CN111363875A - Device and method for reducing and recycling reduced iron and secondary zinc oxide by using zinc-containing and iron-containing solid waste - Google Patents
Device and method for reducing and recycling reduced iron and secondary zinc oxide by using zinc-containing and iron-containing solid waste Download PDFInfo
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- CN111363875A CN111363875A CN202010216864.2A CN202010216864A CN111363875A CN 111363875 A CN111363875 A CN 111363875A CN 202010216864 A CN202010216864 A CN 202010216864A CN 111363875 A CN111363875 A CN 111363875A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/08—Making spongy iron or liquid steel, by direct processes in rotary furnaces
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/006—Starting from ores containing non ferrous metallic oxides
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B19/00—Obtaining zinc or zinc oxide
- C22B19/34—Obtaining zinc oxide
- C22B19/38—Obtaining zinc oxide in rotary furnaces
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Abstract
The invention belongs to the technical field of metallurgical equipment and particularly relates to a device and a method for recovering reduced iron and zinc hypoxide by reducing zinc-containing and iron-containing solid waste. The invention adopts a two-section type short-flow rotary kiln method device and a double-base deep reduction and slag iron separation reduction process technology, and carries out slag iron separation, reduction and smelting by innovating and improving the original process air and heating mode, thereby not only obtaining high-quality reduced iron products with the grade of TFe 90-98%, but also recovering secondary zinc oxide powder products from tail gas, and leading the recovery rate of Zn to reach more than 98%. The wide application of the invention has great significance for comprehensive treatment, harmlessness, benefit, resource and environmental protection of a large amount of Zn-containing and Fe-containing solid wastes and other iron-containing solid wastes even dangerous wastes produced in China every year.
Description
Technical Field
The invention belongs to the technical field of metallurgical equipment and particularly relates to a device and a method for recovering reduced iron and zinc hypoxide by reducing zinc-containing and iron-containing solid waste.
Background
China is a country with abundant iron ore resources but abundant lean iron ore resources. The low-lean slow-release iron ore accounts for over 96 percent of iron ore resources, and a large amount of iron grains such as hematite, limonite, specularite, siderite, oolitic hematite, antelope stone iron ore and the like are fine and low-lean slow-release refractory iron ore in China; the refractory compound ores such as the ferromanganese ore, the laterite-nickel ore, the vanadium-titanium magnetite ore, the ilmenite and the like have no good method for comprehensively developing and utilizing the refractory compound ores.
Meanwhile, billions of tons of zinc-containing and iron-containing dedusting ash, solid waste and even dangerous waste are produced every year, such as: the zinc-containing sulfuric acid slag, the blast furnace-containing fly ash, the zinc-containing electric arc furnace fly ash of a steel plant, zinc-containing converter sludge of the steel plant, tail slag or solid waste such as fly ash of a sintering machine head and zinc concentrate are not comprehensively utilized and developed by a good method, so that resource waste is caused. A large amount of piles will pollute the atmosphere, water and soil, harm human health and even become a disaster. The solid wastes contain Zn, Fe and carbon, and if the solid wastes can be comprehensively and effectively treated, the solid wastes also have economic value and social value and environmental protection value.
According to industrial statistics and authoritative expert identification: smelting of direct reduced iron ton product CO2The discharge amount is 800 kg; blast furnace smelting iron CO2The amount of CO discharged was 1600kg, and therefore, it was not the blast furnace ironmaking (direct reduced iron)2The discharge amount can be reduced by 50%. In China today, the first country of world steel capacity is, the steel yield in China accounts for 73.8% of the whole Asia in 2018, the global yield is 51.3%, blast furnace iron making is dominant, and the yield of direct reduced iron is less than 1% of the total world yield, so that the development of non-blast furnace iron making is imperative in the field of iron and steel metallurgy in China!
The national industrial policy is regulated in clear text for a long time, and vigorous development and construction of non-coke iron-making projects such as direct reduced iron, molten reduced iron and the like are encouraged; encourages the comprehensive utilization and development of iron-containing materials such as various refractory iron ores, raw and composite iron ores, metallurgical solid wastes and the like.
For zinc-containing and iron-containing solid wastes, the conventional device and method cannot recover the secondary zinc oxide byproduct while obtaining a high-quality reduced iron product, and are difficult to recover and comprehensively utilize the waste heat of high-temperature sensible heat.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a device and a method for recovering reduced iron and zinc hypoxide by reducing zinc-containing and iron-containing solid waste.
