AU2017405434A1

AU2017405434A1 - Ore pellet, preparation method therefor, and preparation equipment

Info

Publication number: AU2017405434A1
Application number: AU2017405434A
Authority: AU
Inventors: Gang An; Haoyu CAI; Wenbin Huang; Jixiang HUO; Ming Li; Wenwang LIU; Zejun Ma; Yuandong PEI; Gele QING; Junqing TIAN; Xiaopeng Wang; Weidong Zhang; Yan Zhang; Yong Zhao; Zhixing ZHAO
Original assignee: Shougang Group Co Ltd
Current assignee: Shougang Group Co Ltd
Priority date: 2017-03-22
Filing date: 2017-03-22
Publication date: 2019-01-24
Anticipated expiration: 2037-03-22
Also published as: KR102285165B1; WO2018170767A1; BR112019002449A2; JP6767519B2; CN110402293B; KR20190130554A; JP2019519687A; CN110402293A; AU2017405434B2

Abstract

An ore pellet, a preparation method therefor, and preparation equipment. The mass percent content of components in the ore pellet are: TFe 62.1%-65.82%, FeO 0.2%-0.58%, SiO

Description

ORE PELLET, PREPARATION METHOD THEREFOR,

AND PREPARATION EQUIPMENT

TECHNICAL FIELD [0001] The present invention relates to the technical field of sintered ore powder, and in particular to a pellet, a preparation method, and preparation apparatus thereof.

BACKGROUND OF THE INVENTION [0002] Pellet and sintered ore are main furnace burden for blast furnace ironmaking. The sintered ore is obtained by adding a certain proportion of fuel and flux to various powdery iron-containing raw materials according to the requirement, uniformly mixing the components and performing highignition sintering on a sintering machine. The iron ore powder for sintering is relatively coarse in particle size, and the requirement for the particle size is relatively low, so that multiple kinds of mineral powder can be used. The pellet production has relatively high requirement for the raw materials, and it is required that the pellet raw materials have certain particle sizes and particle size composition, suitable moisture and uniform chemical composition, etc. Compared with the sintered powder, the general pellet powder is finely ground and selected ore powder, which has a high grade, fine particle size and low content of harmful components. Therefore, the pellets have relatively few types of raw materials, relatively low yields and relatively high prices.

[0003] Compared with the sintered ore, the pellet is better in the cold quality and the environmental performance of the production process. The sintered ore has low strength, high returning rate, a large amount of exhaust gas in the production process, high dust concentration and a large amount of dust, and generates pollutants such as dioxins. In addition, the energy consumption of the procedures of the sintering process is more than twice that of the pellet process. The amount of waste gas in the pellet production process is relatively low, very few pollutants such as dioxins are generated in the production process, the energy consumption of the procedures is low, and the dust content is low. With the increasingly severe global environmental requirements, the development of pellet process, and the production and use of the pellet become a trend. To develop the pellet, firstly, there must be sufficient and cost-effective mineral resources. However, the current global pellet mine power is still

-1limited and the price is relatively high, which makes it difficult for steel companies worldwide to develop the pellet process.

SUMMARY OF THE INVENTION [0004] In view of this, the present invention provides a pellet, a preparation method, and preparation apparatus therefore, which can prepare the pellet by using sintered ore powder, thereby being more suitable for practical use.

[0005] In order to achieve the above first objective, the technical solution of the pellet provided by the present invention is as follows:

[0006] The pellet provided by the present invention includes the following components in percentage by mass: TFe 62.1%-65.82%, FeO 0.2%-0.58%, S1O2 1.90%-5.97%, CaO 0.17%-3.23%, MgO 0.18%-0.52%, AI2O3 0.58%-2.66%, and the mass ratio of CaO to S1O2 is 0.035-1.31;

[0007] wherein, when the percentage by mass of S1O2 is less than 3.0%, the mass ratio of CaO to S1O2 is greater than or equal to 1.0.

