CN1863932A - Method for producing sintered ore, method for producing raw material for sintering, granulated pellet, and sintered ore - Google Patents

Abstract

A method for producing a sintered ore (50a) which comprises forming, on the surface of a nucleus particle (51) containing an iron ore, a first coating layer (52) using an iron-containing substance and optionally an SiO2-containing material, and subsequently a second coating layer (53) using limestone and a solid fuel based material, to prepare a granulated particle (50), and then sintering the granulated particle (50), wherein the iron-containing substance used for forming the first coating layer (52) has a porosity of 20 % or less or has a porosity of 20 % or less and a content of Al2O3 of 2.1 mass % or less, and wherein the iron ore for the nucleus particle has a porosity higher than that of the iron-containing substance used for the first coating layer (52) or has a porosity and/or a content of Al2O3 higher than that or those of the iron-containing substance.

Description

The manufacture method of agglomerate, the manufacture method of raw material for sintering, granulated pellet and agglomerate

Technical field

The present invention relates to a kind of manufacture method of raw material for sintering, manufacture method, granulated pellet and the agglomerate of raw material for sintering, specially refer to the effective technology of a kind of agglomeration technique that is applicable to employed raw materials for sintering when the special Lloyd's's sinter machine that utilizes the below to attract is made agglomerate for blast furnace etc.

Background technology

In steel industry, because the low Phosphorus iron ore of fine is exhausted day by day, therefore employed iron ore was changed to limonite class ore in the last few years.And the crystal water of limonite class ore is more than the 6 quality %, considers from the limit of producing capacity, and it is that 3 quality % particle diameter above, that contain more than the 25 quality % is the micro mist limonite class ore of the following micro mist part of 0.25mm that imagination increases crystal water.

When micro mist limonite class ore is made agglomerate as the part of iron ore, use always as the treatment process of the raw materials for sintering shown in first reference technique among Figure 23.At first, to micro mist limonite class ore 101; Particle diameter is the following iron ore 102 of 10mm; And contain SiO by what silica, serpentinite or nickel slag etc. constituted ₂Raw material 103; And Wingdale etc. contains the Wingdale class powder stock 104 of CaO; And in the solid fuel class powder stocks 105 as thermal source such as coke breeze or hard coal, adds an amount of moisture, and utilize that drum mixer 106 mixes, granulation, as linking agent, formation is called the granulated pellet of " false particle " with water.The mixing raw material that is made of this granulation thing is with suitable thickness, for example the thickness with 500-700mm is encased on the chassis of special Lloyd's's sinter machine, light the solid fuel of skin section, lighting the back attracts air to make solid fuel ignition on one side on one side downwards, make blended raw materials for sintering sintering by this heat output, become agglomerate.To agglomerate pulverize, whole grain, obtain the above agglomerate of certain particle diameter.And return mine less than becoming of this particle diameter, can be used as raw materials for sintering and utilize again.

Wherein, because agglomerate burns coke in the raw material through the air in the layer to make by utilizing, so its productivity depends on the ventilation (air permeability) on the chassis.Air permeability on the chassis is divided into from big aspect: the low temperature air permeability before the sintering, and it depends on false particle grain size; High temperature air permeability in the sintering, behind the sintering, its depend on by flowing of melt generates as the pore of the agglomerate of air flow circuit directly.

Therefore, so far, improve for ventilation, carried out much by enlarging the trial that false grain diameter improves the air permeability on the chassis, but because the micro mist limonite ore is a porous matter, even therefore temporarily by the drum mixer granulation, behind the process certain hour, water as linking agent is absorbed in the ore, and the arduous granulation thing of making collapses on sinter machine, causes the deterioration of air permeability.In order to prevent this point, if the moisture will carry out granulation to the micro mist limonite ore in advance the time is increased to more than the predetermined amount, then in drum mixer, can't successfully turn round, the granulation particle diameter descends on the contrary, still air permeability is had a negative impact.

At this problem, for example in patent documentation 1, record: utilize high-speed stirring mixer to handle the ore of micro mist limonite class, granulation water is absorbed in the ore to carry out granulation, thus, compare with the granulation in the common drum mixer, can increase granulation water, improve the air permeability on the sinter machine.

And, in patent documentation 2, record: by more with the micro mist limonite ore to surperficial indentation, ventilating pit, be easy to adhere to the returning mine of micro mist, and iron ore stone minus sieve carry out granulation, help improving granulation.

On the other hand, the angle of the air permeability from guarantee blast furnace, the low temperature intensity of the agglomerate of making is very important, but above-mentioned patent documentation 1,2 disclosed technology are only to improve the countermeasure of low temperature air permeability from the angle of the granulation particle diameter that increases drum mixer, and and reckon without the improvement of low temperature intensity.

Relative with it, following technical scheme has been proposed: optionally adhere to, be coated to the surface of the granulated pellet of iron ore as the Wingdale of fusing assistant with as the coke breeze of thermal source by making in the sintering process, make iron ore and contain SiO in patent documentation 3 ₂Raw material separates from Wingdale and solid fuel class raw material, suppresses the generation of Calucium Silicate powder, improves low temperature intensity.In this technology, after to granulations such as iron ores, carry out granulation by coke breeze, Wingdale to other raw material granulations of obstruction of being insoluble in water, improve granulation, and by making as the Wingdale off normal of fusing assistant in the granulated pellet outside, on the piece surface, generate more high-intensity calcium ferrite behind the sintering, thereby in the prior processing of the technology of making agglomerate, need not too much equipment, can obtain higher low temperature intensity.In this technology, when using the micro mist limonite ore, then become the specifically granulation process shown in second reference technique among Figure 24 as iron ore.That is, at ore 101, other iron ores 102 of micro mist limonite class, contain SiO ₂Raw material 103 grades are added solid fuel class powder stock 105, Wingdale class powder stock 104 by after drum mixer 106 granulations, further carry out granulation.

But, when in fact being suitable for the micro mist limonite ore and implementing above-mentioned patent documentation 3 disclosed methods as iron ore, low temperature intensity improve DeGrain.Also exist many during the iron ore of this problem beyond the such high-quality iron ore of the magnetic iron ore that uses brown iron class ore, high Rock Phosphate (72Min BPL) etc., low Rock Phosphate (72Min BPL).

Patent documentation 1: the spy opens the 2003-129139 communique

Patent documentation 2: the spy opens the 2000-63960 communique

Patent documentation 3:WO01/92588 communique

Summary of the invention

The present invention proposes in view of above problem just, its purpose is to provide a kind of and is using the micro mist limonite ore, when low Rock Phosphate (72Min BPL) is a iron ore beyond the high-quality iron ore of representative, particle diameter in the time of also can enlarging granulation, and the flowability of the melt that generates in the raising sintering process, improve low temperature air permeability and high temperature air permeability, make the manufacture method of the good agglomerate of low temperature intensity behind the sintering, be used to obtain the manufacture method of the raw material for sintering of this agglomerate, granulated pellet as raw material for sintering, and the agglomerate that manufacture method obtained by this agglomerate.

In order to solve above-mentioned problem, first viewpoint of the present invention, a kind of manufacture method of agglomerate is provided, it is characterized in that, has following operation: on the surface of the nuclear particle that contains iron ore, utilize iron compound to form first coating, on the surface of above-mentioned first coating, form second coating by Wingdale and solid fuel class raw material, and form operation as the granulated pellet of raw material for sintering; With the operation of the above-mentioned granulated pellet of sintering, the void content of the employed iron compound of above-mentioned first coating is below 20%, and the iron ore that above-mentioned nuclear particle is used is compared its void content height with the employed iron compound of above-mentioned first coating.

