CN112410566A - Method and device for processing zinc-containing dust through pre-reduction microwave sintering - Google Patents

Method and device for processing zinc-containing dust through pre-reduction microwave sintering Download PDF

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CN112410566A
CN112410566A CN202010192360.1A CN202010192360A CN112410566A CN 112410566 A CN112410566 A CN 112410566A CN 202010192360 A CN202010192360 A CN 202010192360A CN 112410566 A CN112410566 A CN 112410566A
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zinc
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roasting
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CN112410566B (en
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胡兵
叶恒棣
刘呈
谢志诚
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Zhongye Changtian International Engineering Co Ltd
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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
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/001—Dry processes
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0046—Making spongy iron or liquid steel, by direct processes making metallised agglomerates or iron oxide
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • 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
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C22B1/212—Sintering; Agglomerating in tunnel furnaces
    • 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
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C22B1/214—Sintering; Agglomerating in shaft furnaces
    • 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
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/248—Binding; Briquetting ; Granulating of metal scrap or alloys
    • 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
    • C22B19/04—Obtaining zinc by distilling
    • 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
    • C22B19/30—Obtaining zinc or zinc oxide from metallic residues or scraps
    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/16—Dry methods smelting of sulfides or formation of mattes with volatilisation or condensation of the metal being produced
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02P10/20—Recycling

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Abstract

Pre-reduction micro-scaleA method of wave sintering a zinc containing dust, the method comprising: 1) zinc-containing dust and coal powder are mixed, a flux is added into the mixture, and the mixed materials are mixed and pelletized to obtain internally-mixed carbon pellets; 2) the internal carbon pellet enters a microwave heating zone (1) for pre-reduction, and zinc in the internal carbon pellet is gasified in the pre-reduction process; 3) the pellets with carbon added in the pre-reduced and dezincified enter a roasting area (2) to be roasted and crystallized, and then are cooled by a slow cooling area (3) and a cooling area (4) to obtain a blast furnace raw material; 4) CO generated in the roasting process in step 3)2Passing through a microwave heating zone (1), CO2Reacting with C in the internally carbon-added pellets to generate CO, and discharging the zinc gasified in the step 2) along with CO tail gas. The invention combines the pre-reduction sintering technology with the microwave heating technology, realizes the effective separation of elements such as zinc, sodium, potassium and the like and iron, and simultaneously generates high-purity CO gas to obtain high-quality blast furnace raw materials.

Description

Method and device for processing zinc-containing dust through pre-reduction microwave sintering
Technical Field
The invention relates to zinc-containing dust treatment, in particular to a method and a device for treating zinc-containing dust through pre-reduction microwave sintering, and belongs to the technical field of comprehensive utilization of iron-containing dust mud.
Background
China is a big iron and steel country, the yield of crude steel exceeds 8 hundred million tons in 2016, and the production is more steadily increased in recent years. The iron-containing dust and mud produced in the steel smelting process accounts for about 10 percent of the steel yield, nearly 8 million tons/year and is huge in quantity. The iron-containing secondary resources are rich in iron (about 10-68%), contain valuable elements such as carbon (1-40%), zinc (0.5-20%), lead, alkali metal and the like, and have high utilization value, but the dust mud has complex components and high content of the elements such as lead, zinc, alkali metal and the like, so that the utilization is still difficult.
At present, the utilization modes of the iron-containing dust sludge mainly comprise: beneficiation, wet processing, return processing, pyrogenic processing, combined processing and the like. Although the treatment modes are numerous, a universal iron-containing dust and mud treatment mode is not available at present, and the development of an economic, efficient and environment-friendly comprehensive utilization process for iron-containing dust and mud is not slow.
Pre-reduction sintering is a process in which iron ore sintering is carried out under high fuel conditions. Compared with the conventional sintering process, the pre-reduction sintering process has the advantages of stronger reducing atmosphere, higher sintering temperature and high product metallization rate. At first, most of the iron raw materials for pre-reduction sintering are iron powder ores and iron ore concentrates, and the research focuses on product performance, energy conservation and emission reduction. With the progress of research, some scholars at home and abroad find that the removal efficiency of harmful elements in the sintering process is greatly improved compared with that of conventional sintering under the reducing atmosphere and high temperature of pre-reduction sintering. The iron-containing dust and mud are treated by the pre-reduction sintering technology, so that harmful elements and iron can be effectively separated, high-quality metallized sinter can be obtained, the harmful elements can be enriched in dust, and the further treatment is facilitated.
