CN115341061A - Method for efficiently fluidizing and reducing vanadium titano-magnetite fine powder - Google Patents
Method for efficiently fluidizing and reducing vanadium titano-magnetite fine powder Download PDFInfo
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- 229910052720 vanadium Inorganic materials 0.000 title claims abstract description 77
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- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 title claims abstract description 65
- 230000003647 oxidation Effects 0.000 claims abstract description 34
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- 229910052742 iron Inorganic materials 0.000 claims description 23
- 238000012216 screening Methods 0.000 claims description 22
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 18
- 239000010936 titanium Substances 0.000 claims description 18
- 229910052719 titanium Inorganic materials 0.000 claims description 18
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- 238000011946 reduction process Methods 0.000 claims description 13
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- QJZYHAIUNVAGQP-UHFFFAOYSA-N 3-nitrobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid Chemical compound C1C2C=CC1C(C(=O)O)C2(C(O)=O)[N+]([O-])=O QJZYHAIUNVAGQP-UHFFFAOYSA-N 0.000 claims description 3
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- 239000004568 cement Substances 0.000 claims description 3
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- 239000004571 lime Substances 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 235000019422 polyvinyl alcohol Nutrition 0.000 claims description 3
- 235000019353 potassium silicate Nutrition 0.000 claims description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 3
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- FFBHFFJDDLITSX-UHFFFAOYSA-N benzyl N-[2-hydroxy-4-(3-oxomorpholin-4-yl)phenyl]carbamate Chemical compound OC1=C(NC(=O)OCC2=CC=CC=C2)C=CC(=C1)N1CCOCC1=O FFBHFFJDDLITSX-UHFFFAOYSA-N 0.000 description 7
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- 238000000629 steam reforming Methods 0.000 description 2
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- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
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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
- C21B13/0073—Selection or treatment of the reducing gases
-
- 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
-
- 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
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/1218—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by dry processes
-
- 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
- C22B34/00—Obtaining refractory metals
- C22B34/20—Obtaining niobium, tantalum or vanadium
- C22B34/22—Obtaining vanadium
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Abstract
The invention belongs to the fields of chemical industry and metallurgy, and discloses a method for efficiently fluidizing and reducing vanadium titano-magnetite fine powder. The method improves the high-temperature reduction fluidization quality of the vanadium titano-magnetite fine powder with the particle size of less than 0.1mm by adding the binder for granulation modification, prevents the binder from losing flow and achieves the aim of high-efficiency reduction; the vanadium titano-magnetite is preheated by reducing tail gas combustion and oxidized, so that the gas utilization rate and the reduction rate are improved; through heat exchange between the hot reducing ore and the reducing gas, the thermal oxidation tail gas provides heat for the hot curing process, and the energy utilization rate of the system is improved. The method has the advantages of simple process, environmental protection, high resource utilization rate, energy utilization rate and reaction efficiency, and good economic benefit and social benefit.
Description
Technical Field
The invention belongs to the fields of chemical industry and metallurgy, and particularly relates to a method for efficiently fluidizing and reducing vanadium titano-magnetite fine powder.
Background
Vanadium and titanium have very wide application as important rare resources and strategic substances, and about 98 percent of vanadium and 91 percent of titanium are added into vanadium titano-magnetite globally, so the vanadium titano-magnetite has very high comprehensive utilization value.
In the existing process for treating vanadium-titanium magnetite, the vanadium-titanium magnetite smelting by a blast furnace method is in a leading position due to high technical maturity, however, the blast furnace smelting is extremely dependent on metallurgical coke, the environmental pollution is large, and the blast furnace smelting cost is gradually increased along with the shortage of coking coal resources. In addition, most of vanadium in the vanadium-titanium magnetite smelted by the blast furnace method can selectively enter molten iron, the vanadium is extracted by the converter and is well recycled, while titanium enters blast furnace slag, and titanium-containing phases in the slag are complex and have fine particle size distribution, so that titanium resources are difficult to recycle. In order to get rid of the restriction of coking coal resource shortage on the smelting development of vanadium titano-magnetite and adapt to the increasingly improved environmental protection requirement, the non-blast furnace smelting technology has become one of the research hotspots for the smelting of vanadium titano-magnetite. The non-blast furnace smelting technology mainly comprises direct reduction and smelting reduction. The smelting reduction refers to a method for smelting liquid pig iron without a blast furnace, compared with the blast furnace, the smelting reduction only uses coal to replace coke, and the product is similar to the blast furnace, so the problem that the recycling of titanium resources is difficult is also existed.
