CN117431397A - Reduction method of vanadium titanium ore - Google Patents

Reduction method of vanadium titanium ore Download PDF

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CN117431397A
CN117431397A CN202311756699.XA CN202311756699A CN117431397A CN 117431397 A CN117431397 A CN 117431397A CN 202311756699 A CN202311756699 A CN 202311756699A CN 117431397 A CN117431397 A CN 117431397A
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titanium ore
vanadium
vanadium titanium
reduction
reducing
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CN117431397B (en
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唐珏
赵子川
王小艾
冯金格
储满生
刘倬良
李峰
田宏宇
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HBIS Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00Preliminary treatment of ores or scrap
    • C22B1/14Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24Binding; Briquetting ; Granulating
    • C22B1/242Binding; Briquetting ; Granulating with binders
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B13/00Making spongy iron or liquid steel, by direct processes
    • C21B13/0073Selection or treatment of the reducing gases
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B13/00Making spongy iron or liquid steel, by direct processes
    • C21B13/02Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00Preliminary treatment of ores or scrap
    • C22B1/02Roasting processes
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00Preliminary treatment of ores or scrap
    • C22B1/14Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24Binding; Briquetting ; Granulating
    • C22B1/2406Binding; Briquetting ; Granulating pelletizing
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B5/00General methods of reducing to metals
    • C22B5/02Dry methods smelting of sulfides or formation of mattes
    • C22B5/12Dry methods smelting of sulfides or formation of mattes by gases

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
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  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

The invention discloses a method for reducing vanadium titanium ore, which comprises the following steps: pretreatment of raw materials: finely grinding vanadium titanium ore and a binder, and fully drying; preparing green balls: fully mixing pretreated vanadium titanium ore with a binder, stewing, and pelletizing to obtain green pellets; oxidizing and roasting: oxidizing and roasting the green pellets to obtain vanadium-titanium ore oxidized pellets with the strength of 2000-2150N/each vanadium-titanium ore oxidized pellet; direct reduction: and (3) placing the vanadium titanium ore oxidized pellets into a hydrogen-based shaft furnace, and directly reducing under the condition of hydrogen-rich reducing gas to obtain a reduction product. According to the invention, through the cooperative control of raw material pretreatment, green pellet preparation, oxidizing roasting and direct reduction, the metallization rate of the obtained schreyerite metallized pellet product is more than or equal to 94%, and the reduction behavior index meets the production requirement of a hydrogen-based shaft furnace, so that clean utilization of schreyerite resources is realized.

Description

Reduction method of vanadium titanium ore
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to a vanadium-titanium ore reduction method.
Background
The hydrogen-based shaft furnace reduction-electric furnace melting separation process is a non-blast furnace production process different from a long process of a blast furnace-converter, and is a method for reducing iron-containing furnace materials by hydrogen-rich reduction gas under the condition of lower than softening temperature to obtain metallic iron. At present, along with the low-carbon clean hydrogen-based shaft furnace reduction process, the method becomes an important direction of attention of various enterprises, and various possibilities of applying the hydrogen-based shaft furnace process are explored, but compared with the traditional blast furnace process, the hydrogen-based shaft furnace process is high in production cost, and the popularization and application of the hydrogen-based shaft furnace in China are affected.
The vanadium-titanium ore resources in China are rich, the main distribution areas are the Sichuan Panzhihua area, the Hebei Maillard area, the Shanxi Hanzhong area and the like, and not only the iron elements required by steel production are contained in the vanadium-titanium ore resources, but also vanadium, titanium and chromium elements are contained in the vanadium-titanium ore resources, so that the resource cost is lower than that of iron concentrate when the vanadium-titanium ore resources are applied to a hydrogen-based shaft furnace, and other valuable metal elements except metal iron can be obtained through subsequent treatment, and the popularization value of the process is further improved. But during the production process, it was found that due to TiO 2 The problems of low strength of vanadium-titanium ore pellets, poor low-temperature reduction pulverization effect, low reduction rate, low metallization rate of reduction products and the like are solved, and the production and the application of the hydrogen-based shaft furnace are difficult to meet.
In order to improve the strength and the low-temperature reduction degradation performance of the vanadium-titanium ore pellets, methods of prolonging the roasting time and improving the roasting temperature are generally adopted, but the reducibility of the vanadium-titanium ore pellets is further deteriorated, so that technical innovation is necessary for applying the vanadium-titanium magnetite to the production of the hydrogen-based shaft furnace.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art or related art.