The technical scheme for solving the technical problems is as follows: a device for reducing and recovering reduced iron and secondary zinc oxide by utilizing zinc-containing and iron-containing solid waste is characterized by comprising a drying preheating device, a first-stage rotary kiln device and a second-stage rotary kiln device which are sequentially connected, and further comprising a tail gas purification and recovery device and a settling combustion chamber;
the drying and preheating device comprises a drying and preheating roller machine, and the front end of the drying and preheating roller machine is connected with the feeding device through a blanking pipe; the rear end of the drying preheating roller machine is communicated with a high-temperature flue gas nozzle; the front end of the drying preheating roller machine is provided with a tail gas outlet;
the first section of rotary kiln device comprises a first section of rotary kiln, and the front end of the first section of rotary kiln is connected with the first section of rotary kiln feeding device through a first section of rotary kiln blanking pipe; the front end of the first section of rotary kiln is provided with a first section of rotary kiln tail cover, and the first section of rotary kiln tail cover is provided with a raw coke oven gas outlet; the first section of rotary kiln is divided into a feeding section, a heating section and a discharging section from front to back, the outer wall of the rotary kiln of the heating section is provided with a plurality of burners, and the front end of the heating section is provided with a high-temperature flue gas outlet; a combined sealing cover is arranged at the rear end of the section of rotary kiln, a reducing agent injection gun and a temperature adjusting gun are arranged at the tail end of the combined sealing cover, and the reducing agent injection gun is introduced into the section of rotary kiln;
the second-stage rotary kiln device comprises a second-stage rotary kiln, a combined sealing cover is arranged at the front end of the second-stage rotary kiln, and a reducing agent inlet is formed in the combined sealing cover; the rear end of the second-stage rotary kiln is provided with a second-stage rotary kiln hood, a second-stage rotary kiln discharge port is formed in the second-stage rotary kiln hood, and the tail end of the second-stage rotary kiln hood is provided with a pulverized coal injection burner; the pulverized coal injection combustor is respectively connected with a pulverized coal injection fan and an oxygen tank;
the tail gas purification and recovery device comprises a cyclone dust collector and a bag-type dust collector which are connected in sequence; the tail gas outlet is communicated to a chimney or the temperature adjusting gun through a tail gas purifying and recycling device and a tail gas main exhaust fan;
the raw gas outlet is communicated to the settling combustion chamber through a gas booster fan; the high-temperature flue gas outlet is divided into two paths after passing through the heat exchanger: one path is communicated with the high-temperature flue gas nozzle and the settling combustion chamber respectively after passing through a flue gas induced draft fan, and the other path is communicated with the reducing agent spraying gun and the temperature adjusting gun respectively through a Roots blower; the top part of the settling combustion chamber is respectively communicated to the high-temperature flue gas nozzle and the burner.
On the basis of the technical scheme, the invention can be further improved as follows.
Further, the feeding device and the feeding device of the first section of the rotary kiln are the positive and negative pressure dual-purpose explosion-proof feeding device of application number 201920373124.2.
Further, the first-section rotary kiln is a muffle type external heating rotary kiln; the second-stage rotary kiln is an internal combustion rotary kiln.
The second purpose of the invention is to utilize the method for recovering reduced iron and zinc hypoxide by using the solid waste containing zinc and iron, and the method utilizes the device and comprises the following steps:
(1) taking iron-containing and zinc-containing solid waste, mixing, pressing balls, hermetically feeding the iron-containing and zinc-containing solid waste into a drying and preheating roller machine through a feeding device and a blanking pipe, and drying and preheating the iron-containing and zinc-containing solid waste at the temperature of 850-;
(2) crushing, screening, spraying water and stacking the reducing agent, and then polishing to 140 meshes after 120-;
(3) conveying the 480-680 ℃ preheated pellets in the step (1) into a section of rotary kiln in a closed manner through a section of rotary kiln feeding device and a section of rotary kiln blanking pipe; high-temperature flue gas at the temperature of 1000-; pre-reducing the pellets for 2.0-3.0h at 950-;
(4) the reduced material enters the second-stage rotary kiln through the combined sealing cover, and then is added with a reducing agent through a reducing agent inlet, and pure oxygen and coal powder are sent into the second-stage rotary kiln through a coal powder injection burner; deep reduction and slag iron separation reduction are carried out for 0.5-1.0h at the temperature of 1100-; reducing the zinc oxide to obtain metal zinc vapor;
(5) the metal zinc steam in the step (4) enters a section of rotary kiln through a combined sealing cover along with high-temperature coal gas, smoke at the temperature of 920-plus-950 ℃ is pumped into a settling combustion chamber through a raw gas outlet and a coal gas booster fan, the raw gas falls dust and burns in the settling combustion chamber, and the metal zinc steam is oxidized into zinc oxide powder; high-temperature flue gas at the top of the settling combustion chamber enters a section of rotary kiln through a burner, is discharged through a high-temperature flue gas outlet, is directly injected into a high-temperature flue gas nozzle after passing through a heat exchanger and a flue gas induced draft fan or is injected into the high-temperature flue gas nozzle after passing through the settling combustion chamber, enters a drying preheating roller machine, is discharged through a tail gas outlet after being cooled to the temperature of 220 plus 380 ℃, is dedusted by a cyclone deduster and a bag deduster, and is zinc recycled to obtain secondary zinc oxide powder; the clean flue gas is discharged from a chimney through a tail gas main exhaust fan or is introduced into a temperature adjusting gun.