The employed iron compound of above-mentioned first coating preferably has the void content of 1-20%.The iron ore that above-mentioned nuclear particle is used preferably has the void content above 20%.The further preferred void content that surpasses 20-40%.

Above-mentioned granulated pellet is preferably the particle diameter of 3-5mm, and nuclear particle is preferably the particle diameter of 1-2mm.

And, second viewpoint of the present invention provides a kind of manufacture method of agglomerate, it is characterized in that, has following operation: on the surface of the nuclear particle that contains iron ore, utilize iron compound to form first coating, on the surface of above-mentioned first coating, form second coating by Wingdale and solid fuel class raw material, and form operation as the granulated pellet of raw material for sintering; With the operation of the above-mentioned granulated pellet of sintering, the void content of the employed iron compound of above-mentioned first coating is below 20%, and Al ₂O ₃Containing ratio is below the 2.1 quality %, and the iron ore that above-mentioned nuclear particle is used is compared void content and Al with the employed iron compound of above-mentioned first coating ₂O ₃Any one party in the containing ratio or both sides are all high.

In this case, the Al of the employed iron compound of above-mentioned first coating ₂O ₃Containing ratio is preferably below the 1.5 quality %.The Al of the employed iron compound of first coating ₂O ₃Containing ratio is 0.1-1.5 quality % more preferably.And,, can use and satisfy that void content surpasses 20%, and Al as the iron ore that above-mentioned nuclear particle is used ₂O ₃Containing ratio is above any one party among the 2.1 quality % or both sides' iron ore.The void content of the iron ore that above-mentioned nuclear particle is used is preferably above below the 20%-40%.The preferred Al of the iron ore that above-mentioned nuclear particle is used ₂O ₃Containing ratio is for surpassing below the 2.1 quality %-3.5 quality %.Al when the employed iron compound of the-coating ₂O ₃Containing ratio is 1.5 quality % when following, and the iron ore of using as above-mentioned nuclear particle can use Al ₂O ₃Containing ratio surpasses the iron ore of 1.5 quality %.

The 3rd viewpoint of the present invention provides a kind of manufacture method of agglomerate, it is characterized in that, has following operation: on the surface of the nuclear particle that contains iron ore, utilize iron compound to form first coating, on the surface of above-mentioned first coating, form second coating by Wingdale and solid fuel class raw material, and form operation as the granulated pellet of raw material for sintering; Operation with the above-mentioned granulated pellet of sintering, the employed iron compound of above-mentioned first coating is from magnetic iron ore, low Rock Phosphate (72Min BPL), roll scale, reaches one or two or more kinds that select the iron powder, and the employed iron ore of above-mentioned nuclear particle comprises the iron ore beyond magnetic iron ore and the low Rock Phosphate (72Min BPL).

The iron ore of using as above-mentioned nuclear particle can use the micro mist limonite ore.And, can use micro mist limonite ore, limonite ore, reach one or two or more kinds that select in the high Rock Phosphate (72Min BPL).Wherein, high Rock Phosphate (72Min BPL) is meant the ore that contains the above phosphorus (P) of 0.1 quality %, through discovering of the inventor, it is characterized in that micro mist portion contains the Al of higher concentration ₂O ₃

In above-mentioned first to the 3rd viewpoint, above-mentioned nuclear particle can carry out granulation and obtain by the iron ore that above-mentioned nuclear particle is used.At this moment, the iron ore preferably above-mentioned nuclear particle used of above-mentioned nuclear particle comes granulation by the tablets press with high-speed stirring blade.And above-mentioned second coating is the coating Wingdale at first, coats solid fuel class raw material afterwards.

The 4th viewpoint of the present invention provides a kind of granulated pellet, in the manufacturing process of agglomerate, be used as raw material for sintering, used second coating of Wingdale and solid fuel class raw material to constitute by around the nuclear particle that contains iron ore, forming to have used first coating of iron compound and formed thereon, it is characterized in that, the void content of the employed iron compound of above-mentioned first coating is below 20%, the iron ore that constitutes above-mentioned nuclear particle is compared its void content height with the employed iron compound of above-mentioned first coating.

The employed iron compound of above-mentioned first coating preferably has the void content of 1-20%.The iron ore of using as above-mentioned nuclear particle preferably has and surpasses 20% void content.The further preferred void content that surpasses 20-40% of the iron ore that above-mentioned nuclear particle is used.

The 5th viewpoint of the present invention provides a kind of granulated pellet, in the manufacturing process of agglomerate, be used as raw material for sintering, used second coating of Wingdale and solid fuel class raw material to constitute by around the nuclear particle that contains iron ore, forming to have used first coating of iron compound and formed thereon, it is characterized in that the void content of the employed iron compound of above-mentioned first coating is below 20% and Al ₂O ₃Containing ratio is below the 2.1 quality %, and the iron ore that constitutes above-mentioned nuclear particle is compared void content and Al with the employed iron compound of above-mentioned first coating ₂O ₃Any one party in the containing ratio or both sides are all high.

The employed iron compound of above-mentioned first coating preferably has the void content of 1-20%.The Al of the employed iron compound of above-mentioned first coating ₂O ₃Containing ratio is preferably 0.1-1.5 quality %.And,, can use and satisfy that void content surpasses 20%, and Al as the iron ore that above-mentioned nuclear particle is used ₂O ₃Containing ratio is above any one party among the 2.1 quality % or both sides' iron ore.The void content of the iron ore that above-mentioned nuclear particle is used is preferably above below the 20%-40%.The preferred Al of the iron ore that above-mentioned nuclear particle is used ₂O ₃Containing ratio is for surpassing below the 2.1 quality %-3.5 quality %.Al when the employed iron compound of first coating ₂O ₃Containing ratio is 1.5 quality % when following, and the iron ore of using as above-mentioned nuclear particle can use and satisfy Al ₂O ₃Containing ratio surpasses the iron ore of 1.5 quality %.

The 6th viewpoint of the present invention provides a kind of granulated pellet, in the manufacturing process of agglomerate, supply with as raw material for sintering, by around the nuclear particle that contains iron ore, forming first coating that has used iron compound, and formation has thereon been used second coating of Wingdale and solid fuel class raw material and has been constituted, it is characterized in that, the employed iron compound of above-mentioned first coating is from magnetic iron ore, low Rock Phosphate (72Min BPL), roll scale, reach one or two or more kinds that select in the iron powder, the iron ore that constitutes above-mentioned nuclear particle comprises magnetic iron ore and low Rock Phosphate (72Min BPL) iron ore in addition.

Iron ore as above-mentioned nuclear particle is used can use the micro mist limonite ore.And, can use micro mist limonite ore, limonite ore, reach one or two or more kinds that select in the high Rock Phosphate (72Min BPL).And above-mentioned second coating can have: utilize internal layer that Wingdale forms, and the skin that utilizes solid fuel class raw material to form in its outside.

The 7th viewpoint of the present invention provides a kind of agglomerate, it is characterized in that, aggregate by the unit grain structure constitutes, this unit grain structure comprises: based on the core of the ferric oxide that is derived from iron ore, cover its outside the middle layer based on the ferric oxide that is derived from iron compound, and cover the outermost layer based on calcium ferrite in above-mentioned middle layer, wherein, above-mentioned middle layer is than above-mentioned core densification.

The 8th viewpoint of the present invention provides a kind of agglomerate, it is characterized in that, aggregate by the unit grain structure constitutes, this unit grain structure comprises: based on the core of the ferric oxide that is derived from iron ore, cover its outside the middle layer based on the ferric oxide that is derived from iron compound, and cover the outermost layer based on calcium ferrite in above-mentioned middle layer, wherein, densification and Al are compared with above-mentioned core in above-mentioned middle layer ₂O ₃Containing ratio is low.

