CN112266997A - Coal-based hydrogen metallurgy process for raw iron ore - Google Patents
Coal-based hydrogen metallurgy process for raw iron ore Download PDFInfo
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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
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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
- C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
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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
- C21B13/08—Making spongy iron or liquid steel, by direct processes in rotary furnaces
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention discloses a raw ore coal-based hydrogen metallurgy process for iron ores, which is characterized in that the iron ores with the particle size of below 15mm are divided into two size ranges of fine particles and coarse particles, pellets made of the coarse particle iron ores and the fine particle iron ores and 1-15 mm residual carbon are added from a rotary kiln feeding end, 8-15 mm granular high volatile coal and 3-8 mm granular high volatile coal are injected to the front section and the middle section of a rotary kiln hydrogen metallurgy roasting area, and in a thermal state material layer formed by mixing the iron ores, the granular coal and stagnant carbon in a hydrogen metallurgy area, a coal pyrolysis process, a water gasification carbon process and a hydrogen metallurgy process, wherein the coal pyrolysis process, the water gasification carbon process and the iron ore reduction process are jointly dominant in a thermal state, and the hydrogen metallurgy process is highly integrated. The invention uses H2The catalyst is used as a main reducing agent for iron ore hydrogen metallurgy, reduces the roasting temperature of the rotary kiln, shortens the roasting time and reduces the energy consumption of a system.
Description
Technical Field
The invention belongs to the technical field of metal smelting, and particularly relates to a raw ore coal-based hydrogen metallurgy process for iron ore.
Background
The traditional blast furnace iron making is a smelting technology which relies on metallurgical coke as a reducing agent and fuel, and the process is a typical carbon metallurgy process. The annual capacity of blast furnace iron making all over the world is very large, the trend of further development is also shown, a large amount of high-quality metallurgical coke needs to be provided, the high-quality metallurgical coke is refined by expensive caking coking coal, the coking coal all over the world only accounts for 8-10% of the total coal storage amount, and the gradual expansion of blast furnace iron making scale leads the coking coal to be more and more scarce.
In the carbon metallurgy process, the C element in metallurgical coke is CO at high temperature2The gasification generates CO, and the CO is used as a reducing agent to remove the oxygen of the iron oxide in the iron ore. It is prepared from CO2Carbon gasification (CO) as gasifying agent2+ C → 2 CO-165.8 KJ/mol) as core, a series of metallurgical reaction processes for gasifying C into CO and reducing iron oxide, which is a strong endothermic process. Meanwhile, the molecular radius of CO is large, so that the permeation speed in the iron ore is low, and therefore, the iron oxide needs a high temperature condition in the reduction process, and the heat consumption is high.
In the hydrometallurgical process, with H2As reducing agent, H2The reducing agent has small molecular radius, is the most active reducing agent, has the reduction potential which is 11 times that of CO and the permeation speed which is about 5 times that of CO, and can easily permeate into the iron ore. Therefore, compared with carbon metallurgy, hydrogen metallurgy can reduce the reaction temperature, improve the reaction speed, greatly reduce the heat consumption, and has the advantages of great capacity advantage, energy conservation and emission reduction.
The key to realizing the hydrogen metallurgy process is how to obtain cheap H2. Someone will contain a large amount of H2The coke oven gas is recycled into the blast furnace, and H in the coke oven gas is also recycled2And CH therein4Reforming into H2In combination with CO for gas-based reduction shaft furnaces, nuclear hydrogen production and hydrogen metallurgy have also been proposed, but these H' s2The method for reducing iron ore requires the prior production of H2Then adding H2The method is used for reducing iron ores, has complex production process and higher energy consumption and cost, and is not industrially applied.
In fact, sufficient H can be obtained by the thermal intersection of the full pyrolysis process of coal with the iron oxide reduction process2Thereby realizing the hydrogen metallurgy process.
In the conventional wayIn the iron-making process of 'iron burning', coke produced by a coke oven is used as a reducing agent and fuel of a blast furnace. Due to the heat transfer characteristics of the coke oven, the coal pyrolysis occurring in the coking chamber of the coke oven is insufficient, and coal chemical products such as tar, benzene, naphthalene, alkane, alkene, hydrocarbon and the like are produced, H is contained in the coke oven gas2The content is only about 60 percent, and the H is2Has no intersection with the process of reducing the iron ore by the blast furnace.