Further, the iron-containing and zinc-containing solid waste is zinc-containing sulfuric acid residue, blast furnace fly ash, zinc-containing electric arc furnace fly ash of a steel plant, zinc-containing converter sludge of the steel plant or zinc concentrate.
Further, in the step (2), the reducing agent is anthracite, bituminous coal, lignite or biomass particles.
Further, the weight of the reducing agent in the step (2) is 25-70% of the weight of the iron-containing and zinc-containing solid waste in the step (1).
Further, the dosage of the reducing agent in the step (3) is 75-80% of the total weight of the reducing agent in the step (2); the dosage of the reducing agent in the step (4) is 20-25% of the total weight of the reducing agent in the step (2).
The invention has the characteristics and beneficial effects that:
1. the main characteristics of zinc metal are as follows: zinc is a chemical element whose chemical symbol is Zn, atomic number is 30, and is a transition metal in light gray. Zinc (Zinc) is the fourth "common" metal, second only to iron, aluminum and copper. The appearance appeared silvery white. Zinc is hard and brittle at normal temperature but becomes tough at 100-150 ℃. When the temperature exceeds 210 ℃, the zinc becomes brittle again and can be crushed by beating. It has a melting point of 419.5 c and a boiling point of 906 c, and its temperature is relatively low among all metals.
The zinc oxide has chemical formula of ZnO, white hexagonal crystal or powder, no smell, fine quality, melting point of 1975 deg.C, and relative density of 5.606t/m3. ZnO can be reduced into metallic zinc steam in coal-based reducing atmosphere, ZnO + C is Zn + CO, and ZnO is reduced by C even with CO under high-temperature reducing condition2Generated and can also react with C continuously at high temperature to generate CO according to the chemical formula of CO2+C＝2CO。
ZnO may be reduced to metallic zinc in a gas-based reducing atmosphere. The reduction starts at 650 ℃, most of the reduction can be carried out at 800 ℃ or above, but the reduction cannot be completely carried out because of ZnO + H2With Zn + H2O is a reversible reaction, ZnO + H2＝Zn+H2O，Zn+H2O＝ZnO+H2. Therefore, higher temperatures are required for coal-based re-reduction. And the temperature is higher than 950 ℃, and the metal zinc can be converted into zinc vapor to be volatilized.
And the metallic zinc vapour, once leaving the reducing material and entering the reducing gas space, Zn + H2O＝ZnO+H2The effect is small because the product of zinc reduction is ZnO.
Therefore, the reduction mechanism of the zinc-containing material is almost the same as that of the refractory iron ore, and only the reduction of Zn into zinc steam needs to be considered, then the zinc steam is conveyed out of the furnace in a high-temperature reducing flue gas environment at 950-1000 ℃, and then oxidation treatment, cooling and secondary zinc oxide product collection are carried out.
2. In the invention, all flue gas is discharged through a tail gas outlet of the drying preheating roller machine, the temperature of the flue gas is reduced to 220-380 ℃, then the flue gas is dedusted and zinc is collected through a cyclone deduster and a bag deduster, most of secondary zinc oxide powder is collected in the cyclone deduster and the bag deduster, and the Zn grade is 44-68%; the dust at the lower part of the settling combustion chamber also contains some zinc hypoxide powder, but the grade is very low, the zinc content is generally below 15%, and the dust can be used for re-reduction and recovery of ingredients.