[0008] In order to achieve the above second objective, the technical solution of the preparation method of the pellet provided by the present invention is as follows:

[0009] A preparation method of the pellet provided by the present invention includes the following steps:

[0010] finely grinding sintered ore powder to obtain finely ground sintered powder having set parameters;

[0011] performing ore proportioning on the pellet powder and/or boron-containing pellet powder and the finely ground sintered powder to obtain concentrate powder;

[0012] adding a binder to the concentrate powder to obtain an intermediate mixture; and

-2[0013] pelletizing and roasting successively the intermediate mixture to prepare the pellet.

[0014] In order to achieve the above third objective, preparation apparatus of the pellet provided by the present invention is as follows:

[0015] the preparation apparatus of the pellet ore provided by the present invention includes a grinding device, a container, a pelletizing device and a roasting system, [0016] the grinding device is used for finely grinding sintered ore powder to obtain finely ground sintered powder having set parameters;

[0017] the container is used for accommodating concentrate powder obtained by performing ore proportioning on the pellet powder and/or boron-containing pellet powder and the finely ground sintered powder, and an intermediate mixture obtained by adding a binder to the concentrate powder;

[0018] the pelletizing device is used for pelletizing the intermediate mixture to obtain a spherical intermediate product; and [0019] the roasting system is used for performing a roasting process on the spherical intermediate product to obtain the pellet through the roasting process.

[0020] The pellet provided by the present invention is prepared from the sintered ore powder, that is, the pellet with good quality and relatively low environmental cost can be prepared by using the sintered ore powder with poor quality and relatively high environmental cost, so that a simple and beneficial approach is provided for the green development of the metallurgical industry.

[0021] Through the preparation method and the preparation apparatus of the pellet provided by the present invention, the pellet provided by the present invention can be obtained, that is, the pellet with good quality and relatively low environmental cost can be prepared by using the sintered ore powder with poor quality and relatively high environmental cost, so that a simple and beneficial approach is provided for the green development of the metallurgical industry.

-3BRIEF DESCRIPTION OF THE DRAWINGS [0022] Various other advantages and benefits will become apparent to those skilled in the art by reading the detailed description of preferred embodiments below. The drawings are only for the purpose of illustrating the preferred embodiments, but cannot be construed as limitation to the present invention. Throughout the drawings, the same components are denoted by the same reference signs. In the drawings:

[0023] Fig.l is a flowchart of steps of a preparation method of a pellet provided by an embodiment of the present invention;

[0024] Fig.2 is a flowchart of material change in a process of a preparation method of a pellet provided by an embodiment of the present invention;

[0025] Fig.3 is a flowchart of steps of a roasting process involved in a preparation method of a pellet provided by an embodiment of the present invention;

[0026] Fig.4 is a schematic diagram of connection relations among devices in a preparation apparatus of a pellet provided by an embodiment of the present invention;

[0027] Fig.5 is a picture of sintered ore.

[0028] Fig.6 is a picture of the pellet prepared by the preparation method and the preparation apparatus provided by an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION [0029] In order to solve the problems existing in the prior art, the present invention provides a pellet, a preparation method, and preparation apparatus thereof, which can prepare the pellet by using sintered ore powder, thereby being more suitable for practical use.

[0030] In order to further illustrate the technical means and effects of the present invention for achieving predetermined objectives of the invention, the embodiments, structures, features and effects of the pellet, the preparation method and the preparation apparatus thereof proposed

-4according to the present invention are described below in detail with reference to the drawings and preferred embodiments. The wording an embodiment or embodiments in different locations in the following description does not necessarily mean the same embodiment. Furthermore, the particular features, structures, or characteristics of one or more embodiments can be combined in any suitable form.

[0031] The term and/or herein merely represents an association relation that describes associated objects and indicates that three relationships may exist, for example, A and/or B is specifically understood as that: A and B can be included at the same time, the A can exist alone, the B can also exist alone, that is, any of the above three cases can exist.

