JPS5834142A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To manufacture a sintered ore having a stable quality, and to reduce various units, by calculating a melting ratio of a compounding material from various physical property values, compounding ratios and operating conditions of various material ores, and finally deciding the compounding ratio in accordance with the calculated value. CONSTITUTION:A melting ratio of a compounding material is calculated from a high temperature grain porosity, a grain size distribution and a chemical component of various material ores, which have been measured in advance, an estimated volume compounding ratio of each ore in a compounding material obtained by compounding various material ores, and an operating condition. In this case, the melting ratio shall show a volume ratio in sintered cake of the material which has been melted in the manufacturing process of sintered ores. Subsequently, the volume compounding ratio of the material ore is finally decided so that the calculated melting ratio becomes a target melting ratio. In this way, a quality of sintered ores is stabilized by eliminating wasteful manufacture of sintered ores, and various units are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintered ore for iron manufacturing.

Sintered ore is widely used as a raw material for blast furnaces for iron manufacturing. As a standard for judging the quality of sintered ore.

Chemical components include particle size distribution, cold rigidity, reduction powdering property, etc.

Since these are extremely important factors in blast furnace operation, constant management is carried out.

Sintered ore is manufactured by melting fine ore and adhesively bonding it together as a bond. Therefore, the room temperature strength of the sintered ore increases as the number of bonding bonds increases (that is, the amount of unmelted residue decreases).

On the other hand, the main cause of reduction powdering is determined by the amount of hematite (hereinafter referred to as secondary hematite) that has been melted and solidified.If it is melted too much, the amount of secondary hematite increases, and the This will lead to the conversion to t-M. Furthermore, in order to melt a large amount, it is necessary to take a long firing time or to increase fuel consumption. If the amount of melting is small, the cold strength will decrease. These trends are shown in Figure 1111. In reality, an appropriate melting rate is determined from various viewpoints such as the quality of the sintered ore, productivity, and fuel ingredient level (for example, the shaded area @l in FIG. 1).

Here, the melting rate will be described in detail later, but is generally defined as the volume ratio in the sintered cake of something that has a history of melting during the sintered ore manufacturing process.

In the production of sintered ore, the raw materials are a mixture of extremely miscellaneous ores, and their melting properties vary, so even under the same operating conditions, if the raw material composition changes, the melting rate will vary.

In the conventional blending of raw material ores, measuring the melting rate requires a large amount of man-hours, so it is difficult to measure the melting rate without knowing the melting rate.
We had to carry out thorough quality tests on the manufactured products and make repeated changes to the formulation until we achieved a quality that we were satisfied with. Therefore, it takes a lot of time to find the appropriate raw material blending conditions, and wasteful raw material blending and sintered ore production have to be carried out.

The purpose of the present invention is to calculate and estimate the melting rate from the mixed material basket of raw material ore, set the blending ratio of raw material ore in advance based on this, and eliminate wasteful production of sintered ore.

To stabilize the quality of sintered ore and reduce the number of various units
Garu.

The method of the present invention is based on the high-temperature particle porosity 5-grain 1 distribution of various raw material ores measured in advance, the chemical components, the planned volume blending ratio of each ore in the blended raw material containing various raw material ores, and the operational The method is characterized in that the melting rate of the blended raw material f) is calculated from the conditions, and the volume blending ratio of the 15kc raw material ore is finally determined so that the calculated value becomes the target melting rate.

In the production of sintered ore, an extremely wide variety of raw material ores are used, but the melting properties of these raw materials are all different, and even with the same temperature history they exhibit different cages.

As a result of experiments, the present inventors have found that f)F
ez03 and CaO react to form calcium ferrite, creating an initial melt. f) A reaction that progresses the melt so that the melt gradually erodes from the outer periphery of the ore particles to the inside. I discovered something. therefore,
Melting rate Q)-! .

σ is the cumulative housing of this melting reaction and maintains the melting reaction.
) k Time to maintain the required temperature Vv (hereinafter referred to as reaction time 5
It can be expressed by the following equations (11 and (2)) using t), the particle size distribution of the raw material D%, and the linear melting velocity (2) at which melting progresses.

j-cloudy however.

j: Index indicating various ore brands of raw materials i: Index indicating particle size range of grain 1 distribution Qj: Ore brand j
Melting rate (excluding pores and voids) QT: Melting rate of blended raw material (sintered ore) (excluding pores and voids) t: Reaction time (time for keeping the bed temperature IE1100°C or higher) ■j: Ore brand Melting linear velocity Di at jw2 Representative particle diameter wij at particle size range i: Volume fraction Aj at particle size range iK of ore brand j:
The reason why the melting rate differs even at the same reaction time due to the difference in the volumetric content ratio of various ores in the mixed raw material of ore brand J is due to the difference in the particle size distribution on the raw material ore side and the difference in the melting linear velocity. be. This linear melting velocity can be determined for each brand of ore through basic melting experiments.