To this end, the invention provides a method for the reduction of vanadium titanium ore comprising:
pretreatment of raw materials: finely grinding vanadium titanium ore and a binder;
preparing green balls: fully mixing pretreated vanadium titanium ore with a binder, stewing, and pelletizing to obtain green pellets;
oxidizing and roasting: oxidizing and roasting the green pellets to obtain vanadium titanium ore oxidized pellets with the strength of 2000-2150N/g;
direct reduction: placing the vanadium titanium ore oxidized pellets into a hydrogen-based shaft furnace, and directly reducing under the condition of hydrogen-rich reducing gas to obtain a reduction product;
the performance indexes of the vanadium titanium ore metallized pellet product obtained after the reduction product treatment are as follows: the pellet strength is 2000-2150N/m, the reducibility index is more than 0.04, and the low-temperature reduction degradation LTD is realized +6.3 80% or more, low temperature reduction degradation LTD up More than 60%, and the metallization rate is more than or equal to 94%.
Further, the vanadium titanium ore has the total iron content of not less than 50% and TiO as mass fraction 2 The content is 5% -11%, cr 2 O 3 The content is less than 0.2%, V 2 O 5 The content is less than 1%.
Further, after the pretreatment of the raw materials, the vanadium titanium ore accounts for more than 90 percent under 200 meshes, and the binder accounts for more than 90 percent under 200 meshes.
Further, the braising comprises:
mixing vanadium titanium ore with the mass fraction of 98.2-99.5%, binder with the mass fraction of 0.5-1.8% and water with the total mass of 8-10% of the vanadium titanium ore and the binder, and stewing.
Further, the pelletizing includes:
pelletizing the braised material, wherein the water addition amount is 10% -14% of the mass of the braised material during pelletizing, the pelletizing time is 30-50 min, and the green pellet granularity is 8-14 mm.
Further, the oxidizing roasting is performed at 1150-1230 ℃ for 10-25 min.
Further, the oxidizing roasting further includes:
preheating, wherein the preheating temperature is 850-950 ℃ and the preheating time is 10-20 min.
Further, the direct reduction is carried out at 950-1050 ℃ for 60-110 min.
Further, the direct reduction, the reducing gas component includes: h 2 、CO、N 2 And CO 2 The volume of the reducing gas satisfies: h 2 +CO≥90%,H 2 /CO≥2,2%≤CO 2 ≤6%。
Further, the reduction product treatment includes: and taking out the reduction product, placing the reduction product in a closed container, introducing argon gas, and cooling to room temperature to obtain the vanadium-titanium ore metallized pellet product.
According to the reduction method of the vanadium titanium ore, provided by the invention, through the cooperative control of raw material pretreatment, green pellet preparation, oxidizing roasting and direct reduction, the metallization rate of the obtained vanadium titanium ore metallized pellet product is more than or equal to 94%, the reduction behavior index meets the production requirement of a hydrogen-based shaft furnace, and the clean utilization of the vanadium titanium ore resource is realized.
Drawings
Fig. 1 is a process flow chart of a reduction method of vanadium titanium ore provided in an embodiment of the present application.
Detailed Description
In order to better understand the above technical solutions, the following detailed description of the technical solutions of the present application is provided by specific embodiments.
Referring to fig. 1, an embodiment of the present invention provides a method for reducing vanadium titanium ore, comprising:
pretreatment of raw materials: finely grinding vanadium titanium ore and a binder;
preparing green balls: fully mixing pretreated vanadium titanium ore with a binder, stewing, and pelletizing to obtain green pellets;
oxidizing and roasting: oxidizing and roasting the green pellets to obtain vanadium titanium ore oxidized pellets with the strength of 2000-2150N/g;
direct reduction: placing the vanadium titanium ore oxidized pellets into a hydrogen-based shaft furnace, and directly reducing under the condition of hydrogen-rich reducing gas to obtain a reduction product;
the performance indexes of the vanadium titanium ore metallized pellet product obtained after the reduction product treatment are as follows: the pellet strength of the vanadium-titanium ore metallized pellet product is 2000-2150N/pellet, the reducibility index is more than 0.04, and the low-temperature reduction degradation property LTD is achieved +6.3 80% or more, low temperature reduction degradation LTD up More than 60%, and the metallization rate is more than or equal to 94%.