The 9th viewpoint of the present invention provides a kind of agglomerate, it is characterized in that, aggregate by unit grain structure constitutes, and this unit grain structure comprises: core, based on be derived from from micro mist limonite ore, limonite ore, and high Rock Phosphate (72Min BPL) one or two or more kinds the ferric oxide selected; The middle layer covers above-mentioned core, based on be derived from from magnetic iron ore, low Rock Phosphate (72Min BPL), roll scale, and iron powder one or two or more kinds the ferric oxide selected; And outermost layer, cover above-mentioned middle layer, based on calcium ferrite.

The tenth viewpoint of the present invention provides a kind of agglomerate, it is characterized in that, the aggregate of being constructed by unit grain constitutes, and this unit grain structure comprises: core, to be derived from the ferric oxide of micro mist limonite ore; The middle layer covers above-mentioned core, to be derived from the ferric oxide of low Rock Phosphate (72Min BPL); And outermost layer, cover above-mentioned middle layer, based on calcium ferrite.

In the 7th to the tenth viewpoint of the present invention, be that main body is meant with the ferric oxide, contain the ferric oxide more than 70%, be that main body is meant the calcium ferrite that contains more than 70% with the calcium ferrite.

The 11 viewpoint of the present invention provides a kind of manufacture method of raw material for sintering, this raw material for sintering is used for the manufacturing process of agglomerate for blast furnace, it is characterized in that having following operation: first iron ore of micro mist limonite class is carried out granulation and make the operation of nuclear particle; On the surface of above-mentioned nuclear particle, utilize second iron ore beyond above-mentioned first iron ore and contain SiO ₂Raw material forms the operation of first coating; On the surface of above-mentioned first coating, form the operation of second coating by Wingdale and solid fuel class powder stock.

The 12 viewpoint of the present invention provides a kind of manufacture method of raw material for sintering, this raw material for sintering supplies in the manufacturing process of agglomerate for blast furnace, it is characterized in that having following operation: only utilize first iron ore of micro mist limonite class or above-mentioned first iron ore and, make the operation of nuclear particle by tablets press with high-speed stirring blade from the returning mine of sintering circuit; On the surface of above-mentioned nuclear particle, utilize second iron ore beyond above-mentioned first iron ore and contain SiO ₂Raw material forms the operation of first coating; On the surface of above-mentioned first coating, utilize Wingdale class powder stock and solid fuel class powder stock to form the operation of second coating.

The 13 viewpoint of the present invention provides a kind of granulated pellet, is used as raw material for sintering in the manufacturing process of agglomerate for blast furnace, it is characterized in that having: nuclear particle is obtained by the first iron ore granulation of micro mist limonite class; First coating is formed on the surface of above-mentioned nuclear particle, by second iron ore beyond above-mentioned first iron ore and contain SiO ₂Raw material constitutes; With second coating, be formed on the surface of above-mentioned first coating, constitute by Wingdale class powder stock and solid fuel class powder stock.

The 14 viewpoint of the present invention provides a kind of granulated pellet, in the manufacturing process of agglomerate for blast furnace, be used as raw material for sintering, it is characterized in that having: nuclear particle, only utilize first iron ore of micro mist limonite class or above-mentioned first iron ore and, obtain by tablets press granulation with high-speed stirring blade from the returning mine of sintering circuit; First coating is formed on the surface of above-mentioned nuclear particle, by second iron ore beyond above-mentioned first iron ore and contain SiO ₂Raw material constitutes; With second coating, be formed on the surface of above-mentioned first coating, constitute by Wingdale class powder stock and solid fuel class powder stock.

According to the invention described above, on the surface of the nuclear particle that contains iron ore in turn, utilize predetermined iron compound to form first coating, further form second coating by Wingdale and solid fuel class raw material thereon, thereby make granulated pellet as the raw material for sintering that is used to obtain agglomerate, therefore need not numerous pre-treatment etc., can obtain the particle diameter granulated pellet as raw material for sintering bigger, that the low temperature air permeability is good.And, when granulation forms nuclear particle, have the tablets press of high-speed stirring blade by use, can improve intensity, the compactness of nuclear particle, and further improve granulation.

And, granulated pellet as raw material for sintering, the nuclear particle that use is made of the high iron ore of void content is by the particle under the first coating covering state of the low iron compound of void content, the melt of the calcium ferrite that forms on the granulated pellet surface etc. is difficult to arrive the high nuclear particle of void content, can prevent that this melt from being absorbed by the pore of nuclear particle and make mobile decline, can improve the high temperature air permeability by the high workability of melt, sintering reaction carries out on the thickness direction of bed equably, the less agglomerate of returning mine can be obtained, and the high agglomerate of low temperature intensity can be obtained.

Further, as the Al of melt ₂O ₃When containing ratio increased, the viscosity of melt rose, and therefore as the granulated pellet of raw materials for sintering, its state is, by void content and Al ₂O ₃The nuclear particle that the iron ore that in the containing ratio any one or both are all high constitutes is by void content and Al ₂O ₃The low iron compound of containing ratio covers, thereby can prevent that this melt from being absorbed by the pore of nuclear particle and make mobile decline, and can prevent the Al of nuclear particle ₂O ₃The flowability that reaction causes with melt descends, and improves the flowability of melt, and further improves the high temperature air permeability, and sintering reaction carries out on the thickness direction of bed equably, can obtain the less agglomerate of returning mine, and can obtain the high agglomerate of low temperature intensity.

With the concrete industrialized method of foregoing invention thought be, on first coating, use from magnetic iron ore, low Phosphorus ore, roll scale, and iron powder one or two or more kinds the iron compound selected, and cover with this first coating and to comprise magnetic iron ore and low Rock Phosphate (72Min BPL) void content and Al in addition ₂O ₃The nuclear particle of the brown iron class of the micro mist that any one party of containing ratio or both sides are all high ore, brown iron class ore, high Rock Phosphate (72Min BPL) etc., thus stop the calcium ferrite melt that forms on the granulated pellet surface to arrive nuclear particle, and prevent that the flowability of melt from reducing.

According to the present invention, need not numerous pre-treatment etc., the productivity of agglomerate and intensity are worsened, void content and Al such as micro mist limonite class ore, limonite ore, high Rock Phosphate (72Min BPL) ₂O ₃The iron ore that any one party of containing ratio or both sides are all high uses as iron-making raw material, can make agglomerate under low temperature, high temperature air permeability good state, and can improve the low temperature intensity of the agglomerate that is obtained.So, even use high quality raw material raw materials in addition such as existing micro mist limonite ore, low Phosphorus ore, also can obtain excellent characteristic, therefore can effectively utilize resource, industrial value is higher.

Description of drawings

Fig. 1 is that the vesicular structure of expression sintering process is resolved, the concept map of an example of melt flow analytic method.

Fig. 2 is the explanatory view of an example of accompanying drawing picture of the sintered compact of the various iron ores of expression.

Fig. 3 is the line chart of an example of vesicular structure analysis result of the sintered compact of the various iron ores of expression.

Fig. 4 is the explanatory view of an example of the relation of the vesicular structure of sintered compact of the various iron ores of expression and melt flow.

Fig. 5 is the pore footpath Determination of distribution result's of the various iron ores of expression the line chart of an example.

Fig. 6 is the concept map of an example of explanation melt flow decrease reason.

Fig. 7 is the sectional view of an example of expression ideal granulated pellet and sintered compact thereof.

Fig. 8 is the explanatory view of an example of measurement result of EPMA in the sintered compact cross section of low phosphorus ore of expression and micro mist limonite.

