JPS5839746A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To accurately obtain sintered ore with superior productivity, coke unit and quality by regulating the ratio of CaO/SiO2 and the blending rate of SiO2, specifying the ratio of FeO/SiO2 in a fine powder part, and forming molten Ca ferrite preferentially and rapidly in large quantities. CONSTITUTION:An SiO2-base slag making agent contg. >=3% SiO2 is not used at all. A CaO.MgO- or CaO-base slag making agent is sieved at 2mm. classification point, the plus mesh is blended as it is, and all of the minus mesh is crushed to <0.5mm. and blended. Part or the whole of ore contg. >=6% FeO or other iron source is crushed to <0.5mm. and blended, and the ratio of FeO/SiO2 in the fine powder part having <0.5mm. grain size is controlled to 0.8-2.3. The amount of SiO2 in blended starting material 1 is regulated so as to make the SiO<2> content of sintered ore 4.6-5.4%. Thus, the starting material is thoroughly melted, the amount of SiO2 in the resulting sintered ore is reduced, and the reaction of CaO can be accelerated. When the ratio of FeO/SiO2 is within said range, the formation of molten olivine is accelerated, and when the SiO2 content is not within said range, the productivity, strength, reduction powdering index and reduction index are deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintered ore, and includes:
To obtain a method capable of reducing blast furnace fuel ratio and pig iron content without reducing coke consumption rate and quality, and accurately producing sintered ore with improved high-temperature properties. It is.

The sintering process in a sintering machine such as the Dwight Lloyd type involves mixing the raw materials such as iron ore, raw material, slag forming agent, coke, etc., adding water, granulating it, and then charging it into the sintering machine. By igniting the surface layer of the raw material in an ignition furnace and sucking air downward, the coke in the raw material is burned, and the heat generated causes a sintering reaction or melting (semi-melting) reaction between the raw material particles. When iron ore is cooled, it has a particularly high porosity and forms a mineral composition that is completely different from that of the raw iron ore. The goal of such a sintering operation is to meet quality standards and
Since the three points are to improve productivity and reduce coke consumption, normally operations are aimed at improving productivity and reducing coke consumption within the range that can maintain the quality of sintered ore. ing. By the way, the conventional blast furnace charging material (
For example, when considering the properties of sintered ore, islet, etc., the nine temperature ranges are below 1200℃,
The strength, reducibility, reduction pulverization property, swelling property, etc. of the bulk zone before the charging material softens and fuses have been studied and quality controlled, and the results of a recent concrete blast furnace dismantling investigation are as follows: The existence of a cohesive layer was confirmed, and it was found that this cohesive zone has a large effect on the gas flow and permeability in the blast furnace.From these results, the properties of the raw material charged to the blast furnace are as follows. The problem temperature range is also a high temperature range (i.e. over 1200℃)
Emphasis has been placed on improving properties during softening, fusion, melting, and dropping, that is, high-temperature properties. Loaded softening and melting tests are now being carried out for the purpose of more accurate measurement and evaluation of the high temperature properties (reducibility, softening and melting characteristics at high temperatures, and associated changes in air permeability) of raw materials charged to blast furnaces with lids. C,
The cause of the differences in the high-temperature properties of sintered ore is directly due to the amount of melt produced during the slag assimilation reaction process,
Indirectly, it has been found that the reducibility at high temperatures of 1000°C or higher and the composition and amount of gangue before reduction are particularly important. It has been confirmed that the reduction in the amount of gangue in the sintered ore greatly improves the high-temperature properties, and the reduction in the amount of slag in the blast furnace as well as the blast furnace fuel ratio. Low SL where 810 g is less than &2-
Os sintered ore is easily pulverized in the reducing atmosphere within the blast furnace temperature range of 400 to 600°C, and has a reduction pulverization index (RDI: 550C% 30 minutes), which is one of the current quality control items. After 900 rotations in a sintered ore drum held in a reducing atmosphere, the weight ratio of 13 cranes deteriorates significantly, and the sintering time becomes longer, resulting in a decrease in production rate, or a decrease in production rate, or a decrease in production rate. The disadvantage is that the yield and strength (8I) of the case are reduced.

