CN111940456A - Method for recovering iron ore concentrate by pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes - Google Patents
Method for recovering iron ore concentrate by pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/40—Destroying solid waste or transforming solid waste into something useful or harmless involving thermal treatment, e.g. evaporation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C1/00—Magnetic separation
- B03C1/02—Magnetic separation acting directly on the substance being separated
- B03C1/30—Combinations with other devices, not otherwise provided for
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B5/00—Operations not covered by a single other subclass or by a single other group in this subclass
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- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
- C10B57/04—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition
- C10B57/06—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition containing additives
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/46—Gasification of granular or pulverulent flues in suspension
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/46—Gasification of granular or pulverulent flues in suspension
- C10J3/48—Apparatus; Plants
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/72—Other features
- C10J3/725—Redox processes
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
- C10J2300/0913—Carbonaceous raw material
- C10J2300/0946—Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
- C10J2300/0983—Additives
- C10J2300/0986—Catalysts
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J2300/00—Details of gasification processes
- C10J2300/16—Integration of gasification processes with another plant or parts within the plant
- C10J2300/1625—Integration of gasification processes with another plant or parts within the plant with solids treatment
Abstract
The invention belongs to the technical field of solid waste treatment and resource utilization, and provides a method for recovering iron ore concentrate by pyrolyzing and coupling iron-containing waste residues and organic solid waste and reducing the iron-containing waste residues and the organic solid wasteMixing wastes, carrying out pyrolysis coupling reduction reaction, and carrying out magnetic separation on the obtained reducing material to obtain iron ore concentrate. Fe in the waste slag in the process of pyrolysis coupling reduction2O3Can play a role in catalyzing the pyrolysis of the organic solid waste to promote the pyrolysis of the organic solid waste to form a material rich in CO and H2、CH4The pyrolysis gas in turn reacts on Fe in the iron-containing waste slag2O3Has good reduction effect and is converted into Fe3O4Further magnetic separation and recovery are carried out. The method provided by the invention can realize effective reduction and energy cyclization utilization of the organic solid waste, and can effectively reduce and recover iron minerals in the iron-containing waste residues so as to achieve the purposes of 'waste preparation by waste' and resource utilization of waste.
Description
Technical Field
The invention relates to the technical field of solid waste treatment and resource utilization, in particular to a method for recovering iron ore concentrate by pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes.
Background
In recent years, the industrialization and urbanization processes of China are continuously promoted. At present, China becomes the largest industrial country in the world, and has 41 industrial major categories, 207 industrial middle categories and 666 industrial minor categories, so that an independent and complete modern industrial system is formed. Meanwhile, the urbanization level of China is continuously improved, so that a large amount of solid wastes such as industrial solid wastes and municipal domestic wastes are generated. The industrial solid waste is large in quantity, various in types and complex in components, and comprises various tailings, steel smelting waste residues, non-ferrous smelting waste residues and other industrial waste residues, coal-fired power plant fly ash, coal mining and dressing gangue, various furnace slags, desulfurized gypsum, building waste and the like. At present, the treatment modes of industrial solid wastes mainly include comprehensive utilization, landfill, disposal, dumping and discarding and the like. The comprehensive utilization mainly comprises the modes of useful component recovery, material utilization and the like. The treatment and disposal of municipal solid waste mainly includes landfill, fermentation, composting, incineration and utilization.
In the tailings and the waste residues, part of the tailings and the waste residues contain iron, wherein Fe2O3The content of the iron is high, and people generally adopt a magnetic roasting and direct reduction iron mode to recover the iron. However, the magnetic roasting and the direct reduction of iron generally require the use of reducing agents such as coal and coke. Along with the stricter and stricter national environmental protection regulations, the use of coal is gradually tightened, and under the condition, organic solid wastes are used for replacing reducing agents such as coal and the like to carry out the cooperative treatment of iron-containing waste residues, reduce and recover iron minerals, so that the method is more urgent and more important.