Compared with a blast furnace and a smelting reduction method, the direct reduction method for smelting vanadium-titanium magnetite can be used for producing sponge iron and vanadium-titanium-containing slag by reducing at the temperature lower than the melting temperature of iron ore, the energy consumption is low, and meanwhile, gangue components in the ore are not melted for slagging, thereby being beneficial to the recycling of vanadium and titanium resources. The direct reduction method can be divided into a coal-based method and a gas-based method according to the difference of the reducing agent. Coal-based reduction mainly uses a rotary kiln and a rotary hearth furnace as reactors, and a gas-based reduction principle mainly adopts a shaft furnace and a fluidized bed. Compared with coal-based reduction, the gas-based reduction has the advantages of low energy consumption, environmental friendliness and the like. As a typical gas-based direct reduction reactor, a shaft furnace mainly takes lump ore and pellet ore as raw materials, the preparation of the pellet ore gradually becomes a necessary link for the shaft furnace smelting along with the shortage of high-grade high-quality lump ore resources, the preparation process of the pellet ore needs to undergo the steps of pelletizing, green pellet screening, drying preheating, roasting consolidation, cooling screening and the like, the operation is complex, the roasting consolidation step is usually carried out at about 1250 ℃, and the energy consumption is high. Compared with a shaft furnace, the fluidized bed saves the preparation link of pellet ore, can directly process the fine ore, has the advantages of high mass and heat transfer efficiency between gas and solid phases, high reduction rate and the like, and is a vanadium titano-magnetite smelting technology with a great development prospect. During the last decades, there have been great advances in fluidized iron making, and typical fluidized direct reduction iron making processes include the FIOR process, the FINMET process, and the CIRCORED process.
The FIOR process was developed by the Exxon Research and Engineering Company design. Iron ore powder with the granularity of less than 5mm sequentially passes through 4 fluidized bed reactors, the ore powder is preheated to 760 ℃ by a first-stage fluidized bed, the reduction temperature of a second-stage to fourth-stage fluidized bed reactor is 690-780 ℃, and the pressure is 1.11MPa. The metallization rate of the reduced iron ore powder reaches 92%, and the reduced iron ore powder can be hot pressed into blocks (US 5082251). The fluidized reducing gas is obtained by steam reforming of natural gas, H 2 The content is over 90 percent, and the gas is mixed with the purified recycle gas to enter a four-stage fluidized bed reactor, and then enters a third stage and a second stage, and the inside of the bed is in a gas-solid countercurrent state. In the FIOR process, a proper amount of non-sticky inert powder such as CaO, mgO and the like is added to prevent the loss of flow when the iron ore powder is reduced.
The FINMET process was developed by the FIOR venezuela company in conjunction with the austempered steel (VAI) by modifying the FIOR process. Iron ore powder with the particle size of less than 12.7mm sequentially passes through 4 fluidized bed reactors connected in series and flows reversely with the fluidized reducing gas. The temperature of the first-stage fluidized bed reactor is about 550 ℃, the temperature gradually rises downwards, the temperature of the fourth-stage fluidized bed reactor is about 800 ℃, and the pressure is 1.1-1.4MPa. The metallization rate of the outlet product of the four-stage fluidized bed reaches 93 percent, and the content of C is about 0.5 to 3 percent (US 5833734). The fluidized reducing gas consists of fresh gas obtained by steam reforming of natural gas and circulating gas, and is heated to 850 ℃ before entering the four-stage reactor. In order to avoid the occurrence of binding defluidization, raw materials used in the FINMET process are mainly non-binding coarse mineral powder, the content of fine mineral powder (the particle size is less than 0.1 mm) needs to be controlled within 20%, otherwise, inert powder such as CaO, mgO and the like needs to be added.
