CN100430496C

CN100430496C - Iron ore briquetting

Info

Publication number: CN100430496C
Application number: CNB028194586A
Authority: CN
Inventors: G·S·贝罗斯; J·F·甘农
Original assignee: Commonwealth Scientific and Industrial Research Organization CSIRO; Robe River Mining Co Pty Ltd
Current assignee: Commonwealth Scientific and Industrial Research Organization CSIRO; Robe River Mining Co Pty Ltd
Priority date: 2001-08-02
Filing date: 2002-08-02
Publication date: 2008-11-05
Anticipated expiration: 2022-08-02
Also published as: BR0211944B8; JP2011017083A; CN1307317C; WO2003012153A1; JP2004536968A; DE60236172D1; EP1425427A1; KR101068600B1; CA2456191A1; ATE473303T1; AU2002322154B2; CA2456191C; CN1561400A; ZA200400955B; US20050126343A1; AUPR678301A0; KR20100122961A; JP5253701B2; WO2003012152A1; WO2003012154A1

Abstract

A method of producing an iron one briquette that is suitable for use as a blast furnace or other direct reduction furnace feedstock which includes the steps of: (1) mixing: (i) ore having a predetermined particle size distribution with a top size of 4.0 mm or less; and (ii) a flux; to form an ore/flux; (2) adjusting the water content of the ore prior to or during mixing step (1) to optimise briquette quality and product yield; (3) pressing the ore/flux mixture into a green briquette; and (4) indurating the green briquette to from a fured briquette.

Description

Iron ore is pressed group

The present invention relates to produce and be suitable in the iron-smelting process iron ore briquette (briquettes) carrying and use.

From 19 th century later, iron ore briquetting (agglomerating iron ores) method grows up.But, in all existing technologies, only make ball now and sintering process is of great importance, and there is some shortcoming in these technologies.

Make bag and draw together two kinds of different operations: form pellet (pellets) by wet breeze, then under the temperature in 1300 ℃ of zones to its roasting (firing).Make suitable pellet, key is ore should be milled very thin, and general granularity reaches about 60% ore by 45 microns.Generally by adding suitable binders,, it is shaped to pellet then at horizontal drum or in inclined plate.Then the pellet after the moulding is carried out roasting by the technology that is called as fixed (induration) sometimes in the combination of shaft furnace, horizontal belt sinter machine (horizontal travelling grates) or Dwight-Lloyd sintering machine and rotary oven.Make ball and be and a kind of fine concentrate sand is carried out the feasible and industrial attractive method of briquetting, but need mill in a large number, to reach required pellet screening, this is a lot of technology of power consumption.Need be fixed for a long time by the pellet that pyrrhosiderite-hematite ore is made, influenced process economy.Usually add the solid fuel of coke type, to reduce consolidation time, this causes producing toxic discharge again and (comprises Dioxins, NO _XAnd SO _x).

Sintering comprises with solid fuel (being generally coke powder) wet powdered iron ore and other powdered material is carried out granulation, and the mixture after the granulation is put in the ventilative Dwight-Lloyd sintering machine.Because of temperature raises, pass through fire grate (grate) draws air downwards.The after date of lighting through short interrupts the indirect heating to bed, and because of solid fuel ignition in the bed, has a narrow combustion zone to move down and pass bed, and makes each layer be heated to about 1300 ℃ successively.In combustion processes, bond between the pellet, form firm caking.But conventional sintering process causes high-load toxic discharge, especially oxysulfide and Dioxins, and therefore, this technology is because environment reason is undesirable and unacceptable.

The group of pressure (Briquetting) is late period in 19th century and a kind of technology that industrial significance was arranged in 20th century in early days, but the iron ore briquette of production never reaches any significant degree as the blast furnace charging, just reduced after nineteen fifty, and ended in about nineteen sixty.This process implementing gets up to relate to breeze is pressed into the suitable blocks of certain sizes and shape, fixed then this blocks.Once tested various tackiness agents, such as tar and pitch, and/or other additive such as organic product, water glass, ferrous sulfate, magnesium chloride, Wingdale and cement.But pressure group technology the earliest is Glenn Da Er

Technology includes only compound iron ore and water, and to be pressed into pane be the building brick size.Then they are carried the kiln that passes through tunnel, be heated to 1350 ℃, make it sclerosis.

Although the development of the group's of pressure technology generally is devoted to develop suitable tackiness agent, JP 60-243232 has described the flat-section agglomerate, to constitute stable distribution the in the blast furnace.Specifically, this Japanese patent specification discloses, and the flat-section agglomerate reduces manyly than conventional spherical ball nodulizing is easier under comparatively high temps.This agglomerate is formed into the volume between 2 to 30 cubic centimetres, with the balance higher compressive strength, and inferior rotation or roll intensity and shock strength that antagonism causes with increased in size.This Japanese patent specification discloses, and not too easily is reduced than megalump in blast furnace.But, except the size and dimension of agglomerate, do not illustrate that other is critical factor, and in fact any others of producing this agglomerate be not elaborated.

The applicant furthers investigate producing agglomerate by iron ore, and has invented a kind of method that its performance is applicable to the agglomerate of blast furnace and other direct reduction vessel of producing.

The applicant finds that the success of this production method has many key factors.These factors comprise based on mineralogy, porosity, size distribution and chemical constitution and characterize starting material, and then utilize this information to determine to make the suitable required various parameters of the finished product, comprise the molding parameter and the consolidation parameters of optimum agglomerate.

According to the present invention, a kind of method that is suitable for the iron ore briquette of doing blast furnace or other direct reduction furnace charging of producing is provided, this method comprises the steps:

(a) mix: (i) have the ore that predetermined particle size distributes, its upper limit size be 4.0 millimeters or below and (ii) a kind of flux (flux), to form a kind of ore/flux mixture;

(b) mixing step (a) before or during regulate the ore water content, to optimize clumps quality and product yield;

(c) suppressing described ore/flux mixture is green briquette (green briquette); With

(d) fixed this green briquette, the agglomerate (fired briquette) after the formation roasting.

A feature of aforesaid method is, the predetermined particle size that can be formed in without ground ore in the step (a) with flux blended ore particulate distributes.

Preferred this method comprises to be pulverized and the screening ore, distributes with flux blended predetermined particle size to be formed in the step (a).