Pyrolysis of coal refers to a complex process of heating coal in the absence of air or an inert atmosphere, with a series of physical changes and chemical reactions taking place. The main structure of coal is three-dimensional high molecular compound, which is composed of similar structural units linked together by covalent bridge bonds and non-chemical bonds, and the core of these structural units is condensed aromatic ring structure. A certain proportion of small molecular compounds are distributed in the macromolecular structure of the coal, and the characteristic is more obvious in low-rank coal. The pyrolysis of coal is due to the thermal breakdown of weak bond structures in coal, which generates small molecule free radical fragments. When the heating temperature of the coal is higher than the fracture temperature of the weak bond structure in the coal, the weak bond in the macromolecular structure of the coal can be fractured to form small molecular free radical fragments and volatile matters. After the volatile matter leaves the coal particles, the volatile matter is influenced by the surrounding high-temperature environment, and secondary and repeated reactions such as condensation polymerization, cracking and the like can further occur among all substances in the volatile matter. Within the temperature range of 900-1000 ℃, the coal is fully pyrolyzed, and the final gas product is H2Mainly comprises the following steps.
When the iron ore is reduced by adopting a rotary kiln process, the surface of the monomer particle material can simultaneously receive heat transfer amounts of radiation, convection and conduction in the processes of rolling and heating the iron ore in the kiln, and the heat transfer from the surface of the monomer particle to the core part is only conduction heat transfer. After the iron ore with the particle size of 0-15 mm enters the rotary kiln, in terms of the temperature rising process of monomer iron ore particles, the surface of the iron ore is heated firstly and then gradually transfers heat to the core part, the temperature rising time with fine particle size is short, and the temperature rising time with larger particle size is longer. When the whole of any particle iron ore reaches a certain temperature, namely 900-1000 ℃, the iron oxide contained in the iron ore is the least metallurgical thermodynamic condition for reduction, and the iron ore is arranged in a material layerUnder the condition that the internal reducing atmosphere is relatively stable, the higher the temperature is, the higher the metallurgical kinetic condition is, the higher the speed of reduction is. The reduction time required for the surface layer of the fine iron ore and the coarse iron ore is short, and the reduction time required for the core portion of the coarse iron ore is long. If the reduction time of the particle iron ore is to be shortened, the heat transfer problem is firstly solved, and the way of shortening the heat transfer time only improves the temperature gradient inside and outside the particle iron ore, namely the temperature of the surface of the particle iron ore is improved, under the condition of higher temperature, the temperature rise speed of the core part of the coarse particle iron ore is improved to a certain extent, but the temperature of the surface layer of the coarse particle iron ore and the temperature of the fine particle iron ore are higher, and Fe is in the environment of local high temperature above 1000 DEG C3O4Is easy to be further reduced into FeO which can be combined with SiO in iron ore2A series of complex chemical reactions occur to produce a variety of low melting point compounds, which exacerbate rotary kiln "ring formation". In order to relieve the ring formation of the rotary kiln and ensure the stable operation of the rotary kiln, the conventional solution adopted at present can only reduce the roasting temperature of iron ore in the kiln, the actual operation reduction temperature of the rotary kiln is only about 900 ℃, the temperature rise and reduction time of the iron ore are forced to be prolonged, and the productivity is reduced; even so, the overall quality of the reduced material is poor and the metal recovery is generally low.
The prior direct reduction process of the iron ore rotary kiln adopts anthracite or metallurgical coke with high thermal shock resistance as a reducing agent and fuel, and adopts a typical carbon metallurgy process. In order to improve the capacity of the rotary kiln and reduce the energy consumption, some mechanisms also do some transformation work on the traditional rotary kiln process, but the ideal effect is not obtained. For example, in order to improve the utilization rate of the reduced coal, part of the raw coal for reduction is directly sprayed into a rotary kiln roasting area from a discharge end, part of the raw coal for reduction is still roasted in a manner of adding iron ore from a feed end of the rotary kiln, and part of the raw coal for reduction is directly sprayed into the rotary kiln roasting area, so that the utilization rate of the coal can be improved, but after volatile matters are separated out in an in-bed heat of the area, a large amount of combustible gas is concentrated to overflow the surface of the in-bed material and enter a combustion space of the rotary kiln to serve as fuel, so that the temperature of the area is further increased, the ring formation in the kiln is aggravated, and. Therefore, the traditional direct reduction process of the iron ore rotary kiln has the problems of low productivity, high energy consumption, poor quality of reduced ores, ring formation in the kiln and the like.