The CIRCORED process was developed by the ottotai company of germany (Outotec, the original Lurgi metalurgie, lurgi metallurgy) based on a gas-based rapid direct reduction technique of iron ore fines. The reduction system consists of a primary Circulating Fluidized Bed (CFB) and a secondary bubbling Fluidized Bed (FB) (US 5527379, US 5603748). The CFB reactor used in a factory with the production capacity of 50 ten thousand tons/year has the outer diameter of 5.2m, the height of 29.6m, the outer diameter of an external circulation cyclone of 5.5m, the outer diameter of an FB reactor of 7.0m and the total length of 17.5m, and four material chambers are arranged inside the reactor. Fluidizing reducing gas to pure H 2 . The reduction temperature of the first-stage fast fluidized bed is 630-650 ℃, the reduction temperature of the second-stage bubbling fluidized bed is about 680 ℃, and the pressure is 0.4MPa. The obtained reduced iron powder can be hot-pressed into briquettes or directly used for powder metallurgy. As the only commercialized hydrogen direct reduction technology in the world, in order to avoid the caking and the flow loss in the iron ore powder fluidization reduction process, the reduction temperature in the CIRCORED process is controlled below 680 ℃, and the iron ore powder which is about 1mm and is not easy to bind is selected as a raw material.
In addition, many chinese patents also propose fluidized direct reduction ironmaking processes, such as CN103667571B, CN103725819B, CN106319126B, CN106467930B, etc. For the typical gas-solid non-catalytic reaction of the gas-based direct reduction of iron ore, the kinetic process can be described by adopting an unreacted nuclear model (a condensation model), and the relationship between the complete conversion time of particles and the particle size under different control steps (external diffusion, internal diffusion and interfacial chemical reaction) in the condensation model shows that the smaller the particles, the shorter the complete conversion time is required, namely the faster the reduction reaction rate is. From the gas-solid fluidization basic theory, the initial fluidization velocity of the particles is proportional to the square of the particle size, i.e. the smaller the particles, the less the gas amount needed to maintain the fluidization state. Therefore, the finer the raw material ore powder is, the more beneficial the fluidization direct reduction is theoretically, however, the existing fluidization direct reduction iron making process is only suitable for treating the coarse ore powder which is not easy to bond, or needs to add inert substances to inhibit the fine ore powder from flowing out, which can greatly affect the fluidization reduction efficiency, and the advantages of fluidization efficient reduction cannot be fully exerted. This is mainly because fine ore powder (less than 0.1 mm) is easy to be bonded during the fluidized reduction process at high temperature (above 600 ℃), and forms agglomerates with larger particle size and deposits at the bottom of the fluidized bed, which finally results in the loss of flow of the whole bed. Once a loss of flow occurs, the reduction system will have to be shut down, which can cause significant losses to production (Komatina M, gudenau H W. Metalurgija,2004, 10 (204): 309-328).