Disclosure of Invention
In view of the above, the invention provides a method for recovering iron ore concentrate by pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes. The method provided by the invention mixes and pyrolyzes the iron-containing waste residue and the organic solid waste, uses the organic solid waste to replace coal as a reducing agent, and uses Fe in the iron-containing waste residue2O3Reduction to Fe3O4And then the iron ore concentrate is recovered by magnetic separation, so that the cooperative pyrolysis treatment and resource utilization of the iron-containing waste residue and the organic solid waste are realized.
In order to achieve the purpose of the invention, the invention provides the following technical scheme:
a method for recovering iron ore concentrate by pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes comprises the following steps:
(1) mixing iron-containing waste residues and organic solid wastes for carrying out pyrolysis coupling reduction reaction to obtain a reducing material;
(2) and carrying out magnetic separation on the reducing material to obtain iron ore concentrate.
Preferably, the water content of the iron-containing waste residue is less than or equal to 12 percent, and the granularity is less than or equal to 1 mm; fe in the iron-containing waste residue2O3The mass percentage of the component (A) is more than 20%.
Preferably, the volatile content of the organic solid waste is 40-70%.
Preferably, before the pyrolysis coupling reduction, the method further comprises the step of pretreating the organic solid waste; the pretreatment comprises the following steps: and (3) carrying out screening separation and air heavy medium separation on the organic solid waste, and then sequentially drying and crushing.
Preferably, the grain size of the pretreated organic solid waste is less than or equal to 3mm, and the water content is less than or equal to 15%.
Preferably, the pyrolysis coupling reduction reaction comprises a pyrolysis gasification coupling reduction reaction and a reduction reaction; the temperature of the pyrolysis gasification coupling reduction reaction is 450-1050 ℃, and the heat preservation time is 10-75 min; the temperature of the reduction reaction is 500-1000 ℃, and the heat preservation time is 10-75 min.
Preferably, the pyrolysis coupling reduction reaction is performed in a two-stage reactor, specifically: mixing the first part of iron-containing waste residues with the organic solid waste, carrying out pyrolysis gasification coupling reduction reaction in the first section of the reactor, and allowing generated pyrolysis gas to enter the second section of the reactor and the second part of iron-containing waste residues to carry out reduction reaction.
Preferably, the pyrolysis gasification coupling reduction reaction and the reduction reaction in the pyrolysis coupling reduction reaction are respectively performed in two reactors, specifically: mixing the first part of iron-containing waste residue with the organic solid waste, carrying out pyrolysis gasification coupling reduction reaction in a first reactor, introducing generated pyrolysis gas into a second reactor, and carrying out reduction reaction on the second part of iron-containing waste residue.
Preferably, the mass of the organic components in the organic solid waste is 5-45% of the total mass of the first part of the iron-containing waste residues and the organic solid waste; the mass ratio of the first part of iron-containing waste residues to the second part of iron-containing waste residues is (40-65) to (35-60); the granularity of the first part of the iron-containing waste residue is less than or equal to 0.5mm, and the granularity of the second part of the iron-containing waste residue is 0.5-1 mm.
Preferably, the magnetic field intensity of the magnetic separation is 50-1100 mT, and the magnetic separation time is 5-10 min.
The invention provides a method for recovering iron ore concentrate by pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes, which comprises the following steps: (1) mixing iron-containing waste residues and organic solid wastes for carrying out pyrolysis coupling reduction reaction to obtain a reducing material; (2) and carrying out magnetic separation on the reducing material to obtain iron ore concentrate. At the same time, Fe in the iron-containing slag2O3Can play a good catalytic role in the pyrolysis of the organic solid waste, promote the pyrolysis of the organic solid waste and generate CO and H rich2、CH4Pyrolysis gas of CO, H2、CH4The reducing gas in turn reacts on Fe2O3Has better reduction function to convert the Fe into Fe3O4(ii) a Meanwhile, Al in the iron-containing waste residue2O3、SiO2The components of CaO, Ni and the like can effectively promote the tar formed in the pyrolysis process of the organic solid waste to carry out secondary cracking reaction, and promote the carbon dust to carry out water gas conversion reaction to form CO and H2、CH4And reducing gas is added to further promote the reduction of the iron minerals. The method provided by the invention fully couples the catalytic pyrolysis (gasification) process of the organic solid waste with the reduction process of the iron minerals in the iron-containing waste residues, and realizes the pyrolysis of the organic solid waste and the iron to the maximum extentThe mineral is reduced and converted, so that the cooperative treatment and effective resource utilization of two solid wastes are realized, the 'waste preparation by waste' and the effective reduction of the solid wastes are realized, the iron ore concentrate with large demand and good market prospect can be prepared, and the method has good resource benefit, economic benefit and environmental benefit, good market prospect and huge market potential.