According to the reduction method of the vanadium titanium ore, provided by the embodiment of the invention, through the cooperative control of raw material pretreatment, green pellet preparation, oxidative roasting and direct reduction, the strength of the obtained vanadium titanium ore metallized pellet product is 2000-2150N/number, the reducibility index is more than 0.04, and the low-temperature reduction degradation property LTD is achieved +6.3 >80%(LTD +6.3 : particles after pulverization experiments are larger than 6.3 and mm, the total mass ratio of the particles is larger than that of the particles, and the low-temperature reduction pulverization performance LTD is realized up >60%(LTD UP : the ratio of the uncrushed pellets to the total pellets after the pulverization experiment), the reduction behavior index meets the production requirement of the hydrogen-based shaft furnace, the metallization rate is more than 94%, high-quality raw materials are provided for the subsequent electric furnace production, and the clean utilization of the vanadium-titanium ore resources is realized.
In some embodiments, the vanadium-titanium ore has a total iron (TFe) content of not less than 50% by mass, tiO 2 The content is 5% -11%, cr 2 O 3 The content is less than 0.2%, V 2 O 5 The content is less than 1%.
Specifically, the content of vanadium-titanium ore total iron (TFe) is not less than 50% by mass fraction, tiO 2 The content is 5% -11%, cr 2 O 3 The content is less than 0.2%, V 2 O 5 The content is less than 1%, the vanadium-chromium element content in the vanadium-titanium ore is less, the titanium content belongs to the medium titanium level, and belongs to the common medium titanium type vanadium-titanium magnetite (the common type vanadium-titanium magnetite according to the vanadium-chromium content and the medium titanium type vanadium-titanium magnetite according to the titanium content)Titano-magnetite) is a more difficult-to-reduce vanadium-titanium ore resource. Unlike high titanium resource which is very difficult to reduce, the vanadium titanium ore must be improved by adding other minerals with better reducibility, and the titanium vanadium titanium ore in the category can improve the reduction performance of the vanadium titanium ore pellet by the scheme of the embodiment of the invention on the premise of producing by using the vanadium titanium ore resource completely, so that the vanadium titanium ore pellet can meet the requirement of producing and using a hydrogen-based shaft furnace, the utilization rate of the vanadium titanium ore resource is improved, the production cost is reduced, and the utilization efficiency of valuable components is improved.
In some embodiments, the raw material pretreatment results in a vanadium-titanium ore with a 200 mesh or less than 90% ratio and a binder with a 200 mesh or less than 90% ratio.
Specifically, the vanadium titanium ore passes through a sieve with a mesh size of below 200, the proportion of the sieve with the mesh size of below 200 is more than 90%, and the binder passes through a sieve with the mesh size of below 200, and the proportion of the sieve with the mesh size of below 200 is more than 90% after being finely ground. By finely grinding the vanadium titanium ore and the binder, the granularity of the raw materials can be reduced, the specific surface area can be increased, the contact area among particles in pelletizing can be increased, and the pelletizing performance can be improved. Wherein the binder is selected from common ore binder such as bentonite, and comprises CaO and SiO 2 、MgO、Na 2 O and K 2 O, etc.
In some embodiments, the braising comprises: mixing the vanadium ore with the mass fraction of 98.2% -99.5% of the total mass of the vanadium ore and the binder, the binder with the mass fraction of 0.5% -1.8% of the total mass of the vanadium ore and the binder and water with the mass fraction of 8% -10% of the total mass of the vanadium ore and the binder fully.
Specifically, the ideal moisture range for pelletizing iron ore is generally narrower by controlling the stewing parameters, but the wider water amount range can be allowed by adding the binder (bentonite and the like), so that the operation adaptability is increased, and particularly under the condition that the raw materials are excessively wet, the pellets can be normally pelletized due to the strong water absorption of the binder such as bentonite and the like. In addition, the binding agent such as bentonite can improve the strength of green pellets. The strength of green pellets is mainly determined by capillary force, and binders such as bentonite are highly dispersed substances, and after the binders are added, the specific surface area of the mixture is changed, so that the diameter of capillaries in the green pellets is reduced, and the capillary force is increased. The bonding agent such as bentonite can improve the dry bulb strengthDegree and burst temperature. The bentonite can raise the burst temperature of the pellets, and the reason is that the pellets slowly release water due to the buffer effect of the bentonite, so that the pellets are not dehydrated rapidly, and the pellets are prevented from bursting due to overlarge internal vapor pressure. However, too much bentonite affects the iron grade of the final pellet, siO in bentonite 2 It also has inhibiting effect on iron reduction. Meanwhile, the mineral powder can be fully wetted by controlling the moisture, so that the mineral powder is easy to roll and bond into balls, but the mineral powder is difficult to roll due to excessive moisture. In summary, the content of schreyerite, binder and water is controlled as follows: the mass fraction of the vanadium ore is 98.2% -99.5% of the total mass of the vanadium ore and the binder, the mass fraction of the binder is 0.5% -1.8% of the total mass of the vanadium ore and the binder, the addition amount of water is 8% -10% of the total mass of the vanadium ore and the binder, and then the three materials are fully mixed and stewed.