Example 1 [0032] Finely grinding Barca mineral powder to obtain finely ground Barca mineral powder, wherein in the finely ground Barca mineral powder, the percentage by mass of particles with particle sizes less than or equal to 74 gm is greater than or equal to 80%, and the percentage by mass of particles with particle sizes less than or equal to 44 gm is greater than 60%. 99.0kg of concentrate powder of the finely ground Barca mineral powder is weighed, 0.6kg of bentonite is added therein to serve as a binder, 3.3kg of slaked lime is used as a calcium-containing flux, water is used as a liquid medium, the components are uniformly mixed to obtain an intermediate product, wherein in the intermediate product, the percentage by mass of water is 7.0%. The intermediate product is placed in a disc pelletizer for pelleting, the pelleting time is 10 min, green balls with a particle size of 9-16mm are screened, and a roasting process is carried out in a roasting cup to obtain the pellet. The roasting process includes: performing air blowing drying on the green balls at a temperature of 320 °C for 3min, then performing air draft drying at a temperature of 450 °C for 5min, performing preheating at a temperature of 1000°C for 6min, performing roasting at a temperature of 1290 °C for lOmin, then performing soaking at a temperature of 1150 °C for 3min; and air cooling the pellet subjected to the soaking to 150°C.

[0033] The pellet includes the following components in percentage by mass: TFe 63.46%, FeO 0.56%, S1O2 2.32%, CaO 2.76%, MgO 0.27%, AI2O3 2.01%, and the mass ratio of CaO to S1O2 is 1.19.

-5[0034] The pellet has compressive strength of 2879 N/P, a drum index of 93.2%, a reduction expansion rate of 17.2%, and a reduction degree of 73.5%.

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-7[0035] The index requirements for the pellet with qualified quality are follows: the compressive strength is greater than 2400 N and the reduction expansion rate is less than 20%; and it can be seen by comprehensively considering the above-mentioned examples 1-18 of the present invention that the above examples 1-18 of the present invention all satisfy the above index requirements, therefore, the quality of the pellet prepared by the examples 1 -18 of the present invention is qualified.

Table 2. Operation parameters of the preparation method of the pellet provided by the examples 1-18

No.	Concentrate powder	Bentonite kg	Ca-containing flux kg	Percentage by mass of water %	Pelletizing time min	Pelletizer	Roasting equipment
Material composition	Mass kg
1	Finely ground Barca powder	99.0	0.6	Slaked lime 3.3	7.0	10	Disc pelletizer	Roasting cup
2	Finely ground Barca powder	54.17	1.5	—	7.3	11	Disc pelletizer	Roasting cup
Finely ground PB powder	34.47475
Boron-containing pellet powder	0.985985
3	Pellet powder	49.5	1.0	—	7.3	10	Disc pelletizer	Roasting cup
Finely ground Barca powder	19.8
Finely ground PB powder	9.9
Finely ground Newman powder	9.9
4	Pellet powder	57.8	0.6	Slaked lime 3	7.1	11	Disc pelletizer	Roasting cup
Finely ground Barca powder	19.28
Finely ground PB powder	9.64
Finely ground Mac powder	9.64
5	Y angdi powder	19.84	0.8	—	7.0	11	Disc pelletizer	Roasting cup
Finely ground Barca powder	39.68
Finely ground South African powder	29.76
Boron-containing pellet powder	9.92
6	Pellet powder	46.6	0.8	Limestone 6	7.1	11	Disc pelletizer	Roasting cup
Finely ground Barca powder	37.28
Finely ground PB powder	9.32