Detailed Description
The invention provides a method for recovering iron ore concentrate by pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes, which comprises the following steps:
(1) mixing iron-containing waste residues and organic solid wastes for carrying out pyrolysis coupling reduction reaction to obtain a reducing material;
(2) and carrying out magnetic separation on the reducing material to obtain iron ore concentrate.
The invention mixes the waste slag containing iron and the organic solid waste to carry out pyrolysis coupling reduction reaction, thus obtaining the reducing material. The method has no special requirement on the type of the iron-containing waste residue, and the iron-containing waste residue commonly seen in the field can be treated by the method, and specifically can be steel acid-washing sludge, dust removal ash, gas mud, sulfur-iron waste residue, red mud, vanadium-iron residue, ferrochrome waste residue, sulfur-gold concentrate waste residue, converter slag and the like.
In the invention, the moisture content of the iron-containing waste residue is preferably less than or equal to 12 percent, and the granularity is preferably less than or equal to 1 mm; fe in the iron-containing waste residue2O3The content of (b) is preferably 20% by mass or more, more preferably 30% by mass or more. In a specific embodiment of the present invention, if the water content and the particle size of the original iron-containing waste slag do not satisfy the above requirements, it is preferable to dry and pulverize the iron-containing waste slag so that the water content and the particle size of the iron-containing waste slag satisfy the above requirements; if some iron-containing waste residue contains Fe2O3If the content of (b) does not satisfy the above requirements, it is preferable to mix iron-containing slag of different types in proportion so that Fe in the iron-containing slag subjected to the pyrolysis-coupled reduction is contained in the iron-containing slag2O3The content of (b) satisfies the above requirements. The invention makes Fe in the iron-containing waste residue2O3The content of (A) is controlled within the range, so that the pyrolysis coupling reduction process can be ensuredThe process is smoothly performed.
The method has no special requirement on the type of the organic solid waste, and common organic solid waste in the field can be treated by the method, specifically, the organic solid waste can be municipal domestic waste, garden waste, straw, sludge, industrial organic solid waste, organic hazardous waste and the like, wherein the organic hazardous waste can be medical waste.
In the present invention, before the pyrolysis coupling reduction, the organic solid waste is preferably pretreated; the pretreatment preferably comprises the steps of: screening and separating the organic solid waste and sorting the organic solid waste by air heavy media, and then drying and crushing the organic solid waste in sequence; the plastic high polymer and the inorganic components in the organic solid waste are removed by screening separation and air heavy medium separation, wherein the removal rate of the plastic high polymer is preferably more than 96%, and the removal rate of the inorganic components is preferably more than 97%; the present invention has no special requirement for the specific operation method of sieving separation and air heavy medium separation, and the operation method is well known to those skilled in the art. In the present invention, the drying is preferably performed such that the water content of the obtained dried material is 15% or less, and the drying method is preferably solar greenhouse drying, residual heat drying, microwave heating drying, infrared heating drying, or the like; the smashing is preferably carried out by adopting a feed grinder, a straw grinder or a wood grinder, and the granularity of the smashed materials obtained by smashing is preferably less than or equal to 3 mm.
