CN115341061B - 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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- 238000000034 method Methods 0.000 title claims abstract description 110
- 239000000843 powder Substances 0.000 title claims abstract description 96
- 229910052720 vanadium Inorganic materials 0.000 title claims abstract description 70
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 title claims abstract description 70
- 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 64
- 230000009467 reduction Effects 0.000 claims abstract description 96
- 230000008569 process Effects 0.000 claims abstract description 59
- 238000005243 fluidization Methods 0.000 claims abstract description 53
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 46
- 230000003647 oxidation Effects 0.000 claims abstract description 40
- 239000011230 binding agent Substances 0.000 claims abstract description 11
- 238000013007 heat curing Methods 0.000 claims abstract description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 57
- 239000000463 material Substances 0.000 claims description 46
- 239000011362 coarse particle Substances 0.000 claims description 23
- 229910052742 iron Inorganic materials 0.000 claims description 22
- 238000012216 screening Methods 0.000 claims description 22
- 239000002245 particle Substances 0.000 claims description 19
- 238000002156 mixing Methods 0.000 claims description 16
- 238000002485 combustion reaction Methods 0.000 claims description 15
- 238000000926 separation method Methods 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 12
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 11
- 239000011707 mineral Substances 0.000 claims description 11
- GFNGCDBZVSLSFT-UHFFFAOYSA-N titanium vanadium Chemical compound [Ti].[V] GFNGCDBZVSLSFT-UHFFFAOYSA-N 0.000 claims description 11
- 238000011946 reduction process Methods 0.000 claims description 10
- 238000001723 curing Methods 0.000 claims description 6
- 238000000227 grinding Methods 0.000 claims description 6
- 238000004064 recycling Methods 0.000 claims description 5
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 4
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 4
- 239000004568 cement Substances 0.000 claims description 4
- 239000004571 lime Substances 0.000 claims description 4
- 238000001029 thermal curing Methods 0.000 claims description 4
- 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
- 239000002028 Biomass Substances 0.000 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- 229920002472 Starch Polymers 0.000 claims description 3
- 239000000440 bentonite Substances 0.000 claims description 3
- 229910000278 bentonite Inorganic materials 0.000 claims description 3
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 3
- 239000004021 humic acid Substances 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 235000019422 polyvinyl alcohol Nutrition 0.000 claims description 3
- 238000003825 pressing Methods 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
- 239000008107 starch Substances 0.000 claims description 3
- 235000019698 starch Nutrition 0.000 claims description 3
- 239000013589 supplement Substances 0.000 claims description 3
- 239000004115 Sodium Silicate Substances 0.000 claims description 2
- 239000004480 active ingredient Substances 0.000 claims description 2
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims 1
- 230000001590 oxidative effect Effects 0.000 claims 1
- 230000008901 benefit Effects 0.000 abstract description 7
- 238000006243 chemical reaction Methods 0.000 abstract description 5
- 239000000126 substance Substances 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 238000005469 granulation Methods 0.000 abstract description 2
- 230000003179 granulation Effects 0.000 abstract description 2
- 238000005272 metallurgy Methods 0.000 abstract description 2
- 238000012986 modification Methods 0.000 abstract description 2
- 230000004048 modification Effects 0.000 abstract description 2
- 238000006722 reduction reaction Methods 0.000 description 84
- 239000007789 gas Substances 0.000 description 50
- 238000003723 Smelting Methods 0.000 description 14
- 238000001465 metallisation Methods 0.000 description 11
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 8
- 239000010936 titanium Substances 0.000 description 8
- 229910052719 titanium Inorganic materials 0.000 description 8
- 239000003245 coal Substances 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 239000008188 pellet Substances 0.000 description 5
- 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 4
- 238000005265 energy consumption Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000002893 slag Substances 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 230000036962 time dependent Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000005587 bubbling Effects 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000004939 coking Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000002407 reforming Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000000629 steam reforming Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Classifications
-
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacture And Refinement Of Metals (AREA)
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. According to the method, the vanadium titano-magnetite fine powder smaller than 0.1mm is added with the binder for granulation modification, so that the high-temperature reduction fluidization quality of the vanadium titano-magnetite fine powder is improved, the bonding loss is prevented, and the purpose of efficient reduction is achieved; the reduction tail gas is combusted, preheated and oxidized to form vanadium titano-magnetite, so that the gas utilization rate and the reduction rate are improved; the heat is provided for the heat curing process by the thermal oxidation tail gas through heat exchange between the thermal reduction ore and the reducing gas, so that 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 and social benefits.