The microwave is used as a heating means and has the characteristics of selective heating, rapid heating, volume heating, instant heating, metallurgical chemical reaction activation, cleanness and the like; the iron oxide and the coal powder are used as wave absorbers, so that the microwave absorbing capacity is strong, the temperature of the materials can be quickly raised, and the chemical reaction can be accelerated; the microwaves directly act in the reducing material body through the wave-transparent material, so that the conduction heat loss is reduced, no gas is generated during microwave heating, and the exhaust emission is reduced, thereby realizing the purposes of energy conservation and emission reduction.
Disclosure of Invention
Aiming at the defects and shortcomings of the prior art, the invention mainly aims to provide a method and a device for processing zinc-containing dust by pre-reducing microwave sintering. The method combines a pre-reduction sintering technology and a microwave heating technology, realizes effective separation of elements such as zinc, sodium, potassium and the like and iron by utilizing the characteristics of selective heating, rapid heating, volume heating, activated metallurgical chemical reaction and the like of microwaves, and simultaneously generates high-purity CO gas to obtain high-quality blast furnace raw materials.
According to a first embodiment of the invention, a method for pre-reducing microwave sintering zinc-containing dust is provided.
A method for processing zinc-containing dust by pre-reduction microwave sintering, which comprises the following steps:
1) zinc-containing dust and coal powder are mixed, a flux is added into the mixture, and the mixed materials are mixed and pelletized to obtain internally-mixed carbon pellets;
2) the internal carbon pellet enters a microwave heating zone, pre-reduction is carried out in a microwave heating mode, and zinc in the internal carbon pellet is gasified in the pre-reduction process;
3) the pre-reduced and dezincified internal carbon-mixed pellets enter a roasting area to be roasted and crystallized, and then are cooled in a slow cooling area and a cooling area to obtain a blast furnace raw material;
4) CO generated in the roasting process in step 3)2Passing through a microwave heating zone, CO2Reacting with C in the internally carbon-added pellets to generate CO, and discharging the zinc gasified in the step 2) along with CO tail gas.
In the present invention, the method further comprises:
5) recovering zinc from the tail gas discharged in the step 4) to obtain high CO tail gas;
6) part of the high CO tail gas is conveyed to a reburning chamber to be burnt, and part of the high CO tail gas and CO/H2Preparing coal gas, conveying to a roasting area, and providing a heat source for the roasting area.
In the invention, step 3) further comprises: air or oxygen is blown from the cooling zone to provide oxygen for combustion in the firing zone.
Preferably, in the step 1), the ratio of the molar amount of C to the molar amount of Fe in the internally carbon-coordinated pellets is 0.1-1.5:1, preferably 0.2-1:1, and more preferably 0.3-0.8: 1.
Preferably, in the step 2), the temperature of the pre-reduction is 900-.
Preferably, in the step 3), the temperature for the calcination is 1000-.
According to a second embodiment of the present invention, there is provided an apparatus for pre-reducing microwave sintering zinc-containing dust.
An apparatus for pre-reduction microwave sintering treatment of zinc-containing dust or an apparatus for use in the above method, the apparatus comprising a shaft furnace, an off-gas conveying conduit, a gas conveying conduit and an air conveying conduit. The shaft furnace is divided into a microwave heating area, a roasting area, a slow cooling area and a cooling area from top to bottom. The microwave heating area is provided with a plurality of microwave sources which are uniformly distributed outside the microwave heating area. And a tail gas conveying pipeline is connected above the microwave heating area. The roasting area is connected with a gas conveying pipeline. The cooling area is connected with an air conveying pipeline.
Preferably, the apparatus further comprises a zinc recovery unit, the off-gas delivery line being connected to a gas inlet of the zinc recovery unit. Preferably, the device also comprises a reburning chamber, a first tail gas pipeline led out from a gas outlet of the zinc recovery device is connected to the reburning chamber, and a second tail gas pipeline separated from the first tail gas pipeline is connected to the gas conveying pipeline.
Preferably, the apparatus further comprises a sealing hopper disposed above and in communication with the interior of the microwave heating zone.