7	Finely ground Barca powder	57.84	0.5	Slaked lime 3.1	7.0	11	Disc pelletizer	Roasting cup
Pellet powder	28.92
Finely ground Newman powder	9.64
8	Finely ground PB powder	54.17	1.5	—	7.3	11	Disc pelletizer	Roasting cup
Finely ground South African powder	34.47
Finely ground Mac powder	9.85
Boron-containing pellet powder	3.58
9	Pellet powder	88.7	1.4	—	7.3	11	Disc pelletizer	Roasting cup
Finely ground Brazilian sintered powder	4.93
Finely ground South African powder	4.93
10	Finely ground PB powder	49.0	1.3	—	7.2	10	Disc pelletizer	Roasting cup
Pellet powder	44.1
Boron-containing pellet powder	4.9
11	Finely ground Barca powder	88.65	0.8	Slaked lime 3.4	7.4	9	Disc pelletizer	Roasting cup
Pellet powder	9.85
12	Finely ground Indian powder	49.0	1.0	—	7.2	8	Disc pelletizer	Roasting cup
Pellet powder	49.0
13	Pellet powder	87.3	0.2	Slaked lime 3.0	7.0	8.5	Disc pelletizer	Roasting cup
Finely ground Barca powder	9.7
14	Pellet powder	68.25	0.3	Slaked lime 3.2	7.1	9.5	Disc pelletizer	Roasting cup
Finely ground Barca powder	19.5
Finely ground Indian powder	9.75
15	Pellet powder	80	0.7	—	7.2	9.0	Disc pelletizer	Roasting cup
Finely ground Mac powder	15
Finely ground PB powder	5
16	Finely ground Barca powder	50	0.9	—	7.2	9.5	Disc pelletizer	Roasting cup
Pellet powder	30
Finely ground Brazilian sintered powder	10
Finely ground PB powder	10

17	Finely ground Barca powder	70	0.8	—	7.0	10	Disc pelletizer	Roasting cup
Finely ground Y angdi powder	25
Boron-containing pellet powder	5
18	Pellet powder	80	0.5	Limesto ne 5.8	7.1	10	Disc pelletizer	Roasting cup
Finely ground Newman powder	10
Finely ground FMG powder	10

[0036] Hematite (chemical formula: Fe20s) sintered powder can be used alone or with different proportions of magnetite (chemical formula: FesCfi) pellet powder, if limonite (chemical formula: Fe2O3*H2O) sintered powder is contained, 50-90% magnetite pellet powder or hematite (chemical formula: Fe20s) sintered powder or 5-10% boron-containing pellet powder are added.

[0037] Referring to Figs. 5 and 6, wherein Fig.5 shows the sintered ore, and as can be seen from Fig.5, the appearance of the sintered ore is of an irregular porous structure; Fig.6 shows the pellet, and as can be seen from Fig.6, the appearance of the pellet is of a regular circular structure.

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-11Example 19 [0038] Referring to Fig.4, the preparation apparatus of the pellet provided by the example 19 of the present invention includes a grinding device, a container, a pelletizing device and a roasting system. The grinding device is used for finely grinding sintered ore powder to obtain finely ground sintered powder having set parameters; the container is used for accommodating concentrate powder obtained by performing ore proportioning on the pellet powder and/or boron-containing pellet powder and the finely ground sintered powder, and an intermediate mixture obtained by adding a binder to the concentrate powder; the pelletizing device is used for pelletizing the intermediate mixture to obtain a spherical intermediate product; and the roasting system is used for performing a roasting process on the spherical intermediate product to obtain the pellet through the roasting process. In this case, since no calcium-containing flux is added to the intermediate mixture, the obtained pellet is an acidic pellet. As generally provided, the pellet having a mass ratio of CaO to SiC>2 being less than or equal to 0.6 is the acidic pellet.

[0039] The intermediate mixture further includes a calcium-containing flux. In this case, the calcium-containing flux is usually slaked lime (Ca(OH)2) or limestone (CaCCE), and the obtained finished product pellet is a flux pellet or a self-fluxing pellet. As generally provided, the pellet having a mass ratio of CaO to S1O2 being greater than 0.6 is the flux pellet; and the pellet having a mass ratio of CaO to S1O2 being 0.8-1.2 is the self-fluxing pellet.

