the zinc recovery unit is composed of a waste heat boiler, a surface cooler, a bag dust collector and a recovered zinc storage bin, a waste heat boiler is arranged at the kiln tail of the rotary kiln, the waste heat boiler is connected to the surface cooler and the bag dust collector through a flue gas duct, and the bottom of the bag dust collector is The ash discharge port is connected to the recovered zinc storage bin through a pneumatic conveying pump; the flue gas treatment unit is composed of an induced draft fan, a flue gas purification device and a chimney, and the purified flue gas outlet of the bag filter is connected to the flue gas purification device and the chimney through the induced draft fan; the fly ash treatment unit is composed of a water washing tank, a filter press and a wastewater treatment system; an ash discharge hopper is arranged at the kiln tail of the rotary kiln, and the bottom outlet of the ash discharge hopper is connected to the water washing tank through a screw conveyor; the ash discharge port at the bottom of the surface cooler is connected to the water washing tank through a screw conveyor; the water washing tank is connected to the filter press and the wastewater treatment system in sequence through a sewage pipe, the solid phase outlet of the filter press is connected to the raw material conveying device through a material conveying device, and the recycled water outlet of the wastewater treatment system is connected to the water inlet of the high-power mixer.

8. The iron-containing and zinc-containing dust resource recovery and treatment system according to claim 7 is characterized in that: The raw material storage bins include iron-containing and zinc-containing dust storage bins, coal powder storage bins, iron ore concentrate powder storage bins and binder storage bins, among which the iron-containing and zinc-containing dust storage bins include ash bins and mud bins; the tops of the ash bins, coal powder storage bins, iron ore concentrate powder storage bins and binder storage bins are all equipped with bag dust collectors, and the bottom discharge ports are all equipped with manual unloading valves and electric unloading valves; the bottom discharge port of the mud bin is equipped with a screw conveyor and a manual unloading valve.

9. The iron-containing and zinc-containing dust resource recovery and treatment system according to claim 7 is characterized in that: The rotary kiln has a low kiln head and a high kiln tail. The kiln head is provided with an auxiliary gas inlet and a combustion-supporting air inlet. The auxiliary gas inlet is connected to a fuel conveyor, and the combustion-supporting air inlet is connected to a combustion-supporting fan.

10. The iron-containing and zinc-containing dust resource recovery and treatment system according to claim 7 is characterized in that: The wastewater treatment system consists of a filtrate tank, a filtrate pump and a high-salt wastewater zero discharge device which are connected in sequence.

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