In some embodiments, the pelletizing comprises: pelletizing the braised material, wherein the water addition amount is 10% -14% of the mass of the braised material during pelletizing, the pelletizing time is 30-50 min, and the green pellet granularity is 8-14 mm.
Specifically, the pelletizing process is divided into a process of forming a mother sphere, a process of growing the mother sphere and a process of compacting, in the rotation of a disc pelletizer, drip water is added into the schreyerite to carry out uneven drip wetting, so that the local water holding of the schreyerite reaches the capillary water content stage, fine grain schreyerite is pulled to the center of the water drop by capillary force action to form a small polymer, and the small polymer is subjected to rolling and blocking actions in the pelletizer to form the mother sphere. The condition of large mother ball length is that the water content of the surface of the mother ball is close to the proper capillary water content, the mother ball continuously rolls in a ball disc and is further compacted, so that the shape and the size of a capillary tube of the mother ball are changed, excessive capillary water is extruded onto the surface of the ball, the surface of the mother ball is excessively wet, ore particles with low wetting degree are adhered, the mother ball is continuously grown, and at the moment, water is sprayed onto the surface of the mother ball to further adhere ore particles to the surface of the mother ball for growth, and the mother ball is continuously circulated to grow into the ball. The long period of the mother ball needs to spray water and feed materials in time. Meanwhile, the water is less, mineral powder is difficult to agglomerate, and the mineral powder is easy to adhere to a balling disc to cause balling failure due to excessive water addition. The pellet internal structure in the pellet manufacturing process can be controlled by controlling the pellet manufacturing time, the pellet manufacturing time is too short, the green pellets are too loose to cause the poor green pellet performance, the pellet strength is low, the subsequent reduction degradation performance is poor, the pellet manufacturing time is too long, the pellet compaction degree is high, the internal structure is compact, the porosity in the pellet is small, and the gas is difficult to enter the pellet in the subsequent reduction process, so that the pellet reduction performance is poor. The necessity of controlling the pellet size is that the pellet size is too small, the strength is poor, the low-temperature reduction pulverization effect is poor, and if the pellet size is too large, the reducing gas permeation path is long, so that the reducing performance is poor. In summary, the water addition amount is controlled to be 10% -14% of the mass of the braised material during pelletizing, the pelletizing time is 30-50 min, and the green pellet granularity is 8-14 mm.
In some embodiments, the oxidizing roasting is performed at 1150-1230 ℃ for 10-25 min.
Specifically, the control of the roasting temperature and time can ensure that the vanadium titanium ore is fully crystallized, the temperature is too low and the time is too short, so that the vanadium titanium ore is difficult to be completely oxidized and roasted, the internal structure of the pellets is loose, the reduction and pulverization effects are poor, and after the temperature and the roasting time are increased, the vanadium titanium ore is too compact in the pellets, so that the reduction performance is influenced. Therefore, the roasting temperature is controlled to 1150-1230 ℃ and the roasting time is controlled to 10-25 min.
In some embodiments, the oxidative roasting further comprises: preheating, wherein the preheating temperature is 850-950 ℃ and the preheating time is 10-20 min.
Specifically, the preheating function of the pellets is to oxidize ferrous iron into ferric iron, when the temperature is low and the time is short, the conversion in the process is incomplete, so that the strength of the subsequent pellets is too bad, and after the temperature and the time are increased, the green pellets can be directly solidified, the oxidation reaction does not occur, and the too bad strength of the pellets can be caused. Therefore, the preheating temperature is controlled to 850-950 ℃ and the time is controlled to 10-20 min, which is most suitable.
In some embodiments, the direct reduction is performed at a temperature of 950-1050 ℃ for a time of 60-110 minutes.
Specifically, when the reduction temperature is too low, the time required for pellet reduction can be obviously prolonged, and the production efficiency is affected; and when the temperature is too high, the heating energy consumption is too high, the production cost is increased, meanwhile, the temperature is too high, the problems of bonding and too high expansion index are also caused in the reduction process, and the subsequent shaft furnace production is not feasible. Therefore, the direct reduction temperature is controlled to be 950-1050 ℃ and the reduction time is controlled to be 60-110 min under comprehensive consideration.