Preferably the upper limit size that distributes with flux blended predetermined particle size in step (a) is 3.5 millimeters.

Preferred described upper limit size is 3.0 millimeters.

More preferably described upper limit size is 2.5 millimeters.

More preferably described upper limit size is 1.5 millimeters.

More preferably described upper limit size is 1.0 millimeters.

Preferably in step (a), comprise the less than 50% of passing 45 microns screen clothes with the distribution of flux blended predetermined particle size.

More preferably described size-grade distribution comprises the less than 30% of passing 45 microns screen clothes.

More preferably described size-grade distribution comprises the less than 10% of passing 45 microns screen clothes.

Preferred described ore is a kind of hydrated iron ore.

Preferred described hydration ore is the ore that contains pyrrhosiderite.

Preferred described flux size-grade distribution is mainly less than 100 microns.

Preferred described flux size-grade distribution comprise pass 250 microns screen clothes more than 95%.

Preferred described flux is Wingdale.

Preferably, select the ore/flux mixture of generation in the step (a), so that the basicity of the agglomerate after the roasting (basicity) is greater than 0.2.

More preferably described basicity is greater than 0.6.

Term " basicity " is understood to mean (%CaO+%MgO)/(%SiO of agglomerate after the roasting here ₂+ Al ₂O ₃%).

Preferably in this ore/flux mixture, there is not tackiness agent.

Preferably, step (b) comprises the water content of regulating ore, so that described ore/flux mixture water content is the 2-12 weight % of this ore/flux mixture total weight amount.

Term " gross weight of ore/flux mixture " refers to the total amount of (a) this ore/flux mixture dry weight, (b) this mixture inherent moisture weight and the weight of the moisture (if any) that (c) adds to this mixture in the method.

Term " water content " is above (b) and total amount (c).

Preferably, step (b) comprises regulates the ore water content, makes that the water content of described ore/flux mixture is the 2-5 weight % of ore/flux mixture total weight amount for fine and close rhombohedral iron ore stone.

Preferably, step (b) comprises regulates the ore water content, makes that the water content of described this ore/flux mixture is the 4-8 weight % of ore/flux mixture total weight amount for the ore that contains maximum 50% pyrrhosiderites.

Preferably, step (b) comprises regulates the ore water content, makes that the water content of described ore/flux mixture is the 6-12 weight % of this ore/flux mixture total weight amount for the ore that is mainly, promptly contains 50% above pyrrhosiderite.

Preferably, pressing step (c) manufacturing volume is 10 cubic centimetres or following agglomerate.

More preferably, pressing step (c) manufacturing volume is 8.5 cubic centimetres or following agglomerate.

More preferably, pressing step (c) manufacturing volume is 6.5 cubic centimetres or following agglomerate.

Preferably, pressing step (c) comprises and utilizes low rolling pressure to suppress described ore/flux mixture.

Preferably, this described rolling pressure is enough to make the agglomerate of compression strength of green pellet at least 2 kilogram forces.

More preferably, described compression strength of green pellet is at least 4 kilogram forces.

More preferably, described compression strength of green pellet is at least 5 kilogram forces.

Preferably, by ore/flux mixture being applied the method for rolling pressing force of 10-140 thousand newton/centimetre (kN/cm), produce described low rolling pressure.

More preferably, described roll pressing force be 10-60 thousand newton/centimetre.

More preferably, described roll pressing force be 10-40 thousand newton/centimetre.

Preferably, consolidation step (d) is included in 40 minutes described agglomerates of internal heating to maturing temperature.

Preferably, consolidation step (d) is included in 35 minutes described agglomerates of internal heating to maturing temperature.

More preferably, sintering step (d) is included in 30 minutes described agglomerates of internal heating to maturing temperature.

More preferably, sintering step (d) is included in 20 minutes described agglomerates of internal heating to maturing temperature.

More preferably, sintering step (d) is included in 15 minutes described agglomerates of internal heating to maturing temperature.

Preferably, maturing temperature is at least 1200 ℃.

More preferably, maturing temperature is at least 1260 ℃.

More preferably, maturing temperature is at least 1320 ℃.

More preferably, maturing temperature is at least 1350 ℃.

More preferably, maturing temperature is at least 1380 ℃.

Preferably, the crushing strength of the agglomerate after the roasting is at least 200 kilogram forces (kgf).

More preferably, the crushing strength of the agglomerate after the roasting is at least 200 kilogram forces.

Based on petrology characteristic such as mineralogy, mineral paragenesis and microgranular texture, porosity, size distribution and chemistry, iron ore roughly is characterized as being four groups.These groups are:

(a) the fine and close rhombohedral iron ore/magnetic iron ore of HC-;

(b) GC-contains the ore of maximum 50% pyrrhosiderites; And

(c) to contain pyrrhosiderite be main ore to G-, i.e. pyrrhosiderite more than 50% is such as peastone, landwaste and channel settling.

The following several pages of two kinds of special subfamilys that relate to the GC ore of this specification sheets, that is:

(i) HG-is the main ore that contains pyrrhosiderite with the rhombohedral iron ore; And

(ii) GH-rhombohedral iron ore and the approximately uniform ore of pyrrhosiderite content.

Be not bound by theory although do not wish; but it is believed that; bonding mechanism in the green briquette relates to the combination of several keys that comprise particulate machinery chimeric (interlocking), model ylid bloom action power; and under GC and G type raw material condition; hydrogen bonding in various degree depends on the per-cent that the hydrated iron species exist, for example pyrrhosiderite.Now definite, several specific characters of charging are bonded with material impact to forming these, influence the quality and the processing characteristics of agglomerate after green briquette and the roasting.These characteristics are charging water content and flow characteristics, ore chemistry composition, its size distribution and petrology characteristic and porosity.

Preferably, these chargings have the wideest possible size distribution, with high-bulk-density and the enhancing bonding that reaches the ore particulate.As mentioned above, to be considered to be in raw material be by because the caused several agglutinating combinations of chimeric, model ylid bloom action power of particulate machinery and hydrogen bonding under GC and the G type situation to the bonding mechanism of green briquette.Although wide particle diameter distributes and to have increased tap density, and has improved the intensity of green briquette, might agglomerate be the iron ore after precision is sieved.