However, there have been several proposals by Mr. Tashiro and others regarding the production of this low & By increasing the amount of 5tOx in the fine powder part,
b/5Lns or Cab/ (SLOz Agues
) below a certain level, or the fine powder portion tt55-
The method described above is combined with the preheating of the raw material adjusted to a fine powder in this way, and in short, the reduction in the amount of silicate slag produced that is expected due to the trend toward lower and zero density can be reduced by pulverizing the StOz source and increasing the effective StOz. It attempts to compensate by increasing the amount. However, in order to achieve a low 5L01 in this way, there are limits to the use of silicate slag as a binder, and therefore, in order to obtain a desirable low 5LO1 for sintered ore, considerable selection must be made regarding the brand of ore to be blended. In addition, it is impossible to continue the process for a long period of time, and it becomes difficult to continue stable operation with low StOs.

The present invention has been developed after repeated studies in view of the above-mentioned circumstances, and has been devised as a slag-forming agent in blended raw materials.
We do not use any &03 type sludge containing 40 s or more, and sieve the caot + θ type sludge such as dolomite and limestone at the sludge grade point, and the particle size of the sludge on the sieve is At the same time, the total amount under the sieve is pulverized to less than 0.51w and blended, and in addition, some or all of nine ores and other iron sources containing 6- or more hO are pulverized to less than 0.5w. By blending, the FaQ/stO in the fine powder portion of less than 0.5 is controlled to 0.8 to 13, and the 5Lon content of the sintered ore is 4.6 to &411I. It is characterized by controlling the amount of StO snow in the raw material67, thereby reducing the amount of 5JO in the sintered ore, reducing the amount of gangue, productivity, and coke consumption. Calcium 7 Equito series/de and silicate series without deterioration? The sintered ore is strengthened to provide sintered ore with excellent high-temperature properties, and the use of such sintered ore reduces the high death lag ratio and lowers the blast furnace fuel ratio.
The aim is to reduce the

In the present invention as described above.

Scale as ore and other iron sources containing 76- or more
1 FaO such as blowout slag, converter slag, powder under the cylinder, and dust
Miscellaneous raw materials containing 0- or more can be used, and 0.5
CaO/&O weight in the fine powder part less than wxm is 3 to 8
By controlling the temperature, the reaction can be made effective.

Furthermore, dolomite and limestone are generally used as Ca0.4o-based sludge-forming agents, but instead of such dolomite and limestone, quicklime, slaked lime, lightly calcined dolomite, magnesium hydroxide, seawater magnesia, and one of the seven magnesia A species or two or more species can be used.

To further explain the present invention as described above, the sintering reaction of self-fusing sintered ore has little diffusion bonding as an in-phase reaction;
Since most of the bonding is through the melt phase, the roles played by the melt are extremely overlapping. The equilibrium structure is of the so-called fusion bond type in which iron oxide particles are bonded by slag, and the quality and productivity of the sintered ore are greatly influenced by this slag bond. However, in the current process using a Deutroid sintering machine, the reaction time at high temperatures is extremely short, and the heating is not completed until the state reaches a completely molten state. An important issue is how to form gangue into slag quickly and uniformly. Especially by reducing the amount of gangue and getting a low 5! This is extremely important when producing sintered ore), and the reduction in the amount of gangue, that is, the amount of slag, must be compensated for by some means such as increasing the effectiveness of the slag source. is necessary. By the way, the sources of slag have traditionally been CaO-based limestone, quicklime, slaked lime,
& 0 proverbial silica stone % silica sand, bar 0 series CaO series raw dolomite, lightly calcined dolomite),! 0. The main ingredients are gangue components such as serpentinite, NlS2da, or (aQ, !OsMpo), and nine minerals are used, and the slag composition, amount, etc. are adjusted by these. However, in the sintering process, the melt is extracted from the combination of particles that are likely to generate melt in a mixed powder of various chemical compositions, that is, the combination of particles that correspond to the chemical composition region with a low melting point. is generated, its amount increases and spreads as the temperature rises, and through reaction and coalescence between the melts,
Coarse-grained raw materials or raw materials with poor slag-forming properties are often not completely melted and remain unreacted, although the bonding progresses, but the residence time at high temperatures is short. In conventional sintered ore manufacturing operations, 5tOhhII materials such as serpentine, eggplant slag, and silica stone, which have poor slagability, are used.
The O-based slag forming agent often remains as an unsludge-formed ore without fulfilling its function, and it is difficult for the additive sludge-forming agent to fully demonstrate its effect. As a result of various experiments and studies in this regard, we decided to reduce the St Ot in the sintered ore by not using the above-mentioned SLO snow-based slag-forming agent, which has poor slag-forming properties, and compared it. Only Cab and 40-based slagging agents (dolomite, limestone) with good slagging properties are used, and the particle size is adjusted to less than 0.5 fi, and Fao in the fine powder part of less than 0.5 m is used. /5toz to 0.8 to 2.3 is the key point in sintering with a low amount of gangue.