In some embodiments, the direct reduction, the reducing gas composition comprises: h 2 、CO、N 2 And CO 2 The volume of the reducing gas satisfies: h 2 +CO≥90%,H 2 /CO≥2,2%≤CO 2 ≤6%。
Specifically, the volume and the ratio of the hydrogen to the carbon monoxide reach 90%, so that the ratio of the reducing gas in the reducing process is ensured to be enough, and the reducing efficiency is further ensured. When the reduction temperature is above 810 ℃, the reduction efficiency of hydrogen is higher than that of carbon monoxide, the carbon monoxide can aggravate the pulverization of pellets, the too fast reduction efficiency after the hydrogen proportion is improved can lead to the fast conversion of crystal forms in the low-temperature reduction process and also lead to pulverization problems, so that the reduction efficiency and the pulverization problems need to be comprehensively considered, and a great deal of research is needed, and a small amount of carbon dioxide is added to properly slow down the reduction rate so as to improve the pulverization problems, so that H is controlled 2 +CO≥90%,H 2 /CO≥2,2%≤CO 2 ≤6%。
In some embodiments, the reduction product treatment comprises: and taking out the reduction product, placing the reduction product in a closed container, introducing argon gas, and cooling to room temperature to obtain the vanadium-titanium ore metallized pellet product.
Specifically, argon is used as a shielding gas, the cost is relatively low, and the reduced vanadium titanium ore can be protected from being contacted with oxygen in the cooling process, so that the problem of reoxidation is avoided.
Example 1A method for reducing vanadium-titanium ore
A method for reducing vanadium-titanium ore, wherein the content of total iron (TFe) is not less than 50% and TiO is calculated according to mass fraction 2 The content is 5% -11%, cr 2 O 3 The content is less than 0.2%, V 2 O 5 The content is less than 1%. The chemical composition of the vanadium titanium ore of example 1 is shown in table 1 below.
TABLE 1 main chemical composition of vanadium titano-magnetite, wt./wt.%
The reduction method specifically comprises the following steps:
(1) Pretreatment of raw materials: finely grinding vanadium titanium ore and bentonite binder, sieving with a sieve below 200 meshes, wherein the proportion of the sieve below 200 meshes is more than 90%, and then fully drying.
(2) Preparing green balls: comprises stewing materials and pelletizing;
and (3) stewing: mixing vanadium titanium ore with the mass fraction of 98.2% of the total mass of the vanadium titanium ore and the binder, the binder with the mass fraction of 1.8% of the total mass of the vanadium titanium ore and the binder, and water with the mass fraction of 8% of the total mass of the vanadium titanium ore and the binder, and stewing the materials fully.
Pelletizing: pelletizing the braised material by using a disc pelletizer, wherein the water addition amount during pelletizing is 10% of the mass of the braised material, the pelletizing time is 50 min, and the green pellet granularity is controlled to be 8 mm.
(3) Oxidizing and roasting: oxidizing and roasting the green pellets to obtain vanadium-titanium ore oxidized pellets; the process is carried out on a grate-rotary kiln, the preheating temperature is 925 ℃, the preheating time is 18 min, the roasting temperature is 1200 ℃, the roasting time is 25min, and the strength of the obtained vanadium titanium ore oxidized pellets is 2028N/one.
(4) Direct reduction: placing the vanadium titanium ore oxidized pellets into a hydrogen-based shaft furnace, and directly reducing under the condition of hydrogen-rich reducing gas to obtain a reduction product; the reduction temperature was 1050℃and the reduction time was 60 min. The reducing gas comprises the following components in parts by volume: h 2 =80%,CO=10%,N 2 =6%,CO 2 =4%。
(5) Reduction product treatment: and taking out the reduction product, placing the reduction product in a closed container, introducing argon, and rapidly cooling to room temperature to obtain the vanadium-titanium ore metallized pellet product.
Example 2A method for reduction of vanadium titanium ore
A reduction method of vanadium titanium ore, wherein the vanadium titanium ore contains not less than 50% of total iron and no less than 50% of TiO by mass fraction 2 The content is 5% -11%, cr 2 O 3 The content is less than 0.2%, V 2 O 5 The content is less than 1%. Examples2 is the same as in example 1.
The reduction method specifically comprises the following steps:
(1) Pretreatment of raw materials: finely grinding vanadium titanium ore and bentonite binder, sieving with a sieve below 200 meshes, wherein the proportion of the sieve below 200 meshes is more than 90%, and then fully drying.