The particulate upper limit size determined by disintegrating process, but preferably less than 2.5 millimeters, so that make the qualified agglomerate of performance after the roasting after carrying out consolidation process.Generally, HC and HG type ore can be pressed group reach thicker upper limit size, because the intensity institute heat requirement that these starting material are reached after the qualified roasting is lower.Can reduce the upper limit size of this raw material by pulverizing or screening process.Lower limit granularity to particulate does not have absolute limitations, but does not need or do not wish ore is milled into very thin particulate (as it is needed to make ball), because needn't constitute other economical load to the present invention like this.Preferably, the particulate of less than 10% passes 45 microns sieve.

Advantageously should select ore pocket (pocket) size of the group's of pressure device based on the maximum particle size of being pressed group, it is selected also is in order to make fixed performance suitable, to guarantee to obtain gratifying pressure group.Generally, the maximum particle size that obtains gratifying pressure group is the 25-30% of minimum ore pocket size.If maximum particle size surpasses this specification, then may essentially select bigger ore pocket size.

Preferably to control the charging water content, to optimize green briquette quality and product yield.Amount of water should not surpass makes liquid bridge joint (liquid bridging) become the degree of the principal mode of interparticle bonding.This will cause giving birth to (agglomerate) intensity and reduce the disadvantageous effect that reaches thermostability.Moisture deficit can cause the over-pressurization in the agglomerate pressing step, and and green briquette quality and yield is had a negative impact.

According to the feedstock characteristic that is subject to processing ore, the charging water content between 2-12 weight % is used to optimize the green briquette quality and product yield.Fine and close hematite concentrate sand (HC) has low the best and presses group's water content, generally in 2-5 weight % scope.These washed ores are made up of the particulate of precision screening usually, and its smooth surface structure produces the low strength agglomerate, because the chimeric minimizing of particulate.The pyrrhosiderite stone that contains the higher hole of maximum 50% pyrrhosiderites (GC), in 4-8 weight % water content ranges, its pressure is rolled into a ball, and based on the ore (G) of the higher hole of pyrrhosiderite, in 6-12 weight % water content ranges, its pressure is rolled into a ball.These ores have rough surface structure and shape, have strengthened its group's of pressure characteristic.

The inventive method can adopt the conventional group of pressure device.Substantially, this device comprises two adjacent rollers being with ore pocket, and this two adjacent roll is joined in the roll gap district, and the compression charging enters the ore pocket of adjacent pairs, makes agglomerate.For case of the present invention, this two rolls preferred levels centering is to obtain the required processing power of economical rationality.

Although the group of pressure can carry out under the wide region rolling pressure according to purposes, but to the pressure of iron ore group preferably 10-140 thousand newton/centimetre roll compaction power (roll pressing force) operation down, more preferably operate general 10-60 thousand newton/cm range at the low side of this scope.Press group for iron ore, this low voltage operated be important, and make it to utilize wide roll, on the balling press of the highest 1.6m length, obtain high productivity.

Preferably, careful controlled rolling pressure in low pressure range is to optimize the operation of the group of pressure.If rolling pressure is too low, can force roll separately, the thick web of output (thick web) and be out of shape agglomerate has reduced the productive rate and the quality of agglomerate, especially after fixed.If rolling pressure surpasses optimum value, then because of to " clam shell " of agglomerate disengaging ore pocket (clamshell) effect, it is not good the agglomerate closure to occur.This clam shell effect can be more obvious to minor diameter roller and too high rolling pressure, and this can cause ore pocket bonding/obstruction (jamming) again.Although the density of green briquette and crushing strength will increase, the shock strength of agglomerate can be subjected to grievous injury after the roasting.

Preferably, the selection water content influences the flow characteristics by the material of feed system, and this charging water content generally suits at 2-12 weight %.If the feed system water content is too high, feed pressure there is disadvantageous effect, cause yield to reduce and agglomerate quality partly descend (hanging down with green pellet strength is feature).If charging moisture is too low in the feed system, then the gained feed pressure will cause clam shell (clamshelling), cause the wear rate increase and the roasting performance of yield reduction, roll ore pocket inferior.

Operate to described pressure group's available a kind of precompressed real machine feed system of device or with a kind of gravity type boat davit feed system.The gravity type boat davit feed system presses group favourable to carrying out as the high tonnage in iron ore industry.

For balling press, select roller diameter, to guarantee being issued to the agglomerate quality in the productivity of economy.Large diameter roll can be boosted productivity, but has increased the area in roll gap district between two rollers.Roll-gap region between careful control two rollers helps forming the high-quality green briquette, avoids forming the agglomerate of blocked up web (web).Change the optimum moisture content that roller diameter also can change charging, increase expression at this roller diameter and increased the charging water content.Roller diameter generally changes the millimeter in 250-1200.In order to make output reach maximum, preferably, roll should be with the fastest as far as possible speed operation when keeping the agglomerate quality.But,, then can adopt the very slow speed of rolls if productivity belongs to less important concern.

Generally, adopt the speed of rolls 1-20 rev/min of (rpm) scope.In order to keep quality, especially under the high speed of rolls, preferably breaker roll provides the speed of charging to be complementary with the agglomerate throughput rate, and the roll gap area between two rollers can produce formation high-quality agglomerate necessary forces.

Can select any suitable roller width, as long as it is in the balling press pressure capacity scope.Because iron ore presses group to belong to low voltage operated, wide roll is preferred, has increased the ability of roller mill.This roll preferably by level to centering, to use the gravity feed system.No matter be HC, GC (comprising HG and GH), or the iron ore of G, its flow characteristics all is fit to the gravity charging in to the above-mentioned water content ranges of each classification concrete regulation.

The ore pocket shape should not be an acute angle generally, and should be more level and smooth and circular, to improve handling characteristics.For example, about 0.65 length/width and width/depth ratio suit.The ore pocket shape also has special disengaging angle (release angles), and 110-120 °, with the trend of antagonism ore pocket adhesion.

Can make ore pocket dimensionally-optimised according to requirement to consolidation process and raw material upper limit size and ironmaking blast furnace.General agglomerate volume is between the 2-30 cubic centimetre.Preferred this volume 10 cubic centimetres or below.More preferably this volume 8.5 cubic centimetres or below.More preferably this volume is below 6.5 cubic centimetres.