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
As important rare resources and strategic substances, vanadium and titanium have very wide application, and about 98% of vanadium and 91% of titanium in the whole world are endowed in vanadium titano-magnetite, so that the vanadium titano-magnetite has very high comprehensive utilization value.
In the current process for treating vanadium titano-magnetite, the blast furnace method for smelting vanadium titano-magnetite is dominant due to high technical maturity, however, the blast furnace smelting is extremely dependent on metallurgical coke, the environmental pollution is large, and along with the shortage of coking coal resources, the cost of the blast furnace smelting is gradually increased. In addition, vanadium in the vanadium titano-magnetite smelted by the blast furnace method can enter molten iron in a most selective way, vanadium is extracted by a converter and is well recycled, titanium enters blast furnace slag, the titanium-containing phase in the slag is complex, the particle size distribution is fine, and the titanium resource is difficult to recycle. In order to get rid of the restriction of coking coal resource shortage on vanadium titano-magnetite smelting development, and adapt to the increasingly-improved environmental protection requirements, a non-blast furnace smelting technology has become one of research hotspots of vanadium titano-magnetite smelting. Non-blast furnace smelting techniques mainly include direct reduction and melt reduction. The smelting reduction is a method for smelting liquid pig iron without a blast furnace, and compared with the blast furnace, the smelting reduction only uses coal to replace coke, and the product is similar to the blast furnace, so that the problem of difficult recycling of titanium resources also exists.
Compared with blast furnaces and smelting reduction, the direct reduction method for smelting vanadium titano-magnetite can reduce and produce sponge iron and vanadium-containing titanium slag at a temperature lower than the melting temperature of iron ore, so that the energy consumption is lower, and gangue components in the ore are not melted for slag making, thereby being beneficial to recycling vanadium and titanium resources. Direct reduction methods can be classified into coal-based and gas-based methods according to the reducing agent. The coal-based reduction mainly uses a rotary kiln and a rotary hearth furnace as reactors, and the gas-based reduction mainly uses a shaft furnace and a fluidized bed. Compared with coal-based reduction, 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, along with the shortage of high-grade high-quality lump ore resources, the preparation of the pellet ore gradually becomes an essential link for smelting the shaft furnace, the preparation process of the pellet ore needs to be subjected to the steps of pelletizing, green pellet screening, drying and preheating, roasting and solidifying, cooling and screening and the like, the operation is complex, wherein the roasting and solidifying step is usually carried out at about 1250 ℃, and the energy consumption is high. Compared with a shaft furnace, the fluidized bed omits a pellet ore preparation link, can directly process the powder ore, has the advantages of high mass transfer and heat transfer efficiency between gas and solid phases, high reduction rate and the like, and is a vanadium titano-magnetite smelting technology with great development prospect. Over the past several decades, fluidized iron making has evolved significantly, and typical fluidized direct reduction iron making processes include the FIOR process, the FINMET process, the circore process, and the like.
The FIOR process was developed by the Exxon Research and Engineering Company design. Granules and method for producing the sameIron ore powder with the temperature less than 5mm sequentially passes through 4 fluidized bed reactors, the primary fluidized bed preheats the ore powder to 760 ℃, the reduction temperature of the secondary fluidized bed reactor to the quaternary 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 iron ore powder can be hot-pressed into blocks (US 5082251). The fluidization reducing gas is obtained by reforming natural gas steam, H 2 The content exceeds 90%, and the mixture is mixed with purified circulating gas to enter a four-stage fluidized bed reactor, and then the three-stage fluidized bed reactor and the two-stage fluidized bed reactor are in a gas-solid countercurrent state. Proper amounts of non-stick inert powders such as CaO, mgO and the like are added to prevent the loss of flow during the reduction of the iron ore powder in the FIOR process.