(2) Preparing green balls: comprises stewing materials and pelletizing;
and (3) stewing: mixing the vanadium ore with the mass fraction of 99.5% of the total mass of the vanadium ore and the binder, the binder with the mass fraction of 0.5% of the total mass of the vanadium ore and the binder and water with the mass fraction of 10% of the total mass of the vanadium ore and the binder fully.
Pelletizing: pelletizing the braised material by using a disc pelletizer, wherein the water addition amount during pelletizing is 14% of the mass of the braised material, the pelletizing time is 30 min, and the green pellet granularity is controlled to be 14 mm.
(3) Oxidizing and roasting: oxidizing and roasting the green pellets to obtain vanadium-titanium ore oxidized pellets; the process is carried out on a grate-rotary kiln, the preheating temperature is 850 ℃, the preheating time is 20 min, the roasting temperature is 1150 ℃, the roasting time is 25min, and the strength of the obtained vanadium titanium ore oxidized pellets is 2009N/one.
(4) Direct reduction: placing the vanadium titanium ore oxidized pellets into a hydrogen-based shaft furnace, and directly reducing under the condition of hydrogen-rich reducing gas to obtain a reduction product; the reduction temperature was 950℃and the reduction time was 110 min. The reducing gas comprises the following components in parts by volume: h 2 =60%,CO=30%,N 2 =8%,CO 2 =2%。
(5) Reduction product treatment: and taking out the reduction product, placing the reduction product in a closed container, introducing argon, and rapidly cooling to room temperature to obtain the vanadium-titanium ore metallized pellet product.
Example 3A method for reduction of vanadium titanium ore
A reduction method of vanadium titanium ore, wherein the vanadium titanium ore contains not less than 50% of total iron and no less than 50% of TiO by mass fraction 2 The content is 5% -11%, cr 2 O 3 The content is less than 0.2%, V 2 O 5 The content is less than 1%. The chemical composition of the vanadium titanium ore of example 3 was the same as that of example 1.
The reduction method specifically comprises the following steps:
(1) Pretreatment of raw materials: pretreatment of raw materials: finely grinding vanadium titanium ore and bentonite binder, sieving with a sieve below 200 meshes, wherein the proportion of the sieve below 200 meshes is more than 90%, and then fully drying.
(2) Preparing green balls: comprises stewing materials and pelletizing;
and (3) stewing: mixing the vanadium ore with the mass fraction of 99% of the total mass of the vanadium ore and the binder, the binder with the mass fraction of 1% of the total mass of the vanadium ore and the binder and the water with the mass fraction of 9% of the total mass of the vanadium ore and the binder fully.
Pelletizing: pelletizing the braised material by using a disc pelletizer, wherein the water addition amount during pelletizing is 12% of the mass of the braised material, the pelletizing time is 40 min, and the green pellet granularity is controlled to be 10 mm.
(3) Oxidizing and roasting: oxidizing and roasting the green pellets to obtain vanadium-titanium ore oxidized pellets; the process is carried out on a grate-rotary kiln, the preheating temperature is 950 ℃, the preheating time is 10 min, the roasting temperature is 1230 ℃, the roasting time is 15 min, and the strength of the obtained vanadium titanium ore oxidized pellets is 2127N/one.
(4) Direct reduction: placing the vanadium titanium ore oxidized pellets into a hydrogen-based shaft furnace, and directly reducing under the condition of hydrogen-rich reducing gas to obtain a reduction product; the reduction temperature is 1000 ℃ and the reduction time is 80 min. The reducing gas comprises the following components in parts by volume: h 2 =70%,CO=20%,N 2 =4%,CO 2 =6%。
(5) Reduction product treatment: and taking out the reduction product, placing the reduction product in a closed container, introducing argon, and rapidly cooling to room temperature to obtain the vanadium-titanium ore metallized pellet product.
Comparative example 1
The difference from example 1 is the oxidizing roasting conditions. Oxidative calcination of comparative example 1: oxidizing and roasting the green pellets to obtain vanadium-titanium ore oxidized pellets; the process is carried out on a grate-rotary kiln, the preheating temperature is 950 ℃, the preheating time is 20 min, the roasting temperature is 1250 ℃, the roasting time is 15 min, and the strength of the obtained vanadium titanium ore oxidized pellets is 2583N/ore.
Comparative example 2
The difference from example 1 is the oxidizing roasting conditions. Oxidative calcination of comparative example 2: oxidizing and roasting the green pellets to obtain vanadium-titanium ore oxidized pellets; the process is carried out on a grate-rotary kiln, the preheating temperature is 1000 ℃, the preheating time is 15 min, the roasting temperature is 1250 ℃, the roasting time is 15 min, and the strength of the obtained vanadium titanium ore oxidized pellets is 1503N/one.
