Adjustment method of material for sintering and manufacturing method of sintered ore

Abstract

To improve at least one of a product yield, a combustion progression rate, and a production rate of a sintered ore.SOLUTION: A first invention is an adjustment method of a material for sintering to be charged into a sintering machine. From among materials for sintering, other materials for sintering excluding at least part of quick lime, or other materials for sintering excluding at least part of a carbonaceous material and at least part of quick lime are mixed and granulated. After the granulation or during the granulation, the excluded quick lime or the excluded carbonaceous material and quick lime are added. A second invention, a manufacturing method of a sintered ore burns the material for sintering obtained through the first invention of the adjustment method, to manufacture a sintered ore.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for adjusting sintering raw materials to be charged into a sintering machine, and a method for producing sintered ore using the adjusted sintering raw materials. [Background technology]

[0002] In Patent Document 1, sinter raw materials excluding limestone and coke fines are granulated to produce granulated pseudo particles, and then limestone and coke fines are attached to the surfaces of the granulated pseudo particles. By using sinter raw materials with limestone and coke fines attached to the granulated pseudo particles, the production efficiency of sintered ore is improved.

[0003] In Patent Document 2, in a method for granulating sintering raw materials, sintering raw materials excluding pulverized fuel (coke breeze or anthracite powder) are mixed, and then pulverized fuel (or pulverized fuel and quicklime) is added to this mixture, or sintering raw materials excluding pulverized fuel are mixed and granulated, and then pulverized fuel (or pulverized fuel and quicklime) is added to this granulation. By using granulated sintering raw materials in this way, the sintering product yield and the cold strength of the sintered ore are improved, and the air volume consumption rate is reduced, thereby increasing sintering productivity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-169442 [Patent Document 2] Japanese Patent Application Publication No. 7-097639 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve at least one of the product yield, combustion rate, and productivity of sintered ore, there is room for improvement in the sintering raw materials charged into a sintering machine. [Means for solving the problem]

[0006] The first invention of the present application is a method for adjusting sintering raw materials to be charged into a sintering machine. First, the sintering raw materials are mixed with the other sintering raw materials, excluding at least a portion of the quicklime, and granulated. After or during this granulation, the removed quicklime is added later.

[0007] The second invention of the present application is a method for adjusting sintering raw materials to be charged into a sintering machine. First, the sintering raw materials, excluding at least a portion of the carbonaceous material and at least a portion of the quicklime, are mixed and granulated. After or during this granulation, the removed carbonaceous material and quicklime are added.

[0008] The carbonaceous material to be added later can include a highly combustible carbonaceous material having a lower combustion start temperature than coke. The entire amount of the carbonaceous material or the entire amount of quicklime can be added later.

[0009] In the method for producing sintered ore, which is the third invention of the present application, the raw material for sintering obtained by the preparation method of the first or second invention of the present application is fired to produce sintered ore. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve at least one of the product yield, combustion rate, and productivity of sintered ore. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a method of post-adding quicklime (first post-addition method). [Figure 2] FIG. 1 is a diagram illustrating a method of post-adding carbonaceous material and quicklime (first post-addition method). [Figure 3] FIG. 1 is a diagram illustrating a method of adding quicklime later (second method of adding quicklime later). [Figure 4] FIG. 1 is a diagram illustrating a method of post-adding carbonaceous material and quicklime (second post-addition method). DETAILED DESCRIPTION OF THE INVENTION

[0012] In this embodiment, quicklime or a carbonaceous material and quicklime are added later in the process of mixing and granulating raw materials for sintering (raw materials blended for producing sintered ore). "Later addition" means that quicklime or a carbonaceous material and quicklime are not added at the beginning of the process of mixing and granulating raw materials for sintering, but are added when the above-mentioned process is almost completed or after the above-mentioned process is completed.

[0013] (Sintering raw material) The raw materials for sintering include iron ore, auxiliary materials, and carbonaceous materials. As the iron ore, one type of iron ore can be used, or multiple types of iron ore can be used. Examples of auxiliary materials include limestone, quicklime, dolomite, peridotite, and serpentine. In addition to iron ore, miscellaneous materials, auxiliary materials, and carbonaceous materials, the raw materials for sintering can also include return ore and miscellaneous materials. Examples of miscellaneous materials include scale and dust.