Therefore, through technological and technical innovation, the high-temperature reduction fluidization quality of the vanadium titano-magnetite fine powder smaller than 0.1mm is improved, the loss of flow is prevented, the reduction efficiency is improved, the energy consumption is reduced, the production cost is saved, and the method is an important way for realizing the high-efficiency utilization of the vanadium titano-magnetite in China.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a method for efficiently fluidizing and reducing vanadium titano-magnetite fine powder. The method can realize the efficient reduction of the vanadium titano-magnetite fine powder, has the advantages of simple process, environmental protection, high resource utilization rate, energy utilization rate and reaction efficiency, and good economic benefit and social benefit.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for efficiently fluidizing and reducing vanadium titano-magnetite fine powder comprises a mixed briquetting process 1, a thermocuring process 2, a crushing and screening process 3, a combustion pre-oxidation process 4, a fluidization reduction process 5, a heat exchange process 6 and a separation process 7, and specifically comprises the following steps:
1) In the mixed briquetting process 1, vanadium titano-magnetite fine powder and/or fine powder from the crushing and screening process 3 are mixed with a binder, ground and mixed uniformly, and pressed into briquettes;
2) In the thermal curing step 2, the compacted block is heated by the thermal oxidation tail gas from the combustion pre-oxidation step 4 to obtain a cured block;
3) In the crushing and screening process 3, the solidified material is crushed and screened to obtain coarse particles meeting the requirement of high-temperature fluidization reduction, and the rest fine powder is returned to the mixed briquetting process 1 for recycling;
4) In the combustion pre-oxidation process 4, air is introduced to fully combust the reduction tail gas from the fluidized reduction process 5, the coarse-particle mineral powder is preheated and oxidized to obtain thermal oxide ore and thermal oxidation tail gas, and the thermal oxidation tail gas is sent to the thermal solidification process 2;
5) In the fluidized reduction process 5, the thermal oxide ore is reduced by hot reduction gas from the heat exchange process 6, and simultaneously supplementary air is introduced for combustion and heat supplement to obtain thermal reduction ore and reduction tail gas, and the reduction tail gas is sent to the combustion pre-oxidation process 4;
6) In the heat exchange process 6, the hot reducing ore exchanges heat with the reducing gas to obtain cold reducing ore and hot reducing gas, and the hot reducing gas is sent to the fluidized reduction process 5;
7) In the separation process 7, the cold reduced ore is separated to obtain reduced iron powder and a vanadium-rich titanium material.
The vanadium titano-magnetite fine powder contains 40-70% of total iron and TiO 2 The content is 5-20%, and the particle size of the vanadium titano-magnetite fine powder is less than 0.1mm.
In the mixed briquetting process 1, the mixing method of the mineral powder and the binder is grinding and mixing. The mixture is formed by pressing, wherein the pressure is 0.2-20MPa. The binder is one or a combination of more of water glass, bentonite, cement, biomass, humic acid, lime, starch and polyvinyl alcohol. The addition mass of the binder is 0.5-10% of the mass of the fine mineral powder.
In the heat curing process 2, the curing temperature is 20-300 ℃, and the curing time is 1-10h.
In the crushing and screening process 3, the screening particle size of the coarse mineral powder is controlled to be 0.1-5 mm.
In the combustion pre-oxidation procedure 4, the oxidation temperature is 600-800 ℃, the oxidation time is 0.5-2h, and the oxidation pressure is 0.1-1MPa.
In the fluidized reduction procedure 5, the reduction temperature is 600-800 ℃, the reduction time is 0.5-2h, and the reduction pressure is 0.1-1MPa.
In the heat exchange step 6, the reducing gas is a coal gas or a reformed gas, and H is used as the reducing gas 2 And CO as effective components.
Compared with the prior art, the invention has the following outstanding advantages:
(1) According to the invention, the vanadium titano-magnetite fine powder smaller than 0.1mm is mixed with the binder for granulation to obtain coarse particles of 0.1-5mm for high-temperature fluidized reduction, so that the high-temperature reduction fluidization quality is obviously improved, the fluid loss is effectively inhibited, and the high-efficiency reduction of the vanadium titano-magnetite fine powder smaller than 0.1mm is realized;
(2) According to the invention, the vanadium titano-magnetite is preheated and oxidized by combustion of the reduction tail gas, so that the gas utilization rate and the reduction rate are improved;
(3) According to the invention, the heat recovery and utilization method of waste heat such as heat is provided for the thermal curing process by the thermal reduction ore and the reducing gas through heat exchange, and the thermal oxidation tail gas improves the energy utilization rate of the system.