Fig. 9 (a) and (b) be expression with of the present invention first or the sectional view of an example of the structure of the granulated pellet that manufacture method obtained of the raw material for sintering of second embodiment and its sintered compact.

Figure 10 is the figure of the viscosimeter of expression melt.

Figure 11 is the Al that calcium ferrite class melt is added in expression to ₂O ₃The figure of the relation of the viscosity of amount and melt.

Figure 12 is the figure of the infiltration experiment device of expression melt.

Figure 13 is the figure of the relation of expression viscosity of melt and melt seepage velocity.

Figure 14 is the granulation schema of expression as an example of the manufacture method of the raw material for sintering of first embodiment of the present invention.

Figure 15 is the schema of the granulation experiment under the manufacture method of raw material for sintering of the present invention and reference technique.

Figure 16 is the explanatory view that the low temperature intensity of the sintered compact of the present invention and reference technique, reduction disintegration (RDI) is compared contrast.

Figure 17 is the concept map of an example of measuring method of the wettability of expression ore.

Figure 18 is the explanatory view that the lifting height of the water in the determination test of the wettability of various ores is compared contrast.

Figure 19 is the line chart of an example of measuring result of the wettability of the various ores of expression.

Figure 20 is the explanatory view of an example of relation of the adhesion strength of expression contact angle of ore and granulated pellet.

Figure 21 is the explanatory view that the tensile strength of the press body of each ore is compared contrast.

Figure 22 is the granulation schema of expression as an example of the manufacture method of the raw material for sintering of second embodiment of the present invention.

Figure 23 is the mixing of the raw materials for sintering that relates to of expression first reference technique of the present invention, the schema of granulating working procedure.

Figure 24 is the mixing of the raw materials for sintering that relates to of expression second reference technique of the present invention, the schema of granulating working procedure.

Embodiment

Below be elaborated to finishing process of the present invention and the specific embodiment of the present invention.

At first, this character state of studying employed ore is as shown in table 1.

Table 1

	Composition (quality %)						Apparent proportion (g/cm 3)	The Hg amount of being pressed into (cc/g)	Specific surface area (m 2/g)
										CW	T.Fe	FeO	SiO 2	Al 2O 3	CaO
	Low phosphorus ore A	1.33	67.54	0.22	0.70	0.75										0.01	4.14	0.036	0.99
Micro mist limonite B							5.10	62.60	1.50	3.00	1.80	0.01	3.36	0.114	5.33
	Limonite C	8.47	58.8	0.09	4.85	1.23										0.04	2.93	0.087	13.9
Magnetite D							0.20	66.90	7.20	3.04	0.14	0.2	4.31	0.031	0.51

Pore in the agglomerate not only produces a very large impact low temperature intensity because of the structure defective, and is the stream of air, and the air permeability in the sintered layer is produced decisive influence, this phenomenon is quantized, and investigated the influence of various ores.The x-ray ct device 20 of Shi Yonging has test pans 21, and the gas blower 22 that test pans 21 is attracted of the state that reproduces the bed on the sinter machine downwards in the present embodiment.Clipping test pans 21 on the relative position, be provided with X line source 23, and detect the X thread detector 24 of the X line that sees through test pans 21 to test pans 21 exposures, X line source 23 and X thread detector 24 along track 26 under state relative to each other, the coiling test pans 21 around.X thread detector 24 is connected with image analysis apparatus 25, this image analysis apparatus 25 has following function: from the coiling test pans 21 around 23 pairs of these test pans 21 of X line source with various angular illumination, the intensity of detected X line according to seeing through test pans 21, detect the vesicular structure of the inside of the agglomerate in the test pans 21, the flow state of melt, and output visually.

The condition of table 2 expression sintering experiment, table 3 expression experimental level.As shown in table 3, sintering experiment No.1 is the low Rock Phosphate (72Min BPL) A that the low Rock Phosphate (72Min BPL) by 100 quality % constitutes, sintering experiment No.2 is the micro mist limonite ore B that has mixed the micro mist limonite ore of 40 quality % in low Rock Phosphate (72Min BPL), and sintering experiment No.3 is the limonite ore C that has mixed the limonite ore of 40 quality % in low Rock Phosphate (72Min BPL).

Table 2

Test pans	φ100×100mmH
		Wind speed	0.29Nm/s
Coke ratio	5.5％
		CaO in the raw materials for sintering	9.0％
SiO in the raw materials for sintering 2	5.0％

Table 3

Experiment No.	Low phosphorus ore A	Micro mist limonite B	Limonite C
				No.1	100％	-	-
No.2	60％	40％	-
				No.3	60％	-	40％

Vesicular structure is resolved, melt flow is resolved with 60 ^ThIronmaking ConferencePron. (2001), P.817 (N.Oyama etal) carries out for reference.

Fig. 2 represents the X line CT image of the agglomerate after the sintering under each experimental level of sintering experiment No.1-3 is finished.Black among the figure is represented pore, white expression solid.Therefore can confirm: and cooperate low Rock Phosphate (72Min BPL) A (the low Rock Phosphate (72Min BPL) of 100 quality %) and the agglomerating agglomerate is compared, mixed the fully growth of pore in the agglomerate of micro mist limonite ore B (the micro mist limonite ore that cooperates 40 weight % to low Rock Phosphate (72Min BPL)), limonite ore C (to the limonite ore that low Rock Phosphate (72Min BPL) mixes 40 weight %).

Then, with Fig. 2 be the basis branch's width with width correspondence pore that sum up the result as shown in Figure 3.The inclination of Fig. 3 is defined as the growth rate of branch's width, with melt flow exponential relation as shown in Figure 4.Therefore as can be known, when admixed finepowder limonite ore, limonite ore, the flowability of melt descends, and pore can fully not grown up.

Therefore, pore not only exerts an influence to low temperature intensity as the structure defective of agglomerate, and as air flow circuit also left and right sides air permeability to a great extent.According to inventor's result of study so far, when pore generated greatly, this pore was open during destruction, and the result can make high-intensity agglomerate, and air permeability is also good.Therefore, for the intensity of improving agglomerate, the air permeability in the sintered layer, the flowability that how to improve melt just becomes important problem to promote the growth of pore.

Pore footpath distribution situation in the various ores that Fig. 5 represents to measure by mercury penetration method.Therefrom as can be known, the pore amount of micro mist limonite ore B and limonite ore C is more than low Rock Phosphate (72Min BPL) A, and particularly micro mist limonite ore B compares with limonite ore C, and the pore amount in the pore about many 1 μ m, ore is obviously more.Therefore as shown in Figure 6, among the low Rock Phosphate (72Min BPL) A, the melt that is created between ore maintains between ore, and for pore micro mist limonite ore B, limonite ore C how, the melt that is created between ore is easy to be absorbed by the pore in the ore before flowing, and the quantitative change of flowable melt gets not enough, can predict, particularly when using the micro mist limonite ore, this tendency is fairly obvious.

Further, in order to investigate the melting phenomenon of Wingdale and ore, as shown in Figure 7, be manufactured on the granulated pellet that adheres to Wingdale on the surface of hanging down Rock Phosphate (72Min BPL) and micro mist limonite ore respectively, in electric furnace with 1300 ℃ the heating five minutes after, take out sintered compact, its cross section is measured with electron probe microanalyzer (EPMA:Electron Probe Micro-Analyzer).Fig. 8 represents measuring result.Therefrom as can be known: during the calcium ferrite class melt that on being conceived to mineral surface, generates, under the situation of the sintered compact of micro mist limonite ore, compare aluminum oxide (Al with low Rock Phosphate (72Min BPL) ₂O ₃) more concentrate in the melt.Infer that it the reasons are as follows: the micro mist limonite ore is a porous matter, and Al ₂O ₃Amount is than employed low Rock Phosphate (72Min BPL) is many here, and therefore by pore, the aluminum oxide in the ore is discharged in the melt more.