[0014] In this embodiment, the sintering raw materials are divided into two groups, one group is quicklime (all or part), or carbonaceous material (all or part) and quicklime (all or part), and the other group is other sintering raw materials (hereinafter simply referred to as "other sintering raw materials") excluding the raw materials contained in one group (quicklime (all or part), or carbonaceous material (all or part) and quicklime (all or part)).The quicklime (all or part), or carbonaceous material (all or part) and quicklime (all or part) contained in one group is added later.

[0015] (charcoal material) Carbonaceous materials are classified into low-combustibility carbonaceous materials and high-combustibility carbonaceous materials. High-combustibility carbonaceous materials are carbonaceous materials with higher combustibility than low-combustibility carbonaceous materials such as coke and anthracite, i.e., carbonaceous materials with a higher combustion rate than low-combustibility carbonaceous materials. Various measurement methods and measurement results have already been published for the combustion rate of carbonaceous materials, but unless measurements are performed in a well-controlled manner, measurement results may vary greatly. Therefore, the combustion initiation temperature (ignition temperature), which has a substantial correspondence with the combustion rate, is used as an index of combustion rate. In the present invention, high-combustibility carbonaceous materials refer to carbonaceous materials with a lower combustion initiation temperature than low-combustibility carbonaceous materials (coke and anthracite).

[0016] Examples of low-combustibility carbonaceous materials include coke and anthracite. The combustion start temperature of coke is approximately 670°C, and that of anthracite is approximately 690°C. Examples of high-combustibility carbonaceous materials include coal char (semi-coke, lignite char, subbituminous coal char, etc.) and biomass char (oil palm kernel shell charcoal, charcoal char produced by carbonization of wood, etc.). The combustion start temperature of coal char is approximately 430°C to 550°C, and that of biomass charcoal is approximately 470°C.

[0017] (Post-addition method) There are two post-addition methods for adding quicklime or carbonaceous material and quicklime, as described below.

[0018] (First post-addition method) The first post-addition method will be described with reference to Fig. 1 or Fig. 2. Other raw materials for sintering are respectively charged into a plurality of hoppers 11, one hopper 12 shown in Fig. 1 is charged with quicklime, and two hoppers 12 shown in Fig. 2 are charged with carbonaceous material and quicklime, respectively.

[0019] The other sintering raw materials discharged from the multiple hoppers 11 are transported along the transport path CP1 and fed into the granulator 13. The granulator 13 may be any machine capable of granulating the sintering raw materials, and may be, for example, a piston-flow type cylindrical granulator (drum mixer) whose central axis is inclined downward toward the downstream side. In the granulator 13, the other sintering raw materials are granulated while being mixed.

[0020] In granulation using the granulator 13, water is generally added to the sintering raw material. By adding water to the sintering raw material and granulating it, the water acts as a binder, causing relatively fine particles to adhere around relatively coarse particles. This increases the apparent particle size of the sintering raw material, and when the sintering raw material is charged into the sinter machine 14, the void ratio and void diameter of the raw material packed bed increase, improving permeability. Improved permeability speeds up the sintering process and improves the productivity of sintered ore.

[0021] The other sintering raw materials discharged from the granulator 13 are transported along the transport path CP2 to the sinter machine 14. Here, the quicklime (FIG. 1) discharged from the hopper 12, or the carbonaceous material and quicklime (FIG. 2) discharged from the hopper 12, is transported along the transport path CP3 and then added to the other sintering raw materials being transported by the transport path CP2. As a result, the quicklime, or the carbonaceous material and quicklime, together with the other sintering raw materials, move along the transport path CP2 and are then charged into the sinter machine 14. The junction position of the transport path CP3 with the transport path CP2 (i.e., the position where the quicklime, or the carbonaceous material and quicklime are subsequently added) can be determined as appropriate.

