CN114085992A

CN114085992A - Sintered mixture granulation method

Info

Publication number: CN114085992A
Application number: CN202111439900.2A
Authority: CN
Inventors: 唐文博; 胡鹏; 蒋胜; 朱凤湘
Original assignee: Pangang Group Research Institute Co Ltd
Current assignee: Pangang Group Research Institute Co Ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2022-02-25

Abstract

The invention discloses a granulating method of a sintering mixture, relates to the field of metallurgy, and aims to improve the uniformity of the sintering mixture and further improve the economic index of a sintering technology. The technical scheme adopted by the invention is as follows: the granulating method of the sintering mixture is characterized in that only active ash is used as a solvent under the condition that the mass water content of part of sintering materials is more than 10%, and the ratio of the active ash is more than 9%; and (2) carrying out strong mixing in a strong mixer by using a three-stage mixing mode of strong mixing, first mixing and second mixing, carrying out first mixing and second mixing in a cylindrical granulator, and granulating by controlling the filling rate of the cylindrical granulator to be below a threshold value to obtain a sintering mixture. According to the method of the invention, the sintering mixture with the grain diameter of 40mm or more can be eliminated, the proportion of the grain diameter of more than 8mm is reduced, the grain diameter distribution and the chemical components of the mixture are more uniform, and the sintering utilization coefficient, the sinter tumbler index and the sinter yield are all greatly improved.

Description

Method for granulating sinter mixture

Technical Field

The invention relates to the field of metallurgy, in particular to a granulating method of a sintering mixture.

Background

The sintering mixture is formed by uniformly mixing iron ore concentrate, fine ore, solvent and fuel in a cylindrical granulator and granulating. If the water content of part of the iron ore concentrate is too high, the part of the iron ore concentrate can digest the solvent in advance, so that the granulation performance is greatly improved, and the part of the iron ore concentrate can adhere to the solvent far beyond other particles in the granulation process and grow to a size fraction of 40mm or more, so that the solvent content of other size fractions is low. The large-particle-size sintering mixture is difficult to burn through, so that the component difference of the sintering mixture is large. The large-particle-size mixture has too high proportion, partial sintering ore can not be burnt through, and the problems of poor drum strength of the sintering ore and the like occur.

Disclosure of Invention

The invention provides a granulating method of a sintering mixture, and aims to improve the uniformity of the sintering mixture and further improve the economic index of a sintering technology.

The technical scheme adopted by the invention is as follows: the granulating method of the sintering mixture is characterized in that only active ash is used as a solvent under the condition that the mass water content of part of sintering materials is more than 10%, and the ratio of the active ash is more than 9%; and (2) carrying out strong mixing in a strong mixer by using a three-stage mixing mode of strong mixing, first mixing and second mixing, carrying out first mixing and second mixing in a cylindrical granulator, and granulating by controlling the filling rate of the cylindrical granulator to be below a threshold value to obtain a sintering mixture.

Specifically, the method comprises the following steps: the filling rate of the cylindrical granulator is less than 10.8 percent.

Specifically, the method comprises the following steps: the mixing time is 2min, and the mixing time is 5 min.

Specifically, the method comprises the following steps: the content difference between every two of 1-3 mm, 3-5 mm and 5-8 mm grain sizes in the sintered mixture is less than 5 percent;

specifically, the method comprises the following steps: the different grain sizes of the sintered mixture have TFe content range less than 3 percent and CaO content range less than 1 percent.

The invention has the beneficial effects that: according to the method of the invention, the sintering mixture with the grain diameter of 40mm or more can be eliminated, the proportion of the grain diameter of more than 8mm is reduced, the grain diameter distribution and the chemical components of the mixture are more uniform, and the sintering utilization coefficient, the sinter tumbler index and the sinter yield are improved.

Detailed Description

The following examples and comparative examples further illustrate the invention.

According to the granulating method of the sintering mixture, only active ash is used as a solvent under the condition that the mass water content of part of sintering materials is more than 10%, and the proportion of the active ash is more than 9%. And (2) carrying out strong mixing in a strong mixer by using a three-stage mixing mode of strong mixing, first mixing and second mixing, carrying out first mixing and second mixing in a cylindrical granulator, and granulating by controlling the filling rate of the cylindrical granulator to be below a threshold value to obtain a sintering mixture.

The mass water content of the sintered material used in the examples of the present invention and the comparative examples is shown in table 1. As can be seen from Table 1, the water content of the white horse concentrate and the 58 th national height is greatly different from that of other sintering materials, and the water content is over 10 percent.

TABLE 1 Mass moisture content of the respective sinter materials

Sample name	Water content%
		White horse concentrate	10.2
Australia mine	6.4
		Medium powder	3.8
Gas ash	3.7
		Plain concentrate	6.2
Height of 58 nation	10.5
		Coke powder	0.8
Limestone	2.3
		Active ash	0
Dust removal ash	0

In both the comparative example and the example, the mass water content of the mixed sintering material is controlled to be 7.5%, the sintering alkalinity is 1.90, the addition of return ores (external preparation) is 30%, the granulation time is 5min for first mixing and 5min for second mixing, 2.5kg of bed charge is laid, the sintering ignition time is 2min, the ignition temperature is 1050 +/-50 ℃, and the proportioning scheme and the granulation scheme of the sintering material are respectively shown in the table 2 and the table 3.

Table 2 dosing schedules for comparative examples and examples

TABLE 3 granulation protocol

Name (R)	Granulation method	Granulation time/min	Filling rate/%)	New material amount/kg
					Comparative example	First mixing and second mixing	5+5	11.83	70
Example 1	Forced mixing + primary mixing + secondary mixing	2+5+5	12.02	70
					Example 2	Forced mixing + primary mixing + secondary mixing	2+5+5	9.74	60

The sintering experiments of the above schemes were carried out, and the results of the detection and analysis of the sintering mixture were shown in tables 4 and 5, respectively.