According to above result of study, can expect:, should be the structure of Fig. 9 as the granulated pellet structure of the best.Promptly, shown in the sectional view of Fig. 9 (a), the structure of the granulated pellet 50 of present embodiment is: used first coating 52 of the low iron compound of void content to coat to nuclear particle 51 usefulness that contain the higher iron ore of void content, further used second coating 53 that is made of Wingdale 14 and solid fuel class raw material 15 to coat to its outside.

This is based on following consideration: even the arduous Wingdale that separates is to suppress the generation of Calucium Silicate powder, and make melt based on calcium ferrite, but when the void content of the iron ore that directly contacts with the Wingdale that forms melt is higher, the melt that forms during sintering is drawn by pore, it is not enough that melt becomes, melt can't be fully mobile, but by the high iron ore of this void content is used as nuclear particle, and coat the low iron compound of void content thereon, further coat the Wingdale that generates melt thereon, the Wingdale of iron ore that separable void content is high and formation melt can equally with existing low Rock Phosphate (72Min BPL) carry out sintering.

Therefore shown in Fig. 9 (b), sintering the sintered particles 50a behind the granulated pellet 50 comprise with the lower section: based on fusion nuclear particle (core) 51a of the ferric oxide that is derived from iron ore; Cover its outside, based on the middle layer 52a of the ferric oxide that is derived from iron compound; Cover middle layer 52a, based on the outermost layer 53a of calcium ferrite, wherein fusion nuclear particle (core) 51a is porous matter structure relatively, middle layer 52a is the structure than fusion nuclear particle (core) 51a densification.When sintering, the calcium ferrite that constitutes outermost layer 53a exists as melt, and acceleration of sintering forms the agglomerate that the aggregate by sintered particles 50a constitutes.

Then to holding Al ₂O ₃The result of amount influence that the viscosity of melt is produced describe.

To CaO:20 quality %, Fe ₂O ₃: in the melt of 80 quality % (calcium ferrite class melt), the outside respectively Al that adds 1,2,6,8,10 quality % ₂O ₃Reagent, the viscosity of the melt that measurement is obtained.Lob test method(s) shown in Figure 10 is adopted in the viscosity measurement of melt, when lob, calculates according to the translational speed of balance indicator in certain interval.Figure 11 represents measuring result.As shown in figure 11, can confirm along with Al ₂O ₃The increase of amount, melt viscosity rises.

Then the viscosity of melt and the experimental result of seepage velocity are described.

Utilize the seepage velocity of measurement device melt shown in Figure 12 at this.Particularly, the different melt of viscosity that drips in the packing layer that installs the direction granulated glass sphere is tried to achieve the viscosity of melt and the relation of seepage velocity by measuring its seepage velocity.

Figure 13 represents experimental result.As shown in figure 13, can confirm that when melt viscosity rose, the seepage velocity of melt descended.Therefore can think: along with Al ₂O ₃The seepage velocity of the melt that the increase of amount, viscosity are risen descends, and because of the decline of its seepage velocity has hindered the growth of the pore in the agglomerate, these have further caused combustible deterioration, and the decline of low temperature intensity of high temperature air permeability, coke.

Consider this Al ₂O ₃Influence, when the nuclear particle 51 as the granulated pellet in the sectional view of Fig. 9 (a) 50 uses void content and Al ₂O ₃When any one party of amount or all high iron ore of both sides, first coating 52 as coating nuclear particle 51 preferably uses void content and Al ₂O ₃Measure low iron compound.

This be because, as the Al of the iron ore that directly contacts with the Wingdale that forms melt ₂O ₃Measure more for a long time, the Al of melt ₂O ₃Containing ratio uprises, and melt viscosity rises, and melt is possible can't be fully mobile, and used this void content and Al as coating ₂O ₃First coating 52 of the nuclear particle 51 of the iron ore that any one party of amount or both sides are all high uses void content and Al ₂O ₃Measure less iron compound, by isolated nuclei particle 51 with form the Wingdale of melt, can prevent that this melt from being absorbed by the pore of nuclear particle and make mobile decline, and can prevent the Al of nuclear particle ₂O ₃The decline of the flowability that causes with melt reaction can improve the flowability of melt, further improves the high temperature air permeability, and further improves low temperature intensity.

In this case, also shown in Fig. 9 (b), sintering the sintered particles 50a behind the granulated pellet 50 by constituting with the lower section: based on fusion nuclear particle (core) 51a of iron ore; Cover its outside, based on the middle layer 52a of iron compound; Cover middle layer 52a, based on the outermost layer 53a of calcium ferrite.And fusion nuclear particle (core) 51a is that relative porous matter and/or height contain Al ₂O ₃Structure, middle layer 52a is than fusion nuclear particle (core) 51a densification and Al ₂O ₃The structure that containing ratio is low.In this case, when sintering, the calcium ferrite that constitutes outermost layer 53a exists as melt, acceleration of sintering, and form the agglomerate that the aggregate by sintered particles 50a constitutes.

Under above-mentioned any one situation, are the materials that constitute agglomerate owing to constitute the iron compound of first coating 52, therefore need to a certain degree above iron content rate, be preferably more than the 40 quality %.And, contain SiO in first coating 52 usually ₂Raw material.But contain SiO ₂Raw material not necessarily also can only be made of iron ore.First coating 52 has the melt that will be formed by the Wingdale in second coating 53 as mentioned above from nuclear particle 51 isolating effects, and void content need be for below 20%, as the Al that considers ₂O ₃When influencing, need make void content is below 20% and Al ₂O ₃Containing ratio is below the 2.1 quality %.When void content surpassed 20%, generation was used for the insufficient problem of agglomerating melt.And, work as Al ₂O ₃When containing ratio surpasses 2.1 quality %, the tendency that exists the viscosity that is used for the agglomerating melt to uprise.Al ₂O ₃The containing ratio scope more preferably is below the 1.5 quality %.Al ₂O ₃There is not lower limit in containing ratio, but contains the Al more than the 0.1 quality % in iron compound usually ₂O ₃, therefore 0.1 quality % is actual lower limit.And void content does not have special lower limit yet, but because the void content of iron compound is generally more than 1%, therefore 1% is actual lower limit.

As the iron ore that constitutes nuclear particle 51, use void content than the high iron ore of the employed iron compound of above-mentioned first coating.And, when considering Al ₂O ₃Influence the time, use void content and A1 ₂O ₃The iron ore that any one party in the containing ratio or both are all high.So can obtain to form the effect of first coating 52.As nuclear particle 51, when using void content to surpass 20% nuclear particle, have than obvious effects.When considering Al ₂O ₃Influence the time, satisfy void content in use and cross 20% and Al ₂O ₃When containing ratio was crossed any one party of 2.1 quality % or both sides' material, effect was more obvious.Except iron ore, also can contain SiO in the nuclear particle 51 ₂Raw material.But if contain Wingdale, effect then of the present invention reduces, so does not contain Wingdale in the nuclear particle 51.The iron ore that constitutes nuclear particle 51 also can mix multiple the use.When using multiple iron ore, void content, Al ₂O ₃Containing ratio can be respectively with average void content, average A l ₂O ₃Containing ratio is held, these average void content, average A l ₂O ₃Containing ratio satisfies above-mentioned relation and gets final product, and part also can be used void content or void content and Al ₂O ₃The iron ore that containing ratio is low.

Second coating 53 can be formed by Wingdale 14 and 15 mixing of solid fuel class raw material, also can have following double-layer structural: at first coat Wingdale 14 as internal layer, coat solid fuel class raw material 15 afterwards as outer.

