CN109161680B

CN109161680B - Segregation ore blending sintering method for iron ore

Info

Publication number: CN109161680B
Application number: CN201811163940.7A
Authority: CN
Inventors: 王永红; 刘建波; 杜屏
Original assignee: Jiangsu Shagang Group Co Ltd; Zhangjiagang Hongchang Steel Plate Co Ltd; Jiangsu Shagang Iron and Steel Research Institute Co Ltd
Current assignee: Jiangsu Shagang Group Co Ltd; Zhangjiagang Hongchang Steel Plate Co Ltd; Jiangsu Shagang Iron and Steel Research Institute Co Ltd
Priority date: 2018-10-03
Filing date: 2018-10-03
Publication date: 2020-05-22
Anticipated expiration: 2038-10-03
Also published as: CN109161680A

Abstract

This applicationDiscloses a segregation ore blending sintering method of iron ore, which comprises the following steps: s1 selecting different SiO from 2-4₂The iron ore powder in the 2-4 kinds consists of mixed ore with SiO in between₂The difference of the mass percent is 3.0-10.0%; s2 controlling SiO in the mixed ore₂The mass percent is 5.0 +/-0.5 percent, the mass of the mixed ore accounts for 30-50 percent of the total mass of the rich ore powder, the concentrate powder, the auxiliary material and the mixed ore during sintering in the step S3, and the proportion of the 2-4 kinds of iron ore powder is adjusted to realize SiO₂Segregation between coarse and fine particles; and S3, mixing the rich mineral powder, the concentrate powder, the auxiliary material, the flux and the fuel uniformly, and sintering. The invention has the advantages of improving the physical strength of the sintered ore, improving the grain size composition of the sintered ore, reducing the energy consumption and improving the productivity.

Description

Segregation ore blending sintering method for iron ore

Technical Field

The invention relates to the technical field of iron ore smelting, in particular to a segregation ore blending sintering method of iron ore.

Background

Sintering is a process method for iron ore powder agglomeration. The main purpose of sintering is to generate a liquid phase through the reaction of calcium oxide in the flux with iron oxide and silicon oxide in iron ore, the liquid phase is bonded with surrounding large-particle unmelted ore in the cooling process to generate a block body with certain strength and excellent metallurgical property, and the block body is sent into a blast furnace for smelting.

The iron ore powder has different reaction capacities with calcium oxide in the flux due to different silicon contents, and has different capacities and speeds for generating liquid phase. When the iron ore powder has low SiO₂Under the condition of adding certain CaO content, the generation and the flow of a liquid phase can be promoted, and the strength of a sinter bonding phase generated in the cooling process is high; accordingly, when the iron ore powder has high SiO content₂In case of adding CaO in a certain amount, a large amount of liquid can be generatedThe phase is easy to flow, but the strength of the bonding phase of the sinter generated in the cooling process is low, the crushing degree is large in the transportation process, and the integral granularity of the sinter is small.

The related analysis data show that SiO in the iron ore powder₂The content decreases with increasing particles. Generally high SiO₂The content of the mineral powder is smaller in granularity and low in SiO₂The granularity of the ore powder is coarse; when the two types of mineral powder are used for sintering at the same time, SiO can be caused due to natural segregation in the material distribution process₂The ore powder with high content is finer and is mostly attached to SiO as adhesive powder₂The large particles with low content can cause low consolidation strength of the produced sintering ore, and excessive powder ore is generated during crushing, so that the overall granularity of the sintering ore is small, and the blast furnace smelting is influenced.

Disclosure of Invention

The invention aims to provide a method for reasonably matching and using different SiO₂A segregation ore blending sintering method for iron ore. By using the method for sintering, the physical strength of the sintered ore can be improved, the grain size composition of the sintered ore can be improved, the energy consumption can be reduced, and the productivity can be improved.

In order to achieve the above object, the present invention provides the following technical solutions.