3. The invention comprehensively recycles the recovered high-temperature flue gas at 1000 ℃, reduces a herringbone multi-pipe cooling device with the length of dozens of meters, reduces working procedures, reduces equipment investment and reduces floor area. Moreover, a secondary zinc oxide powder product and a high-quality reduced iron product with the grade of TFe 90-98% can be obtained simultaneously, and the dezincification rate of the reduced material reaches more than 96%.
Drawings
FIG. 1 is a schematic longitudinal cross-sectional view of the present invention;
in the figure, 1, a settling combustion chamber; 2. drying and preheating the roller machine; 3. a blanking pipe; 4. a feeding device; 5. a high-temperature flue gas nozzle; 6. a tail gas outlet; 7. a first section of rotary kiln; 8. a section of rotary kiln blanking pipe; 9. a first section of rotary kiln feeding device; 10. a section of rotary kiln tail cover; 11. a raw gas outlet; 12. burning a nozzle; 13. a high-temperature flue gas outlet; 14. a joint sealing boot; 15. a reducing agent spray gun; 16. a temperature adjusting gun; 17. a second-stage rotary kiln; 18. a reductant inlet; 19. a kiln head cover of a two-section rotary kiln; 20. a discharge port of the second-stage rotary kiln; 21. a pulverized coal injection burner; 22. a pulverized coal injection fan; 23. an oxygen tank; 24. a cyclone dust collector; 25. a bag-type dust collector; 26. a tail gas main exhaust fan; 27. a chimney; 28. a coal gas booster fan; 29. a heat exchanger; 30. a flue gas induced draft fan; 31. roots blower.
Detailed Description
The principles and features of this invention are described below in conjunction with the drawings and examples, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.
The specification of the drying waste heat roller used in the embodiment of the invention is phi 800mm × 16m, the specification of the first section rotary kiln is phi 1000mm × 32m, and the specification of the second section rotary kiln is phi 1200mm × 8 m.
A device for reducing and recovering reduced iron and secondary zinc oxide by utilizing zinc-containing and iron-containing solid waste is characterized by comprising a drying preheating device, a first-stage rotary kiln device and a second-stage rotary kiln device which are sequentially connected, and further comprising a tail gas purification and recovery device and a settling combustion chamber 1;
the drying and preheating device comprises a drying and preheating roller machine 2, and the front end of the drying and preheating roller machine is connected with a feeding device 4 through a blanking pipe 3; the rear end of the drying preheating roller machine is communicated with a high-temperature flue gas nozzle 5; the front end of the drying preheating roller machine is provided with a tail gas outlet 6;
the first section of rotary kiln device comprises a first section of rotary kiln 7, and the front end of the first section of rotary kiln is connected with a first section of rotary kiln feeding device 9 through a first section of rotary kiln blanking pipe 8; a section of rotary kiln tail cover 10 is arranged at the front end of the section of rotary kiln, and a raw coke oven gas outlet 11 is arranged on the section of rotary kiln tail cover; the first section of the rotary kiln is divided into a feeding section, a heating section and a discharging section from front to back, a plurality of burners 12 are arranged on the outer wall of the rotary kiln of the heating section, and a high-temperature flue gas outlet 13 is arranged at the front end of the heating section; a combined sealing cover 14 is arranged at the rear end of the first section of rotary kiln, a reducing agent spraying gun 15 and a temperature adjusting gun 16 are arranged at the tail end of the combined sealing cover, and the reducing agent spraying gun is introduced into the first section of rotary kiln;
the second-stage rotary kiln device comprises a second-stage rotary kiln 17, a combined sealing cover is arranged at the front end of the second-stage rotary kiln, and a reducing agent inlet 18 is formed in the combined sealing cover; the rear end of the second-stage rotary kiln is provided with a second-stage rotary kiln hood 19, a second-stage rotary kiln discharge port 20 is arranged on the second-stage rotary kiln hood, and the tail end of the second-stage rotary kiln hood is provided with a pulverized coal injection burner 21; the pulverized coal injection burner is respectively connected with a pulverized coal injection fan 22 and an oxygen tank 23;
the tail gas purification and recovery device comprises a cyclone dust collector 24 and a bag-type dust collector 25 which are connected in sequence; the tail gas outlet is communicated to a chimney 27 or the temperature adjusting gun through a tail gas and tail gas purifying and recycling device and a tail gas main exhaust fan 26;
the raw gas outlet is communicated to the settling combustion chamber through a gas booster fan 28; the high-temperature flue gas outlet is divided into two paths after passing through a heat exchanger 29: one path is respectively communicated to the high-temperature flue gas nozzle and the settling combustion chamber after passing through a flue gas induced draft fan 30, and the other path is respectively communicated to the reducing agent spraying gun and the temperature adjusting gun through a Roots blower 31; the top part of the settling combustion chamber is respectively communicated to the high-temperature flue gas nozzle and the burner.