Staggered ore pocket structure is preferred, because can make useful space utilization the best on the roll crown like this, and therefore makes the processing power maximization.

Preferably, at the influence of complex relationship between property of raw material and agglomerate size and select consolidation method and condition.

Need consider the relation between agglomerate volume, shape and raw material petrology characteristic.The charging chemical constitution can have material impact to agglomerate performance after the roasting.Except that water content, charging also comprises the iron ore that is made of ferric oxide and gangue material, wherein adds promisingly to make the agglomerate after the roasting reach the required required flux of base.Test-results shows, described flux should be preferably divides through dusting cover, generally pass 250 microns＞95%, to reach the required performance of agglomerate after the roasting.

Although do not wish to be bound by theory, it is believed that the bonding mechanism of agglomerate relates to the diffusion bonding and the recrystallize of ferric oxide particles after the roasting, and the slagging scorification under higher flux content (slag bonding).Therefore, flux content and maturing temperature and the roasting time on certain degree all have strong influence to the agglomerate performance.Rising base level can improve reduction intensity and consolidation strength, forms the bonding phase because higher flux content can impel, and prevents the distortion under the reductive condition.

Fixed belt type roasting machine (straight grate), chain grate machine rotary kiln (grate-kiln) or the continuous rotary kiln type technology utilized is finished.

Having been found that and compared by the pellet of same material manufacturing, is very heat-staple optimizing the green briquette of making under the roasting distribution occasion.Must be the charging ore grinding poling fine granularity of making ball, generally make pass 45 microns nearly 60%, and the general slow drying under＜200 ℃ low temperature of these pellets is to avoid spallation (spalling).On the contrary, as noted before, be used for that of the present invention can successfully to carry out fixed charging ore but can be much thick, therefore its upper limit size need not be ground to and make the needed same degree of pellet preferably up to 2.5 millimeters.This characteristic represents that the group's of pressure operation investment cost reduces, and is better than conventional pellet manufacturing installation.

A key property of agglomerate of the present invention be can be when rapid heating withstand high temperatures, such as in 30 minutes, more preferably in 20 minutes, be heated to maturing temperature.This just in time is different from pyrrhosiderite stone that routine recognizes how to the situation of consolidation condition response, has promptly occurred pyrrhosiderite stone this moment and heat by dehydroxylation and free water removal district the time too soon and spallation.

As noted before, have now found that agglomerate thermostability of the present invention is high more a lot of than pellet, can be to be heated and unlikely spallation than the fast a lot of speed of pellet.This can make heating period short a lot.Therefore, agglomerate productivity can be apparently higher than the pellet that utilizes same material.For example, in belt chain grate machine rotary kiln, agglomerate productivity can reach about 30 tons of/square metre days, and contrasts with the pellet productivity formation of 16 tons of/square metre days in same kiln of HG ore.

Should be understood that understanding, although here with reference to the publication of prior art, this reference does not constitute this area has formed the general general knowledge of part to all these files approval in Australia or any other country.

Now method by way of example only with reference to the accompanying drawings, is described the preferred embodiments of the invention, wherein:

Fig. 1 is the suitable device synoptic diagram that has 250 mm dia rolls and pre-compacted feed system that is used to implement the inventive method;

Fig. 2 is the suitable device synoptic diagram that has 450 mm dia rolls and gravity feed system that is used to implement the inventive method;

Fig. 3 is the suitable device synoptic diagram that has 650 mm dia rolls and gravity feed system that is used to implement the inventive method;

Fig. 4 founds all agglomerate yields of centimetre almond type and 4 cubic centimetre long almond type ore pockets graph of a relation to charging water content with 6 sides for the HG raw material on 450 millimeters rolls;

Fig. 5 is that the charging water content is to the graph of a relation of green briquette intensity effect when using the different size ore pocket for HG circle material on 450 millimeters rolls;

Fig. 6 is for the HG material during with 650 millimeters rolls and 7.5 cubic centimetres " pillow ", and the charging water content is to the graph of a relation of green briquette intensity effect;

Fig. 7 shows for 450 millimeters rolls and 9 cubic centimetres of almond type roll compaction power the agglomerate performance; The influence of thickness, green pellet strength and green density;

Fig. 8 shows the rolling figure that influences to green pellet strength of roll during with 650 millimeters rolls and 7.5 cubic centimetres " pillow " to the HG material;

Roll compaction power was to the figure that influences of green pellet strength when Fig. 9 showed the GH material with 650 millimeters rolls and 7.5 cubic centimetres " pillow ";

Figure 10 is for 90 kilograms/square centimeter of rolling pressures and charging water content 6 weight %, when utilizing 450 millimeters rolls and 9 cubic centimetres of almond type ore pockets, shows that the speed of rolls is to the agglomerate performance: the influence of thickness, green pellet strength and green density;

Figure 11 is the operation optimum range (operating window) for balling press that has precompressed real machine, 250 millimeters rolls, 4 cubic centimetres of almond type ore pockets and HG material.

Figure 12 shows the fixed temperature distribution of agglomerate in 500 millimeters deep beds;

Figure 13 shows the agglomerate consolidation temperature distribution plan of making agglomerate under high productivity and is distributing than the pellet typical case consolidation temperature of making pellet under the poor efficiency;

Figure 14 utilizes 650 millimeters rolls and 7.5 cubic centimetres " pillow ", shows when the gap chain grate machine rotary kiln medium chain grate machine cycle (grate cycle) the finishes average bed temperature figure that influences to the agglomerate made with the GH material;

Figure 15 utilizes 650 millimeters rolls and 7.5 cubic centimetres " pillow ", shows when the chain grate machine rotary kiln medium chain grate machine rotary kiln baking end cycle of the gap average bed temperature figure that influences to the agglomerate made with the GH material;

Figure 16 utilizes 650 millimeters rolls and 7.5 cubic centimetres " pillow ", shows in the test period process of gap chain grate machine rotary kiln the figure that influences in (1380 ℃) the following time of maturing temperature to the agglomerate made with the GH material;

Figure 17 utilizes 650 millimeters rolls and 7.5 cubic centimetres " pillow ", shows in the chain grate machine rotary kiln test period process of gap the figure that influences in (1380 ℃) the following time of maturing temperature to the agglomerate made with the GH material;

Figure 18 is the figure that influences that 7.5 cubic centimetres of GH agglomerates during the residence time is to rotary kiln in the test period of rotary kiln process only are described.