Disclosure of Invention
The invention provides a raw ore coal-based hydrogen metallurgy process for iron ore, which aims to solve a plurality of problems of the traditional rotary kiln direct reduction process for iron ore. The process adopts high volatile coal such as brown coal as reductant and fuel, and uses H2As a main reducing agent for directly reducing iron ore, the method realizes the high integration of the dehydration and pyrolysis process of coal and the dehydration and reduction process of iron ore in a thermal state in a kiln, adopts a reasonable feeding mode according to the precipitation characteristics of volatile components of coal with different particle sizes, and fundamentally solves the problem of ring formation of the rotary kiln by effectively controlling the roasting temperature of the rotary kiln and the reducing atmosphere in a feed layer of a hydrometallurgy roasting area, thereby improving the roasting quality and the productivity of the iron ore and reducing the energy consumption.
Therefore, the invention adopts the following technical scheme:
a coal-based hydrogen metallurgy process for raw iron ores comprises the following steps:
s1, screening iron ore with the particle size of below 15mm into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, screening residual carbon into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, and classifying high-volatile coal into two size fractions of 3-8 mm fine particles and 8-15 mm coarse particles;
s2, mixing 0-1 mm iron ore, a binder and a liquid-phase hardening and tempering agent according to a weight ratio of 100: (1-3): (2-4) uniformly mixing the ingredients, adding water into a pelletizer, and pelletizing to obtain wet pellets with the particle size phi of 5-15 mm;
s3, mixing the wet balls prepared in the step S2 with 1-15 mm iron ore and 1-15 mm residual carbon, adding the mixture into a rotary kiln from a feeding end, blowing 8-15 mm high-volatile coal to the front section of a hydrogen metallurgy roasting area of the rotary kiln, and blowing 3-8 mm high-volatile coal to the middle section of the hydrogen metallurgy roasting area of the rotary kiln; controlling the time of the pellets in the kiln to be 35-50 min and the temperature of the high-temperature section to be 1120-1220 ℃;
s4, discharging the high-temperature material with the temperature of above 1050 ℃ obtained in the step S3 into an oxygen-free cooling device for cooling, and discharging the material after cooling to normal temperature;
s5, adding the normal-temperature material obtained in the step S4 into a dry magnetic separator for dry magnetic separation to obtain a magnetic reduction material and nonmagnetic carbon residue;
the non-magnetic carbon residue is subjected to particle size classification through a screening device, and is screened into two particle sizes of 0-1 mm fine particles and 1-15 mm coarse particles, the 0-1 mm carbon residue is discharged as coal ash, and the 1-15 mm carbon residue is returned to a batching system for utilization; and the magnetic reduction material is subjected to fine grinding by using a dry grinding machine and then is subjected to magnetic separation by using a dry magnetic separator, and the iron powder with the iron grade of more than 83% and the metallization rate of about 95% can be obtained after tailings are removed.
Furthermore, the mass of the high volatile coal added into the rotary kiln in the step S2 accounts for 25-35% of the mass of the iron ore.
Furthermore, the front section and the middle section of the kiln body of the rotary kiln are respectively provided with 2-4 kiln back fans, and the kiln back fans supply normal-temperature air into the kiln along the length direction of the rotary kiln according to process requirements.
Furthermore, the high volatile coal is lignite, and the volatile content is more than 40%.
Further, the iron ore screening in the step S1 uses an iron ore grain size classifier.
Further, in the step S1, a carbon residue classifier is used for carbon residue screening.
Further, in the step S1, a coal classifier is used to classify the high volatile coal.
The process principle of the invention is as follows:
after the mixed material consisting of the iron ore and the dead granular carbon is fed into the kiln, the mixed material is heated in the process of rolling in the kiln, the temperature is continuously increased, and when the mixed material is moved to the middle section of the kiln body of the rotary kiln, the material temperature reaches over 1000 ℃. The granulated coal injected from the discharge end of the rotary kiln is distributed to all places of the rear section of the kiln body along the length direction of the kiln body according to the process requirement, enters a material layer along with the material rolling and is uniformly mixed with other materials, a material layer distribution area formed by mixing iron ore, stagnant carbon and granulated coal is formed in the rotary kiln, and a hydrogen metallurgy process which is dominated by the combination of oxygen element in the iron ore, hydrogen element in the granulated coal and carbon element in the stagnant carbon and is highly integrated in a coal full pyrolysis process, a water carbon gasification process and an iron oxide reduction process under a thermal state can be generated in a thermal state material layer in the area; the dead carbon existing in the area comprises dead granular carbon entering from a rotary kiln feeding end and dead carbon containing active granular carbon formed in a middle-rear section after full pyrolysis of granular coal entering a material layer at the front section of the area, and a space in which the hydrogen metallurgy process in the rotary kiln occurs is called a rotary kiln hydrogen metallurgy roasting area.