According to a third embodiment of the present invention, there is provided an apparatus for pre-reducing microwave sintering processing zinc-containing dust.
A device for processing zinc-containing dust by pre-reduction and microwave sintering or a device used in the method comprises a trolley, a tail gas conveying pipeline, a gas conveying pipeline and an air conveying pipeline. According to the trend of the internally-carbon-added pellets, the trolley is sequentially divided into a microwave heating area, a roasting area, a slow cooling area and a cooling area. The microwave heating area is provided with a plurality of microwave sources which are uniformly distributed outside the microwave heating area. And a tail gas conveying pipeline is connected above the microwave heating area. The roasting area is connected with a gas conveying pipeline and an air conveying pipeline.
Preferably, the apparatus further comprises a zinc recovery unit, the off-gas delivery line being connected to a gas inlet of the zinc recovery unit. Preferably, the device also comprises a reburning chamber, a first tail gas pipeline led out from a gas outlet of the zinc recovery device is connected to the reburning chamber, and a second tail gas pipeline separated from the first tail gas pipeline is connected to the gas conveying pipeline.
Preferably, the apparatus further comprises a sealing hopper disposed above and in communication with the interior of the microwave heating zone.
Preferably, the device further comprises an airway tube. The gas-guide tube is led out from the bottom of the roasting area and is connected to the bottom of the microwave heating area.
In the method for processing the zinc-containing dust by pre-reduction microwave sintering, the raw materials used by the method are the zinc-containing dust (such as iron-containing dust mud and the like) and coal powder, the microwave and the coal gas are used as heat sources, and the coal powder has double functions of a reducing agent and a heating body. The invention combines the pre-reduction sintering technology and the microwave heating technology, zinc-containing dust, coal powder and flux are firstly proportioned according to a certain proportion, and after the materials are uniformly mixed, the internal carbon-mixed pellet is obtained by pelletizing. Wherein, the pre-reduction sintering refers to a process for sintering iron ore under high fuel conditions, so that the ratio of the molar quantity of C to the molar quantity of Fe in the internally carbon-added pellets is 0.1-1.5:1, preferably 0.2-1:1, and more preferably 0.3-0.8: 1. The molar ratio of C/Fe in the internally-matched carbon pellets is different, so that the removal rate of elements such as zinc and the like after the treatment by the process is different, and correspondingly, the residual carbon amount, the sinter yield and the like are changed along with the removal rate. The prepared internal carbon pellet enters a microwave heating zone through a sealed hopper, and is pre-reduced in a microwave heating mode. Wherein the temperature of the pre-reduction is 900-1300 ℃, preferably 950-1250 ℃, and more preferably 1000-1200 ℃. The internally-matched carbon pellets realize low-temperature rapid reduction of iron oxide in a microwave heating zone with lower free oxygen content, and elements such as zinc, sodium, potassium and the like and iron are effectively separated by utilizing the characteristics of selective heating, rapid heating, volume heating, activated metallurgical chemical reaction and the like of microwaves (zinc gasification in the pre-reduction process). The pellets subjected to pre-reduction and dezincification enter a roasting region to be subjected to high-temperature crystallization (wherein the roasting temperature is 1000-1400 ℃, preferably 1100-1350 ℃ and more preferably 1200-1300 ℃), and then are cooled in a slow cooling region and a cooling region and then discharged to obtain the high-quality blast furnace raw material. Preferably, during firing in the firing zone, air or oxygen is blown to provide oxygen for firing in the firing zone. At the same time, CO is generated during the roasting process2Passing through a microwave heating zone, and under the condition of high temperature, CO2And the zinc is reacted with C in the internal carbon pellet to generate CO, so that the reduction is accelerated, and the gasified zinc is discharged from a tail gas conveying pipeline along with CO tail gas in the pre-reduction process.
Preferably, the tail gas conveying pipelineAnd the discharged tail gas enters a zinc recovery device to complete the recovery of zinc, and high-purity CO tail gas is obtained. Preferably, a part of the high CO tail gas is conveyed to the reburning chamber through a first tail gas pipeline for burning, and the waste heat is utilized; one part enters the gas conveying pipeline through the second tail gas pipeline and is mixed with CO/H2The coal gas is prepared to provide a heat source for a roasting area, thereby realizing the recycling of tail gas.