The character state of the iron compound of the various iron ores of table 4 expression etc.Shown in this table 4, the void content of low Rock Phosphate (72Min BPL), micro mist limonite ore, roll scale is below 20%, even the Al that considers ₂O ₃Influence is because Al ₂O ₃Containing ratio is below the 2.1 quality %, and therefore the iron content rate as first coating 52 is suitable.If its iron content rate of iron powder that produces in system ironworks except that roll scale is more than the 40 quality %, void content is below 20%, the iron compound that also can be used as first coating 52 uses.When considering Al ₂O ₃Influence the time, if Al in addition ₂O ₃Containing ratio is that 2.1 quality % are following, and the iron compound that can be used as first coating 52 uses.

On the other hand, because the void content of limonite ore, micro mist limonite ore, high Rock Phosphate (72Min BPL) (high P ore) crosses 20%, so use as nuclear particle 51.The Al of high Rock Phosphate (72Min BPL) particularly ₂O ₃Containing ratio surpasses 2.1 quality %, when it is used as nuclear particle, need take into full account Al ₂O ₃Influence.

As mentioned above, the iron ore that constitutes nuclear particle 51 can contain multiple, if compare average void content and average A l with the iron compound of first coating 52 ₂O ₃The scope that any one party of containing ratio or both sides are all high also can contain low Rock Phosphate (72Min BPL), micro mist limonite ore and roll scale, iron powder on a small quantity.

And, even for example identical low Rock Phosphate (72Min BPL), owing to void content, Al ₂O ₃Therefore the containing ratio difference, both use low Rock Phosphate (72Min BPL) to nuclear particle 51 and first coating 52, use void content and Al as nuclear particle 51 ₂O ₃The material that any one party of containing ratio or both sides are all high also can obtain effect.

Consider the kind of iron ore, sintering shown in Fig. 9 (b) the sintered particles 50a behind the granulated pellet 50, as fusion nuclear particle (core) 51a, use be derived from from micro mist limonite ore, limonite ore, and high Rock Phosphate (72Min BPL) select one or two or more kinds with the material of ferric oxide as main body, as the middle layer 52a that covers its outside, uses be derived from from micro mist limonite ore, low Rock Phosphate (72Min BPL), roll scale, reach select the iron powder one or two or more kinds with the material of ferric oxide as main body.

Table 4

The mineral name	Al 2O 3Amount (quality %)	Void content (%)	Granularity (mm)	P measures (quality %)	FeO measures (quality %)	Appropriate location in the granulated pellet
							Low phosphorus ore 1	0.75	7.2	0.287	0.02	0.27	First coating
Low phosphorus ore 2	0.7	5.6	0.037	0.035	0.17	First coating
							Low phosphorus ore 3	2.03	18.2	0.303	0.067	0.25	First coating
Low phosphorus ore 4	1.36	10.5	0.354	0.02	0.3	First coating
							Magnetite	0.58	2.8	0.042	0.018	27.5	First coating
Limonite
	1	1.38	32.8	0.466	0.036	0.1	Nuclear particle
Limonite
	2	2.7	31.1	0.427	0.041	0.3	Nuclear particle
The micro mist limonite								1.98	33.5	0.158	0.063	0.2	Nuclear particle
	High Rock Phosphate (72Min BPL)	2.16	25.5	0.188	0.123	0.2	Nuclear particle
Roll scale								0.34	1.8	0.112	0.028	55	First coating

Then the manufacturing process to the granulated pellet of present embodiment with the cross-sectional configuration shown in above-mentioned Fig. 9 (a) describes.Figure 14 is the granulation schema of an example of the manufacture method of the raw materials for sintering that relates to of expression first embodiment of the present invention.Wherein, nuclear particle 51 uses the micro mist limonite ore, and the iron compound of first coating 52 uses low Rock Phosphate (72Min BPL).

At first, micro mist limonite ore 11 usefulness first tablets press 16 is carried out granulation, thereby make the nuclear particle 51 that constitutes by micro mist limonite ore 11.

And, this nuclear particle 51 as nuclear, is utilized low Rock Phosphate (72Min BPL) 12 and utilizes as required to contain SiO ₂Raw material 13 carries out granulation by second tablets press 17, forms first coating 52 on nuclear particle 51, granulated pellet in the middle of obtaining.

Then; the middle granulated pellet that will have this first coating 52 is as nuclear; utilize Wingdale 14 and solid fuel class raw material 15 in the 3rd tablets press 18, to carry out granulation, thereby can obtain the granulated pellet 50 (Fig. 9 (a)) of the multi-ply construction that constitutes by nuclear particle 51, first coating 52, second coating 53.In this case, as mentioned above, at first coat Wingdale 14, coat solid fuel class raw material 15 afterwards as outer as internal layer, also can be with second coating as double-layer structural.

And, as the SiO that contains that contains in first coating 52 ₂Raw material 13 can use silica, serpentinite, nickel slag etc.And, when using iron ore, in iron ore, also contain the SiO about 3-5 quality % as iron compound ₂Contain SiO ₂Raw material 13 is preferably meal, the preferred not enough 2mm of median size, for example 0.1-1.0mm.And the solid fuel class raw material 15 as containing in second coating 53 can use coke, hard coal etc.The all preferred meal of Wingdale 14 and solid fuel class raw material 15, median size is preferably below the 0.5mm, more preferably 0.25mm.

For the effect of the granulated pellet 50 that proves above-mentioned present embodiment, carried out granulation experiment shown in Figure 15.

When granulation experiment No.1 represents to utilize agglomeration technique shown in Figure 23, all raw materials of the iron ore 101-solid fuel class powder stock 105 of micro mist limonite class are carried out granulation equably in 300 seconds with drum mixer 106 situation.

When granulation experiment No.2 represented to utilize agglomeration technique shown in Figure 24, (micro mist limonite ore 101-contained SiO with the raw material beyond Wingdale, the coke ₂Raw material 103) in 240 seconds, after the granulation, utilize Wingdale 104 and solid fuel class raw material 105 to pass through the further situation of granulation in 60 seconds of drum mixer 106 with drum mixer 106.

Granulation experiment No.3 is the situation of first embodiment of the present invention, only carries out the granulation in 120 seconds with micro mist limonite ore 11 by first tablets press 16, behind the formation nuclear particle 51, is nuclear with this nuclear particle 51, utilizes low Rock Phosphate (72Min BPL) 12 and contains SiO ₂Raw material 13 carries out 240 seconds granulation by second tablets press 17; thereby granulation forms first coating 52; and utilize Wingdale 14 and solid fuel class raw material 15 on this first coating 52, to form second coating 53, thereby form the granulated pellet 50 of the multi-ply construction shown in Fig. 9 (a) with granulation in 60 seconds by the 3rd tablets press 18.

Granulation experiment No.4 is the situation of following second embodiment of the present invention, specifically discusses after a while.

Figure 16 represents the low temperature intensity of sintered compact and the measuring result of reduction disintegration.Therefrom as can be known, by adopting the manufacture method of present embodiment, have good low-temperature intensity, and can improve the intensity after the reduction.Table 5 expression utilizes the result who carries out sintering experiment according to the granulated pellet of the method manufacturing of Figure 15.Therefrom as can be known, by adopting the inventive method (first embodiment: granulation experiment No.3), can improve productivity, low temperature intensity (shutter intensity, reduction disintegration (RDI)), yield rate simultaneously.