Drawings
FIG. 1 is a flow chart of the method for the high-efficiency fluidized reduction of vanadium titano-magnetite fine powder according to the present invention;
FIG. 2 is a diagram showing the change of metallization ratio with time in high-temperature fluidized reduction of vanadium titano-magnetite fine powder with a size of less than 0.1mm and a modified material obtained by the method of example 2;
FIG. 3 is a diagram showing the change of metallization ratio with time in high-temperature fluidized reduction of vanadium titano-magnetite fine powder with a size of less than 0.1mm and a modified material obtained by the method of example 3;
FIG. 4 is a graph showing the change of metallization ratio with time in high-temperature fluidized reduction of vanadium titano-magnetite fine powder with a size of less than 0.1mm and the modified material obtained by the method described in example 4.
Detailed Description
The invention is explained in further detail below with reference to the figures and the description of embodiments.
Example 1
As shown in fig. 1, the method for high-efficiency fluidized reduction of vanadium titano-magnetite fine powder comprises a mixed briquetting process 1, a thermosetting process 2, a crushing and screening process 3, a combustion pre-oxidation process 4, a fluidized reduction process 5, a heat exchange process 6 and a separation process 7, and specifically comprises the following steps:
1) In the mixed briquetting process 1, vanadium titano-magnetite fine powder and/or fine powder from the crushing and screening process 3 are mixed with a binder, ground and mixed uniformly, and pressed into briquettes;
2) In the thermosetting step 2, the compacted block is heated by the thermal oxidation tail gas from the combustion pre-oxidation step 4 to obtain a solidified material;
3) In the crushing and screening process 3, the solidified material is crushed and screened to obtain coarse particles meeting the requirement of high-temperature fluidization reduction, and the rest fine powder is returned to the mixed briquetting process 1 for recycling;
4) In the combustion pre-oxidation process 4, air is introduced to fully combust the reduction tail gas from the fluidized reduction process 5, the coarse-particle mineral powder is preheated and oxidized to obtain thermal oxide ore and thermal oxidation tail gas, and the thermal oxidation tail gas is sent to the thermal solidification process 2;
5) In the fluidized reduction process 5, the thermal oxide ore is reduced by hot reduction gas from the heat exchange process 6, and simultaneously, supplementary air is introduced for combustion and heat supplement to obtain thermal reduction ore and reduction tail gas, and the reduction tail gas is sent to the combustion pre-oxidation process 4.
6) In the heat exchange step 6, the hot reducing ore exchanges heat with the reducing gas to obtain cold reducing ore and hot reducing gas, and the hot reducing gas is sent to the fluidized reduction step 5.
7) In the separation process 7, the cold reduced ore is separated to obtain reduced iron powder and vanadium-rich titanium materials.
Example 2
This example uses the high efficiency fluidized reduction method of vanadium titano-magnetite fine powder described in example 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 40%, tiO) with the particle size of less than 0.1mm is mixed 2 Content about 20%) is added with 2% of water glass, the mixture is ground, mixed evenly and pressed into blocks under 0.2MPa, and then the blocks are placed at 300 ℃ for curing for 1 hour to obtain the curing material. Crushing and screening the solidified material to obtain coarse particles of 0.1-5mm, and oxidizing in the air at 600 ℃ for 2h under the oxidation pressure of 1MPa to obtain the thermal oxide ore. And placing the thermal oxide ore in reducing gas at 600 ℃ for fluidized reduction for 2h, wherein the reduction pressure is 1MPa, so as to obtain the thermal reduction ore. And the reduced iron powder and the vanadium-rich titanium material can be obtained after heat exchange and separation of the hot reduced ore. As shown in figure 2, the metallization rate of the vanadium titano-magnetite fine powder with the thickness less than 0.1mm and the modified material of the method of the invention changes with time in high-temperature fluidization reduction. The vanadium titano-magnetite fine powder with the particle size less than 0.1mm can not be normally fluidized and reduced under the experimental condition, but the modified material of the method of the invention canThe mixture is stably fluidized and reduced for 2 hours until the metallization rate is about 90 percent. In addition, the fluidized reduction rate of the modified material of the method is obviously higher than that of the vanadium titano-magnetite fine powder with the particle size of less than 0.1mm.