The embodiment of the application discloses a segregation ore blending sintering method of iron ore, which comprises the following steps:

s1 selecting different SiO from 2-4₂The iron ore powder in the 2-4 kinds consists of mixed ore with SiO in between₂The difference of the mass percent is 3.0-10.0%;

s2 controlling SiO in the mixed ore₂The mass percent is 5.0 +/-0.5 percent, the mass of the mixed ore accounts for 30-50 percent of the total mass of the rich ore powder, the concentrate powder, the auxiliary material and the mixed ore during sintering in the step S3, and the proportion of the 2-4 kinds of iron ore powder is adjusted to realize SiO₂Segregation between coarse and fine particles;

and S3, mixing the rich mineral powder, the concentrate powder, the auxiliary material, the flux and the fuel uniformly, and sintering.

Preferably, in the segregation blending sintering method of the iron ore, the fuel is coke powder, and the mass percentage of the particle size of 1-3mm is more than 65%.

Preferably, in the method for sintering the segregated mixed iron ore, the auxiliary material is one of mixed sludge and rolled iron oxide scale.

Preferably, in the above method for sintering iron ore by segregation blending, the coarse particles are high silicon particles, SiO₂The mass percent content is more than 5.0 percent, the mass percent of the high-silicon particles with the particle diameter of more than 3mm is more than 20 percent, the fine particles are low-silicon particles, SiO₂The mass percentage content is less than 3 percent, the grain diameter is less than 1mm, and the mass percentage of the low silicon grains is more than 50 percent.

Preferably, in the method for sintering the segregated mixed ore of iron ore, the mass percentage of water in the mixed ore is 7.5 ± 0.5%.

Preferably, in the segregation ore blending sintering method for iron ore, the rich ore powder grade is more than 55%; the mass percentage of the refined mineral powder with the grain diameter less than 0.074mm is 50-70%, and the grade is more than 60%.

The invention is prepared by mixing SiO₂2-4 kinds of iron ore powder with the content difference of 3-10% are sieved in different size fractions due to SiO₂The content can be increased along with the reduction of the particle size, the large-particle iron ore with high silicon content is increased through reasonable collocation, the small-particle iron ore with low silicon content is controlled, the reaction of the large-particle high-silicon ore and surrounding flux can be promoted, the generation and the flowing of liquid phase are facilitated, the consolidation strength of a sintering binding phase is improved, the physical strength of a sintering mineral is improved, the particle size composition is improved, the productivity is improved, and the energy consumption is reduced. Because the procurement cost of the high-silicon ore is relatively low, the method can improve SiO₂The use proportion of the large-particle ore with high content is beneficial to reducing the cost of sintering ore blending.

Detailed Description

Technical solutions in the embodiments of the present invention will be described in detail below, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The segregation ore blending sintering method of the iron ore comprises the following steps:

s1 selecting different SiO from 2-4₂The iron ore powder in the 2-4 kinds consists of mixed ore with SiO in between₂The difference of the mass percent is 3.0-10.0%, and the mass percent of the water in the mixed ore is 7.5 +/-0.5%.

S2 control of SiO in mixed ore₂The mass percent is 5.0 +/-0.5 percent, the mass of the mixed ore accounts for 30-50 percent of the total mass of the rich ore powder, the concentrate powder, the auxiliary material and the mixed ore during sintering in the step S3, the proportion of the 2-4 kinds of iron ore powder is adjusted, and SiO is realized₂Segregation between coarse particles and fine particles, the fuel is coke powder, and the mass percentage of the particle diameter of 1-3mm is more than 65%. The auxiliary material is one of mixed sludge and steel rolling iron scale. The coarse particles are high silicon particles, SiO₂The mass percent is more than 5.0 percent, the mass percent of high silicon particles with the particle diameter of more than 3mm is more than 20 percent, and the fine particles are low silicon particles and SiO₂The mass percentage content is less than 3 percent, and the mass percentage of the low-silicon particles with the particle diameter of less than 1mm is more than 50 percent.