Table 5

Experiment No.	No.1	No.2	No.3
				Prilling process	Evenly granulation	Outer dress granulation type	First embodiment
Mean wind speed (m/s)	3.19	3.36	4.32
				Yield rate (%)	81.1	76.7	78.6
Shutter intensity (%)	79.9	80.1	82.5
				Productivity (t/Hrm 2)	1.24	1.36	1.48
Harmonic mean particle diameter (mm)	0.74	0.81	0.91
				JIS-RI(％)	71	74	77
RDI(％)	55	52	46
				Remarks	First reference technique	Second reference technique	The present invention

Further, the inventor obtains following opinion by studying the granulation of micro mist limonite ore repeatedly.

Utilize the device of evaluation ore wettability shown in Figure 17, obtain Figure 18, Figure 19, result shown in Figure 20.That is wettability evaluating apparatus 30, shown in Figure 17 is by constituting with the lower section: the cylindrical shell 31 of having filled the ore powder of evaluation object; Cover the gauze 32 of the lower end of this cylindrical shell 31; The tank 33 of storage of water 34, the lower end that water 34 soaks the cylindrical shell 31 that is covered by gauze 32.

In this wettability evaluating apparatus 30, the lifting height h (cm) of the water 34 in the cylindrical shell 31, establish the diameter of particle that is filled in cylindrical shell 31 be the viscosity of R (cm), water be the surface tension of η, water-air be the contact angle of γ, water and powder be θ (°), elapsed time after soaking is t (second), suitable parameter (Fitting Parameter) when being φ, can be expressed as following formula (1).

$h={\left(\frac{\mathrm{\&phi;R\&gamma;}\cos \mathrm{\&theta;}}{2\mathrm{\&eta;}}\right)}^{\frac{1}{2}}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="A20048002938100331.png,A20048002938100401.png"\; state="\{\{state\}\}">t</figure-callout>}}^{\frac{1}{2}}$ Formula (1)

H: the lifting height of water (cm)

R: particle diameter (cm)

η: the viscosity of water

γ: the surface tension of water one air

θ: the contact angle of water and powder (°)

T: time (second)

φ：Fitting Parameter

Figure 18 (a) and (b) expression respectively magnet class ore, the brown iron class of micro mist ore, low Phosphorus ore are filled in each cylindrical shell 31 of wettability evaluating apparatus 30 of Figure 17, in water 34, soak simultaneously after 5 seconds, and the lifting height of the water after 30 seconds.

The lifting height of the water in the cylindrical shell 31 the when cylindrical shell 31 that each ore that Figure 19 represents to hang down phosphorus ore (contact angle: 45 °), micro mist limonite (contact angle: 61 °), limonite (contact angle: 37 °), magnetite (contact angle: 68 °), low phosphorus ore (contact angle: 55 °) is filled into wettability evaluating apparatus 30 is measured and the measuring result of the relation in elapsed time.

According to Figure 18 and Figure 19; except special magnetic iron ore; the micro mist limonite ore is the ore the poorest with the wettability of water in the ore of this time investigating (low phosphorus ore, limonite etc.); therefore as shown in figure 20; the capillary adhesion strength based on water of the granulated pellet made from tablets press is lower; the collapse of the particle of arduous granulation hinders air permeability in sintering process.

But, as shown in figure 21, when pressurizeing by the variation of the surface shape of micro mist limonite ore, other ores of strength ratio that can find molding obviously increase, as shown in table 6, find to utilize mobile number (fluid number=centrifugal force/gravity) comparatively more effective than the granulation that big high-speed stirring mixers (making the counterrotating formation of agitating vane (Agitator) in the inside of concave disk (Disk)) such as drum mixer carry out the brown iron class of micro mist ore.

Table 6

	Disc	Agitator
			Drum mixer	1.9×10 -3	-
Pelletizer (pelletizer)	3.4×10 -2	-
			Adjust stirring mixer	1.4×10 -1	7.1
Briquetting press (briquet machine)	Compacting pressure: 80kg/mm 2About

※ number=centrifugal force/the gravity that flows

According to this opinion,, implemented the manufacture method of raw material for sintering shown in Figure 22 as second embodiment of the present invention.

The difference of Figure 22 and above-mentioned Fig. 1 is, replaces first tablets press 16 of the nuclear particle 51 of the brown iron class of formation micro mist ore 11 to carry out granulation with high-speed stirring mixer 16A.As high-speed stirring mixer 16A, can use the inside of dish (Disk) to make Eirich mixing machine, the レ デ イ ゲ mixing machine of the counterrotating formation of agitating vane (Agitator) at matrix.In this case, the rotating speed of agitating vane for example can be 50-300rpm.

And as required can to the brown iron class of micro mist ore 11 mix from after the returning mine of sintering circuit, and pass through high-speed stirring mixer 16A granulation.In the granulation process that this homogenizer 16A carries out, become the powerful each other state that pressurizes of particle of micro mist limonite ore 11, therefore as shown in figure 21, by the increase effect of tensile strength, can increase the intensity of the nuclear particle 51 that constitutes by the brown iron class of micro mist ore 11.

Carried out the granulation experiment according to this second embodiment.The granulation experiment No.4 correspondence of this granulation experiment and Figure 15.Wherein, only using the brown iron class of micro mist ore 11 (perhaps mix as required and return mine) to carry out 120 seconds granulation by high-speed stirring mixer 16A, behind the formation nuclear particle 51, is nuclear with this nuclear particle 51, utilizes other iron ore classes 12 and contains SiO ₂Raw material 13; carry out 240 seconds granulation by second tablets press 17; thereby granulation forms first coating 52; further utilize Wingdale 14 and solid fuel class raw material 15; on this first coating 52, form second coating 53 by the 3rd tablets press 18, thereby granulation obtains the granulated pellet 50 of the multi-ply construction shown in Fig. 9 (a) with granulation in 60 seconds.

Table 7 has relatively been represented first embodiment shown in Figure 14 (No.3 is tested in granulation) and has been utilized the sintering experiment result of the granulated pellet that granulation process obtained 50 of second embodiment of high-speed stirring mixer 16A shown in Figure 22 (granulation experiment No.4).From table 7 also as can be known,, high-speed stirring mixer 16A can be confirmed to use, shutter intensity, and the productivity etc. of the agglomerate behind the sintering of granulated pellet 50 can be further improved by the experiment same with table 5.

Table 7

Experiment No.	No.3	No.4
			Prilling process	First embodiment	Second embodiment
Mean wind speed (m/s)	4.32	4.56
			Yield rate (%)	78.6	79.6
Shutter intensity (%)	82.5	84.1
			Productivity (t/Hrm 2)	1.48	1.55
Harmonic mean particle diameter (mm)	0.91	1.03
			JIS-RI(％)	77	76
RDI(％)	46	40
			Remarks	The present invention	The present invention

The present invention can be widely used in having used the sintering process of low-quality iron ores such as the brown iron class of micro mist ore, brown iron class ore, high Rock Phosphate (72Min BPL).

Claims (23)

1. the manufacture method of an agglomerate is characterized in that,

Has following operation: on the surface of the nuclear particle that contains iron ore, utilize iron compound to form first coating, on the surface of described first coating, form second coating by Wingdale and solid fuel class raw material, form operation as the granulated pellet of raw material for sintering; With the operation of the described granulated pellet of sintering,

The void content of the employed iron compound of described first coating is below 20%,

The iron ore that described nuclear particle is used is compared its void content height with the employed iron compound of described first coating.

2. the manufacture method of agglomerate according to claim 1 is characterized in that, the void content of the iron ore that described nuclear particle is used satisfies above 20%.

3. the manufacture method of an agglomerate is characterized in that,

Has following operation: on the surface of the nuclear particle that contains iron ore, utilize iron compound to form first coating, on the surface of described first coating, form second coating by Wingdale and solid fuel class raw material, form operation as the granulated pellet of raw material for sintering; With the operation of the described granulated pellet of sintering,

The void content of the employed iron compound of described first coating is below 20% and Al ₂O ₃Containing ratio is below the 2.1 quality %, and the iron ore that described nuclear particle is used is compared void content and Al with the employed iron compound of described first coating ₂O ₃Any one party in the containing ratio or both sides are all high.