In the invention, the device corresponding to the method for processing the zinc-containing dust by pre-reduction microwave sintering comprises two schemes. The first scheme is a shaft furnace structure, and the shaft furnace is divided into a microwave heating area, a roasting area, a slow cooling area and a cooling area from top to bottom. And a plurality of microwave sources are uniformly arranged outside the microwave heating area to ensure that the internally-distributed carbon pellets are uniformly heated in the microwave heating area. A tail gas conveying pipeline is connected above the microwave heating area, and CO generated in the roasting process2When passing upward through the microwave heating zone, CO is generated under high temperature2And the CO reacts with C in the internal carbon pellet to generate CO, and the CO tail gas and the zinc gasified in the pre-reduction sintering process are discharged from a tail gas conveying pipeline. The roasting area is connected with a gas conveying pipeline, and the gas is conveyed to the roasting area through the gas conveying pipeline to provide a heat source for the roasting area. The cooling area is connected with an air conveying pipeline, so that air or oxygen can be conveniently blown into the cooling area to provide oxygen for combustion in the roasting area.
The second scheme is a trolley structure, and the trolley is divided into a microwave heating area, a roasting area, a slow cooling area and a cooling area according to the trend of the carbon pellets distributed in the trolley. And a plurality of microwave sources are uniformly arranged outside the microwave heating area to ensure that the internally-distributed carbon pellets are uniformly heated in the microwave heating area. The upper part of the microwave heating area is connected with a tail gas conveying pipeline, and an air guide pipe is connected between the bottom of the microwave heating area and the bottom of the roasting area. CO produced during calcination2Introducing into microwave heating zone via bottom gas-guide tube, and introducing CO at high temperature2And the CO reacts with C in the internal carbon pellet to generate CO, and the CO tail gas and the zinc gasified in the pre-reduction sintering process are discharged from a tail gas conveying pipeline. The roasting area is connected with a gas conveying pipeline, and the gas is conveyed to the roasting area through the gas conveying pipeline to provide a heat source for the roasting area. The roasting area is also connected with airA delivery duct to facilitate blowing air or oxygen to provide oxygen for combustion in the firing zone. The trolley structure is a horizontal structure, and the additional air guide pipe is used for realizing flue gas circulation of the trolley structure.
Preferably, the device further comprises a zinc recovery device and a reburning chamber. And (4) enabling the tail gas discharged from the tail gas conveying pipeline to enter a zinc recovery device, and recovering zinc in the tail gas to obtain high-purity CO tail gas. A part of high CO tail gas enters a reburning chamber for burning, and waste heat is utilized; part of the high CO tail gas is mixed with CO/H2The coal gas is prepared to enter a roasting area to provide a heat source for the roasting area, and the cyclic utilization of tail gas is realized.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention combines the pre-reduction sintering technology with the microwave heating technology, realizes the effective separation of elements such as zinc, sodium, potassium and the like and iron, and simultaneously generates high-purity CO gas to obtain high-quality blast furnace raw materials;
2. according to the invention, the microwave is adopted to directly heat the internally-matched carbon pellets, and the characteristics of selective heating, rapid heating, volume heating, activated metallurgical chemical reaction and the like of the microwave are utilized to rapidly raise the temperature of the material and accelerate the chemical reaction; moreover, the microwave heating does not generate gas, so that the exhaust emission is reduced, and the aims of energy conservation and emission reduction are fulfilled;
3. according to the invention, the molar ratio of C/Fe in the internally-matched carbon pellets prepared from the zinc-containing dust and the coal powder is adjusted, so that the reducing atmosphere in the pre-reduction sintering process is stronger, the sintering temperature is higher, the product metallization rate is higher, the removal rate of harmful elements in the sintering process is greatly improved, and the yield of sintered ores is also ensured;
4. part of the high-purity CO gas generated in the invention can be used for reburning chamber combustion, and the waste heat is utilized, and part of the high-purity CO gas can be prepared into coal gas to be conveyed to the roasting area, so that a heat source is provided for the roasting area, and the recycling of tail gas is realized.
Drawings
FIG. 1 is a process flow diagram of a method for pre-reducing microwave sintering zinc-containing dust according to the present invention;
FIG. 2 is a schematic structural diagram of a shaft furnace for processing zinc-containing dust by pre-reduction microwave sintering according to the present invention;
FIG. 3 is a schematic structural diagram of a trolley for processing zinc-containing dust by pre-reduction microwave sintering according to the present invention.