In the invention, the volatile content of the organic solid waste is preferably 40-70%, and more preferably 45-68%. In an embodiment of the present invention, if the volatile content of a certain organic solid waste does not satisfy the above requirements, it is preferable to mix different types of organic solid wastes in such a proportion that the volatile content of the organic solid waste subjected to the pyrolysis coupling reduction satisfies the above requirements, and the mixing is preferably performed after the organic solid waste is pretreated. The invention controls the content of volatile matters in the organic solid waste within the range, and can ensure the full and effective operation of the pyrolysis coupling reduction process.
In the present invention, the pyrolysis-coupled reduction reaction preferably includes a pyrolysis-gasification-coupled reduction reaction and a reduction reaction; the temperature of the pyrolysis gasification coupling reduction reaction is preferably 450-1050 ℃, more preferably 500-900 ℃, further preferably 550-850 ℃, the heat preservation time is preferably 10-75 min, more preferably 10-65 min, further preferably 15-60 min, and the heating rate is preferably 10-95 ℃/min; the temperature of the reduction reaction is preferably 500-1000 ℃, more preferably 550-950 ℃, further preferably 550-850 ℃, and the heat preservation time is preferably 10-75 min, more preferably 15-65 min, further preferably 15-55 min; the heating rate is preferably 10-95 ℃/min.
In the present invention, the pyrolysis coupling reduction reaction is preferably implemented in two ways, which are described below:
the first mode is as follows: the pyrolysis coupling reduction reaction is carried out in a two-section reactor, and specifically comprises the following steps: mixing the first part of iron-containing waste residues with the organic solid waste, carrying out pyrolysis gasification coupling reduction reaction in the first section of the reactor, and allowing generated pyrolysis gas to enter the second section of the reactor and the second part of iron-containing waste residues to carry out reduction reaction. The present invention does not require a special two-stage reactor, as is well known to those skilled in the art. In a specific embodiment of the present invention, preferably, a first portion of the iron-containing waste residue and the organic solid waste are mixed, the mixture is placed in a first section of a reactor, a second portion of the iron-containing waste residue is placed in a second section of the reactor, the reactor is heated, the first portion of the iron-containing waste residue and the organic solid waste are subjected to pyrolysis gasification coupled reduction reaction, generated pyrolysis gas enters the second section, the second portion of the iron-containing waste residue is subjected to reduction reaction, and the reduction reaction is maintained by heat of the pyrolysis gas and heat generated by heating the reactor together.
The second mode is as follows: the pyrolysis gasification coupling reduction reaction and the reduction reaction in the pyrolysis coupling reduction reaction are respectively carried out in two reactors, and specifically, the method comprises the following steps: mixing the first part of iron-containing waste residue with the organic solid waste, carrying out pyrolysis gasification coupling reduction reaction in a first reactor, and feeding generated pyrolysis gas into a second reactor to carry out reduction reaction with the second part of iron-containing waste residue. The reactor of the present invention has no particular requirement, and a reactor well known to those skilled in the art can be used; in a specific embodiment of the present invention, preferably, the first reactor is communicated with the second reactor, the first portion of the iron-containing waste residue is mixed with the organic solid waste, the mixture is placed in the first reactor, the second portion of the iron-containing waste residue is placed in the second reactor, then the reactors are heated, the first portion of the iron-containing waste residue and the organic solid waste are subjected to pyrolysis gasification coupled reduction reaction, and the generated pyrolysis gas enters the second reactor and the second portion of the iron-containing waste residue is subjected to reduction reaction.
In the above two implementation manners, part of the heat required by the reduction reaction is maintained by the heat brought by the pyrolysis gas, and the pyrolysis gas generated by the pyrolysis gasification coupled reduction reaction continuously enters the reduction reaction, which is equivalent to that the pyrolysis gasification coupled reduction reaction and the reduction reaction can be performed simultaneously.
In both implementations, the off-gas from the reduction reaction is preferably mixed with the off-gas from the combustion and used for dehydration and drying of the raw material (iron-containing slag or organic solid waste).