[0040] The preparation apparatus of the pellet provided by the example 13 of the present invention further includes a first screen and a second screen. The mesh diameter of the first screen is 74 gm, and the mesh diameter of the second screen is 44 gm. In this case, the particles trapped on the first screen are determined to have a particle size of greater than 74 gm, and the particles capable of passing through the first screen are determined to have a particle size of less than or equal to 74 gm; and further, the particles trapped on the second screen are determined to have a particle size of greater than 44gm, and the particles capable of passing through the second screen are determined to have a particle size of less than or equal to 44gm. At this time, in order to ensure that the particles having the particle size smaller than the mesh diameter can smoothly pass through the first screen and/or the second screen, a table concentrator device can also be provided, the table concentrator device is used for shaking the first screen and/or the second screen in the horizontal direction, so that various angles of the particles on the first screen and/or the second screen may touch the screen

-12meshes, thereby avoiding wrong trap caused by the contact angle misalignment of the particles and the first screen and/or the second screen. In addition, in order to avoid the blockage of the screen meshes due to the distribution of particles with sizes similar to the diameter of the screen meshes on the upper surface of the screen, a first stirring mechanism and/or a second stirring mechanism may also be provided, the first stirring mechanism is used for stirring the upper surface of the first screen, the second stirring mechanism is used for stirring the upper surface of the second screen, so that the particles directly covering the upper surfaces of the first screen and/or the second screen are in an active state, thus further enhancing the screening efficiency of the first screen and/or the second screen.

[0041] The second screen is arranged below the first screen. In this case, as the mesh diameter of the first screen is greater than the mesh diameter of the second screen, the particles having particle sizes less than or equal to the mesh diameter of the first screen leaking from the first screen can directly drop on the outer surface of the second screen, thus a transfer container is not needed to transfer the particles onto the outer surface of the second screen, and therefore the technical solution is simpler, and the operation is more convenient.

[0042] The preparation apparatus of the pellet provided by the example 13 of the present invention further includes a third screen, the value range of the mesh diameter of the third screen is 9-16mm, and the third screen is used for screening green balls with particle sizes of 9-16mm.

[0043] The preparation apparatus of the pellet provided by the example 19 of the present invention further includes a clock for measuring time intervals of the pelletizing and/or roasting process. In this case, the time control of the pelletizing and/or roasting process can be more precise. In addition, in order to control the pelletizing time more easily, an alarm can also be provided, when the pelletizing time reaches a preset time, the alarm automatically emits an alarm, and the alarm can be selected from one or more of a buzzer, a signal light, a short message, a qq message, a voice message and a WeChat message.

[0044] In order to automatically convey the green balls sieved through the third screen into the roasting system, a conveying mechanism can also be provided, and the green balls are automatically

-13conveyed into the roasting system by the conveying mechanism, so that the operation is more convenient and faster.

[0045] The preparation apparatus of the pellet provided by the example 19 of the present invention further includes a temperature control device for adjusting the temperature of the roasting system. In this case, the temperature of each stage of the roasting process can be more accurately controlled, and thus the test result is more accurate.

[0046] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once mastering the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all the changes and modifications that fall within the scope of the present invention.

[0047] Apparently, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention belong to the scope of the claims of the present invention and the equivalent technology thereof, the present invention is also intended to encompass these modifications and variations.

Claims

1. A pellet, comprising the following components in percentage by mass: TFe 62.1%65.82%, FeO 0.2%-0.58%, SiO₂ 1.90%-5.97%, CaO 0.17%-3.23%, MgO 0.18%-0.52%, AI2O3 0.58%-2.66%, and the mass ratio of CaO to S1O2 is 0.035-1.31;

wherein when the percentage by mass of S1O2 is less than 3.0%, the mass ratio of CaO to S1O2 is greater than or equal to 1.0.

2. A preparation method of the pellet according to claim 1, comprising the following steps: finely grinding sintered ore powder to obtain finely ground sintered powder having set parameters;

performing ore proportioning on the pellet powder and/or boron-containing pellet powder and the finely ground sintered powder to obtain concentrate powder;

adding a binder to the concentrate powder to obtain an intermediate mixture; and pelletizing and roasting successively the intermediate mixture to prepare the pellet.