In this melting experiment, calcium ferrite was melted in a crucible, the measurement sample was immersed according to the reaction time, and the erosion length was measured. -Linear velocity area was determined. Examples of the experimental results σ) are shown in Table '1.

Table 1 The present inventors have found that the melting linear velocity can be estimated by the following equation (3) from the results of melting experiments and the physical properties of the raw ore σ). #ll Edge Linear Velocity There is a close correlation with the particle porosity (hereinafter referred to as high-temperature particle porosity) and chemical components immediately before the melting reaction, excluding high-temperature decomposition and vaporization in ore particles. (3 ) It was confirmed that there was a good correlation between the linear melting velocity calculated by the formula and the measured value, as shown in Figure 2, depending on the amount of water.

Vj=ki(B)j+to 2(AlzOs)j+ks(8
i0z)j+4(Cab)j106(FeO)i10k
s (MgO)
j+ ＊(TiOz)+kxo・・・・・・・−・
・・・・・・・・・・・・・・・・・・・・・・・・(3)
However, ks-kto: constant (E) j: high temperature particle porosity of ore brand j (AI 2
0m) j ~ (TiOz) j: Content rate of each chemical component in ore brand jK Conventionally, it took a lot of man-hours to actually measure the porosity of high-temperature particles 4-I
As a result of experiments, the present inventors found that the high-temperature particle porosity E is determined by the particle porosity EO at room temperature and the content of crystal water CW and carbonate MCOs, which are the main components of high-temperature vaporization in ore. Using the following equation (4), we confirmed that it can be calculated well (see Figure 6)6 (E)j=1- (1-et(cw) j-C2( Me
Os) j]x (1-(12o) jl...
・・・・・・・・・・・・・・・・・・・・・・・・
...(4) However.

(CW)j: Crystal water content (McO
s) j: Carbonate content rate in ore brand j <BO>j:
Room-temperature particle porosity C1, Cz in ore brand j: Constant reaction time t is within one layer i! One history is determined by the time for which the temperature is maintained at 1100°C or higher. Since the temperature history in the bed is determined by operating conditions and the amount of fuel added, it is advisable to understand it in advance through operational tests and measurements. Further, the reaction time can be generally expressed as a function of firing time, ignition furnace energy level, and fuel addition rate, and an example of the relationship is shown in FIG. 4f.

By substituting the reaction time, a material particle size distribution, and various physical properties of the raw ore into equations (1) to (4) above, it is possible to calculate the melting rate of the blended raw material, and this calculated value indicates the appropriate quality. The volume mixing ratio of the raw material ore can be finally determined to match the target value to be obtained.

<Actual example> The test was carried out under the conditions shown in Table 2.

! Table 2 Reaction time t is given as a function of firing time, ignition furnace energy level, and fuel addition rate. The average time I was determined to be 6.4 minutes in total. The appropriate melting rate was set at 80% from FIG. Various raw material ores f)
Table 6 shows the results of calculating the melting rate of Humi ore during firing based on the physical properties of the brands. Based on this result, the results of actual operation for one month using the blended raw materials shown in Table 4 are shown in Table 4, and the results are compared with the conventional method. and shown in Table 5.

Table 5 shows that the product produced by the method of the present invention has less roughness, no wasteful sintered ore i-ker, and coke #1.
I can see that the Rin position is decreasing.

Table 6 whisper Table 4 Table 5

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between melting rate and sintered ore quality. Figure 2 is a graph showing the correlation between actually measured values, calculated values, and σ° of linear melting velocity. Figure 3 is a graph showing the correlation between the measured value of high-temperature particle porosity and the calculation cylinder. Figure 4 is a graph showing the relationship between reaction time and various conditions. Patent applicant: Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] High-temperature porosity of various raw material ores measured in advance. The melting rate of the blended raw material is calculated from the particle size distribution, chemical components, the planned volume ratio of each ore in the blended raw material containing each harvested raw ore, and the operating conditions, and the calculated value is the target melting rate. Naruyo'Sk A method for producing sintered ore characterized by the fact that it ultimately determines the volumetric ratio of the raw material ore.