And S3, mixing with the rich mineral powder, the concentrate powder, the auxiliary material, the flux and the fuel uniformly, and sintering. The grade of the rich mineral powder is more than 55 percent; the mass percentage of the refined mineral powder with the grain diameter less than 0.074mm is 50-70%, and the grade is more than 60%.

The iron ore powder with the small size fraction smaller than 1mm and the part of the iron ore powder with the size fraction of 1-3mm is used as adhesive powder and is bonded with the large particle size fraction in the sintering and granulating process. SiO due to the sieved iron ore in S1₂The difference is large, the high silicon core is formed in S2, the granulating ball and the fusing agent on the low silicon surface generate liquid phase firstly, and then the non-fused high silicon core ore is bonded. When the iron ore powder has low SiO₂Low Al content₂O₃When the content is in the content range, the generation and the flow of a liquid phase are promoted under the same external CaO adding condition, and the consolidation effect of the iron ore powder is improved.

The examples will now be carried out from a sinter pot experimental set-up. In the embodiment, the ore powder is selected from 2, and 3 or 4 ore powders are also suitable.

(1) Screening of mineral powder

Selecting two ore powders A, B with different silicon dioxide contents; wherein TFe mass content of the mineral powder A is 60 percent, and SiO is₂The mass content is 10.5 percent, wherein>The 5mm size fraction is 45%; TFe content of the B mineral powder is 64 percent, and SiO is₂In an amount of 1.9%, wherein<The size fraction of 1mm is 40%.

(2) Ore blending operation

Selecting ore raw materials required for sintering: rich mineral powder, concentrate powder and auxiliary materials; the rich mineral powder is iron ore which is directly mined in the nature and is not subjected to mineral separation but is simply crushed, and the grade of the rich mineral powder is over 55 percent; the concentrate powder is obtained by crushing, grinding and dressing the ore powder with the granularity of less than 0.074mm accounting for 50-70% of the ore powder and the grade of the ore powder is more than 60%.

Keeping SiO in the mixed ore₂The mass content is 5.0 percent, the proportion sum of the mineral powder A and the mineral powder B is controlled to be 36 percent, the proportion sum of the rest rich mineral powder is 46 percent, the proportion of the concentrate powder is 8 percent, and the auxiliary material is 10 percent.

(3) Scheme(s)

The ore blending structure is maintained unchanged, and the SiO of the final sintering ore is ensured₂Changing the proportion of the mineral powder A, B under the condition of keeping MgO and R unchanged to realize SiO₂Segregation among coarse and fine ore powders.

The following table shows the grain size compositions and the grain size SiO of the mixed ore of the examples and comparative examples of the present invention₂The mass percentage content is as follows:

(4) mixing and granulating

Respectively preparing the blended ore of the reference scheme and the embodiment according to ore blending operation and scheme, adding limestone, quicklime, dolomite, fuel and return ores into a mixer according to the alkalinity requirement and the process production requirement of the sintered ore, and mixing and granulating; the mixer is a horizontal two-section mixer, and the return fines are powder ores with the particle size of less than 5mm after sintering; the limestone and dolomite are limestone powder and dolomite powder with the granularity of less than 3mm and the content of more than 80 percent after being crushed; the quicklime is active quicklime with the effective calcium oxide content of more than 80 percent and the activity of more than 200 ml.

(5) Cloth material

Distributing the obtained mixture in a sintering cup through a distributing hopper; the cloth hopper is controlled by a motor, rotates for 360 degrees in the cloth process, and is distributed from bottom to top, so that the effect of natural segregation is achieved.

(6) Firing sintering

Igniting, exhausting and sintering the distributed material; the ignition is performed with high purity propane gas.

(7) Crushing and screening

And crushing, dropping and screening the sintered ore, and calculating and analyzing sintering indexes.

(8) Test results, two tests were performed.