Coal is fully pyrolyzed in the rotary kiln coal-based hydrogen metallurgy process: the coal-based hydrogen metallurgy method adopts high volatile coal, and the coal is pyrolyzed into carbon-rich dead carbon and hydrogen-rich volatile at the temperature of 350-400 ℃. Pyrolysis of coal at low temperatures is not sufficient and produces hydrogen-rich volatiles including large molecular weight gases such as tars, benzene, naphthalene, alkanes, alkenes, hydrocarbons, and H2、H2O、CO、CO2、H2S and other small molecular weight gases; in the material bed space of the rotary kiln hydro-metallurgical roasting area, when the temperature reaches more than 950 ℃, the tar, benzene, naphthalene, alkane, alkene, hydrocarbon and other high molecular weight gases can generate secondary and multiple pyrolysis, and finally the generated gas product can be H2Mainly, a large amount of solid active granular carbon is produced simultaneously, and the full pyrolysis of the coal is realized.
Any granular coal is sprayed into the surface of the material layer in the hydro-metallurgical roasting area of the rotary kiln from the discharge end, and in the parabolic movement process of the combustion space, because the surface temperature of the granular coal is rapidly raised, a small amount of volatile matters are separated out on the surface of the granular coal, and the granular coal enters the combustion space of the rotary kiln and is used as fuel after being fully pyrolyzed. After any granular coal falls to the surface of the material layer, the granular coal can rapidly enter the material layer along with the rolling and advancing of the roasted material to contact with peripheral high-temperature materials, volatile matters released in the temperature rising process of the surface layer and the shallow layer of the granular coal can enter gaps of the high-temperature material layer, and H is generated through full pyrolysis2And activated granular carbon, H2Will act directly as a reducing agent for the reduction of iron oxides in the hot state, while the activated carbon particles will stay on the surface of the iron ore or coal pellets.
Surface of any particle coal in the rotary kiln hydrogen metallurgy roasting zone material layerAnd the shallow layer is heated to form a high-temperature area, the temperature reaches about 950 ℃, any part of the core from shallow to deep undergoes a heating process, when the temperature of a certain part reaches 350-400 ℃, the coal at the certain part can be subjected to insufficient pyrolysis to release volatile matters, and the volatile matters can be subjected to sufficient pyrolysis to generate H when passing through the surface of the granulated coal and the high-temperature area of the shallow layer in the overflow process2And activated granular carbon, H2The active granular carbon will stay on the surface and shallow layer of the stagnant granular carbon generated by the granular coal.
H generated by fully pyrolyzing granular coal in a material layer of a rotary kiln hydrogen metallurgy roasting area2The produced high-temperature dead granular carbon with active granular carbon can roll along with the material layer and directly serve as a reducing agent for reducing iron oxide in a hot state. H2H produced after reduction of iron oxides2The O and the high-temperature stagnant granular carbon with the active granular carbon carry out carbon gasification reaction to generate H2And CO, H2Then used as a reducing agent to reduce iron oxide and generate new H2Produce a severe coupling effect; due to the selectivity of the chemical reaction, most of the CO overflows from the material layer and is used as fuel in the combustion space of the rotary kiln. Only when the volatile matter of the granular coal in the material bed is completely separated out, the iron ore and the high-temperature dead coal are carried out by CO2A series of metallurgical reduction reactions taking carbon gasification reaction as a core. The stagnant granular carbon is derived from three parts: (1) adding 1-15 mm of carbon residue into the rotary kiln from a feeding end; (2) after 8-15 mm of high-volatile coal is sprayed to the front section of a hydrogen metallurgy roasting area of the rotary kiln, fully pyrolyzing the high-volatile coal to obtain carbon particles; (3) and (3) spraying high-volatile coal with the thickness of 3-8 mm to the middle section of a hydrogen metallurgy roasting area of the rotary kiln, and fully pyrolyzing to obtain carbon particles.
The coal pyrolysis hydrogen reduction process inside the rotary kiln hydro-metallurgy roasting zone material layer: in the high volatile coal, the content of hydrogen element is generally 4-5%, and H is obtained by fully pyrolyzing the coal2About 70 percent of the intermediate energy is used for reducing iron ore, and the part H2About 40 percent of oxygen in the iron ore can be removedThe process is referred to as the "coal pyrolysis hydrogen reduction process".
The carbon gasification hydrogen reduction process inside the rotary kiln hydro-metallurgical roasting zone material layer comprises the following steps: h produced by coal pyrolysis2Reduction of iron oxide to produce H2O，H2The O and the high-temperature stagnant granular carbon with the active granular carbon are subjected to carbon gasification reaction to generate H2And CO, H2Reducing iron oxide as reducing agent to obtain H2O will gasify carbon to generate new H2And co. Due to the selectivity of chemical reaction, only a small part of CO generated in the process participates in the reaction of reducing iron oxide, most of CO is discharged into a hearth to be used as fuel, and about 50% of oxygen in iron ore can be removed through the process, so that the process is called as a carbon hydrogen gasification reduction process.