Reference numerals: a: a shaft furnace; b: a trolley; 1: a microwave heating zone; 2: a roasting zone; 3: a slow cooling zone; 4: a cooling zone; 5: a zinc recovery unit; 6: a reburning chamber; 7: sealing the hopper; l1: a tail gas conveying pipeline; l2: a gas delivery conduit; l3: an air delivery conduit; l4: a first tail gas pipeline; l5: a second tail gas pipeline; l6: an air duct.
Detailed Description
According to a first embodiment of the invention, a method for pre-reducing microwave sintering zinc-containing dust is provided.
A method for processing zinc-containing dust by pre-reduction microwave sintering, which comprises the following steps:
1) zinc-containing dust and coal powder are mixed, a flux is added into the mixture, and the mixed materials are mixed and pelletized to obtain internally-mixed carbon pellets;
2) the internal carbon pellet enters a microwave heating zone 1, pre-reduction is carried out in a microwave heating mode, and zinc in the internal carbon pellet is gasified in the pre-reduction process;
3) the pellets with carbon added after pre-reduction and dezincification enter a roasting area 2 to be roasted and crystallized, and then are cooled by a slow cooling area 3 and a cooling area 4 to obtain a blast furnace raw material;
4) CO generated in the roasting process in step 3)2Passing through a microwave heating zone 1, CO2Reacting with C in the internally carbon-added pellets to generate CO, and discharging the zinc gasified in the step 2) along with CO tail gas.
In the present invention, the method further comprises:
5) recovering zinc from the tail gas discharged in the step 4) to obtain high CO tail gas;
6) part of the high CO tail gas is conveyed to a reburning chamber 6 to be burnt, and part of the high CO tail gas and CO/H2And preparing coal gas, conveying the coal gas to the roasting area 2, and providing a heat source for the roasting area 2.
In the invention, step 3) further comprises: air or oxygen is blown from the cooling zone 4 to provide oxygen for the combustion in the calcination zone 2.
Preferably, in the step 1), the ratio of the molar amount of C to the molar amount of Fe in the internally carbon-coordinated pellets is 0.1-1.5:1, preferably 0.2-1:1, and more preferably 0.3-0.8: 1.
Preferably, in the step 2), the temperature of the pre-reduction is 900-.
Preferably, in the step 3), the temperature for the calcination is 1000-.
According to a second embodiment of the present invention, there is provided an apparatus for pre-reducing microwave sintering zinc-containing dust.
An apparatus for pre-reduction microwave sintering treatment of zinc-containing dust or for use in the above method, the apparatus comprising a shaft furnace a, an off-gas duct L1, a gas duct L2 and an air duct L3. The shaft furnace A is divided into a microwave heating area 1, a roasting area 2, a slow cooling area 3 and a cooling area 4 from top to bottom. Wherein, microwave heating zone 1 is equipped with a plurality of microwave sources, and a plurality of microwave sources evenly distributed is in microwave heating zone 1's outside. An exhaust gas conveying pipeline L1 is connected above the microwave heating area 1. The roasting zone 2 is connected with a gas conveying pipeline L2. An air delivery duct L3 is connected to the cooling zone 4.
Preferably, the plant further comprises a zinc recovery plant 5, said off-gas duct L1 being connected to the gas inlet of the zinc recovery plant 5. Preferably, the plant further comprises a reburning chamber 6, a first tail gas line L4 leading from the gas outlet of the zinc recovery plant 5 is connected to the reburning chamber 6, and a second tail gas line L5 branching from the first tail gas line L4 is connected to the gas conveying line L2.
Preferably, the apparatus further comprises a sealing hopper 7, said sealing hopper 7 being arranged above the microwave heating zone 1 and communicating with the interior of the microwave heating zone 1.
According to a third embodiment of the present invention, there is provided an apparatus for pre-reducing microwave sintering processing zinc-containing dust.