The FINMET process was developed by FIOR Venezuela corporation in combination with the Oldhamia (VAI) by the modified FIOR method. Iron ore powder with the granularity smaller than 12.7mm sequentially passes through 4 fluidized bed reactors connected in series and flows reversely with fluidization reducing gas. The temperature of the primary fluidized bed reactor is about 550 ℃, the temperature of the secondary fluidized bed reactor is about 800 ℃ and the pressure is 1.1-1.4MPa, and the temperature of the secondary fluidized bed reactor is gradually increased downwards. The metallization rate of the fourth-stage fluidized bed outlet product reaches 93%, and C is about 0.5-3% (US 5833734). The fluidized reducing gas consists of fresh gas and recycle gas obtained after natural gas steam reforming, and is heated to 850 ℃ before entering the four-stage reactor. In order to avoid cohesive failure, raw materials used in the FINMET process mainly comprise coarse ore powder which is not easy to adhere, the content of fine ore powder (granularity is smaller than 0.1 mm) must be controlled within 20%, otherwise inert powder such as CaO, mgO and the like needs to be added.
The CIRCORED process was developed by Ottotai, germany (Oulotec, original Lurgi Metallurgie, lurgi Metallurgical Co.) based on the gas-based rapid direct reduction technology of iron ore fines. The reduction system consisted of a primary Circulating Fluidized Bed (CFB) and a secondary bubbling Fluidized Bed (FB) (US 5527379, US 5603748). The CFB reactor used in the 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 the FB reactor of 7.0m, the total length of 17.5m and four material chambers inside. Fluidization of the reducing gas to pure H 2 . The reduction temperature of the primary fast fluidized bed is 630-650 ℃, the reduction temperature of the secondary bubbling fluidized bed is about 680 ℃, and the pressure is 0.4MPa. The obtained reduced iron powder can be hot-pressed into blocks or directly used for powder metallurgy. Acting asThe method is the only commercialized hydrogen direct reduction technology in the world, in order to avoid cohesive failure in the fluidization reduction process of the iron ore powder, the reduction temperature in the CIRCORED process is controlled below 680 ℃, and the iron ore powder which is not easy to adhere is selected as the raw material about 1mm.
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 direct reduction of the iron ore gas base, the dynamic process can be described by an unreacted nuclear model (a shrinking nuclear model), and the relation 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 can be known, so that the smaller the particles, the shorter the required complete conversion time, namely the faster the reduction reaction rate. From the gas-solid fluidization theory, it is known that the initial fluidization velocity of particles is proportional to the square of the particle size, i.e., the smaller the particles, the less gas is required to maintain the fluidized state. Therefore, in theory, the finer raw mineral powder is more beneficial to fluidization direct reduction, however, the existing fluidization direct reduction ironmaking process is only suitable for treating coarse mineral powder which is not easy to adhere, or inert substances are needed to be added to inhibit the loss flow of fine mineral powder, which can have larger influence on fluidization reduction efficiency, and the advantages of fluidization high-efficiency reduction can not be fully exerted. This is mainly because fine ore fines (less than 0.1 mm) are extremely prone to binding during fluidized reduction at high temperatures (above 600 c), form agglomerates of larger particle size and deposit on the bottom of the fluidized bed, eventually leading to lost flow throughout the bed. Once the lost flow occurs, the reduction system will have to be stopped, which will cause a significant loss of production (Komatina M, gubenau H w. Metalugija, 2004, 10 (204): 309-328).
Therefore, through technological innovation, the high-temperature reduction fluidization quality of 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 vanadium titano-magnetite in China.