Example 1
A method for reducing and recycling reduced iron and zinc hypoxide by utilizing zinc-containing and iron-containing solid waste comprises the following steps:
(1) adopting zinc-containing sulfuric acid cinder (the components are shown in table 1) in Zhongning city, adding lime powder accounting for 12% of the weight of the zinc-containing sulfuric acid cinder and coal powder accounting for 6% of the weight of the zinc-containing sulfuric acid cinder, uniformly mixing and grinding the materials, spraying clear water accounting for 5-6% of the weight of the mixed materials, and pressing the mixture into pellets by a ball press, wherein the pellet granularity phi is 20mm, × 15mm and the thickness of the pellets is 15 mm;
TABLE 1
(2) Crushing and screening the long-term bituminous coal (the components are shown in the table 2) serving as a reducing agent into particles of 3-20 mm, spraying water, and stacking for 2 days to ensure that the water content of the long-term bituminous coal reaches 12%; grinding into 120-mesh coal powder by using a coal powder grinding machine;
TABLE 2
(3) High-temperature flue gas at 880 plus 980 ℃ is injected into a drying preheating roller machine through a high-temperature flue gas nozzle, the oxidized pellets are dried and preheated to 480 ℃, the zinc-containing oxidized pellets are hermetically added into a section of rotary kiln, and 460kg of reducing agent is added according to the weight of a pellet drying agent; wherein 360kg of reducing agent (accounting for 78 percent of the adding amount of the reducing agent) is conveyed into the first-section rotary kiln from a reducing agent injection gun, and the rest 22 percent of reducing agent is hermetically fed into the second-section rotary kiln from a combined sealing cover by adopting a screw conveyer;
the heating heat source of the first-stage rotary kiln is recycled raw gas, 1080-1150 ℃ high-temperature flue gas obtained by a settling combustion chamber is injected into a heating chamber of the first-stage rotary kiln through a plurality of burners, the reduction temperature of the heating section of the first-stage rotary kiln is 950-1000 ℃, the kiln tail smoke discharge temperature is 950-990 ℃, the reduction time is 2.2 hours, and the rotation speed of the first-stage rotary kiln is 0.5 r/min; the kiln head temperature of the second-stage rotary kiln is 1100-1350 ℃, the kiln tail flue gas temperature is 930-980 ℃, the high-temperature flue gas in the second-stage rotary kiln completely enters the first-stage rotary kiln, the rotating speed of the second-stage rotary kiln is 0.6r/min, and the slag-iron separation and reduction time is 0.5 h;
(4) carrying out water quenching and cooling on the reduced material discharged from the discharge port of the second-stage rotary kiln, and then carrying out magnetic separation to separate out granular iron, reduced metal iron powder (the components are shown in a table 3) and residual dry distillation coal coke; the temperature of a tail gas outlet of the drying preheating roller machine is 360 ℃, secondary zinc oxide powder is effectively collected after dust removal and zinc collection by a cyclone dust collector and a bag-type dust collector, and clean flue gas is exhausted by a tail gas main exhaust fan and a chimney.