The device for processing the zinc-containing dust by pre-reduction and microwave sintering or the device used in the method comprises a trolley B, a tail gas conveying pipeline L1, a gas conveying pipeline L2 and an air conveying pipeline L3. According to the trend of the internally carbon-added pellets, the trolley B is sequentially divided into a microwave heating area 1, a roasting area 2, a slow cooling area 3 and a cooling area 4. Wherein, microwave heating zone 1 is equipped with a plurality of microwave sources, and a plurality of microwave sources evenly distributed is in microwave heating zone 1's outside. An exhaust gas conveying pipeline L1 is connected above the microwave heating area 1. The roasting zone 2 is connected with a gas conveying pipeline L2 and an air conveying pipeline L3.
Preferably, the plant further comprises a zinc recovery plant 5, said off-gas duct L1 being connected to the gas inlet of the zinc recovery plant 5. Preferably, the plant further comprises a reburning chamber 6, a first tail gas line L4 leading from the gas outlet of the zinc recovery plant 5 is connected to the reburning chamber 6, and a second tail gas line L5 branching from the first tail gas line L4 is connected to the gas conveying line L2.
Preferably, the apparatus further comprises a sealing hopper 7, said sealing hopper 7 being arranged above the microwave heating zone 1 and communicating with the interior of the microwave heating zone 1.
Preferably, the device further comprises an airway tube L6. The gas guide pipe L6 is led out from the bottom of the roasting area 2 and connected to the bottom of the microwave heating area 1.
Example 1
As shown in fig. 2, an apparatus for pre-reducing microwave sintering treatment of zinc-containing dust comprises a shaft furnace a, an off-gas conveying pipeline L1, a gas conveying pipeline L2 and an air conveying pipeline L3. The shaft furnace A is divided into a microwave heating area 1, a roasting area 2, a slow cooling area 3 and a cooling area 4 from top to bottom. Wherein, microwave heating zone 1 is equipped with a plurality of microwave sources, and a plurality of microwave sources evenly distributed is in microwave heating zone 1's outside. An exhaust gas conveying pipeline L1 is connected above the microwave heating area 1. The roasting zone 2 is connected with a gas conveying pipeline L2. An air delivery duct L3 is connected to the cooling zone 4.
Example 2
Example 1 was repeated except that the apparatus further included a zinc recovery unit 5, and the off-gas transfer line L1 was connected to the gas inlet of the zinc recovery unit 5.
Example 3
Example 2 was repeated except that the apparatus further included a recombustion chamber 6, a first exhaust gas conduit L4 leading from the gas outlet of the zinc recovery apparatus 5 was connected to the recombustion chamber 6, and a second exhaust gas conduit L5 branched from the first exhaust gas conduit L4 was connected to the gas carrying conduit L2.
Example 4
Example 3 is repeated except that the apparatus further comprises a sealing hopper 7, said sealing hopper 7 being arranged above the microwave heating zone 1 and communicating with the interior of the microwave heating zone 1.
Example 5
As shown in fig. 3, the apparatus for processing zinc-containing dust by pre-reduction microwave sintering comprises a trolley B, an off-gas conveying pipeline L1, a gas conveying pipeline L2 and an air conveying pipeline L3. According to the trend of the internally carbon-added pellets, the trolley B is sequentially divided into a microwave heating area 1, a roasting area 2, a slow cooling area 3 and a cooling area 4. Wherein, microwave heating zone 1 is equipped with a plurality of microwave sources, and a plurality of microwave sources evenly distributed is in microwave heating zone 1's outside. An exhaust gas conveying pipeline L1 is connected above the microwave heating area 1. The roasting zone 2 is connected with a gas conveying pipeline L2 and an air conveying pipeline L3.
The apparatus further comprises a zinc recovery unit 5, the off-gas duct L1 being connected to a gas inlet of the zinc recovery unit 5. The apparatus further comprises a reburning chamber 6, a first exhaust gas conduit L4 leading from the gas outlet of the zinc recovery apparatus 5 is connected to the reburning chamber 6, and a second exhaust gas conduit L5 branching from the first exhaust gas conduit L4 is connected to the gas conveying conduit L2.
The device also comprises a sealing hopper 7, wherein the sealing hopper 7 is arranged above the microwave heating area 1 and is communicated with the inside of the microwave heating area 1.
Example 6
Example 5 was repeated except that the device also included an airway tube L6. The gas guide pipe L6 is led out from the bottom of the roasting area 2 and connected to the bottom of the microwave heating area 1.