Disclosure of Invention
Aiming at the problems existing 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 simple process, environment friendliness, high resource utilization rate, energy utilization rate and reaction efficiency, and has good economic and social benefits.
To achieve the purpose, the invention adopts the following technical scheme:
the method comprises a mixing briquetting process 1, a heat curing 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 of:
1) In the mixing and briquetting process 1, vanadium titano-magnetite fine powder and/or fine powder from the crushing and screening process 3 are added with a binder, and are evenly mixed by grinding, and are pressed into blocks;
2) In the heat curing process 2, the pressed block is heated by the thermal oxidation tail gas from the combustion pre-oxidation process 4 to obtain a cured material;
3) In the crushing and screening step 3, the solidified material is crushed and screened to obtain coarse particles meeting the high-temperature fluidization reduction requirement, and the rest fine powder is returned to the mixing and briquetting step 1 for recycling;
4) In the combustion pre-oxidation step 4, air is introduced to fully burn the reduction tail gas from the fluidization reduction step 5, the coarse particle mineral powder is preheated and oxidized to obtain thermal oxidation ore and thermal oxidation tail gas, and the thermal oxidation tail gas is sent to the thermal curing step 2;
5) In the fluidized reduction process 5, the hot oxidized ore is reduced by hot reducing gas from the heat exchange process 6, and supplementary air is introduced to burn and supplement heat at the same time, so that hot reduced ore and reduced tail gas are obtained, and the reduced tail gas is sent to the combustion pre-oxidation process 4;
6) In the heat exchange process 6, heat exchange is carried out between the hot reducing ore and the reducing gas to obtain cold reducing ore and hot reducing gas, and the hot reducing gas is sent to the fluidization reduction process 5;
7) In the separation process 7, the cold reduced ore is separated to obtain reduced iron powder and vanadium-titanium-rich material.
The content of total iron in the vanadium titano-magnetite fine powder is 40-70%, tiO 2 The content is 5-20%, and the grain diameter of the vanadium titano-magnetite fine powder is less than 0.1mm.
In the mixing and briquetting step 1, the mixing method of mineral powder and 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 a plurality of sodium silicate, 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 ore powder is controlled to be 0.1-5 mm.
In the combustion pre-oxidation step 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 process 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 gas or reformed gas, H 2 And CO as an active ingredient.
Compared with the prior art, the invention has the following outstanding advantages:
(1) According to the invention, the 0.1-5mm coarse particles obtained by adding the binder into the 0.1mm vanadium titano-magnetite fine powder for granulation are used for high-temperature fluidization reduction, so that the high-temperature reduction fluidization quality of the vanadium titano-magnetite fine powder is remarkably improved, the lost flow is effectively inhibited, and the high-efficiency reduction of the 0.1mm vanadium titano-magnetite fine powder is realized;
(2) The method preheats and oxidizes the vanadium titano-magnetite through the combustion of the reduction tail gas, thereby improving the gas utilization rate and the reduction rate;
(3) According to the invention, through heat exchange between the thermal reduction ore and the reducing gas, the waste heat recovery and utilization method for providing heat for the thermal curing process by the thermal oxidation tail gas, and the like, the energy utilization rate of the system is improved.
Drawings
FIG. 1 is a flow chart of a method for efficient fluidization reduction of vanadium titano-magnetite fine powder according to the present invention;
FIG. 2 is a graph showing the time-dependent change of the metallization rate of fine powder of vanadium titano-magnetite smaller than 0.1mm and the modified material of the method described in example 2 in high-temperature fluidization reduction;
FIG. 3 is a graph showing the time-dependent change of the metallization rate of fine powder of vanadium titano-magnetite smaller than 0.1mm and the modified material of the method described in example 3 in high-temperature fluidization reduction;
FIG. 4 shows the time-dependent metallization rate of fine powder of vanadium titano-magnetite smaller than 0.1mm and the modified material of the method described in example 4 in high-temperature fluidization reduction.