CIL stem momme 0 in the fine powder part of less than 0.5 m
The proverb is 3 to 8, or (CaO
+stO snow) amount to 7- or more and CaO/5LO
It is preferable that n be 3-8.

As a first approximation of the main ore components of self-fluxing sintered ore, “CCa”
O% 5LOB and considering the generation process of melt in sintered ore in the CaO-5LOx-iron oxide system, if the acid As shown in the figure, two low melting point chemical composition regions of 1300C or less are observed, namely Mu and -. ttri1
There are two types of combinations of particles that generate melt at a relatively low temperature of 000℃ or less: silicate region A and calcium ferrite F system region B〉-〇aO-iron oxide combination. The probability of turning into a liquid is 1&-1PK larger,
That is, in the sintering process, the contact point between CaO and iron oxide produces low melting point calcium ferrite by wJs reaction, and there is a high probability that a melt will be generated and react with it.
As shown in the table, its reactivity is extremely good compared to other systems, so even if the amount of gangue (Stog amount) is small, if the reaction between CaO and iron oxide is promoted, it can be compared to conventional silicate-based slag.
Calcium ferrite-based slag is used instead of the throat to strengthen the throat, and the quality and productivity of sintering are sufficiently maintained and improved.

Table 1 A10hCaO%stofu and rot 1 false reactivity O
Mark: 1250'C 5 minutes "t" l1M × mark: No melting at 1400C 5 minutes, except for reaction due to solid phase diffusion.

In addition, in the above-mentioned case, the sintering raw material is generally made of coarse grains of 1 to 5111 as the core during the mixing and granulation process, as shown in Figure 2.3, and the II@ contains less than 0.5 K. gI with fine powder attached! Similar particles are formed, and the generation of sludder melt starts from this attached nine-fine powder raw material, then #IIf-Ii
In order to proceed with sintering by melting the coarse grained raw materials, the amount of gangue (!Os amount) must be reduced, and in this case, this slag melt must be generated quickly and in a certain amount or more.
Figure 1 shows the low melting point region B' of calcium ferrite.
are also shown, but CaOb such as dolomite and limestone
By finely pulverizing the 40-based slag-forming agent, sintered ore with favorable productivity, Y-x unit consumption, and quality can be obtained even from raw materials with a small amount of gangue.

In the present invention, as mentioned above, limestone (CaCO5) and dolomite (MICDa-(1'acO3) are used, but other CaO-based sludge-forming agents such as quicklime (cao), slaked lime (Ca(OH)m), and light Baked ty w ito (40
Of course, the same effect can be obtained if the particles such as 11CaO) are refined to less than 0.5+w.

Also, in the case of using seawater magnesia, I-Gnequa Acrylic 7 Car, magnesium hydroxide, etc. to adjust the components of MIO, if it is finely granulated to less than 0.5 wax as shown in Figure 5, it will oxidize with MIlo. By the reaction of iron, a large amount of a solid solution of magnesia ferrite (which is diffracted as magnetite) is produced, and nine effects according to the present invention can be obtained. Therefore, the CaO,44 of the present invention
The term 0-based sludge-forming agent refers to all the above-mentioned CaO-based and hIIO-based sludge-forming agents that do not contain 5L (h) of 3 or more.