Example 7
As shown in fig. 1, a method for pre-reducing microwave sintering zinc-containing dust comprises the following steps:
1) zinc-containing dust and coal powder are mixed, a flux is added into the mixture, and the mixed materials are mixed and pelletized to obtain internally-mixed carbon pellets;
2) the internal carbon pellet enters a microwave heating zone 1, pre-reduction is carried out in a microwave heating mode, and zinc in the internal carbon pellet is gasified in the pre-reduction process;
3) the pellets with carbon added after pre-reduction and dezincification enter a roasting area 2 to be roasted and crystallized, and then are cooled by a slow cooling area 3 and a cooling area 4 to obtain a blast furnace raw material;
4) CO generated in the roasting process in step 3)2Passing through a microwave heating zone 1, CO2Reacting with C in the internally carbon-added pellets to generate CO, and discharging the zinc gasified in the step 2) along with CO tail gas.
Example 8
A method of pre-reducing microwave sintering zinc-containing dust using the apparatus of example 4, the method comprising the steps of:
1) zinc-containing dust and coal powder are mixed, a flux is added into the mixture, and the mixed materials are mixed and pelletized to obtain internally-mixed carbon pellets;
2) the internal carbon pellet enters a microwave heating zone 1, pre-reduction is carried out in a microwave heating mode, and zinc in the internal carbon pellet is gasified in the pre-reduction process;
3) the pellets with carbon added after pre-reduction and dezincification enter a roasting area 2 to be roasted and crystallized, and then are cooled by a slow cooling area 3 and a cooling area 4 to obtain a blast furnace raw material;
4) CO generated in the roasting process in step 3)2Passing through a microwave heating zone 1, CO2Reacting with C in the internally carbon-added pellets to generate CO, and discharging the gasified zinc in the step 2) along with CO tail gas;
5) recovering zinc from the tail gas discharged in the step 4) to obtain high CO tail gas;
6) part of the high CO tail gas is conveyed to a reburning chamber 6 to be burnt, and part of the high CO tail gas and CO/H2And preparing coal gas, conveying the coal gas to the roasting area 2, and providing a heat source for the roasting area 2.
Example 9
Example 8 was repeated except that step 3) further included: air is blown from the cooling zone 4 to provide oxygen for combustion in the firing zone 2.
Example 10
Example 9 was repeated, except that in step 2) the temperature of the pre-reduction was 1200 ℃.
Example 11
Example 10 was repeated except that in step 3), the calcination temperature was 1300 ℃.
Example 12
Example 11 is repeated, the zinc-containing dust and the coal powder internally added are pre-reduced and roasted in a pre-reduction microwave sintering shaft furnace structure device, wherein when the molar ratio of C/Fe of the internally added carbon pellets is 0.5, the removal rates of K, Na and Zn in the sintering process reach higher levels of 73.86%, 59.44% and 60.08%, the residual carbon content is 0.98%, the sinter ore yield is 72.52%, and the drum strength is 67.97%.
Example 13
Example 11 is repeated, the zinc-containing dust and the coal powder internally matched are adopted to carry out pre-reduction and roasting in a pre-reduction microwave sintering shaft furnace structure device, wherein when the molar ratio of C/Fe of the internally matched carbon pellets is 0.7, the removal rates of K, Na and Zn reach the highest values, which are 82.62%, 67.69% and 84.72% respectively. In addition, the residual carbon content was 2.66%, the sintered ore yield was 72.67%, and the drum strength was 76.62%.
From examples 12 and 13, it can be seen that when the method and the device of the present invention are used for performing pre-reduction microwave sintering treatment on the zinc-containing dust, the molar ratio of C/Fe in the internal carbon pellet prepared from the zinc-containing dust and the coal powder is adjusted, so that the reducing atmosphere in the pre-reduction sintering process is stronger, the sintering temperature is higher, and the product metallization rate is higher, and meanwhile, the characteristics of selective heating, rapid heating, volume heating, activation of metallurgical chemical reactions and the like of microwaves are fully utilized, so that the removal rate of harmful elements in the sintering process can be greatly increased, high-quality metallized sintering ore can be obtained, and the purposes of energy saving and emission reduction can be achieved.