Comparative example 3
The difference from example 1 is that the reducing gas component volume is different. The reducing gas composition volume of comparative example 3 is: h 2 =50%,CO=40%,N 2 =6%,CO 2 =4%。
Comparative example 4
The difference from example 1 is that the reducing gas component volume is different. The reducing gas composition volume of comparative example 4 is: h 2 =80%,CO=10%,N 2 =10%。
The reduction properties of the schreyerite metallized pellet products prepared in examples 1 to 3 and comparative examples 1 to 4 are shown in table 2.
Table 2 Performance index of the schreyerite metallized pellet products prepared in examples 1 to 3 and comparative examples 1 to 4
Discussion of results:
the pellet strength is low, 2000N/pellet strength which does not meet the shaft furnace standard can influence the reduction dynamics condition of the pellet, the higher the pellet strength is, the lower the reducibility index is, when the pellet strength exceeds 2150N/pellet strength, the reducibility index is lower than 0.04, the reducibility index is low, namely the reduction rate is low, the production time needs to be prolonged, the production efficiency is low, the cost is increased, and the pellet strength is controlled to be 2000-2150N/pellet. The low-temperature reduction degradation performance is poor, the air flow distribution of the shaft furnace is affected, and the shaft furnace is not smooth. The metallization rate is low, the national standard of the metallized pellets cannot be met, and meanwhile, the energy consumption of the subsequent process is increased, so that the overall production flow is not smooth.
As can be seen from examples 1 to 3, inUnder the conditions of reasonable pellet strength, reduction temperature, reduction atmosphere and the like, the reducibility index and reduction degradation of the vanadium-titanium ore pellets are within reasonable ranges, namely the reducibility index is more than 0.04, and the low-temperature reduction degradation property LTD is achieved +6.3 80% or more, low temperature reduction degradation LTD up More than 60 percent, can meet the production requirement of the shaft furnace. And the schreyerite pellets produced in examples 1-3 have a metallization rate of more than 94%, and provide a high-quality raw material for subsequent electric furnace production.
As can be seen from comparative example 1, when the pellet strength is too high, the low-temperature reduction degradation performance of the pellet is excellent, but the reduction performance is too poor.
As can be seen from comparative example 2, when the pellet strength is too low, the reduction performance is remarkably improved, but the reduction degradation performance at low temperature is extremely poor, and it is difficult to meet the production requirements.
As can be seen from comparative example 3, H 2 When the volume ratio of the vanadium-titanium ore pellets to CO is smaller than 2, the reducibility index of the vanadium-titanium ore pellets is 0.03825, and meanwhile, the low-temperature reduction degradation performance is poor, so that the production requirements are difficult to adapt.
As can be seen from comparative example 4, CO was not added to the reducing gas 2 The reducibility index of the vanadium-titanium ore pellets is 0.0541, but the low-temperature reduction degradation index LTD +6.3 =73.85%,LTD UP =91.25%, and has poor pulverization properties, and is difficult to meet production requirements.
In conclusion, the reduction method of the vanadium titanium ore provided by the embodiment of the invention solves the problems that the vanadium titanium ore is poor in pellet strength, difficult to reduce to a final point and poor in reduction degradation performance in the existing hydrogen-based shaft furnace process. On the premise of not carrying out ore blending and upgrading on the vanadium titanium ore, the high-efficiency clean reduction of vanadium titanium resources is realized through the cooperative control of the strength of the vanadium titanium ore raw material and the strength of the pellet, the high-metallization-rate vanadium titanium ore pellet with the metallization rate of more than or equal to 94% is produced, and a high-quality raw material is provided for the subsequent electric furnace production. Has the following advantages:
(1) The vanadium-titanium ore pellets are reduced by the reducing gas with high hydrogen-carbon ratio, so that the reduction performance of the vanadium-titanium ore pellets is improved, and the carbon emission in the production link can be further reduced under the high hydrogen reduction condition.
(2) The strength of the vanadium titanium ore oxidized pellets is 2000-2150N/obtained through the raw material pretreatment, green pellet preparation and oxidizing roasting process, so that the reducibility index and low-temperature reduction degradation performance of the pellets are ensured.
(3) By adding small amounts of CO to the reducing gas 2 The pulverization performance of the vanadium-titanium ore pellets is improved, and various reduction indexes are ensured to meet the requirements of the hydrogen-based shaft furnace.