In the pyrolysis gasification coupling reduction reaction, Fe in the iron-containing waste slag2O3Can play a good catalytic role in promoting the organic solid waste to be pyrolyzed to generate CO and H2、CH4The pyrolysis gas can in turn lead Fe in the iron-containing waste residue2O3Reduction to Fe3O4Then the pyrolysis gas enters into reduction reaction and iron-containing waste residue to react, so that Fe in the iron-containing waste residue2O3Reduction to Fe3O4. In addition, Al in the iron-containing slag in the reduction reaction2O3、SiO2The components of CaO, Ni and the like can play a role of catalysis, promote tar carried in pyrolysis gas to perform secondary cracking reaction, promote carbon dust to perform water gas conversion reaction, and then form more CO and H-rich products2The reducing gas promotes the reduction of iron minerals in the iron-containing waste residue.
In the two implementation manners, the mass of the organic components in the organic solid waste is preferably 5-45% of the total mass of the first part of the iron-containing waste residue and the organic solid waste. In the specific embodiment of the invention, inorganic components in the organic solid waste can be removed through pretreatment, and the content of the organic components in the organic solid waste is directly measured by the mass ratio of the pretreated organic solid waste; the mass ratio of the first part of iron-containing waste residue to the second part of iron-containing waste residue is preferably (40-65): 35-60), and more preferably (45-60): 40-55; the granularity of the first part of iron-containing waste residue is preferably less than or equal to 0.5mm, and the granularity of the second part of iron-containing waste residue is preferably 0.5-1 mm.
After the pyrolysis coupling reduction is finished, the obtained reduced material is subjected to magnetic separation to obtain iron ore concentrate. In the invention, the materials generated by the pyrolysis gasification coupling reduction reaction and the materials generated by the reduction reaction jointly form the reducing material; the method preferably comprises the steps of naturally cooling the materials generated by the pyrolysis gasification coupling reduction reaction and the materials generated by the reduction reaction to room temperature, weighing, and then entering a magnetic separator for magnetic separation; the magnetic field intensity of the magnetic separation is preferably 50-1100 mT, more preferably 100-1000 mT, and the magnetic separation time is preferably 5-10 min.
The tailings left after magnetic separation are mainly semicoke generated by pyrolysis of organic solid wastes, and the obtained semicoke is preferably used as fuel to provide heat for pyrolysis gasification coupling reduction reaction through combustion.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.
Example 1
The iron-containing waste residue selected in the embodiment is steel pickling sludge, the water content is 10.5%, the iron grade is 29.80%, and Fe2O3The content is 35.7%; the organic solid waste is domestic waste, the domestic waste is subjected to screening separation and air heavy medium separation, plastic and inorganic components are removed, the removal rate is respectively more than 98%, and then the domestic waste is crushed until the granularity is less than 3mm, and the volatile matter content of the domestic waste is 58.5%.
Carry out pyrolysis coupling reduction in two segmentation reactors, mix domestic waste and first part steel acid pickling mud, place the first section of two segmentation reactors in the mixture, place the second section of two segmentation reactors in the second part of second part steel acid pickling mud, wherein the quality of domestic waste organic component is 8% of domestic waste and the total quality of first part steel acid pickling mud, the granularity of first part steel acid pickling mud is 0.5mm, the granularity of second part steel acid pickling mud is 1.0mm, the mass ratio of first part steel acid pickling mud and second part steel acid pickling mud is 55: 45.
according to the difference of pyrolysis gasification coupling reduction reaction temperature (hereinafter referred to as pyrolysis temperature), experiments are divided into 7 groups, specifically: heating the reactor to carry out pyrolysis gasification coupling reduction reaction on the household garbage and the first part of steel pickling sludge, wherein the heating temperature is respectively 400 ℃, 500 ℃, 600 ℃, 640 ℃, 680 ℃, 720 ℃ and 800 ℃, the heat preservation time is 10min, and the generated pyrolysis gas enters the second section and the second part of steel pickling sludge to carry out reduction reaction.