TABLE 4 composition of particle size of sintered mix%

Scheme(s)	＞8mm	5～8mm	3～5mm	1～3mm	＜1mm	＞3mm
							Comparative example	19.3	20.6	17.4	28.5	14.2	57.3
Example 1	20.3	21.5	18.9	29.2	10.1	60.7
							Example 2	8.1	30.5	32.1	27.2	1.6	70.7

TABLE 5 sinter mix chemical composition analysis%

Injecting: the chemical components with the granularity are the results of chemical analysis on the sintered mixture part without the oversize granularity (40mm or more)

According to the tables, compared with the comparative example, after the proportion of the active ash is increased, if the new material amount is not adjusted, the filling rate of the cylindrical granulator is slightly increased, the ultra-large particle size fraction larger than 40mm in the sintering mixture is eliminated, the proportion of the particle size fraction smaller than 1mm in the sintering mixture is reduced, the proportions of other particle sizes are increased, the differences among the particle sizes of 1-3 mm, 3-5 mm and 5-8 mm in the sintering mixture are still large, and the uniformity of the sintering mixture is not greatly improved. After the three-section type mixing is used, the active ash proportion is increased, the new material amount is adjusted, the filling rate of the cylindrical granulator is reduced, the particle size fraction of the sintered mixture larger than 40mm and with the ultra-large particle size fraction larger than 8mm and smaller than 1mm is eliminated, the proportion of the particle size fraction larger than 8mm and smaller than 1mm is obviously reduced, the proportion of the intermediate particle size fraction is obviously increased, the content difference of interstitial substances of the particle size fractions of 1-3 mm, 3-5 mm and 5-8 mm in the sintered mixture is obviously reduced, and the uniformity of the sintered mixture is greatly improved.

From the chemical composition of the sintering mixture, after a strong mixer is added for strong mixing and the content of active ash is increased, the sintering mixture TFe, CaO and TiO are sintered₂The content tends to be uniform, and the phenomenon that large-grain-level sintering mixture increases along with the increase of the active ash proportion does not occur, which shows that the strong mixing can fully and uniformly mix the white horse concentrate with high moisture content and the active ash which is difficult to be uniformly mixed, so that the white horse concentrate and the active ash are uniformly distributed in each grain-level sintering mixture, and the grain size and the chemical component distribution of the sintering mixture tend to be uniform.

The increase of the active ash proportion is beneficial to improving the granulation effect of the sintering mixture, and the increase of the strong mixing can lead the material distribution to tend to be uniform. The filling rate of the cylindrical granulator is reduced to be below a threshold value, and the granulating effect of the sintering mixture can be obviously improved. The filling rate threshold value of the cylindrical granulator used in the experiment is about 10.8%, when the filling rate of the cylindrical granulator is above the threshold value, the active ash proportion is increased, the proportion of the sintered mixture in the size fraction of less than 1mm is reduced, and the proportion of other size fractions is increased; when the filling rate of the cylindrical granulator is below a threshold value, the active ash proportion is increased, the particle fraction proportion of the sintered mixture is reduced from less than 1mm to more than 8mm, the particle fraction proportion of the sintered mixture is increased from 3mm to 5mm, the particle fraction proportion of the sintered mixture is reduced from 1mm to 3mm, the three particle fractions tend to be uniform, the difference of the proportions is reduced, and the particle fraction of the sintered mixture tends to be uniform.

The sintering economics of the comparative examples and examples are shown in Table 6.

TABLE 6 economic indices of sintering technique

Scheme(s)	Using coefficient/t/(m)²·h)	Tumbler index/%	Percent of yield%
				Comparative example	1.23	74.2	75.82
Example 1	1.27	74.7	76.12
				Example 2	1.33	75.5	77.43

As can be seen from table 6, in the examples, due to the improvement of the particle size composition and chemical components of the sintering mixture, the component difference of different particle sizes is reduced, and the proportion of the sintering mixture with large particle size which is difficult to be fired through is reduced, so that the sintering utilization coefficient, the sinter drum index and the sinter yield are all greatly improved. The invention uses a three-stage mixing mode and increases the proportion of active ash in the sintering material, is beneficial to the uniform distribution of the granularity and chemical components of the sintering mixture, and can greatly improve the sintering utilization coefficient, the drum index of the sintering ore and the finished product rate of the sintering ore.

Claims

1. The granulating method of the sintering mixture is characterized in that: under the condition that the mass water content of the partially sintered material is more than 10%, only active ash is used as a solvent, and the ratio of the active ash is more than 9%; and (2) carrying out strong mixing in a strong mixer by using a three-stage mixing mode of strong mixing, first mixing and second mixing, carrying out first mixing and second mixing in a cylindrical granulator, and granulating by controlling the filling rate of the cylindrical granulator to be below a threshold value to obtain a sintering mixture.

2. The method of pelletizing a sinter mix as claimed in claim 1, wherein: the filling rate of the cylindrical granulator is less than 10.8 percent.

3. The method of pelletizing a sinter mix as claimed in claim 1, wherein: the mixing time is 2min, and the mixing time is 5 min.

4. A method of pelletizing a sinter mix as claimed in claim 1, 2 or 3, wherein: the content difference between every two of 1-3 mm, 3-5 mm and 5-8 mm grain sizes in the sintering mixture is less than 5%.

5. A method of pelletizing a sinter mix as claimed in claim 1, 2 or 3, wherein: the different grain sizes of the sintered mixture have TFe content range less than 3 percent and CaO content range less than 1 percent.