3. The preparation method of the pellet according to claim 2, wherein the pellet is an acidic pellet.

4. The preparation method of the pellet according to claim 2, wherein the step of adding the binder to the concentrate powder to obtain the intermediate mixture further comprises: adding a calcium-containing flux to the concentrate powder.

5. The preparation method of the pellet according to claim 4, wherein the pellet is a flux pellet and a self-fluxing pellet.

6. The preparation method of the pellet according to claim 2 or 4, wherein the sintered powder is selected from any one or a mixture of several of Barca powder, PB powder, Mac powder, Newman powder, Yangdi powder, FMG powder, Brazilian sintered powder, South African powder or Indian powder.

7. The preparation method of the pellet according to claim 2 or 4, wherein in the finely ground sintered powder, the percentage by mass of particles with particle sizes less than or equal to 74 gm is greater than 80%; and the percentage by mass of particles with particle sizes less than or equal to 44 gm is greater than 60%.

8. The preparation method of the pellet according to claim 4, wherein when the binder and the calcium-containing flux are added to the concentrate powder to obtain the intermediate mixture, the value range of mass ratio of the concentrate powder to the binder to the calciumcontaining flux is (99.5-92.5): (0-1.5): (0-6).

9. The preparation method of the pellet according to claim 8, further comprising a step of uniformly mixing the concentrate powder, the binder and the calcium-containing flux.

10. The preparation method of the pellet according to claim 9, wherein the uniform mixing process of the concentrate powder, the binder and the calcium-containing flux is achieved via a liquid medium; and the liquid medium is water.

11. The preparation method of the pellet according to claim 2, wherein the value range of the pelletizing duration is 8-1 lmin.

12. The preparation method of the pellet according to claim 2, further comprising a step of selecting green balls with particle sizes of 9-16mm between the pelletizing process and the roasting process.

13. The preparation method of the pellet according to claim 2, wherein the process conditions of the roasting process successively comprise:

air blowing drying, wherein the value range of the temperature is 250-350°C, and the value range of the duration is 2-3 min;

-16air draft drying, wherein the value range of the temperature is 400-550°C, and the value range of the duration is 4-5min;

preheating, wherein the value range of the temperature is 800-1000°C, and the value range of the duration is 6-1 Omin;

roasting, wherein the value range of the temperature is 1260-1300°C, and the value range of the duration is 7-12min;

soaking, wherein the value range of the temperature is 1100-1150°C, and the value range of the duration is 2-3 min; and cooling, wherein the value range of the temperature is lowered to be less than or equal to 150°C after the cooling procedure.

14. Preparation apparatus of the pellet according to claim 1, comprising a grinding device, a container, a pelletizing device and a roasting system, wherein the grinding device is used for finely grinding sintered ore powder to obtain finely ground sintered powder having set parameters;

the container is used for accommodating concentrate powder obtained by performing ore proportioning on the pellet powder and/or boron-containing pellet powder and the finely ground sintered powder, and an intermediate mixture obtained by adding a binder to the concentrate powder;

the pelletizing device is used for pelletizing the intermediate mixture to obtain a spherical intermediate product; and the roasting system is used for performing a roasting process on the spherical intermediate product to obtain the pellet through the roasting process.

15. The preparation apparatus of the pellet according to claim 14, wherein the intermediate mixture further comprises a calcium-containing flux.

16. The preparation apparatus of the pellet according to claim 14, further comprising a first screen and a second screen, wherein the mesh diameter of the first screen is 74gm, and the mesh diameter of the second screen is 44gm.

17. The preparation apparatus of the pellet according to claim 16, wherein the second screen is arranged below the first screen.

18. The preparation apparatus of the pellet according to claim 14, further comprising a third screen, wherein the value range of the mesh diameter of the third screen is 9-16mm, and the third screen is used for screening green balls with particle sizes of 9-16mm.

19. The preparation apparatus of the pellet according to claim 14, further comprising a clock used for measuring time intervals of a pelletizing process and/or a roasting process.

20. The preparation apparatus of the pellet according to claim 14, further comprising a temperature control device used for adjusting the temperature of the roasting system.