And cooling the material generated by the pyrolysis gasification coupling reduction reaction and the material generated by the reduction reaction to room temperature, then entering a magnetic separator, and carrying out magnetic separation under the condition that the magnetic field intensity is 250mT to obtain iron ore concentrate.
The magnetic separation recovery and the iron grade of the resulting iron concentrate are listed in table 1.
TABLE 1 influence of pyrolysis temperature on magnetic separation recovery and iron grade of pickled sludge
| Temperature/. degree.C | 400 | 500 | 600 | 640 | 680 | 720 | 800 |
| Percent recovery% | 55.56 | 68.65 | 80.35 | 88.47 | 91.05 | 85.72 | 80.69 |
| Iron grade/% | 50.50 | 53.46 | 56.65 | 61.07 | 66.33 | 63.29 | 57.19 |
As can be seen from the data in table 1, as the pyrolysis temperature increases, the magnetic recovery rate of the acid-washed sludge increases and then decreases, and reaches a maximum of 91.05% at 680 ℃. The grade of the iron ore concentrate is gradually increased and then decreased along with the increase of the pyrolysis temperature, and the grade of the iron ore concentrate reaches 66.33% at the maximum value at 680 ℃. Therefore, from the viewpoint of achieving efficient recovery of resources, 680 ℃ may be selected as the pyrolysis temperature for pyrolysis recovery of the steel pickling sludge.
Example 2
The pyrolysis temperature was controlled to 680 ℃, the amounts of domestic waste added in the pyrolysis gasification coupled reduction reaction were controlled to 5%, 6%, 7%, 8%, 9%, 10%, and 11%, respectively, and the other conditions were the same as in example 1.
The resulting magnetic separation recovery and the iron grade of the iron concentrate are listed in table 2.
Table 2 influence of the addition ratio of the organic components in the domestic garbage on the magnetic separation recovery rate and grade of the acid-washed sludge
As can be seen from the data in table 2, as the addition ratio of the household garbage increases, the magnetic recovery rate of the acid-washed sludge increases and then gradually decreases, and the maximum recovery rate of 92.03% is obtained when the addition amount is 8%, and the grade of the magnetic iron concentrate increases and then decreases, and reaches the maximum value of 67.17% when the addition amount of the household garbage is 9%.
Example 3
The pyrolysis temperature was controlled to 680 ℃, the amount of the domestic garbage added in the pyrolysis gasification coupled reduction reaction was controlled to 8%, and the holding times (hereinafter referred to as pyrolysis times) of the pyrolysis gasification coupled reduction reaction were controlled to 10min, 20min, 30min, 40min, 50min, 60min, and 70min, respectively, and the other conditions were the same as in example 1.
The magnetic separation recovery and the iron grade of the resulting iron concentrate are listed in table 3.
TABLE 3 influence of the holding time on the magnetic separation recovery and grade of the acid-washed sludge
| Holding time/min | 10 | 20 | 30 | 40 | 50 | 60 | 70 |
| Percent recovery% | 75.06 | 78.44 | 84.56 | 91.19 | 88.92 | 86.78 | 83.89 |
| Iron grade/% | 58.45 | 60.56 | 63.77 | 66.98 | 64.65 | 58.51 | 57.29 |
According to the data in table 3, it can be seen that the magnetic recovery rate of the iron ore concentrate increases and then decreases with the increase of the pyrolysis time, and when the retention time is 40min, the recovery rate of the iron ore concentrate is 91.19%, and the grade is 66.98%.
Example 4
The pyrolysis temperature is controlled to be 680 ℃, the adding amount of the domestic garbage in the pyrolysis gasification coupling reduction reaction is controlled to be 8%, the heat preservation time of the pyrolysis gasification coupling reduction reaction is controlled to be 40min, and the magnetic field strength of the magnetic separation is respectively controlled to be 100mT, 150mT, 210mT, 280mT, 350mT, 420mT and 500mT, and other conditions are consistent with those of the embodiment 1.
The magnetic separation recovery and the iron grade of the resulting iron concentrate are listed in table 4.