Detailed Description
The invention is described in further detail below with reference to the drawings and the detailed description.
Example 1
As shown in fig. 1, the method for efficiently fluidizing and reducing vanadium titano-magnetite fine powder comprises a mixing and briquetting process 1, a heat curing process 2, a crushing and screening process 3, a combustion pre-oxidation process 4, a fluidizing and reducing process 5, a heat exchanging process 6 and a separating process 7, and specifically comprises the following steps:
1) In the mixing and briquetting process 1, vanadium titano-magnetite fine powder and/or fine powder from the crushing and screening process 3 are added with a binder, and are evenly mixed by grinding, and are pressed into blocks;
2) In the heat curing process 2, the pressed block is heated by the thermal oxidation tail gas from the combustion pre-oxidation process 4 to obtain a cured material;
3) In the crushing and screening step 3, the solidified material is crushed and screened to obtain coarse particles meeting the high-temperature fluidization reduction requirement, and the rest fine powder is returned to the mixing and briquetting step 1 for recycling;
4) In the combustion pre-oxidation step 4, air is introduced to fully burn the reduction tail gas from the fluidization reduction step 5, the coarse particle mineral powder is preheated and oxidized to obtain thermal oxidation ore and thermal oxidation tail gas, and the thermal oxidation tail gas is sent to the thermal curing step 2;
5) In the fluidized reduction process 5, the hot oxidized ore is reduced by hot reducing gas from the heat exchange process 6, and supplementary air is introduced to burn and supplement heat at the same time, so that hot reduced ore and reduced tail gas are obtained, and the reduced 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 fluidization reduction step 5.
7) In the separation process 7, the cold reduced ore is separated to obtain reduced iron powder and vanadium-titanium-rich material.
Example 2
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 40% and TiO) with particle size smaller than 0.1mm is prepared 2 About 20 percent of water glass with the content of 2 percent is added, and the mixture is ground, mixed uniformly, pressed into blocks under the pressure of 0.2MPa, and then is cured for 1 hour at the temperature of 300 ℃ to obtain the cured material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 600 ℃ for oxidation for 2 hours under the oxidation pressure of 1MPa to obtain the thermally oxidized ore. And (3) placing the thermal oxide ore into reducing gas at 600 ℃ for fluidization reduction for 2 hours, wherein the reduction pressure is 1MPa, and obtaining the thermal oxide ore. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material. As shown in figure 2, the change rule of the metallization rate of the vanadium titano-magnetite fine powder smaller than 0.1mm and the modified material of the method in the invention in high-temperature fluidization reduction with time. Vanadium titano-magnetite fine powder smaller than 0.1mm can not be normally fluidized-reduced under experimental conditions, and the modified material of the method can be stably fluidized-reduced for 2 hours to about 90% of metallization rate. In addition, the fluidization reduction rate of the modified material of the method is obviously higher than that of vanadium titano-magnetite fine powder smaller than 0.1mm.
Example 3
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 70% and TiO) with particle size smaller than 0.1mm is prepared 2 About 5 percent of humic acid with the content of 10 percent is added, and the mixture is ground, mixed uniformly, pressed into blocks under 20MPa, and then is cured for 2 hours at 200 ℃ to obtain the curing material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 800 ℃ for oxidation for 0.5h under the oxidation pressure of 0.1MPa to obtain the thermally oxidized ore. The thermally oxidized ore is placed in reducing gas at 800 ℃ for fluidization reduction for 0.5h, andthe original pressure is 0.1MPa, and the thermal reduction ore is obtained. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material. As shown in figure 3, the change rule of the metallization rate of the vanadium titano-magnetite fine powder smaller than 0.1mm and the modified material of the method in the invention in high-temperature fluidization reduction with time. Vanadium titano-magnetite fine powder smaller than 0.1mm can not be normally fluidized-reduced under experimental conditions, and the modified material of the method can be stably fluidized-reduced for 0.5h to about 88% of metallization rate. In addition, the fluidization reduction rate of the modified material of the method is obviously higher than that of vanadium titano-magnetite fine powder smaller than 0.1mm.