TABLE 3
Example 2
A method for reducing and recycling reduced iron and zinc hypoxide by utilizing zinc-containing and iron-containing solid waste comprises the following steps:
(1) the steel-containing blast furnace fly ash (the components are shown in table 4) is adopted, 30% of the steel-containing blast furnace fly ash containing iron and no carbon powder is added, the C content is less than 15% after mixing, the materials are uniformly mixed and ground, clear water with the mixed material weight of 5-6% is sprayed, and a ball press machine is adopted for pressing balls, wherein the pellet granularity phi is 20mm, × 15mm and the thickness is 15 mm;
TABLE 4
(2) Crushing and screening the long-term bituminous coal (the components are shown in the table 2) serving as a reducing agent into particles of 3-20 mm, spraying water, and stacking for 2 days to ensure that the water content of the long-term bituminous coal reaches 12%; grinding into 120-mesh coal powder by using a coal powder grinding machine;
(3) pumping 860-990 ℃ high-temperature flue gas into a drying and preheating roller machine through a high-temperature flue gas nozzle, drying and preheating the oxidized pellets to 470 ℃, hermetically adding the zinc-containing dedusting ash oxidized pellets into a section of rotary kiln, and adding 250kg of reducing agent according to the weight of a pellet dry agent; 200kg of reducing agent (accounting for 80 percent of the adding amount of the reducing agent) is conveyed into the first-section rotary kiln from a reducing agent injection gun, and the rest 20 percent of reducing agent is hermetically fed into the second-section rotary kiln from a combined sealing cover by adopting a screw conveyer;
the heating heat source of the first section of rotary kiln is recycled raw gas, high-temperature flue gas at 1100-1150 ℃ obtained by a settling combustion chamber is injected into the heating chamber of the first section of rotary kiln through a plurality of burners, the reduction temperature of the heating section of the first section of rotary kiln is 950-1000 ℃, the exhaust gas temperature of the kiln tail is 950-980 ℃, the reduction time is 2.0h, and the rotation speed of the first section of rotary kiln is 0.5 r/min; the kiln head temperature of the second-stage rotary kiln is 1100-1350 ℃, the kiln tail flue gas temperature is 940-990 ℃, the high-temperature flue gas in the second-stage rotary kiln completely enters the first-stage rotary kiln, the rotating speed of the second-stage rotary kiln is 0.5r/min, and the slag iron separation and reduction time is 0.5 h;
(4) carrying out water quenching and cooling on the reduced material discharged from the discharge port of the second-stage rotary kiln, and then carrying out magnetic separation to separate out granular iron (the components are shown in the table 5), reduced metal iron powder (the components are shown in the table 5) and residual dry distillation coal coke; the temperature of a tail gas outlet of the drying preheating roller machine is 340 ℃, secondary zinc oxide powder is effectively collected after dust removal and zinc collection by a cyclone dust collector and a bag-type dust collector, and clean flue gas is exhausted by a tail gas main exhaust fan and a chimney.
TABLE 5
Example 3
A method for reducing and recycling reduced iron and zinc hypoxide by utilizing zinc-containing and iron-containing solid waste comprises the following steps:
(1) the method comprises the following steps of (1) uniformly mixing and grinding the materials by adopting zinc-containing fly ash (the components are shown in table 6) of a sunshine steel plant and adding 6% of lime powder and 6% of coal powder, spraying clear water accounting for 5-6% of the weight of the mixed materials, and pressing the pellets by using a ball press, wherein the pellet granularity phi is 20mm, × 15mm and the thickness of the pellets is 15 mm;
TABLE 6
(2) Crushing and screening the long-term bituminous coal (the components are shown in the table 2) serving as a reducing agent into particles of 3-20 mm, spraying water, and stacking for 2 days to ensure that the water content of the long-term bituminous coal reaches 12%; grinding into 120-mesh coal powder by using a coal powder grinding machine;
(3) injecting 870-plus-980-DEG C high-temperature flue gas into a drying preheating roller machine through a high-temperature flue gas nozzle, drying and preheating the oxidized pellets to 470 ℃, hermetically adding the zinc-containing oxidized pellets into a section of rotary kiln, and adding 400kg of reducing agent according to the weight of pellet dry agent; wherein 320kg of reducing agent (accounting for 80 percent of the adding amount of the reducing agent) is conveyed into the first-section rotary kiln from a reducing agent injection gun, and the rest 20 percent of reducing agent is hermetically fed into the second-section rotary kiln from a combined sealing cover by adopting a screw conveyer;
the heating heat source of the first section of rotary kiln is recycled raw gas, high-temperature flue gas at 1100-1150 ℃ obtained by a settling combustion chamber is injected into the heating chamber of the first section of rotary kiln through a plurality of burners, the reduction temperature of the heating section of the first section of rotary kiln is 970-980 ℃, the exhaust gas temperature of the kiln tail is 950-960 ℃, the reduction time is 2.0h, and the rotation speed of the first section of rotary kiln is 0.5 r/min; the kiln head temperature of the second-stage rotary kiln is 1100-1350 ℃, the kiln tail flue gas temperature is 950-980 ℃, the high-temperature flue gas in the second-stage rotary kiln completely enters the first-stage rotary kiln, the rotating speed of the second-stage rotary kiln is 0.5r/min, and the slag-iron separation and reduction time is 0.5 h;
(4) carrying out water quenching and cooling on the reduced material discharged from the discharge port of the second-stage rotary kiln, and then carrying out magnetic separation to separate out granular iron (the components are shown in a table 7), reduced metal iron powder (the components are shown in a table 7) and residual dry distillation coal coke; the temperature of a tail gas outlet of the drying preheating roller machine is 360 ℃, secondary zinc oxide powder is effectively collected after dust removal and zinc collection by a cyclone dust collector and a bag-type dust collector, and clean flue gas is exhausted by a tail gas main exhaust fan and a chimney.