The carbon reduction process inside the material layer of the rotary kiln hydrogen metallurgy roasting area comprises the following steps: only when the volatile matters in the granulated coal are separated out to a certain degree, the iron oxide in the iron ore and the high-temperature dead granular carbon with the active granular carbon are subjected to CO treatment2The reduction rate of the process to iron ore is only about 10 percent, and the process is called as a carbon reduction process.
In the roasting process of the iron ore in the hydrogen metallurgy rotary kiln, the loss on ignition of the iron ore is generally 26-33%, the loss on ignition of the iron ore and the consumption of the granular coal are all converted into combustible gas H2The CO is about 97 percent, a small amount of tar, benzene, naphthalene, alkane, alkene, hydrocarbon and the like exist, combustible gas overflows from the material layer and serves as high-temperature gas fuel for the rotary kiln, and the heat released by the fuel in the combustion process can meet the heat requirement of the rotary kiln.
In the process of heating any particle of coal entering the high-temperature material layer, the surface of the particle of coal firstly receives the radiation heat transfer of peripheral high-temperature materials, the heat received by the surface of the particle of coal is then transferred to the core part, and the transfer is the slowest in the radiation, convection and transfer modes of the heat transfer; therefore, the temperature of the deep layer and the core part of the coal particles lags behind the surface layer and the shallow layer in the temperature rise process, and the larger the particle size of the coal particles isThe longer the lag time. The invention aims to improve the pair H2The effective utilization rate of the coal is controlled by adjusting the size fraction range of the coal granules2The escape speed is that the granularity of the granular coal is generally selected to be 3-15 mm.
The iron ore reduction is established on the basis of hydrogen metallurgy, the process energy consumption of the rotary kiln is greatly reduced, namely, the effective heat for reducing iron oxide and physically heating materials is greatly reduced, which means that the capacity can be greatly improved on the premise of the same heat transfer quantity. More importantly, the reaction temperature point of hydrogen metallurgy is low, and iron oxide is reduced at a lower temperature; because the heat transfer quantity depends on the difference between the temperature of the combustion space and the temperature of the material, more heat can be transferred into the material layer under the same temperature of the combustion space, and the use efficiency of the heat is improved.
The invention realizes the high integration of the coal full pyrolysis process and the iron ore metallurgical reduction process in a thermal state, and the whole iron making process only adopts high volatile coal such as lignite and the like, and does not need coking coal. The reduction of iron oxides is converted from the traditional metallurgical coke-based carbon metallurgy process to "H" iron2+ activated granular carbon "dominated hydrometallurgical processes.
The temperature of the 8-15 mm granular high volatile coal and the 3-8 mm granular high volatile coal in the front section and the middle section material layer entering the hydrogen metallurgy roasting area of the rotary kiln is rapidly increased, and the H contained in the coal and the granular high volatile coal2Except a small amount of O directly enters the flue gas, most of O is heated in the material layer and is separated out to the gaps of the thermal state material layer, and H2O can partially gasify the active granular carbon and the dead carbon in a thermal state to generate H2And CO, which will overflow the bed of material for use as fuel, H, due to the selectivity of the chemical reaction2Will participate in the hydrogen metallurgy process of the iron ore and decompose siderite in the medium-grain iron ore to generate Fe3O4And generating CO gas, wherein the CO part participates in the reduction reaction of the medium-sized iron ore; 8-15 mm granular high volatile coal and 3-8 mm granular high volatile coal are pyrolyzed to release volatile matter, and H is produced in the thermal state material layer through secondary and multiple pyrolysis2Higher amounts of gas and activated granular carbon; h produced by the above reaction2Can reduce iron ore and generate H2O, part H2O reintegration materialThe active granular carbon or dead carbon in the layer is subjected to carbon gasification reaction to generate H2And CO, H2And reducing the iron ore as a reducing agent so as to form a coupling effect, so that the dehydration of the subsequent kiln-entering materials, the high integration of the coal pyrolysis process and the iron ore metallurgical reduction process in a thermal state are realized, and CO overflows from a material layer and enters a combustion space to be used as fuel.
The invention has the beneficial effects that:
1. reduction of iron ore to H2Is mainly and easily obtained
A large amount of H is generated after the volatile components of the coal in the material layer are fully pyrolyzed2，H2Formation of gaseous H after reduction of iron oxides2O，H2Gasifying carbon O and generating new H2And CO; due to the selectivity of the chemical reaction, H is used in the whole reduction process2Reduced mainly to H2The method is easy to obtain and use in production, and realizes the thermal intersection of the coal full pyrolysis and the iron oxide reduction process.