4. the manufacture method of agglomerate according to claim 3 is characterized in that, the iron ore that described nuclear particle is used satisfies void content and surpasses 20%, reaches Al ₂O ₃Containing ratio surpasses any one party or the both sides among the 2.1 quality %.

5. the manufacture method of an agglomerate is characterized in that,

Has following operation: on the surface of the nuclear particle that contains iron ore, utilize iron compound to form first coating, on the surface of described first coating, form second coating by Wingdale and solid fuel class raw material, form operation as the granulated pellet of raw material for sintering; With the operation of the described granulated pellet of sintering,

The employed iron compound of described first coating is from magnetic iron ore, low Rock Phosphate (72Min BPL), roll scale, reaches one or two or more kinds that select the iron powder, and the employed iron ore of described nuclear particle comprises the iron ore beyond magnetic iron ore and the low Rock Phosphate (72Min BPL).

6. the manufacture method of agglomerate according to claim 5 is characterized in that, the iron ore that described nuclear particle is used is from micro mist limonite ore, limonite ore, reaches one or two or more kinds that select the high Rock Phosphate (72Min BPL).

7. according to the manufacture method of claim 1,3, any described agglomerate of 5, it is characterized in that described nuclear particle carries out granulation by the iron ore that described nuclear particle is used and obtains.

8. according to the manufacture method of claim 1,3, any described agglomerate of 5, it is characterized in that described second coating at first coats Wingdale, coat solid fuel class raw material afterwards.

9. granulated pellet, in the manufacturing process of agglomerate, be used as raw material for sintering, by around the nuclear particle that contains iron ore, forming first coating that has used iron compound, and formation has thereon been used second coating of Wingdale and solid fuel class raw material and has been constituted, it is characterized in that

The void content of the employed iron compound of described first coating is below 20%, and the iron ore that constitutes described nuclear particle is compared its void content height with the employed iron compound of described first coating.

10. granulated pellet according to claim 9 is characterized in that, the iron ore that described nuclear particle is used satisfies void content and surpasses 20%.

11. granulated pellet, in the manufacturing process of agglomerate, be used as raw material for sintering, by around the nuclear particle that contains iron ore, forming first coating that has used iron compound, and formation has thereon been used second coating of Wingdale and solid fuel class raw material and has been constituted, it is characterized in that

The void content of the employed iron compound of described first coating is below 20% and Al ₂O ₃Containing ratio is below the 2.1 quality %, and the iron ore that constitutes described nuclear particle is compared void content and Al with the employed iron compound of described first coating ₂O ₃Any one party in the containing ratio or both sides are all high.

12. granulated pellet according to claim 11 is characterized in that, the iron ore that constitutes described nuclear particle satisfies void content and surpasses 20%, reaches Al ₂O ₃Containing ratio surpasses any one party or the both sides among the 2.1 quality %.

13. granulated pellet, in the manufacturing process of agglomerate, be used as raw material for sintering, by around the nuclear particle that contains iron ore, forming first coating that has used iron compound, and formation has thereon been used second coating of Wingdale and solid fuel class raw material and has been constituted, it is characterized in that

The employed iron compound of described first coating is from magnetic iron ore, low Rock Phosphate (72Min BPL), roll scale, reaches one or two or more kinds that select the iron powder, and the iron ore that constitutes described nuclear particle comprises magnetic iron ore and low Rock Phosphate (72Min BPL) iron ore in addition.

14. granulated pellet according to claim 13 is characterized in that, the iron ore that constitutes described nuclear particle is from micro mist limonite ore, limonite ore, reaches one or two or more kinds that select the high Rock Phosphate (72Min BPL).

15., it is characterized in that described second coating has: utilize internal layer that Wingdale forms, and the skin that utilizes solid fuel class raw material to form in its outside according to claim 9,11, any described granulated pellet of 13.

16. agglomerate, it is characterized in that, aggregate by the unit grain structure constitutes, this unit grain structure comprises: based on the core of the ferric oxide that is derived from iron ore, cover its outside the middle layer based on the ferric oxide that is derived from iron compound, and cover the outermost layer based on calcium ferrite in described middle layer, wherein, described middle layer is than described core densification.

17. agglomerate, it is characterized in that, aggregate by the unit grain structure constitutes, this unit grain structure comprises: based on the core of the ferric oxide that is derived from iron ore, cover its outside the middle layer based on the ferric oxide that is derived from iron compound, and cover the outermost layer based on calcium ferrite in described middle layer, wherein, densification and Al are compared with described core in described middle layer ₂O ₃Containing ratio is low.

18. an agglomerate is characterized in that, is made of the aggregate of unit grain structure, this unit grain structure comprises: core, based on be derived from from micro mist limonite ore, limonite ore, and high Rock Phosphate (72Min BPL) one or two or more kinds the ferric oxide selected; The middle layer covers described core, based on be derived from from magnetic iron ore, low Rock Phosphate (72Min BPL), roll scale, and iron powder one or two or more kinds the ferric oxide selected; And outermost layer, cover described middle layer, based on calcium ferrite.

19. an agglomerate is characterized in that, the aggregate of being constructed by unit grain constitutes, and this unit grain structure comprises: the core of porous matter, to be derived from the ferric oxide of micro mist limonite ore; The middle layer of compact substance covers described core, to be derived from the ferric oxide of low Rock Phosphate (72Min BPL); And outermost layer, cover described middle layer, based on calcium ferrite.

20. the manufacture method of a raw material for sintering, this raw material for sintering is used for the manufacturing process of agglomerate for blast furnace, it is characterized in that, has following operation:

First iron ore of micro mist limonite class is carried out granulation and make the operation of nuclear particle;

On the surface of described nuclear particle, utilize second iron ore beyond described first iron ore and contain SiO ₂Raw material forms the operation of first coating; With

On the surface of described first coating, form the operation of second coating by Wingdale and solid fuel class powder stock.

21. the manufacture method of a raw material for sintering, this raw material for sintering is used for the manufacturing process of agglomerate for blast furnace, it is characterized in that, has following operation:

Only utilize first iron ore of micro mist limonite class or described first iron ore and, make the operation of nuclear particle by tablets press with high-speed stirring blade from the returning mine of sintering circuit;

On the surface of described nuclear particle, utilize second iron ore beyond described first iron ore and contain SiO ₂Raw material forms the operation of first coating; With

On the surface of described first coating, utilize Wingdale and solid fuel class powder stock to form the operation of second coating.

22. a granulated pellet is used as raw material for sintering in the manufacturing process of agglomerate for blast furnace, it is characterized in that having:

Nuclear particle is obtained by the first iron ore granulation of micro mist limonite class;

First coating is formed on the surface of described nuclear particle, by second iron ore beyond described first iron ore and contain SiO ₂Raw material constitutes; With

Second coating is formed on the surface of described first coating, is made of Wingdale and solid fuel class powder stock.

23. a granulated pellet is used as raw material for sintering in the manufacturing process of agglomerate for blast furnace, it is characterized in that having:

Nuclear particle only utilizes first iron ore of micro mist limonite class or described first iron ore and from the returning mine of sintering circuit, obtains by the tablets press granulation with high-speed stirring blade;

First coating is formed on the surface of described nuclear particle, by second iron ore beyond described first iron ore and contain SiO ₂Raw material constitutes; With

Second coating is formed on the surface of described first coating, is made of Wingdale and solid fuel class powder stock.

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