In the specific implementation of the present invention, the sludge forming agent as described above is sieved with a classification point of 2101 as necessary,
The coarse grains on the sieve with a size of 2 m or more are used as they are to ensure air permeability, and those of 2+u+ or less are used after being molded.

In other words, it is sieved at two classification points and divided into 9 coarse grains.
The air permeability of the sintered pedd is improved as shown in FIG. 4 when the sintered peddium chloride is mixed with the sintered peddad, and the productivity thereof can be improved.

However, if it is not possible to adjust the desired blending relationship with only particles of 2111 or less in quantity, K will pulverize some or all of the coarse particles of 21111 or more and become a source of sludder melt. ( C
aO+:5LOs) amount is 7- or more, and the C
aO/5Ox is set to 3 to 8. That is, this (CaO+ 5
The relationship between the amount of t(h) and the strong WIL &, I of the obtained sintered ore is -G, (CaO + sLOm) of 5 vm
When the amount is 6 to 1 part), the strength of the sintered ore increases rapidly and a desirable product can be obtained. In this case, if the CaO/5tOx is maintained at 3 to 8, calcium 7-elite melt can be preferentially produced rapidly and in large quantities, resulting in sintering with a low amount of gangue (5LOx). It becomes possible to produce high-quality burnt feed ore even from raw materials.

Regarding the circumstances during this period, Ca in the fine powder part of 0.5 wg or less, which is the starting point of the melt and which is the low melting point region B at 1200 ° C or less shown in Fig.
By controlling O/5tOx to 3 to 8 as shown in the figure, the production of a calcium 7 Elai F-based melt suitable for the sintering process is promoted, and the low melting point region (C) below 1200°C is appropriately controlled. I'll get it. Regarding the relationship between Fa O/840 snow, as shown in Fig. 6, by setting Fa O/840 snow of the fine powder portion of 0.5 wi or less to 0.8 to 2.3, the osobin system in the sintering process can be reduced. It is possible to promote the production of melt and form a low melting point region of 1150° C. or lower.

Furthermore, in the present invention, Sto in the sintered ore is 4.6 to 5.
4-, and this relationship is discussed separately in Section 7.
This is an underestimation as summarized in the figure.

That is, as shown in the upper part of Fig. 7, when SLO* becomes 4.6 seconds or less, the production rate and strength decrease, and RDI also deteriorates. When a CaO-based slag forming agent is crushed, R1 is extremely deteriorated. Therefore, the range that satisfies all of these production rate, strength, RDI and RI is StO of 4.6 to 5.4 inches.

In any case, CaO/&01 and S
By adjusting the blending ratio of tO, and preferentially producing calcium ferrite melt rapidly and in large quantities, productivity, coke consumption rate, and It is possible to accurately produce high-quality burnt ore. The reaction rate of 47 is increased by reducing the amount of slag source mixed. By doing so, the quality and productivity can be maintained and improved, and round feed ore can be obtained appropriately.

The ores with high hO used in the present invention refer to madanetite or maghetite ores and iron sand containing 6 or more hO, and these include FnO.
Miscellaneous raw materials containing 4i- or more (9 scale, slag,
A similar effect can be obtained by using converter slag, etc.).

In addition, in the present invention, (CaO+
! Rounding with an Os) amount of 7 or more, miscellaneous raw materials with a relatively high amount of &0 (st (hs or more)) and CaO, J404 sludge-forming agents such as limestone and dolo!ite are finely ground and used, Among these, as miscellaneous raw materials having a relatively high amount of 5t03, in addition to the converter slag, it is also possible to use under-sieve powder, ejected slag, dust, etc.

Since the conventional technology uses aO, a slag-forming agent, it is necessary to select the ore brand considerably in order to reduce SL Oz in the sintering raw material. However, with the method of the present invention that does not use sto or slag-forming agents at all, there is no need to select ore brands.
, 840g has a low stO of around 5-, and the sintered ore has a long-term El
It becomes possible to manufacture the product continuously.