[0022] (Second post-addition method) Next, the second post-addition method will be described with reference to Fig. 3 or Fig. 4. In Fig. 3 or Fig. 4, the same components as those described in Fig. 1 or Fig. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. In the first post-addition method, quicklime, or carbonaceous material and quicklime, is added to other sintering raw materials discharged from the granulator 13, but in the second post-addition method, quicklime, or carbonaceous material and quicklime are added inside the granulator 13.

[0023] The other sintering raw materials supplied from the hopper 11 to the granulator 13 are granulated while moving from the inlet end to the outlet end of the granulator 13, but the quicklime, or the carbonaceous material and quicklime, are added midway along the path of movement from the inlet end to the outlet end of the granulator 13. Inside the granulator 13, in a region upstream of the position where the quicklime, or the carbonaceous material and quicklime, are added, the other sintering raw materials are mixed and granulated, but in a region downstream of the position where the quicklime, or the carbonaceous material and quicklime, are added, the other sintering raw materials and the added quicklime, or the added carbonaceous material and quicklime, are mixed and granulated.

[0024] When quicklime or a carbonaceous material and quicklime are added later inside the granulator 13, the timing of adding the quicklime or the carbonaceous material and quicklime can be set based on the total granulation time of the granulator 13. The total granulation time can be the time from when the sintering raw materials are charged into the granulator 13 to when they are discharged, but can exclude the time until the granulation binder (water, etc.) is added (i.e., the time when the sintering raw materials are simply mixed). The timing of the later addition can be a time zone after 80% of the total granulation time, preferably a time zone between 80% and 96% of the total granulation time. When the sintering raw materials move at a constant speed inside the granulator 13, the timing of the later addition can be determined by the distance in the longitudinal direction of the granulator 13.

[0025] Regarding the later addition of the carbonaceous material, the entire amount of the carbonaceous material can be added later, or only a portion of the carbonaceous material can be added later. When a portion of the carbonaceous material is added later, the remainder of the carbonaceous material can be charged into the granulator 13 together with the other raw materials for sintering. Regarding the later addition of the quicklime, the entire amount of the quicklime can be added later, or only a portion of the quicklime can be added later. When a portion of the quicklime is added later, the remainder of the quicklime can be charged into the granulator 13 together with the other raw materials for sintering.

[0026] In the sintering machine 14, the charged sintering raw materials are heated by the combustion of carbonaceous material, thereby producing sintered ore. When the sintering raw materials are charged into the sintering machine 14, a raw material packed bed is formed inside the sintering machine 14, and the upper part of the raw material packed bed is ignited, causing the raw material packed bed to combust and produce a sintered cake. The sintered cake is crushed and sized to obtain sintered ore of a predetermined particle size. [Example]

[0027] Examples of the present invention will be described below, but the present invention is not limited to the examples described below.

[0028] (Sintering test) The firing process was carried out using a miniaturized sintering machine (hereafter referred to as the "pot"). The diameter of the pot was 300 mm, and the height (layer thickness) of the pot was 600 mm. The ignition and re-ignition times were both 1 minute (heat amount 25 MJ / ton of raw material). The negative suction pressure during firing was adjusted using the motor inverter on the suction side of the blower so that the measured value below the pot was constant at 1200 mmAq (11.8 kPa).

[0029] Below the pot, the temperature was measured using a thermocouple along with the pressure. When firing using a pot, the temperature below the pot begins to rise and peaks when the combustion zone reaches the bottom of the packed bed, and then drops as the coke combustion is completed. Three minutes after the exhaust gas temperature measured below the pot reached its peak, the suction by the blower was stopped. The sintering time was defined as the time from the start of ignition until the exhaust gas temperature reached its peak.

[0030] The raw materials used in the sintering test are shown in Table 1 below.

[0031] [Table 1]

[0032] As the iron ore, iron ores of brands A to F were prepared. The blending ratios [mass %] of these iron ores are as shown in Table 1 above. As the auxiliary materials, limestone, peridotite, quicklime, and dolomite were prepared. The blending ratios [mass %] of these auxiliary materials are as shown in Table 1 above. Meanwhile, return ore and carbonaceous material were blended with the iron ore and auxiliary materials, and the blending ratio of the return ore was 15 mass % with respect to the total mass (100 mass %) of the iron ore and auxiliary materials.