Example 4
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 62% and TiO) with particle size smaller than 0.1mm is prepared 2 About 15% of the content of the cement) and the fine powder from the crushing and screening step 3 are added with 0.5% of cement, and the mixture is ground, uniformly mixed, pressed into blocks under 10MPa, and then cured for 10 hours at 20 ℃ to obtain a cured material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 700 ℃ for oxidization for 1h under the oxidization pressure of 0.5MPa to obtain the thermally oxidized ore. And (3) placing the thermal oxide ore into reducing gas at 700 ℃ for fluidization reduction for 1.5 hours, wherein the reduction pressure is 0.8MPa, and obtaining the thermal oxide ore. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material. As shown in FIG. 4, the change rule of the metallization rate of the vanadium titano-magnetite fine powder smaller than 0.1mm and the modified material of the method in the invention in high-temperature fluidization reduction with time. Vanadium titano-magnetite fine powder smaller than 0.1mm can not be normally fluidized-reduced under experimental conditions, and the modified material of the method can be stably fluidized-reduced for 1.5h to about 91% of metallization rate. In addition, the fluidization reduction rate of the modified material of the method is obviously higher than that of vanadium titano-magnetite fine powder smaller than 0.1mm.
Example 5
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (the total iron content is about 53% and TiO is prepared) with the particle size smaller than 0.1mm 2 Content ofAbout 12 percent) adding 5 percent bentonite, grinding, mixing uniformly, pressing into blocks under 15MPa, and curing for 5 hours at 250 ℃ to obtain the curing material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 600 ℃ for oxidization for 1h under the oxidization pressure of 0.1MPa to obtain the thermally oxidized ore. And (3) placing the thermal oxide ore into reducing gas at 800 ℃ for fluidization reduction for 1h, wherein the reduction pressure is 0.5MPa, and obtaining the thermal oxide ore. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material.
Example 6
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (the total iron content is about 45% and TiO is less than 0.1mm in particle size) 2 The content of about 15 percent) is added with 10 percent of biomass (treated by alkali liquor), and the mixture is ground and mixed uniformly, pressed into blocks under 15MPa, and then is cured for 3 hours at 90 ℃ to obtain the cured material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 640 ℃ for oxidation for 0.8h under the oxidation pressure of 0.3MPa to obtain the thermally oxidized ore. And (3) placing the thermal oxide ore into reducing gas at 780 ℃ for fluidization reduction for 0.5h, wherein the reduction pressure is 0.8MPa, and obtaining the thermal oxide ore. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material.
Example 7
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 47% and TiO) with particle size smaller than 0.1mm is prepared 2 About 10 percent of the content of the lime is added with 7 percent of lime, the mixture is ground and mixed uniformly, the mixture is pressed into blocks under 5MPa, and the blocks are cured for 4 hours at 50 ℃ to obtain the cured material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 680 ℃ for oxidation for 1h under the oxidation pressure of 0.4MPa to obtain the thermally oxidized ore. And (3) placing the thermal oxide ore into reducing gas at 730 ℃ for fluidization reduction for 1.2 hours, wherein the reduction pressure is 0.6MPa, and obtaining the thermal oxide ore. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material.
Example 8
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder as described in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (the total iron content is about 53% and TiO is prepared) with the particle size smaller than 0.1mm 2 The content of about 14 percent) is added with 5 percent of starch, the mixture is ground and mixed uniformly, the mixture is pressed into blocks under 3MPa, and the blocks are cured for 6 hours at 180 ℃ to obtain the cured material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 660 ℃ for oxidization for 1.5h under the oxidization pressure of 0.1MPa to obtain the thermally oxidized ore. And (3) placing the thermal oxide ore into reducing gas at 800 ℃ for fluidization reduction for 1.8 hours, wherein the reduction pressure is 0.3MPa, and obtaining the thermal oxide ore. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material.