Figure 19 utilizes 650 millimeters rolls and 7.5 cubic centimetres " pillow ", and in the chain grate machine rotary kiln test period process of gap bed height and chain grate machine grate firing (gratefiring profile) figure that influences to the agglomerate made with the GH material that distributes is described;

Figure 20 utilizes 650 millimeters rolls and 7.5 cubic centimetres " pillow ", illustrates that in the chain grate machine rotary kiln test period process of gap bed height and chain grate machine grate firing distribute to the figure that influences of the agglomerate made with the GH material;

Figure 21 illustrates the influence of crushing strength after base and maturing temperature are to the roasting of the agglomerate made with HG material, 250 millimeters rolls and 4 cubic centimetres of almond type ore pockets;

Figure 22 illustrates that for HG material, 250 millimeters rolls and 4 milliliters of agglomerates that almond type ore pocket is made base is to the agglomerate reducing property; Reduction after, reduction back crushing strength (CSAR) and the influence of reducing property exponential.

Embodiment 1

Finish the group of pressure with three kinds of differential roller press of differential roller diameter, width and feed system.

Initial test utilizes Taiyo K-102A double roll press to carry out, and its nominal capacity is 300 kilograms/hour.250 millimeters of this machine roller diameters, 36 millimeters of width are feature with spiral type precompressed real machine.The synoptic diagram of its major parts is described, can be referring to Fig. 1.

The agglomerate of manufacturing is a pillow shape, and its nominal size is 13 * 19 * 28 millimeters, and volume is 4 cubic centimetres.Around each roller periphery 30 ore pockets of one row are arranged.

One of two rollers are fixed, and another " floating roll " sets off with an oily vapour filling push rod (an oiland gas filled ram) and lean against on this stationary roll.To the pressurization of the oil in this push rod, to provide roll shop building required carrying capacity.

Also utilize Komarek BH400 double roll press, the group of pressure, its roller diameter is 450 millimeters, 75 millimeters of width.By gravity charging is added roll gap district between two rollers from the hopper that is arranged on roll top.Its major parts synoptic diagram can be referring to Fig. 2.

Make the agglomerate of different size, its details is as follows:

(1) nominal is 17.5 * 28 * 34.3 millimeters, 8.9 cubic centimetres of volumes.Arrange to have double 48 ore pockets (9 cubic centimetres of almond types) around the staggered centering of each row's periphery.

(2) nominal is 14.5 * 22.1 * 33.9 millimeters, 6.3 cubic centimetres of volumes.Arrange to have double 60 ore pockets (6 cubic centimetres of almond types) around the staggered centering of each roller periphery.

(3) nominal is 15.2 * 21.7 * 22.9 millimeters, 3.9 cubic centimetres of volumes.Arrange to have three row's 58 ore pockets (4 cubic centimetres of spheries) around the staggered centering of each row's periphery.

(4) nominal is 11.2 * 17.3 * 32.1 millimeters, 3.9 cubic centimetres of volumes.Arrange to have double 72 ore pockets (4 cubic centimetres of elongated shapes) around the symmetrical centering of each roller periphery.

One of two rollers are fixed, and another " floating roll " sets off with oily vapour filling push rod and lean against on this stationary roll.To the pressurization of the oil in the push rod, to provide roll shop building required specific pressing force.

130 millimeters of 650 millimeters of a kind of diameters and roller width have also been utilized

52/6.5 double roll press, the group of pressure.From being arranged on the hopper of top, charging is added roll gap district between two rollers by gravity.Roll gap district area between a kind of by utilizing " roll gap district setter " control two rollers.Its major parts synoptic diagram can be referring to Fig. 3.

The agglomerate of making is " pillow " shape, and 30 * 24 * 16 millimeters of its nominal sizes form 7.5 cubic centimetres of volumes.Symmetry is traversed the roll crown arrangement 77 ore pockets of four rows.

One of two rollers are fixed, and simultaneously another " floating roll " sets off with oily vapour filling push rod and lean against on this stationary roll.To the pressurization of the oil in the push rod, to provide roll shop building required specific pressing force.

Embodiment 2

Studied the influence of charging water content.

Fig. 4 explanation, the charging water content has material impact to using as the yield with 6 cubic centimetres and 4 cubic centimetres agglomerates of the balling press manufacturing of 450 millimeters rolls as described in the embodiment 1.Add charging by the gravity breaker roll, roll is operated under the rolling pressure of the stationary roll speed of 20rpm and 90 kilograms/square centimeter simultaneously.

Control to the charging water content also is important, because change of moisture content influences the green briquette performance, such as green briquette intensity, resistance to abrasion and shatter strength.Fig. 5 and 6 has illustrated this point.

Fig. 5 explanation, during with the ore pocket of 450 millimeters rolls, gravity feed system and wide variety of sizes, the relation between the intensity of charging water content and the agglomerate made by HG.

Fig. 6 explanation, for the HG material, the agglomerate made from 650 millimeters rolls and 7.5 cubic centimetres of ore pockets has same relation.

In optimum water content about 6% time, green briquette intensity is tending towards increasing to maximum.Water content surpasses 7.5%, and green briquette intensity is low, and is defective.

The charging water content is less to the shatter strength and the living resistance to abrasion influence of agglomerate.

Embodiment 3

As noted before, although the operation of the group of pressure can be finished under the rolling pressure of wide range, preferably, the group of pressure should finish under low pressure.For the pressure group of iron ore, this low voltage operated be important, and started on balling press with wide roll realize high throughput rate may.

But, as noted before, if optimize to press group's operation, then carefully controlled rolling pressure in this low pressure range.If rolling pressure is too low, control the roll gap district area between two rollers again absent-mindedly, then two rollers are forced to separate, and thick web of output (thick web) and the agglomerate that is twisted have damaged product yield and agglomerate quality, especially after fixed.If rolling pressure surpasses optimum value, then because of agglomerate being broken away from " clam shell " effect of ore pocket, it is bad the agglomerate closure to occur.Although the density of green briquette and crushing strength can increase, the shock strength of the agglomerate evil that will be badly damaged after the roasting.