The sintering index is as follows:

the sintered ore particle size compositions for the different embodiments are as follows:

scheme(s)

>40mm

25-40mm

16-25mm

10-16mm

5-10mm

<5mm

Comparative example 1

6.2％

19.4％

21.7％

10.9％

18.6％

23.2％

Comparative example 2

6.8％

18.7％

22.3％

11.3％

18.5％

22.7％

Example 1

5.1％

20.4％

25.7％

11.9％

17.3％

19.7％

Example 2

4.7％

19.7％

26.3％

11.7％

17.6％

20.0％

Two effective parallel experiments were performed for each protocol,according to sintering indexes, SiO is adjusted under the condition of not changing the ore blending structure₂The segregation distribution of the content among the large and small particles can improve the sintering yield and the barrate index, reduce the solid fuel consumption and improve the yield; SiO is carried out₂After the content is distributed in segregation among large and small particles, the utilization coefficient is improved by 4.5-15.6%, the yield is improved by 2.3-3.6%, the barrate index is improved by 1.1-2.3%, and the solid fuel consumption is reduced by 2-4 kg/t.

As can be seen from the composition of the sintered ore granularity, the SiO is adjusted under the condition of not changing the ore blending structure₂The segregation distribution of the content among the large and small particles improves the grain size composition and the grain diameter of the sintered ore>The particle diameter of 40mm is reduced by 1.7-3.1 percentage points<The 5mm particles are reduced by 2.7-3.5 percentage points, and the particle size distribution is more uniform.

The invention is realized by mixing different SiO₂Screening the rich mineral powder with the content, and adjusting the proportion of large and small particles to ensure that the SiO of the uniformly mixed ore is mixed₂Under the condition of keeping the content basically unchanged, the purpose of segregation ore blending is achieved, so that high SiO in the mixture is ensured₂Is coated with low SiO₂The adhesive powder is wrapped, so that the formation and the flow of a liquid phase adhesive phase in the sintering process are promoted, the consolidation strength of the sinter is improved, the yield is increased, and the grain size composition of the sinter is more uniform. Meanwhile, the price of the high-silicon rich mineral powder is lower than that of the low-silicon rich mineral powder, so that the raw material cost for sintering can be reduced by using the method for carrying out segregation ore blending sintering.

The present embodiments are to be considered as illustrative and not restrictive, and the scope of the patent is to be determined by the appended claims.

Claims

1. A segregation ore blending sintering method of iron ore is characterized by comprising the following steps:

s1 selecting 2-4 different SiO₂The iron ore powder in the 2-4 kinds consists of mixed ore with SiO in between₂Quality ofThe difference of the percentages is 3.0-10.0%;

s2 controlling SiO in the mixed ore₂The mass percent is 5.0 +/-0.5 percent, the mass of the mixed ore accounts for 30-50 percent of the total mass of the rich ore powder, the concentrate powder, the auxiliary material and the mixed ore during sintering in the step S3, and the proportion of the 2-4 kinds of iron ore powder is adjusted to realize SiO₂Segregation between coarse and fine grains, the coarse grain being a high silicon grain, SiO₂The mass percent content is more than 5.0 percent, the mass percent of the high-silicon particles with the particle diameter of more than 3mm is more than 20 percent, the fine particles are low-silicon particles, SiO₂The mass percentage content is less than 3 percent, the particle size is less than 1mm, and the mass percentage of the low-silicon particles is more than 50 percent;

2. The method of claim 1 wherein the fuel is coke breeze and the mass percentage of the particle size of 1-3mm is > 65%.

3. The method of claim 1 wherein the auxiliary material is one of mixed sludge and mill scale.

4. The method of claim 1 wherein the mass percent of water in the mixed ore is 7.5 ± 0.5%.

5. The method of claim 1 wherein the rich ore fines grade is > 55%; the mass percentage of the refined mineral powder with the grain diameter less than 0.074mm is 50-70%, and the grade is more than 60%.