Example 9
The embodiment adopts the method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder in the embodiment 1. Firstly, vanadium titano-magnetite fine powder (total iron content about 63% and TiO) with particle size smaller than 0.1mm is prepared 2 About 8% of polyvinyl alcohol with the content of 7% is added, and the mixture is ground, mixed uniformly, pressed into blocks under 8MPa, and then cured for 3 hours at 130 ℃ to obtain the cured material. Crushing and screening the solidified material to obtain coarse particles with the diameter of 0.1-5mm, and placing the coarse particles in air at 600 ℃ for oxidation for 0.8h under the oxidation pressure of 0.7MPa to obtain the thermally oxidized ore. And (3) placing the thermal oxide ore into reducing gas at 800 ℃ for fluidization reduction for 1.7 hours, wherein the reduction pressure is 0.2MPa, and obtaining the thermal oxide ore. The heat exchange and separation of the hot reduced ore can obtain reduced iron powder and vanadium-titanium-rich material.
The percentages in the invention are not illustrated, and are all mass percent.
The method can be realized by the upper and lower limit values of the interval and the interval value of the process parameters (such as temperature, time and the like), and the examples are not necessarily listed here.
The invention may be practiced without these specific details, using any knowledge known in the art.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the appended claims.
Claims (5)
1. The method comprises a mixing briquetting process (1), a heat curing 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 of:
1) In the mixing and briquetting process (1), vanadium titano-magnetite fine powder with the particle size smaller than 0.1mm and/or fine powder from the crushing and screening process (3) are added with a binder, and are evenly mixed by grinding, and are pressed into blocks; the addition mass of the binder is 0.5-10% of the mass of the fine mineral powder;
2) In the heat curing process (2), heating the pressed block to 20-300 ℃ through 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 mixing and briquetting process (1) for recycling;
4) In the combustion pre-oxidation step (4), introducing air to fully combust the reduction tail gas from the fluidization reduction step (5), preheating and oxidizing coarse particle mineral powder at 600-800 ℃ to obtain thermally oxidized ore and thermally oxidized tail gas, and sending the thermally oxidized tail gas to the thermal curing step (2); in the combustion pre-oxidation step (4), the oxidation time is 0.5-2h, and the oxidation pressure is 0.1-1MPa;
5) In the fluidized reduction process (5), the thermally oxidized ore is reduced at 600-800 ℃ by hot reducing gas from the heat exchange process (6), and supplementary air is introduced to burn and supplement heat at the same time, so that thermally reduced ore and reduced tail gas are obtained, and the reduced tail gas is sent to the combustion pre-oxidation process (4); in the fluidized reduction process (5), the reduction time is 0.5-2h, and the reduction pressure is 0.1-1MPa;
6) In the heat exchange process (6), heat exchange is carried out between the hot reducing ore and the reducing gas to obtain cold reducing ore and hot reducing gas, and the hot reducing gas is sent to the fluidization reduction process (5);
7) In the separation process (7), the cold reduced ore is separated to obtain reduced iron powder and vanadium-titanium-rich material.
2. The method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder according to claim 1, wherein the content of total iron in the vanadium titano-magnetite fine powder is 40-70%, and the content of TiO is 2 The content is 5-20%.
3. The method for high-efficiency fluidization reduction of vanadium titano-magnetite fine powder according to claim 1 or 2, wherein in the mixing and briquetting process (1), the mixing method of mineral powder and 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 a plurality of sodium silicate, bentonite, cement, biomass, humic acid, lime, starch and polyvinyl alcohol.
4. The method for efficient fluidization reduction of fine powder of vanadium titano-magnetite according to claim 1 or 2, wherein the curing time is 1 to 10 hours in the heat curing process (2).
5. The method for efficient fluidized reduction of vanadium titano-magnetite fine powder according to claim 1 or 2, wherein in the heat exchanging step (6), the reducing gas is gas or reformed gas, and H is used as the reducing gas 2 And CO as an active ingredient.
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