Fig. 7 explanation, for raw material HG, with the ore pocket of 9 cubic centimetres of 450 mm dia rolls and nominals, when making in the gravity filling machine, rolling pressure is to the influence of agglomerate thickness and quality (measuring with crushing strength).This figure explanation when rolling pressure hangs down to 60 kilograms/square centimeter, has obtained qualified green briquette intensity.

Fig. 8 and 9 explanations utilize the pressing force that roll obtained of 650 millimeters of diameters and the influence of green briquette intensity.This work is finished with HG and GH type raw material, illustrates at rolling pressure and relation object between life (agglomerate) intensity to be similar to the same with 450 millimeters (roll of diameter) work.Specifically, this figure shows, snap-in force be 20,000 newton/centimetre under obtained qualified green briquette intensity.

Also found snap-in force to the shatter strength of agglomerate with give birth to resistance to abrasion and can produce material impact, when rolling pressure increased, two parameters all responded increase.

Embodiment 4

Also studied roller speed.

Found that the roller speed of measuring with rotations per minute (rpm) can exert an influence to the force value that puts on charging.

Increase roller speed, make the shortening of the residence time in the roll gap district between two rollers, therefore, apply lower pressure, then the time is more longer.Rolling pressure mainly can be used for controlling the force value that puts on charging, and can change roller speed so that productivity reaches maximum.But, importantly, consider that roller speed is to the influence of agglomerate thickness and green briquette intensity when optimizing the operation of the living group of pressure.

For raw material HG, have the gravity feed machine of 450 millimeters rolls of diameter, roller speed is shown among Figure 10 the influence of agglomerate thickness and quality (measuring with crushing strength).

This figure explanation increases with roller speed, and thickness and green briquette intensity reduce.

Embodiment 5

Employing is as the process variable of balling press as described in the embodiment 1, i.e. roller speed, pre-compacted motor speed and rolling pressure and agglomerate density are determined the operation optimum range of system of this concrete pressure group.

Sketch map shown in Figure 11 is on the Taiyo press, with 250 millimeters rolls, is formed an embodiment of the pressure group operation optimum range of 4 cubic centimetres of agglomerates of nominal by the HG material.

For simplifying curve, rolling pressure is fixed on 150 kilograms/square centimeter, and the pre-compacted motor speed is fixed on 20 rev/mins.Charging water content by 4-12 weight % has been represented a series of curves.Each curve representation causes forming the condition of all agglomerates.

There is a low feed pressure district on curve the right, and this district does not have the filling ore pocket, or agglomerate is not firm and be easy to break.There is the too high district of a feed pressure on the curve left side.The appearance agglomerate is cut off with ore pocket and is stopped up.Cross this strength range, below 6 kilogram forces, agglomerate too a little less than, bear incessantly that ore pocket breaks away from, and remain in the ore pocket, or break when breaking away from.More than 30 kilogram forces, can not reach further compacting.Agglomerate is thick, and beginning " clam shell ".The strength range of 6-30 kilogram force defines the outer gauge that its interior available sample material and Taiyo balling press form whole agglomerates.

For determining the operation optimum range, must consider some product and mass parameter, comprise yield, density, crushing strength and whereabouts (drop)/shatter strength.As long as considered these performances, with regard to one of definable belong to press group method operational zone than the zonule.

In Figure 11, this zone appears between 5 and 9 rev/mins of the roller speed and is between the 6-18 kilogram force in green briquette intensity.

Embodiment 6

Found to compare with the pellet that is formed by same material, the green briquette of making under optimal conditions is very stable to heat.This point is shown in Figure 12 and 13.

Figure 12 has shown in the laboratory scale consolidation test process of simulation belt type roasting machine method (straight grate process) temperature profile in three sites in inlet gas and exit gas and the agglomerate bed.

Bed temperature is by being placed on the thermocouple measurement at 100,250 and 500 millimeters away from the bed top places be.

Found that these agglomerates are heat-staple when with by the rapid heating of speed shown in the figure time.This fabulous drying property allowed the inlet air temperature degree to be increased to 1340 ℃ and the unlikely agglomerate spallation that makes from envrionment temperature in 10 minutes.

Figure 13 shows agglomerate consolidation temperature distribution plan, makes the HG ore agglomerate of 4 cubic centimetres of nominals, and its productivity is 32 tons of/square metre days and 25 tons of/square metre days.As a comparison, this figure has also represented the typical consolidation temperature of pellet is distributed.This pellet distribution is the distribution after a kind of optimization, so that pellet spallation minimum, and performance maximum after the roasting.The productivity that pellet is made in this pellet distribution reaches 16 tons of/square metre days, is significantly less than the productivity to agglomerate.These agglomerates and pellet are to be made by the ore of same-type.

Agglomerate productivity height is because the thermostability of green briquette, and it can make the agglomerate can be by rapid heating.

The thermostability of having found these agglomerates is not unique to a certain consolidation method and a certain ore type.

Embodiment 7

Adopted a kind of chain grate machine-rotary kiln system of pilot scale, the performance when determining that agglomerate enters rotary kiln (kiln) and flows out chain grate machine (grate) before.

This equipment is made of a pot type fire grate (pot grate) and a periodic kiln (batch kiln).Be simulation Dwight-Lloyd sintering machine (travelling grate), adopted the LGP gas burner to form flame temperature.This pot type fire grate stream of can having full communication between the higher and lower levels.Utilization is arranged in the tank skin and the thermopair by tank skin, measures the material temperature of whole bed.These mensuration are considered to be in the temperature of agglomerate in the firing cycle process.Because the size of the agglomerate of testing, possible these temperature measurings demonstrations be agglomerate outside temperature but not internal temperature.Measured temperature is likely the agglomerate outside temperature and is in a kind of mixing temperature of the gas temperature of this position in the bed.

Figure 14 shows the living nominal size of being made by GH material (d95=1 millimeter) is that the temperature of 7.5 cubic centimetres agglomerate is how originally to be elevated to the about 300-400 of maximum value ℃ average bed temperature to drop to minimum temperature then again and be～700 ℃.Then intensity increases once more under comparatively high temps.And its intensity drops to the Schwellenwert that is lower than green briquette intensity under～700 ℃.This transmits for the material from chain grate machine to rotary kiln is a key factor.Because minimum in its intensity of this temperature range, as long as distributing, roasting is included in the transmission from chain grate machine to kiln under this temperature, can estimate its degradation amount maximum.