[0033] The carbonaceous materials used were coke breeze (low combustibility carbonaceous material) and compressed charcoal (high combustibility carbonaceous material) as shown in Table 2 below. The compressed charcoal was formed from the carbonized product obtained by carbonizing wood. Table 2 below shows the analytical values ​​(proximate analysis values ​​and elemental analysis values) of each carbonaceous material.

[0034] [Table 2]

[0035] The blending ratio of the carbonaceous material was adjusted so that the amount of coke fines and fixed carbon was equal to 4.5% by mass relative to the total mass (100% by mass) of iron ore and auxiliary materials. The particle size distribution of the carbonaceous material is as shown in Table 3 below.

[0036] [Table 3]

[0037] (Base 1) Coke breeze was used as the carbonaceous material, and the blending ratio of the carbonaceous material was 4.5% by mass. All raw materials for sintering (iron ore, auxiliary materials, carbonaceous material, and return ore) were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute. Next, water was added to the drum mixer to achieve a target moisture content of 7.5% by mass (excluding all figures), and the mixture in the drum mixer was granulated for a specified time (4 minutes).

[0038] (Base 2) Coke breeze was used as the carbonaceous material, and the blending ratio of the carbonaceous material was 4.5% by mass. The sintering raw materials (iron ore, auxiliary materials, and return fines) other than the carbonaceous material (total amount) were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute. Next, water was added to the drum mixer to achieve a target moisture content of 7.5% by mass (excluding figures), and the mixture in the drum mixer was granulated for a predetermined time (3 minutes 45 seconds). Next, the carbonaceous material (total amount) was added to the mixture in the drum mixer and granulated for a predetermined time (15 seconds). Note that when the carbonaceous material (total amount) was added later, the drum mixer was temporarily stopped.

[0039] (Base 3) Coke fines and compressed charcoal were used as the carbonaceous materials, and the blending ratio of the carbonaceous materials was 4.96% by mass. Here, the blending ratio of coke fines was 3.47% by mass (70% by mass of the total amount of the carbonaceous materials), and the blending ratio of compressed charcoal was 1.49% by mass (30% by mass of the total amount of the carbonaceous materials). The raw materials for sintering (iron ore, auxiliary materials, and return fines) other than the carbonaceous materials (all total amounts) were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute.

[0040] Next, water was added to the drum mixer so that the target moisture content was 7.5% by mass (excluding the above figures), and the mixture in the drum mixer was granulated for a predetermined time (3 minutes 45 seconds). Next, the carbonaceous material (all amounts) was added to the mixture in the drum mixer, and the mixture was granulated for a predetermined time (15 seconds). Note that when the carbonaceous material (all amounts) was added later, the drum mixer was temporarily stopped.

[0041] (Example 1) Coke breeze was used as the carbonaceous material, and the blending ratio of the carbonaceous material was 4.5% by mass. The sintering raw materials (iron ore, auxiliary materials, carbonaceous material, and return ore) excluding the quicklime (total amount) were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute. Next, water was added to the drum mixer to achieve a target moisture content of 7.5% by mass (excluding figures), and the mixture in the drum mixer was granulated for a predetermined time (3 minutes 45 seconds). Next, the quicklime (total amount) was added to the mixture in the drum mixer, and granulation was continued for a predetermined time (15 seconds). Note that the drum mixer was temporarily stopped when the quicklime (total amount) was added later.

[0042] (Example 2) Coke breeze was used as the carbonaceous material, and the blending ratio of the carbonaceous material was 4.5% by mass. The sintering raw materials (iron ore, auxiliary materials, and return fines) excluding the carbonaceous material (total amount) and quicklime (total amount) were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute. Next, water was added to the drum mixer to achieve a target moisture content of 7.5% by mass (excluding all figures), and the mixture in the drum mixer was granulated for a predetermined time (3 minutes 45 seconds). Next, the carbonaceous material (total amount) and quicklime (total amount) were added to the mixture in the drum mixer, and granulated for a predetermined time (15 seconds). Note that the drum mixer was temporarily stopped when the carbonaceous material (total amount) and quicklime (total amount) were added later.