2. High heat transfer efficiency, high reduction speed and high productivity in hydrogen metallurgy
The reaction temperature point of hydrogen metallurgy is low, and more heat of the material layer can be introduced into the furnace at the same combustion space temperature, so that the reduction speed of the iron ore is accelerated, the process energy consumption is low, and the productivity can be greatly improved on the premise of the same heat transfer quantity.
3. The iron ore hydrogen metallurgy process has high product quality and good production stability of the rotary kiln
The reducing agent in the process adopts high volatile coal with the granularity of 3-15 mm, the granular coal is sprayed into the front section and the middle section of a hydrogen metallurgy roasting area of the rotary kiln, the volatile matter is slowly and continuously released in the process that the surface of the granular coal is heated and internally transfers heat, and the volatile matter enters a high-temperature environment to be pyrolyzed for two times or more times to produce H-rich coal2Gas, H2Ready to use in production, and H2The molecular radius is small, and the penetrability to the iron ore is strong under a certain temperature condition, so the roasting quality of the iron ore can be improved.
4. The iron ore hydrogen metallurgy process has high productivity and low energy consumption
The required reaction of iron ore hydrometallurgy compared with the traditional direct reduction processThe temperature point is low, which means that more heat can be transferred into the material layer under the same combustion space temperature, or the capacity of the hydrogen metallurgy rotary kiln is higher on the premise of the same heat transfer quantity; at the same time H2The reduction potential and the penetration capacity of the iron ore are far stronger than those of CO, so that the reduction speed is higher, and the iron ore can be directly reduced under the same time, temperature and reducing atmosphere conditions.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The invention is further illustrated below with reference to fig. 1:
a coal-based hydrogen metallurgy process for raw iron ores comprises the following steps:
example 1:
s1, an iron ore granularity grading machine is used for screening iron ore with the granularity of below 15mm into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, a residual carbon granularity grading machine is used for screening residual carbon into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, and a coal granularity grading machine is used for grading high-volatile coal into two size fractions of 3-8 mm fine particles and 8-15 mm coarse particles. In particular, the high volatile coal is preferably lignite, and the volatile content is more than 40%.
S2, mixing 0-1 mm iron ore, a binder and a liquid-phase hardening and tempering agent according to a weight ratio of 100: 1: 4, uniformly mixing the ingredients, adding water into a pelletizer, and pelletizing to obtain wet pellets with the particle size phi of 9-12 mm; particularly, the mass of the high volatile coal added into the rotary kiln accounts for 32-35% of the mass of the iron ore.
S3, mixing the wet balls prepared in the step S2 with 1-15 mm iron ore and 1-15 mm residual carbon, adding the mixture into a rotary kiln from a feeding end, blowing 8-15 mm high-volatile coal to the front section of a hydrogen metallurgy roasting area of the rotary kiln, and blowing 3-8 mm high-volatile coal to the middle section of the hydrogen metallurgy roasting area of the rotary kiln; controlling the time of the pellets in the kiln to be 45-50 min and the temperature of the high-temperature section to be 1120-1160 ℃.
And S4, discharging the high-temperature material with the temperature of above 1050 ℃ obtained in the step S3 into an oxygen-free cooling device for cooling, and discharging the material after cooling to normal temperature.
S5, adding the normal-temperature material obtained in the step S4 into a dry magnetic separator for dry magnetic separation to obtain a magnetic reduction material and nonmagnetic carbon residue;
the non-magnetic carbon residue is subjected to particle size classification through a screening device, and is screened into two particle sizes of 0-1 mm fine particles and 1-15 mm coarse particles, the 0-1 mm carbon residue is discharged as coal ash, and the 1-15 mm carbon residue is returned to a batching system for utilization; and the magnetic reduction material is subjected to fine grinding by using a dry grinding machine and then is subjected to magnetic separation by using a dry magnetic separator, and the iron powder with the iron grade of more than 83% and the metallization rate of about 95% can be obtained after tailings are removed.
Example 2
S1, an iron ore granularity grading machine is used for screening iron ore with the granularity of below 15mm into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, a residual carbon granularity grading machine is used for screening residual carbon into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, and a coal granularity grading machine is used for grading high-volatile coal into two size fractions of 3-8 mm fine particles and 8-15 mm coarse particles. In particular, the high volatile coal is preferably lignite, and the volatile content is more than 40%.