For belt type roasting machine method (straight grate process), found that to the selected bed height of consolidation process be not critical, nor be subjected to avoiding the agglomerate distortion of bed bottom to reach the constraint of the general selected gas permeability of reasonable production rate again simultaneously.In addition, when the agglomerate volume surpassed 6 cubic centimetres, the bed air penetrability was involved not quite by the height of bed.Therefore, this consolidation method can not be subjected to the restriction of this variable, and makes situation as making ball exercise.Can select the green briquette producing depth with the optimization production rate, and the unlikely quality that involves.

A kind ofly obtain with regard to the better roasting product than other consolidation method with regard to making, chain grate machine-kiln process has some advantage.It also can heat agglomerate by high temperature range in some way more equably, and this mode has reduced the thermograde in the agglomerate, and has avoided causing the inhomogeneous contraction of agglomerate disruptive.In addition, because all agglomerates all stand same maturing temperature and time in this rotary kiln, the agglomerate quality is more even than belt type roasting machine method.

There is the possibility of producing the agglomerate that is suitable for direct-reduction process, as long as adopt the starting material of suitable grade.

Embodiment 8

Studied maturing temperature.

In chain grate machine-rotary kiln pilot scale equipment, all adopt the roasting of same fire grate section (gratesection) to distribute the agglomerate that roasting GH material (d95=1 millimeter) is 7.5 cubic centimetres.After being sent to this rotary kiln, apply same roasting and distribute, but different be by shown in changed the maturing temperature that is reached.The results are shown in Figure 15.

Show obviously among Figure 15 that will reach intensity after the suitable roasting to the agglomerate of this this size, the maturing temperature in the kiln should be at least 1380 ℃.

Figure 15 has also shown rolling intensity (rolling index-TI) and resistance to abrasion (abrasion index-AI) improve with maturing temperature.

Embodiment 9

Maturing temperature and the roasting time under this temperature have been studied.

To the agglomerate of 7.5 cubic centimetres of the nominals of making, in a series of chain grate machines-rotary kiln test, carry out roasting by GH material (d95=1 millimeter).Chain grate machine grate firing distributes identical, only is that roasting time was changed to 9 minutes from 6 minutes in the kiln under this maturing temperature.Keep in the kiln total roasting time identical, obtain extra roasting time, so that have than 6 minutes roasting time heating rate faster to 9 minutes roasting time of 1380 ℃ according to kiln internal heating speed.

In addition, adopt 7.5 cubic centimetres of used identical roastings of case are distributed, 6.3 cubic centimetres of GH agglomerates are also tested.

Presentation of results is in Figure 16 and 17.

For the GH agglomerate of 7.5 cubic centimetres of nominals, because of roasting time in the kiln is longer, intensity of roasting increases obviously.This is owing to the penetration of heat to agglomerate in the firing cycle process is bigger.

6.3 the roasting performance of cubic centimetre GH agglomerate is better than the agglomerate that 7.5 cubic centimetres of cases are made, and means that the penetration of heat factor is an important factor to the formation of agglomerate roasting performance.This result also illustrates when penetration of heat in the agglomerate is not enough, can not form enough intensity to roasting product.

Embodiment 10

Studied the influence of the residence time in the chain grate machine rotary kiln.

In the chain grate machine rotary kiln of the gap of pilot scale,, carried out roasting to by GH material (d95=1 millimeter) and 7.5 cubic centimetres of agglomerates of making of nominal.Green briquette is packed in the kiln that is preheated to 500 or 1000 ℃.Agglomerate is applied roasting distribute, and the record total residence time.The results are shown among Figure 18.

Figure 18 shows that the performance after the roasting increases with the residence time and improves, and has shown that abundant heating products is to reaching the importance of required final performance.

The influence of rapid heating does not weaken greatly because of the chain grate machine tool layer degree of depth.This point is shown in Figure 19 and 20.This green briquette bed is a highly air-permeable, and limit air does not flow, and situation about usually occurring during with pellet is the same.The maximum producing depth of available is not limited, but probably more than 300 millimeters.This considerably beyond in chain grate machine-rotary kiln sintered system in addition best pelletizing bed may reach.

Embodiment 11

Studied the influence of agglomerate chemistry.

By in retort furnace, under specified temp and time, agglomerate being carried out roasting, determine the Effect on Performance of agglomerate after base and temperature are to the roasting of being made by the HG material.It the results are shown in Figure 21.

Chemical analysis is agglomerate after the roasting for preparing under the different bases, obtains the result of agglomerate after the roasting, its grade during from base 1.2 63.81% Fe be changed to when base 0.2 Fe up to 65.93%, reflected that flux adds degree.

As can be seen from Figure 21, increase the increase that reaches with base from 0.2 to 0.8 with temperature, crushing strength increases.Because temperature raises in all research ranges, it is more obvious that this influence becomes, and (crushing strength) might reach 300 kilogram forces under 1295 ℃ and 0.6 base and under 1280 ℃ and 0.8 base.

The explanation that increase causes intensity to increase to base changes relevant with bonding mechanism.The particulate bonding takes place under the low basic bamboo level, and this is because the result of ferric oxide recrystallize and formation ferric oxide-ferric oxide key.Melt takes place down and forms in rising base level, low temperature, has strengthened the fusing of ferric oxide crystalline, and has made slagging scorification become more obvious, causes higher intensity under same temperature.

Embodiment 12

Utilize all agglomerates and standard reduction test method JIS8713/IS07215, to carrying out reduction test at 10 minutes HG agglomerate of 1300 ℃ of following roastings.Expansion after reducing power, the reduction and crushing strength (CSAR) the results are shown in Figure 22.

Reducing power index (RI) keeps relative stability in described base scope.RI 53.8% being changed to when base 1.00 and just surpassing 62.2% under the base 0.20.