[0043] (Example 3) Coke breeze and compressed charcoal were used as the carbonaceous material, and the blending ratio of the carbonaceous material was 4.96% by mass. Here, the blending ratio of coke breeze was 3.47% by mass (70% by mass of the total amount of the carbonaceous material), and the blending ratio of compressed charcoal was 1.49% by mass (30% by mass of the total amount of the carbonaceous material). The sintering raw materials (iron ore, auxiliary raw materials, and return fines) other than the carbonaceous material (all amounts) and quicklime (all amounts) were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute.

[0044] Next, water was added to the drum mixer so that the target moisture content was 7.5% by mass (excluding the above figures), and the mixture in the drum mixer was granulated for a predetermined time (3 minutes 45 seconds). Next, the carbonaceous material (all amounts) and quicklime (all amounts) were added to the mixture in the drum mixer, and the mixture was granulated for a predetermined time (15 seconds). Note that the drum mixer was temporarily stopped when the carbonaceous material (all amounts) and quicklime (all amounts) were added later.

[0045] (Comparative Example 1) Coke breeze was used as the carbonaceous material, and the blending ratio of the carbonaceous material was 4.5% by mass. The carbonaceous material (all of it) and the sintering raw materials (iron ore, auxiliary materials, and return fines) excluding a portion of the limestone were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute. Next, water was added to the drum mixer to achieve a target moisture content of 7.5% by mass (excluding all figures), and the mixture in the drum mixer was granulated for a specified time (3 minutes 45 seconds).

[0046] Next, the carbonaceous material (all) and limestone (part) were added to the mixture in the drum mixer and granulated for a predetermined time (15 seconds). Here, for the limestone (part) added later, the blending ratio was adjusted so that the quicklime (1.0 mass%) used in Invention Example 2 and CaO were equal in amount, and the remaining limestone was initially charged into the drum mixer together with iron ore, etc. Note that when the carbonaceous material (all) and limestone (part) were added later, the drum mixer was temporarily stopped.

[0047] (Comparative Example 2) Coke breeze and compressed charcoal were used as the carbonaceous material, and the blending ratio of the carbonaceous material was 4.96 mass%. Here, the blending ratio of coke breeze was 3.47 mass% (70 mass% of the total amount of the carbonaceous material), and the blending ratio of compressed charcoal was 1.49 mass% (30 mass% of the total amount of the carbonaceous material). The carbonaceous material (all amounts) and the raw materials for sintering (iron ore, auxiliary raw materials, and return fines) excluding limestone (partial amount) were charged into a drum mixer (diameter 1 m, rotation speed 23 rpm) and mixed for 1 minute.

[0048] Next, water was added to the drum mixer to achieve a target moisture content of 7.5% by mass (excluding the above figures), and the mixture in the drum mixer was granulated for a predetermined time (3 minutes 45 seconds). Next, the carbonaceous material (all amounts) and limestone (partial amount) were added to the mixture in the drum mixer, and granulated for a predetermined time (15 seconds). Here, for the limestone (partial amount) added later, the blending ratio was adjusted so that the quicklime (1.0% by mass) used in Example 3 and CaO were equal in amount, and the remaining limestone was initially charged into the drum mixer along with iron ore, etc. Note that when the carbonaceous material (all amounts) and limestone (partial amount) were added later, the drum mixer was temporarily stopped.

[0049] (Evaluation of sintered ore) By conducting a sintering test using the above-mentioned raw materials for sintering, the product yield, burning speed (FFS) and productivity were calculated for each condition.

[0050] (finished product yield) The product yield is the yield of sintered ore (product), and is the mass (Ms) of the sintered ore (product) on the sieve obtained by dropping the sinter cake obtained after sintering from a height of 2 m five times and sieving it through a sieve with a mesh size of 5 mm, divided by the mass (Mt) of the original sintered cake excluding the bedding ore. Specifically, the product yield R is calculated based on the following formula (1):

[0051]

number

[0052] (burning rate) The combustion progression rate [mm / min] is the value obtained by dividing the layer thickness of the sintering raw material layer (the size in the height direction of the sintering pot) when the sintering raw material is filled in the pot by the time from the time when ignition of the sintering raw material layer begins to the time when the combustion zone reaches the bottom of the sintering raw material layer (referred to as the arrival time). In this example, the arrival time was the time when the temperature of the exhaust gas reached the point where it shows the highest temperature (BTP; Burn Through Point).