It will be readily appreciated by those skilled in the art that the above advantageous ways can be freely combined and superimposed without conflict. The foregoing description of the preferred embodiment of the present invention is not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The foregoing is merely a preferred embodiment of the present application and it should be noted that it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the technical principles of the present application, and these modifications and variations should also be regarded as the scope of the present application.

Claims (10)

1. A method for reducing vanadium titanium ore, comprising:
pretreatment of raw materials: finely grinding vanadium titanium ore and a binder;
preparing green balls: fully mixing pretreated vanadium titanium ore with a binder, stewing, and pelletizing to obtain green pellets;
oxidizing and roasting: oxidizing and roasting the green pellets to obtain vanadium titanium ore oxidized pellets with the strength of 2000-2150N/g;
direct reduction: placing the vanadium titanium ore oxidized pellets into a hydrogen-based shaft furnace, and directly reducing under the condition of hydrogen-rich reducing gas to obtain a reduction product;
the performance indexes of the vanadium titanium ore metallized pellet product obtained after the reduction product treatment are as follows: the pellet strength is 2000-2150N/m, the reducibility index is more than 0.04, and the low-temperature reduction degradation LTD is realized +6.3 80% or more, low temperature reduction degradation LTD up More than 60%, and the metallization rate is more than or equal to 94%.
2. The method for reducing vanadium titanium ore according to claim 1, wherein the vanadium titanium ore has a total iron content of not less than 50% by mass and a TiO 2 The content is 5% -11%, cr 2 O 3 The content is less than 0.2%, V 2 O 5 The content is less than 1%.
3. The method of reducing vanadium titanium ore according to claim 1 or 2, wherein the raw material pretreatment is performed such that the vanadium titanium ore is at a ratio of 200 mesh or less of 90% or more and the binder is at a ratio of 200 mesh or less of 90% or more.
4. A method of reducing a vanadium titanium ore according to claim 1 or claim 2, wherein the smoldering material comprises:
mixing vanadium titanium ore with the mass fraction of 98.2-99.5%, binder with the mass fraction of 0.5-1.8% and water with the total mass of 8-10% of the vanadium titanium ore and the binder, and stewing.
5. The method of reducing vanadium titanium ore according to claim 4, wherein the pelletizing comprises:
pelletizing the braised material, wherein the water addition amount is 10% -14% of the mass of the braised material during pelletizing, the pelletizing time is 30-50 min, and the green pellet granularity is 8-14 mm.
6. The method for reducing vanadium titanium ore according to claim 1 or 2, wherein the oxidizing roasting is performed at 1150-1230 ℃ for 10-25 min.
7. The method for reducing vanadium titanium ore according to claim 6, wherein the oxidative calcination further comprises:
preheating, wherein the preheating temperature is 850-950 ℃ and the preheating time is 10-20 min.
8. The method for reducing vanadium titanium ore according to claim 1 or 2, wherein the direct reduction is performed at 950-1050 ℃ for 60-110 min.
9. The method of reducing vanadium titanium ore according to claim 8, wherein the direct reduction, reducing gas composition comprises: h 2 、CO、N 2 And CO 2 The volume of the reducing gas satisfies: h 2 +CO≥90%,H 2 /CO≥2, 2%≤CO 2 ≤6%。
10. A method of reducing a vanadium titanium ore according to claim 1 or 2, wherein the reduction product treatment comprises: and taking out the reduction product, placing the reduction product in a closed container, introducing argon gas, and cooling to room temperature to obtain the vanadium-titanium ore metallized pellet product.
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CN105886755A (en) * 2016-04-18 2016-08-24 华南理工大学 Low-grade vanadium titano-magnetite oxidized pellet expansion restraining and upgrading process for gas-based shaft furnace
CN107267748A (en) * 2017-06-14 2017-10-20 东北大学 A kind of high vanadium high-chromic vanadium-titanium ferroferrite pelletizing
WO2018228155A1 (en) * 2017-06-14 2018-12-20 东北大学 Preparation method for high-vanadium high-chromium type vanadium titanium magnetite pellets
CN109852790A (en) * 2019-02-01 2019-06-07 东北大学 A method of middle low alkalinity is prepared containing the full vanadium titanium self fluxed pellet of chromium
CN110484720A (en) * 2019-09-11 2019-11-22 中南大学 A kind of technique that drying grate roasting-gas-based shaft kiln prereduction-electric furnace restores comprehensive utilization of V-Ti magnetite deeply

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103667572A (en) * 2013-12-09 2014-03-26 东北大学 Gas-based shaft-furnace direct-reduction smelting method for high-chromium-content vanadium-titanium magnetite
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