Exponent of expansion has shown some response, and 11% is changed to 14.8% of intermediate range under the minimum base, is reduced to zero when base 1.20.The response that reduction back crushing strength (CSAR) performance changes the base level greatly, scope is for 0.20 time that 22 kilogram forces to base is 121 kilogram forces 1.20 times from base.This variation of reduction intensity has reflected the crushing strength result after the roasting, and relevant with the agglomerate bonding variation in mutually after the roasting.Low base agglomerate is the master that is bonded as with ferric oxide-ferric oxide key, and decays in reduction process.The base level raises, and it is more obvious that slagging scorification becomes.These keys are more stable between reduction period, illustrate that base is higher and almost do not have or do not expand at 1.20 o'clock reduction intensities.For the agglomerate of being made by GH and G, slagging scorification also becomes a kind of prior adhesive form, higher this moment SiO ₂And Al ₂O ₃Content has caused the flux interpolation to increase.This agglomerate generally proves after the reduction more firm, because reduction process does not cause the broken ring of non-iron bonding phase.The high-quality ore deposit is such as HC, and it is few to need to add flux, almost only depends on the bonding of oxide compound-oxide compound, therefore has intensity level after the lower reduction.

Can carry out many modifications and the unlikely spirit and scope of the invention that departs to the invention described above embodiment.

Claims

1. produce the method that is suitable for the iron ore briquette of doing blast furnace or other direct reduction furnace charging for one kind, comprise the following steps:

(a) mix: (i) have the ore that predetermined particle size distributes, its upper limit size be 4.0 millimeters or below; (ii) a kind of flux is to form ore/flux mixture;

(b) mixing step (a) before or during regulate the ore water content so that the water content of ore/flux mixture is the 2-12 weight % of this ore/flux mixture total weight amount.；

(c) suppressing described ore/flux mixture is green briquette; With

(d) fixed described green briquette is with the agglomerate after the formation roasting.

2. according to the method for claim 1 definition, also comprise and pulverizing and the screening ore, distribute with flux blended predetermined particle size to be formed in the step (a).

3. according to the method for definition in claim 1 or 2, wherein the upper limit size that distributes with the predetermined particle size of flux blended ore in step (a) is 3.5 millimeters.

4. according to the method for definition in the claim 3, wherein upper limit size is 3.0 millimeters.

5. according to the method for definition in the claim 3, wherein upper limit size is 2.5 millimeters.

6. according to the method for definition in the claim 3, wherein upper limit size is 1.5 millimeters.

7. according to the method for definition in the claim 3, wherein upper limit size is 1.0 millimeters.

8. according to the method for definition in the claim 1, wherein distributing with the predetermined particle size of flux blended ore in step (a) comprises the less than 50% of passing 45 microns screen clothes.

9. according to the method for definition in the claim 8, wherein predetermined ore grain size comprises the less than 30% of passing 45 microns screen clothes.

10. according to the method for definition in the claim 8, wherein predetermined ore grain size comprises the less than 10% of passing 45 microns screen clothes.

11. according to the method for definition in the claim 1, wherein ore is the hydrated iron ore.

12. according to the method for definition in the claim 11, wherein the hydration ore is the ore that contains pyrrhosiderite.

13. according to the method for definition in the claim 1, wherein the flux size-grade distribution is based on less than 100 microns.

14. according in the claim 1 definition method, wherein the flux size-grade distribution comprise pass 250 microns screen clothes greater than 95%.

15. according to the method for definition in the claim 1, wherein be chosen in ore/flux mixture of making in the step (a) so that in step (d) after the roasting of manufacturing the basicity of agglomerate greater than 0.2.

16. according to the method for definition in the claim 15, wherein basicity is greater than 0.6.

17. the method according to definition in the claim 1 does not wherein have tackiness agent in ore/flux mixture.

18. according to the method for definition in the claim 1, wherein step (b) comprises and regulates quarry water content, so that for the ore of fine and close rhombohedral iron ore, the water content of its ore/flux mixture is the 2-5 weight % of this ore/flux mixture total weight amount.

19. according to the method for claim 1 definition, wherein step (b) comprises adjusting quarry water content, so that for the ore that contains maximum 50% pyrrhosiderites, the water content of its ore/flux mixture is the 4-8 weight % of this ore/flux mixture total weight amount.

20. method according to claim 1 definition, wherein step (b) comprises adjusting quarry water content, so that for being the main ore that promptly contains 50% above pyrrhosiderite with the pyrrhosiderite, the water content of its ore/flux mixture is the 6-10 weight % of this ore/flux mixture total weight amount.

21. according to the method for definition in the claim 1, wherein pressing step (c) manufacturing volume is 6 cubic centimetres or following agglomerate.

22. according to the method for definition in the claim 1, wherein pressing step (c) manufacturing volume is 8.5 cubic centimetres or following agglomerate.

23. according to the method for definition in the claim 1, wherein pressing step (c) manufacturing volume is 6.5 cubic centimetres or following agglomerate.

24. according to the method for each definition among the claim 21-23, wherein pressing step (c) comprises utilizing is enough to make the rolling pressure that living ultimate compression strength is at least the agglomerate of 2 kilogram forces and suppresses described ore/flux mixture.

25. according in the claim 24 definition method, wherein rolling pressure be by the mixture to described ore/flux apply 10-140 thousand newton/centimetre the roller pressing force produce.

26. according in the claim 24 definition method, wherein the roller pressing force be 10-40 thousand newton/centimetre.

27. according to the method for definition in the claim 1, wherein consolidation step (d) is included in 40 minutes described agglomerates of internal heating to maturing temperature.

28. according to the method for definition in the claim 27, wherein step (d) is included in 35 minutes internal heating agglomerates to maturing temperature.

29. according to the method for definition in the claim 27, wherein step (b) is included in 30 minutes described agglomerates of internal heating to maturing temperature.

30. according to the method for definition in the claim 27, wherein step (d) is included in 20 minutes internal heating agglomerates to maturing temperature.

31. according to the method for definition in the claim 27, wherein step (d) is included in 15 minutes internal heating agglomerates to maturing temperature.

32. according to the method for each definition among the claim 27-31, wherein maturing temperature is at least 1200 ℃.

33. according to the method for definition in the claim 32, wherein maturing temperature is at least 1260 ℃.

34. according to the method for definition in the claim 32, wherein maturing temperature is at least 1320 ℃.

35. according to the method for definition in the claim 32, wherein maturing temperature is at least 1350 ℃.

36. according to the method for definition in the claim 32, wherein maturing temperature is at least 1380 ℃.

37. according to the method for definition in the claim 1, wherein the crushing strength of agglomerate is at least 200 kilogram forces after the roasting.

38. a roasting agglomerate of making according to each method among the claim 1-37, its crushing strength is at least 200 kilogram forces.