Example 3
In this example, the method of high-efficiency fluidized reduction of vanadium titano-magnetite fine powder described in example 1 was used. Firstly, vanadium titano-magnetite fine powder (total iron content about 70%, tiO) with the particle size of less than 0.1mm is ground 2 Content about 5%) is added with 10% humic acid, and the mixture is ground, mixed evenly and pressed into blocks under 20MPa, and then is cured for 2h at 200 ℃ to obtain the cured material. Crushing and screening the solidified material to obtain coarse particles of 0.1-5mm, and oxidizing in the air at 800 ℃ for 0.5h under the oxidizing pressure of 0.1MPa to obtain the thermal oxide ore. And (3) placing the thermal-oxidized ore in reducing gas at 800 ℃ for fluidization reduction for 0.5h, wherein the reduction pressure is 0.1MPa, so as to obtain the thermal-reduced ore. And the reduced iron powder and the vanadium-rich titanium material can be obtained after heat exchange and separation of the hot reduced ore. As shown in figure 3, the metallization rate of the vanadium titano-magnetite fine powder with the thickness less than 0.1mm and the modified material of the method of the invention changes with time in high-temperature fluidization reduction. The vanadium titano-magnetite fine powder with the diameter less than 0.1mm can not be normally fluidized and reduced under the experimental condition, and the modified material of the method can be stably fluidized and reduced for 0.5h to about 88 percent of metallization rate. In addition, the fluidized reduction rate of the modified material of the method is obviously higher than that of the vanadium titano-magnetite fine powder with the particle size of less than 0.1mm.
Example 4
In this example, the method of high-efficiency fluidized reduction of vanadium titano-magnetite fine powder described in example 1 was used. Firstly, vanadium titano-magnetite fine powder (total iron content about 62%, tiO) with the particle size of less than 0.1mm is mixed 2 Content about 15%) and the fine powder from the crushing and screening process 3, 0.5% of cement is added, the mixture is ground and uniformly mixed, the mixture is pressed into blocks under 10MPa, and the blocks are solidified for 10 hours at 20 ℃ to obtain the solidified material. Crushing and screening the solidified material to obtain coarse particles of 0.1-5mm, and oxidizing in the air at 700 ℃ for 1h under the oxidizing pressure of 0.5MPa to obtain the thermal oxide ore. And placing the hot oxidized ore in reducing gas at 700 ℃ for fluidization reduction for 1.5h, wherein the reduction pressure is 0.8MPa, and obtaining the hot reduced ore. Heat exchange of hot reduced oreAnd separating to obtain reduced iron powder and vanadium-rich titanium material. As shown in FIG. 4, the metallization ratio of the vanadium titano-magnetite fine powder with a diameter of less than 0.1mm and the modified material obtained by the method of the present invention changes with time in high-temperature fluidized reduction. The vanadium titano-magnetite fine powder with the diameter less than 0.1mm can not be subjected to normal fluidized reduction under experimental conditions, and the modified material prepared by the method can be stably subjected to fluidized reduction for 1.5 hours until the metallization rate is about 91%. In addition, the fluidized reduction rate of the modified material of the method is obviously higher than that of the vanadium titano-magnetite fine powder with the particle size of less than 0.1mm.
Example 5
This example uses the high efficiency fluidized reduction method of vanadium titano-magnetite fine powder described in example 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 53%, tiO) with the particle size of less than 0.1mm is mixed 2 Content about 12%) is added with 5% of bentonite, the mixture is ground and mixed evenly and pressed into blocks under 15MPa, and then the blocks are solidified for 5 hours at 250 ℃ to obtain solidified materials. Crushing and screening the solidified material to obtain coarse particles of 0.1-5mm, and oxidizing in the air at 600 ℃ for 1h under the oxidizing pressure of 0.1MPa to obtain the thermal oxide ore. And placing the thermal-oxidized ore in reducing gas at 800 ℃ for fluidization reduction for 1h, wherein the reduction pressure is 0.5MPa, and obtaining the thermal-reduced ore. And the reduced iron powder and the vanadium-rich titanium material can be obtained after heat exchange and separation of the hot reduced ore.