Claims (10)

1. A method for processing zinc-containing dust by pre-reduction microwave sintering, which comprises the following steps:
1) zinc-containing dust and coal powder are mixed, a flux is added into the mixture, and the mixed materials are mixed and pelletized to obtain internally-mixed carbon pellets;
2) the internal carbon pellet enters a microwave heating zone (1), pre-reduction is carried out in a microwave heating mode, and zinc in the internal carbon pellet is gasified in the pre-reduction process;
3) the pellets with carbon added in the pre-reduced and dezincified enter a roasting area (2) to be roasted and crystallized, and then are cooled by a slow cooling area (3) and a cooling area (4) to obtain a blast furnace raw material;
4) CO generated in the roasting process in step 3)2Passing through a microwave heating zone (1), CO2Reacting with C in the internally carbon-added pellets to generate CO, and discharging the zinc gasified in the step 2) along with CO tail gas.
2. The method of claim 1, wherein: the method further comprises the following steps:
5) recovering zinc from the tail gas discharged in the step 4) to obtain high CO tail gas;
6) part of the high CO tail gas is conveyed to a reburning chamber (6) for burning, and part of the high CO tail gas and CO/H2Prepared into coal gas, and is conveyed to the roasting area (2) to provide a heat source for the roasting area (2).
3. The method according to claim 1 or 2, characterized in that: the step 3) also comprises the following steps: air or oxygen is blown from the cooling zone (4) to provide oxygen for the combustion in the roasting zone (2).
4. The method according to any one of claims 1-3, wherein: in the step 1), the ratio of the molar weight of C to the molar weight of Fe in the internally carbon-added pellets is 0.1-1.5:1, preferably 0.2-1:1, and more preferably 0.3-0.8: 1.
5. The method according to any one of claims 1-4, wherein: in the step 2), the temperature of the pre-reduction is 900-.
6. The method according to any one of claims 1-5, wherein: in the step 3), the temperature for roasting is 1000-1400 ℃, preferably 1100-1350 ℃, and more preferably 1200-1300 ℃.
7. An apparatus for pre-reduction microwave sintering of zinc containing dust or for use in the method according to any of claims 1 to 6, comprising a shaft furnace (A), an off-gas conveying duct (L1), a gas conveying duct (L2) and an air conveying duct (L3); the shaft furnace (A) is divided into a microwave heating area (1), a roasting area (2), a slow cooling area (3) and a cooling area (4) from top to bottom; wherein, the microwave heating area (1) is provided with a plurality of microwave sources which are uniformly distributed outside the microwave heating area (1); a tail gas conveying pipeline (L1) is also connected above the microwave heating zone (1); the roasting area (2) is connected with a gas conveying pipeline (L2); the cooling area (4) is connected with an air conveying pipeline (L3).
8. An apparatus for pre-reducing microwave sintering treatment of zinc containing dust or for use in the method according to any of claims 1-6, comprising a trolley (B), an off-gas conveying conduit (L1), a gas conveying conduit (L2) and an air conveying conduit (L3); according to the trend of the internally carbon-mixed pellets, the trolley (B) is sequentially divided into a microwave heating area (1), a roasting area (2), a slow cooling area (3) and a cooling area (4); wherein, the microwave heating area (1) is provided with a plurality of microwave sources which are uniformly distributed outside the microwave heating area (1); a tail gas conveying pipeline (L1) is also connected above the microwave heating zone (1); the roasting area (2) is connected with a gas conveying pipeline (L2) and an air conveying pipeline (L3).
9. The apparatus of claim 7 or 8, wherein: the device also comprises a zinc recovery device (5), wherein the tail gas conveying pipeline (L1) is connected to a gas inlet of the zinc recovery device (5); preferably, the device also comprises a reburning chamber (6), a first tail gas pipeline (L4) led out from a gas outlet of the zinc recovery device (5) is connected to the reburning chamber (6), and a second tail gas pipeline (L5) branched from the first tail gas pipeline (L4) is connected to a gas conveying pipeline (L2); and/or
The device also comprises a sealing hopper (7), wherein the sealing hopper (7) is arranged above the microwave heating area (1) and is communicated with the inside of the microwave heating area (1).
10. The apparatus of claim 8 or 9, wherein: the device further comprises an airway tube (L6); the gas guide pipe (L6) is led out from the bottom of the roasting area (2) and is connected to the bottom of the microwave heating area (1).
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