TABLE 7
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (7)
1. A device for reducing and recovering reduced iron and secondary zinc oxide by utilizing zinc-containing and iron-containing solid waste is characterized by comprising a drying preheating device, a first-stage rotary kiln device and a second-stage rotary kiln device which are sequentially connected, and further comprising a tail gas purification and recovery device and a settling combustion chamber;
the drying and preheating device comprises a drying and preheating roller machine, and the front end of the drying and preheating roller machine is connected with the feeding device through a blanking pipe; the rear end of the drying preheating roller machine is communicated with a high-temperature flue gas nozzle; the front end of the drying preheating roller machine is provided with a tail gas outlet;
the first section of rotary kiln device comprises a first section of rotary kiln, and the front end of the first section of rotary kiln is connected with the first section of rotary kiln feeding device through a first section of rotary kiln blanking pipe; the front end of the first section of rotary kiln is provided with a first section of rotary kiln tail cover, and the first section of rotary kiln tail cover is provided with a raw coke oven gas outlet; the first section of rotary kiln is divided into a feeding section, a heating section and a discharging section from front to back, the outer wall of the rotary kiln of the heating section is provided with a plurality of burners, and the front end of the heating section is provided with a high-temperature flue gas outlet; a combined sealing cover is arranged at the rear end of the section of rotary kiln, a reducing agent injection gun and a temperature adjusting gun are arranged at the tail end of the combined sealing cover, and the reducing agent injection gun is introduced into the section of rotary kiln;
the second-stage rotary kiln device comprises a second-stage rotary kiln, a combined sealing cover is arranged at the front end of the second-stage rotary kiln, and a reducing agent inlet is formed in the combined sealing cover; the rear end of the second-stage rotary kiln is provided with a second-stage rotary kiln hood, a second-stage rotary kiln discharge port is formed in the second-stage rotary kiln hood, and the tail end of the second-stage rotary kiln hood is provided with a pulverized coal injection burner; the pulverized coal injection combustor is respectively connected with a pulverized coal injection fan and an oxygen tank;
the tail gas purification and recovery device comprises a cyclone dust collector and a bag-type dust collector which are connected in sequence; the tail gas outlet is communicated to a chimney or the temperature adjusting gun through a tail gas purifying and recycling device and a tail gas main exhaust fan;
the raw gas outlet is communicated to the settling combustion chamber through a gas booster fan; the high-temperature flue gas outlet is divided into two paths after passing through the heat exchanger: one path is communicated with the high-temperature flue gas nozzle and the settling combustion chamber respectively after passing through a flue gas induced draft fan, and the other path is communicated with the reducing agent spraying gun and the temperature adjusting gun respectively through a Roots blower; the top part of the settling combustion chamber is respectively communicated to the high-temperature flue gas nozzle and the burner.
2. The apparatus as claimed in claim 1, wherein the section of rotary kiln is a muffle type external heating rotary kiln; the second-stage rotary kiln is an internal combustion rotary kiln.