Furthermore, by combining the selection of ore brands, it is temporarily possible to produce sintered ore with an extremely low stO of around 4.61 or lower.

The following are specific examples of the method using the final feathering method, together with conventional methods and reference examples for comparison.

Example: Prepare the following brands of iron ore, limestone, silica stone, dolomite, coke, return ore, etc., and use these to create a car body composition according to conventional example (■) as shown in Table 2 below. It is. 2nd Table 10, 5 隨SlO螞藤194 0.5m5FaO-1,24 Q, 5wrFsO/&Om = Q, 64-Q, SmC
aO-λ18 That is, in this Table 2, &O is 5.9-1, and silica, j40 source, and dolomite are used as C:&5L02 sources.

The items shown in Table 2 are reduced in &0 machining by the usual method,
Examples of blended sintered ores to achieve low &01 sintered ore (5LOs: 4.6 to 4-) are shown in Table 3 below as a reference example.

In addition, the specific S4O of t shown in Table 3 is &
4 whispers.

The specific formulation IF1 according to the present invention for these % Orc is shown in the following table j14, and its C & 0
The source limestone and dolomite T 2 wa are sieved at the classification point, and those with a particle size of 2- or more are blended as is, and 2-
Those with less than
FaO/S40*t (L adjusted to 8 to 2.3 in the fine powder portion of less than α5- by grinding part or all of the S of the ore and the raw material to less than α51III,
Furthermore, in order to reduce the amount of sLO in the sintered ore, the mixture of silica, serpentine, dolomite, and limestone was adjusted to t-1m.

However, the above-mentioned L5 songs shown in Tables 2 to 4 were each granulated by adding water, and this
o- A test pot was used to vacuum the sintered ore with a negative pressure of 1300 mAq. rate(
The RD eyes are summarized as shown in the Kyu OSS table.

Iris 5 table, that is, 44 DK of conventional example 1, and 7 St of reference example 1
With the low #RIIc amount of O, the production rate, strength, and product yield deteriorate, and the 7Ow8 sintering operation and m-feeding properties are greatly deteriorated. % of Koori et al.
It is possible to improve strength, product yield, and RDI without deteriorating production rate.
It's a friend who can greatly improve each and every one of them. That is, tFfl was determined by considering air permeability, softening or melting temperature 1L @ warehouse as the evaluation criteria for IL&Group properties, and the one according to the present invention was found to be extremely preferable.

Real JIifIλ The conventional $112 formulation for serpentine 'tNlE is Hisano J!
811 K As shown, the reference f42 which was designed to reduce the amount of z r and uot in the conventional method and produce low S4O and sintered mineral concentrate is as follows wL7
The mixture will be 1 eel as shown in the table.

Furthermore, the end result (therefore, as in the case of real JliiN1, its CaO source is limestone, Doro1i)? Classify with 2 haze, group 2 or more into one, crush 2 or less to make fine particles with a total amount of less than 1151, and aim to increase the amount of CaO in this particle size range of less than α5■. 0.
Part less than 5 ■OFaO/5Lot t O, 8~2.3
The composition of Example 20 of the present invention, which was controlled in the same manner as Example 1, is as shown in Table 8 below.

However, this n et al. 6th~a! ! Sintered ore was produced in the same manner as in NlK for each formulation shown in Table 8, and the production rate was 5fiil! , the result of determining tII such as product yield t! ! The following 0IIs table shows the actual J1
The production rate, strength, product yield, and RDI of the same machine described in ml111 in Reference Example 2 are cloudy and 0K.
51L, %0 according to real IlO real Il1 example 2 is sont
I would like to become much more educated.

Iris 911 Example % OK of Example 1 mentioned above, and the particle size of dolomite and lime at % O of the same composition as in Table 4.
The total amount of the sludge-forming agent with a classification point of -2 dew and less than 5 sq. without being sieved was finely pulverized to less than α5 sq. and blended. In other words, the formulation example according to this IAtjA actual Jm example in this case is
:As shown in RK.

As mentioned above, t-α5■ CaO/5tO in Table 2
x is 112, and that in Table 3 is LO8.