S2, mixing 0-1 mm iron ore, a binder and a liquid-phase hardening and tempering agent according to a weight ratio of 100: 3: 3, uniformly mixing the ingredients, adding water into a pelletizer, and pelletizing to obtain wet pellets with the particle size phi of 5-9 mm; particularly, the mass of the high volatile coal added into the rotary kiln accounts for 25-28% of the mass of the iron ore.
S3, mixing the wet balls prepared in the step S2 with 1-15 mm iron ore and 1-15 mm residual carbon, adding the mixture into a rotary kiln from a feeding end, blowing 8-15 mm high-volatile coal to the front section of a hydrogen metallurgy roasting area of the rotary kiln, and blowing 3-8 mm high-volatile coal to the middle section of the hydrogen metallurgy roasting area of the rotary kiln; the time of the pellets in the kiln is controlled to be 35-40 min, and the temperature of the high-temperature section is controlled to be 1190-1220 ℃.
And S4, discharging the high-temperature material with the temperature of above 1050 ℃ obtained in the step S3 into an oxygen-free cooling device for cooling, and discharging the material after cooling to normal temperature.
S5, adding the normal-temperature material obtained in the step S4 into a dry magnetic separator for dry magnetic separation to obtain a magnetic reduction material and nonmagnetic carbon residue;
the non-magnetic carbon residue is subjected to particle size classification through a screening device, and is screened into two particle sizes of 0-1 mm fine particles and 1-15 mm coarse particles, the 0-1 mm carbon residue is discharged as coal ash, and the 1-15 mm carbon residue is returned to a batching system for utilization; and the magnetic reduction material is subjected to fine grinding by using a dry grinding machine and then is subjected to magnetic separation by using a dry magnetic separator, and the iron powder with the iron grade of more than 83% and the metallization rate of about 95% can be obtained after tailings are removed.
Example 3:
s1, an iron ore granularity grading machine is used for screening iron ore with the granularity of below 15mm into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, a residual carbon granularity grading machine is used for screening residual carbon into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, and a coal granularity grading machine is used for grading high-volatile coal into two size fractions of 3-8 mm fine particles and 8-15 mm coarse particles. In particular, the high volatile coal is preferably lignite, and the volatile content is more than 40%.
S2, mixing 0-1 mm iron ore, a binder and a liquid-phase hardening and tempering agent according to a weight ratio of 100: 2: 2, uniformly mixing the ingredients, adding water into a pelletizer, and pelletizing to obtain wet pellets with the particle size phi of 12-15 mm; particularly, the mass of the high volatile coal added into the rotary kiln accounts for 29-31% of the mass of the iron ore.
S3, mixing the wet balls prepared in the step S2 with 1-15 mm iron ore and 1-15 mm residual carbon, adding the mixture into a rotary kiln from a feeding end, blowing 8-15 mm high-volatile coal to the front section of a hydrogen metallurgy roasting area of the rotary kiln, and blowing 3-8 mm high-volatile coal to the middle section of the hydrogen metallurgy roasting area of the rotary kiln; controlling the time of the pellets in the kiln to be 40-45 min and the temperature of the high-temperature section to be 1160-1190 ℃.
And S4, discharging the high-temperature material with the temperature of above 1050 ℃ obtained in the step S3 into an oxygen-free cooling device for cooling, and discharging the material after cooling to normal temperature.
S5, adding the normal-temperature material obtained in the step S4 into a dry magnetic separator for dry magnetic separation to obtain a magnetic reduction material and nonmagnetic carbon residue;
the non-magnetic carbon residue is subjected to particle size classification through a screening device, and is screened into two particle sizes of 0-1 mm fine particles and 1-15 mm coarse particles, the 0-1 mm carbon residue is discharged as coal ash, and the 1-15 mm carbon residue is returned to a batching system for utilization; and the magnetic reduction material is subjected to fine grinding by using a dry grinding machine and then is subjected to magnetic separation by using a dry magnetic separator, and the iron powder with the iron grade of more than 83% and the metallization rate of about 95% can be obtained after tailings are removed.
It should be noted that the above are only some embodiments of the present invention, and it should be noted that, for those skilled in the art, many modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.