3. A method for reducing and recovering reduced iron and zinc hypoxide by utilizing zinc-containing and iron-containing solid waste is characterized in that the device of claim 1 is utilized, and the method comprises the following steps:
(1) taking iron-containing and zinc-containing solid waste, mixing, pressing balls, hermetically feeding the iron-containing and zinc-containing solid waste into a drying and preheating roller machine through a feeding device and a blanking pipe, and drying and preheating the iron-containing and zinc-containing solid waste at the temperature of 850-;
(2) crushing, screening, spraying water and stacking the reducing agent, and then polishing to 140 meshes after 120-;
(3) conveying the 480-680 ℃ preheated pellets in the step (1) into a section of rotary kiln in a closed manner through a section of rotary kiln feeding device and a section of rotary kiln blanking pipe; high-temperature flue gas at the temperature of 1000-; pre-reducing the pellets for 2.0-3.0h at 950-;
(4) the reduced material enters the second-stage rotary kiln through the combined sealing cover, and then is added with a reducing agent through a reducing agent inlet, and pure oxygen and coal powder are sent into the second-stage rotary kiln through a coal powder injection burner; deep reduction and slag iron separation reduction are carried out for 0.5-1.0h at the temperature of 1100-; reducing the zinc oxide to obtain metal zinc vapor;
(5) the metal zinc steam in the step (4) enters a section of rotary kiln through a combined sealing cover along with high-temperature coal gas, smoke at the temperature of 920-plus-950 ℃ is pumped into a settling combustion chamber through a raw gas outlet and a coal gas booster fan, the raw gas falls dust and burns in the settling combustion chamber, and the metal zinc steam is oxidized into zinc oxide powder; high-temperature flue gas at the top of the settling combustion chamber enters a section of rotary kiln through a burner, is discharged through a high-temperature flue gas outlet, is directly injected into a high-temperature flue gas nozzle after passing through a heat exchanger and a flue gas induced draft fan or is injected into the high-temperature flue gas nozzle after passing through the settling combustion chamber, enters a drying preheating roller machine, is discharged through a tail gas outlet after being cooled to the temperature of 220 plus 380 ℃, is dedusted by a cyclone deduster and a bag deduster, and is zinc recycled to obtain secondary zinc oxide powder; the clean flue gas is discharged from a chimney through a tail gas main exhaust fan or is introduced into a temperature adjusting gun.
4. The method according to claim 3, wherein the iron and zinc-containing solid waste is zinc-containing sulfuric acid residue, blast furnace dust, zinc-containing electric arc furnace dust of a steel mill, zinc-containing converter sludge of the steel mill or zinc concentrate.
5. The method according to claim 3, wherein the reducing agent in step (2) is anthracite, bituminous coal, lignite or biomass particles.
6. The method of claim 3, wherein the weight of the reducing agent in the step (2) is 25-70% of the weight of the iron-containing zinc-containing solid waste in the step (1).
7. The method according to claim 3, wherein the amount of the reducing agent used in step (3) is 75-80% of the total weight of the reducing agent used in step (2); the dosage of the reducing agent in the step (4) is 20-25% of the total weight of the reducing agent in the step (2).
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| CN202010216864.2A CN111363875A (en) | 2020-03-25 | 2020-03-25 | Device and method for reducing and recycling reduced iron and secondary zinc oxide by using zinc-containing and iron-containing solid waste |
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| CN202010216864.2A CN111363875A (en) | 2020-03-25 | 2020-03-25 | Device and method for reducing and recycling reduced iron and secondary zinc oxide by using zinc-containing and iron-containing solid waste |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112111656A (en) * | 2020-08-12 | 2020-12-22 | 北京科技大学 | Method for co-processing zinc-containing and iron-containing dust by blast furnace and rotary kiln |
| CN112301178A (en) * | 2020-11-10 | 2021-02-02 | 烟台市红森林节能环保科技有限公司 | Device and method for gas-based reduction of metal oxide fine ore |
| CN115558796A (en) * | 2022-11-04 | 2023-01-03 | 昆明理工大学 | Method for resource extraction of zinc oxide from waste tire coupled blast furnace ash |
| CN115740476A (en) * | 2022-11-28 | 2023-03-07 | 李慧斌 | Metal oxide reduction device, application and metal powder preparation method |
-
2020
- 2020-03-25 CN CN202010216864.2A patent/CN111363875A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112111656A (en) * | 2020-08-12 | 2020-12-22 | 北京科技大学 | Method for co-processing zinc-containing and iron-containing dust by blast furnace and rotary kiln |
| CN112301178A (en) * | 2020-11-10 | 2021-02-02 | 烟台市红森林节能环保科技有限公司 | Device and method for gas-based reduction of metal oxide fine ore |
| CN115558796A (en) * | 2022-11-04 | 2023-01-03 | 昆明理工大学 | Method for resource extraction of zinc oxide from waste tire coupled blast furnace ash |
| CN115740476A (en) * | 2022-11-28 | 2023-03-07 | 李慧斌 | Metal oxide reduction device, application and metal powder preparation method |
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