Example 6
This example uses the high efficiency fluidized reduction method of vanadium titano-magnetite fine powder described in example 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 45%, tiO) with the particle size of less than 0.1mm is ground 2 Content of about 15 percent) is added with 10 percent of biomass (treated by alkali liquor), the mixture is ground and mixed evenly and pressed into blocks under 15MPa, and then the blocks are solidified for 3 hours at 90 ℃ to obtain the solidified material. Crushing and screening the solidified material to obtain coarse particles with the particle size of 0.1-5mm, and oxidizing the coarse particles in air at 640 ℃ for 0.8h under the oxidation pressure of 0.3MPa to obtain the thermal oxide ore. And placing the thermal oxide ore in reducing gas at 780 ℃ for fluidized reduction for 0.5h, wherein the reduction pressure is 0.8MPa, and obtaining the thermal reduction ore. And the reduced iron powder and the vanadium-rich titanium material can be obtained after heat exchange and separation of the hot reduced ore.
Example 7
This example adoptsThe method for efficiently fluidizing and reducing the vanadium titano-magnetite fine powder is described in example 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 47%, tiO) with the particle size of less than 0.1mm is ground 2 Content about 10%) is added with 7% lime, and the mixture is ground, mixed evenly, pressed into blocks under 5MPa, and then solidified for 4 hours at 50 ℃ to obtain the solidified material. Crushing and screening the solidified material to obtain coarse particles of 0.1-5mm, and oxidizing in air at 680 ℃ for 1h under the oxidation pressure of 0.4MPa to obtain the thermal oxide ore. And (3) placing the thermal-oxidized ore in reducing gas at 730 ℃ for fluidized reduction for 1.2h, wherein the reduction pressure is 0.6MPa, so as to obtain the thermal-reduced ore. The heat-reduced ore can obtain reduced iron powder and vanadium-rich titanium materials after heat exchange and separation.
Example 8
In this example, the method of high-efficiency fluidized reduction of vanadium titano-magnetite fine powder described in example 1 was used. Firstly, vanadium titano-magnetite fine powder (total iron content about 53%, tiO) with the particle size of less than 0.1mm is mixed 2 Content about 14%) is added with 5% of starch, the mixture is ground, mixed evenly and pressed into blocks under 3MPa, and then the blocks are placed at 180 ℃ for curing for 6 hours to obtain the cured material. Crushing and screening the solidified material to obtain coarse particles with the particle size of 0.1-5mm, and oxidizing the coarse particles in the air at 660 ℃ for 1.5 hours under the oxidation pressure of 0.1MPa to obtain the thermal oxide ore. And placing the thermal-oxidized ore in reducing gas at 800 ℃ for fluidization reduction for 1.8h, wherein the reduction pressure is 0.3MPa, and obtaining the thermal-reduced ore. And the reduced iron powder and the vanadium-rich titanium material can be obtained after heat exchange and separation of the hot reduced ore.
Example 9
This example uses the high efficiency fluidized reduction method of vanadium titano-magnetite fine powder described in example 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 63%, tiO) with the particle size of less than 0.1mm is ground 2 The content is about 8 percent), 7 percent of polyvinyl alcohol is added, the mixture is ground and mixed evenly and pressed into blocks under 8MPa, and then the blocks are placed at 130 ℃ for curing for 3 hours to obtain the curing material. Crushing and screening the solidified material to obtain coarse particles of 0.1-5mm, and oxidizing in the air at 600 ℃ for 0.8h under the oxidizing pressure of 0.7MPa to obtain the thermal oxide ore. And placing the thermal oxide ore in reducing gas at 800 ℃ for fluidization reduction for 1.7h, wherein the reduction pressure is 0.2MPa, and obtaining the thermal reduction ore. And the reduced iron powder and the vanadium-rich titanium material can be obtained after heat exchange and separation of the hot reduced ore.