TABLE 4 influence of magnetic field intensity on magnetic separation recovery and grade of acid-washed sludge
| Magnetic field intensity mt | 100 | 150 | 210 | 280 | 350 | 420 | 500 |
| Percent recovery% | 74.09 | 79.78 | 84.67 | 89.39 | 91.45 | 93.62 | 94.95 |
| Iron grade/% | 68.56 | 66.33 | 65.78 | 62.57 | 60.92 | 58.55 | 55.79 |
According to the data in table 4, it can be seen that the magnetic separation recovery rate of the iron concentrate is continuously increased with the increase of the magnetic field intensity, but the iron grade shows a gradually decreasing trend. When the magnetic separation strength is more than 300mT, although the recovery rate of the iron concentrate can be improved to more than 90 percent, the iron grade is reduced to less than 60 percent. Obviously, in order to achieve a higher iron grade in the actual magnetic separation process, a suitable magnetic field strength must be selected.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and even optimization can be made without departing from the principle of the present invention, and these modifications and optimization should be considered as the protection scope of the present invention.
Claims (10)
1. A method for recovering iron ore concentrate by the pyrolysis coupling reduction of iron-containing waste residues and organic solid wastes is characterized by comprising the following steps:
(1) mixing iron-containing waste residues and organic solid wastes for carrying out pyrolysis coupling reduction reaction to obtain a reducing material;
(2) and carrying out magnetic separation on the reducing material to obtain iron ore concentrate.
2. The method according to claim 1, wherein the iron-containing waste residue has a moisture content of 12% or less and a particle size of 1mm or less; fe in the iron-containing waste residue2O3The mass percentage of the component (A) is more than 20%.
3. The method according to claim 1, wherein the organic solid waste has a volatile content of 40 to 70%.
4. The method of claim 1, further comprising pre-treating the organic solid waste prior to the pyrolytically coupled reduction; the pretreatment comprises the following steps: and (3) carrying out screening separation and air heavy medium separation on the organic solid waste, and then sequentially drying and crushing.
5. The method as claimed in claim 4, wherein the pretreated organic solid waste has a particle size of 3mm or less and a moisture content of 15% or less.
6. The method of claim 1, wherein the pyrolysis-coupled reduction reaction comprises a pyrolysis-gasification-coupled reduction reaction and a reduction reaction; the temperature of the pyrolysis gasification coupling reduction reaction is 450-1050 ℃, and the heat preservation time is 10-75 min; the temperature of the reduction reaction is 500-1000 ℃, and the heat preservation time is 10-75 min.
7. The method according to claim 6, wherein the pyrolysis-coupled reduction reaction is carried out in a two-stage reactor, in particular: mixing the first part of iron-containing waste residues with the organic solid waste, carrying out pyrolysis gasification coupling reduction reaction in the first section of the reactor, and allowing generated pyrolysis gas to enter the second section of the reactor and the second part of iron-containing waste residues to carry out reduction reaction.
8. The method according to claim 6, wherein the pyrolysis gasification coupled reduction reaction and the reduction reaction in the pyrolysis coupled reduction reaction are respectively performed in two reactors, specifically: mixing the first part of iron-containing waste residue with the organic solid waste, carrying out pyrolysis gasification coupling reduction reaction in a first reactor, introducing generated pyrolysis gas into a second reactor, and carrying out reduction reaction on the second part of iron-containing waste residue.
9. The method according to claim 7 or 8, wherein the mass of the organic components in the organic solid waste is 5-45% of the total mass of the first part of the iron-containing waste residue and the organic solid waste; the mass ratio of the first part of iron-containing waste residues to the second part of iron-containing waste residues is (40-65) to (35-60); the granularity of the first part of the iron-containing waste residue is less than or equal to 0.5mm, and the granularity of the second part of the iron-containing waste residue is 0.5-1 mm.
10. The method of claim 1, wherein the magnetic separation has a magnetic field strength of 50-1100 mT and a magnetic separation time of 5-10 min.
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