The conditions for producing sintered ore are the same as those described in Example 1.

In the same way as in Actual JII Square Table Example 2, serpentinite 'iw is not used, and the proportions are the same, but as in Actual JII Example 3, the total amount of the 7O slag forming agent is finely pulverized to α5w or less. A combination example is the following 1
As shown in Table 1.

In addition, Cao/S in the less than 0.5-fine powder portion of Table 116 mentioned above! O* was 118 h), and Caa/&LOt at %O1m in Table 7 was 1.10.

Further, the production of sintered ore O was the same as in Example 1.

However, these actual example 14 [↓T's specific production rate, strength, finished product - 1fL original nursing estimate and R11
The case of Example 1゜2 described in 1ii and the column of piIIIl are shown together, and the result is shown in the following Table 12.

12 In the table, ie, those according to these embodiments 13 and 4, it was found that the strength and product yield were the same as those of Examples 1 and 2.

According to the present invention as explained above, it is possible to improve the strength, product yield, reduction pulverizability, etc. by how much rt% and φ without impairing productivity, and to improve the fuel ratio and φ for blast furnace operation. It is an invention that can be manufactured into a limited amount of sintered ore that can reduce each of the concentrations in pig iron, and is industrially highly effective.

[Brief explanation of drawings]

The drawings show the technical contents of the present invention, and FIG. 1 shows CaO-, S! Figures 2 and 3 show the low melting point region of the O, -Fh, and 01 systems, and Figures 2 and 3 show the relationship between powder adhesion and particle size distribution. Figure 5 shows the relationship between bar 0 and the production amount of magnetite-magnesioferrite isosolute, and Figure 6 shows the relationship between the sinter strength and the sintered ore strength. Q
, Chart showing the relationship between fine powder and medium gangue amount O of s- or less, @71
1 is a low melting point region I of CaO-ao, -Fan> system 01000°C or less! This is a clear diagram. Tokken Applicant Nippon Kokan Co., Ltd. Inventor Hiroshi Yamaoka Kube M 6m Yutaka Daido Kazuhiro Furukawa Agent Japanese speaker Shirakawa - Yoshi 1゛1゛1゛1゛゛1゛1゛1謔' 2nd essay纂 J ＠ 邊 fl ＼ /4//σ(%) Procedural amendment (Karamutsu Showa 57.2..54 Japan Patent Office Commissioner Island 1) Haruki Tono 1, case display Showa% % permission m = stag 332 No. 3, relationship with the person making the amendment f # name of applicant (Mr. Button Nippon Steel Tube Co., Ltd. 4, agent'57.'1.2♂ day dispatch 6, specification subject to amendment 7, Contents of the amendment As shown in the attached sheet, contents of the amendment 4. Name of 1 invention of the application as follows (Order to be corrected)
“Method for producing sintered ore”

Claims (1)

[Scope of Claims] 1. No STO or sludge containing 3 or more of 5EO as a sludge forming agent in the blended raw materials. It is sieved at a classification point, and the upper part is blended in the same particle size state, and the total amount under the sieve is pulverized to less than 0.5 square meters. By pulverizing some or all of the powder to less than 0.5 M and blending it, the A in this fine powder part of less than 0.5
O/sL0° is controlled to 0.8~L3, and the aO of sintered ore is
A method for producing sintered ore comprising sintering a scissor blended raw material, characterized in that the StO content of the blended raw material is adjusted so that the content is 4.6 to 5.41G. 2. Claims sgi that use round wire raw materials containing 10 or more hO such as scale, slag, converter slag, under-sieve powder, and dust as ores and other iron sources containing 6s or more of FsO. The method for producing sintered ore described in . 3. C a O/S in the fine powder part less than 0.5 m
Claim Ii to control L false to 3 to 8! A method for producing sintered ore according to item I or j112. 4. Quicklime (Ca
b), slaked lime (Cm(oa))s Lightly calcined C1ffite (CaO 40), magnesium hydroxide (+(OH)), seawater madanesia, magnesia 7car, one or more types of docemite, The method for producing sintered ore according to claims 1 to 3, which is used as a partial or complete substitute for limestone.