In the present invention,% is not specified, and is a mass percentage content.
The method can be realized by upper and lower limit values of intervals of process parameters (such as temperature, time and the like) and interval values, and embodiments are not listed.
Conventional technical knowledge in the art can be used for the details which are not described in the present invention.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (7)
1. The method for efficiently fluidizing and reducing the vanadium titano-magnetite fine powder comprises a mixed briquetting process (1), a thermocuring process (2), a crushing and screening process (3), a combustion pre-oxidation process (4), a fluidizing and reducing process (5), a heat exchange process (6) and a separation process (7), and specifically comprises the following steps:
1) In the mixed briquetting process (1), vanadium titano-magnetite fine powder with the grain size of less than 0.1mm and/or fine powder from the crushing and screening process (3) are mixed with a binder, ground, mixed uniformly and pressed into briquettes;
2) In the thermal curing process (2), the pressed lump material is heated to 20-300 ℃ by the thermal oxidation tail gas from the combustion pre-oxidation process (4) to obtain a cured material;
3) In the crushing and screening process (3), the solidified material is crushed and screened to obtain coarse-particle mineral powder with the particle size of 0.1-5mm, and the rest fine powder is returned to the mixed briquetting process (1) for recycling;
4) In the combustion pre-oxidation process (4), air is introduced to fully combust the reduction tail gas from the fluidized reduction process (5), the coarse-grained mineral powder is preheated and oxidized at the temperature of 600-800 ℃ to obtain thermal oxide ore and thermal oxidation tail gas, and the thermal oxidation tail gas is sent to the thermal solidification process (2);
5) In the fluidized reduction process (5), the thermal oxide ore is reduced at 600-800 ℃ by hot reducing gas from the heat exchange process (6), and simultaneously supplementary air is introduced for combustion and heat supplement to obtain thermal reduction ore and reduction tail gas, and the reduction tail gas is sent to the combustion pre-oxidation process (4);
6) In the heat exchange process (6), the hot reducing ore exchanges heat with the reducing gas to obtain cold reducing ore and hot reducing gas, and the hot reducing gas is sent to the fluidized reduction process (5);
7) In the separation process (7), the cold reduced ore is separated to obtain reduced iron powder and a vanadium-rich titanium material.
2. The method of claim 1, wherein the vanadium titano-magnetite fine powder is prepared by high-efficiency fluidized reduction of 40-70% total iron and TiO 2 The content is 5-20%.
3. The method for the high-efficiency fluidized reduction of vanadium titano-magnetite fine powder according to claim 1 or 2, characterized in that in the mixed briquetting process (1), the mixing method of the mineral powder and the binder is grinding and mixing; the mixture is formed by pressing, wherein the pressure is 0.2-20MPa; the binder is one or a combination of more of water glass, bentonite, cement, biomass, humic acid, lime, starch and polyvinyl alcohol; the addition mass of the binder is 0.5-10% of the mass of the fine mineral powder.
4. The method for the high-efficiency fluidized reduction of vanadium titano-magnetite fine powder according to any one of claims 1 to 3, characterized in that in the heat curing process (2), the curing time is 1 to 10 hours.
5. The method for the high-efficiency fluidized reduction of vanadium titano-magnetite fine powder according to any one of claims 1 to 4, characterized in that in the combustion pre-oxidation process (4), the oxidation time is 0.5 to 2h and the oxidation pressure is 0.1 to 1MPa.
6. The method for the high-efficiency fluidized reduction of vanadium titano-magnetite fine powder according to any one of claims 1 to 5, characterized in that in the fluidized reduction process (5), the reduction time is 0.5 to 2 hours and the reduction pressure is 0.1 to 1MPa.
7. The method for the high-efficiency fluidized reduction of vanadium titano-magnetite fine powder according to any one of claims 1 to 6, characterized in that in the heat exchange process (6), the reducing gas is coal gas or reformed gas, and H is used as H 2 And CO as effective components.
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