Claims (7)
1. A coal-based hydrogen metallurgy process for raw iron ores is characterized by comprising the following steps:
s1, screening iron ore with the particle size of below 15mm into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, screening residual carbon into two size fractions of 0-1 mm fine particles and 1-15 mm coarse particles, and classifying high-volatile coal into two size fractions of 3-8 mm fine particles and 8-15 mm coarse particles;
s2, mixing 0-1 mm iron ore, a binder and a liquid-phase hardening and tempering agent according to a weight ratio of 100: (1-3): (2-4) uniformly mixing the ingredients, adding water into a pelletizer, and pelletizing to obtain wet pellets with the particle size phi of 5-15 mm;
s3, mixing the wet balls prepared in the step S2 with 1-15 mm iron ore and 1-15 mm residual carbon, adding the mixture into a rotary kiln from a feeding end, blowing 8-15 mm high-volatile coal to the front section of a hydrogen metallurgy roasting area of the rotary kiln, and blowing 3-8 mm high-volatile coal to the middle section of the hydrogen metallurgy roasting area of the rotary kiln; controlling the time of the pellets in the kiln to be 35-50 min and the temperature of the high-temperature section to be 1120-1220 ℃;
s4, discharging the high-temperature material with the temperature of above 1050 ℃ obtained in the step S3 into an oxygen-free cooling device for cooling, and discharging the material after cooling to normal temperature;
s5, adding the normal-temperature material obtained in the step S4 into a dry magnetic separator for dry magnetic separation to obtain a magnetic reduction material and nonmagnetic carbon residue;
the non-magnetic carbon residue is subjected to particle size classification through a screening device, and is screened into two particle sizes of 0-1 mm fine particles and 1-15 mm coarse particles, the 0-1 mm carbon residue is discharged as coal ash, and the 1-15 mm carbon residue is returned to a batching system for utilization; and the magnetic reduction material is subjected to fine grinding by using a dry grinding machine and then is subjected to magnetic separation by using a dry magnetic separator, and the iron powder with the iron grade of more than 83% and the metallization rate of about 95% can be obtained after tailings are removed.
2. The raw ore coal-based hydrometallurgical process of iron ore according to claim 1, wherein the mass of the high volatile coal added to the rotary kiln in step S2 is 25-35% of the mass of the iron ore.
3. The raw ore coal-based hydrogen metallurgy process for iron ore according to claim 1, wherein 2-4 kiln back-draught fans are respectively arranged at the front section and the middle section of the kiln body of the rotary kiln, and the kiln back-draught fans supply normal-temperature air into the kiln along the length direction of the rotary kiln according to process requirements.
4. The process of claim 1, wherein the high volatile coal is lignite and the volatile content is above 40%.
5. The raw ore coal-based hydrometallurgical process of claim 1, wherein said iron ore screening of step S1 uses an iron ore sizer.
6. The raw ore coal-based hydrometallurgical process of iron ore according to claim 1, wherein the carbon residue screening in step S1 uses a carbon residue size classifier.
7. The raw ore coal-based hydrometallurgical process of claim 1, wherein said step S1 uses a coal classifier for classifying high volatile coal.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113684336A (en) * | 2021-07-21 | 2021-11-23 | 酒泉钢铁(集团)有限责任公司 | Direct reduction process of iron ore coal-based step-by-step oxygenation-segmented hydrogen increasing rotary kiln |
| CN113699370A (en) * | 2021-07-21 | 2021-11-26 | 酒泉钢铁(集团)有限责任公司 | Process for producing semisteel by coal-based hydrogen metallurgy, hot agglomeration and electric furnace in iron ore concentrate rotary kiln |
| CN114247563A (en) * | 2021-11-20 | 2022-03-29 | 酒泉钢铁(集团)有限责任公司 | Method for separating carbon residue from iron ore direct reduction material |
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| CN110195156A (en) * | 2019-06-14 | 2019-09-03 | 甘肃酒钢集团宏兴钢铁股份有限公司 | A kind of iron ore rotary kiln coal base hydrogen metallurgical technology and its device |
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| CN110195155A (en) * | 2019-06-14 | 2019-09-03 | 甘肃酒钢集团宏兴钢铁股份有限公司 | A kind of refractory iron ore bone coal base either shallow hydrogen metallurgical technology and its device |
| CN110195156A (en) * | 2019-06-14 | 2019-09-03 | 甘肃酒钢集团宏兴钢铁股份有限公司 | A kind of iron ore rotary kiln coal base hydrogen metallurgical technology and its device |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113684336A (en) * | 2021-07-21 | 2021-11-23 | 酒泉钢铁(集团)有限责任公司 | Direct reduction process of iron ore coal-based step-by-step oxygenation-segmented hydrogen increasing rotary kiln |
| CN113699370A (en) * | 2021-07-21 | 2021-11-26 | 酒泉钢铁(集团)有限责任公司 | Process for producing semisteel by coal-based hydrogen metallurgy, hot agglomeration and electric furnace in iron ore concentrate rotary kiln |
| CN114247563A (en) * | 2021-11-20 | 2022-03-29 | 酒泉钢铁(集团)有限责任公司 | Method for separating carbon residue from iron ore direct reduction material |
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