[0053] (production rate) The production rate is the production rate of sinter [t / d / m 2 The production rate P is calculated by dividing the mass of sinter (product) Ms [t] by the effective area S [m 2 ] and sintering time ts [h], and is calculated based on the following formula (2).

[0054]

number

[0055] Table 4 below shows the measurement results of product yield, combustion progress rate, and production rate for the above-mentioned Bases 1, 2, and 3, Invention Examples 1, 2, and 3, and Comparative Examples 1 and 2. In Table 4 below, the product yield, combustion progress rate, and production rate for Base 1 are each set to a reference value (1.00). The product yield, combustion progress rate, and production rate for Bases 2 and 3, Invention Examples 1, 2, and 3, and Comparative Examples 1 and 2 are shown as ratios to the reference value for Base 1. Table 4 below also shows the type of carbonaceous material and the addition method of the carbonaceous material, limestone, and quicklime. With regard to the addition method, "before" means adding to the drum mixer from the beginning, and "after" means adding later.

[0056] [Table 4]

[0057] Comparing Base 1 and Base 2, in Base 2 where carbonaceous material was added later, the production rate improved as the combustion rate increased.

[0058] Comparing Bases 2 and 3, Base 3 uses compressed charcoal in addition to coke powder as the carbonaceous material, and the powdering of the compressed charcoal reduces the permeability, resulting in a slower combustion rate than Base 2. In addition, due to the slower combustion rate, Base 2 also had lower product yields and production rates than Base 1.

[0059] According to Example 1, by adding quicklime later, the product yield was slightly reduced compared to Base 1, in which no post-addition was performed, but the combustion rate was significantly improved, thereby improving the productivity.

[0060] In Example 2, by adding quicklime together with the coke fines, the product yield, combustion rate, and productivity were all improved compared to Base 2, in which only the coke fines were added later, and Comparative Example 1, in which limestone was added together with the coke fines. In Comparative Example 1, the combustion rate and productivity were improved compared to Base 2, but in Example 2, the product yield, combustion rate, and productivity were even more improved compared to Base 2.

[0061] In Example 3, by adding quicklime together with the coke fines and compressed charcoal, the product yield, combustion rate, and productivity were all improved compared to Base 3, in which the coke fines and compressed charcoal were added later, and Comparative Example 2, in which limestone was added later together with the coke fines and compressed charcoal. In Comparative Example 2, the product yield, combustion rate, and productivity were improved compared to Base 3, but in Example 3, the product yield, combustion rate, and productivity were even more improved compared to Base 3.

[0062] Quicklime has a lower heat absorption capacity than limestone and can reduce thermal inhibition when burning carbonaceous materials. Therefore, as described above, it is believed that Example 2 was improved over Comparative Example 1, and Example 3 was improved over Comparative Example 2 in terms of product yield, combustion rate, and productivity. Furthermore, as shown in Base 3, when a highly combustible carbonaceous material is added to the carbonaceous material, the product yield, combustion rate, and productivity are lower than those of Base 2. However, as shown in Example 3, by adding quicklime later, the product yield, combustion rate, and productivity are improved compared to those of Base 2. This allows not only low-combustible carbonaceous materials (coke breeze) but also highly combustible carbonaceous materials (compressed charcoal) to be used as the carbonaceous material, thereby broadening the options for carbonaceous materials. [Explanation of symbols]

[0063] 11, 12: hopper, 13: granulator, 14: sintering machine, CP1 to CP3: conveying path

Claims

1. A method for adjusting raw materials for sintering to be charged into a sintering machine, comprising: Among the raw materials for sintering, the raw materials for sintering other than at least a part of the quicklime are mixed and granulated; A method for preparing a raw material for sintering, characterized in that the removed quicklime is added after or during the granulation.

2. A method for adjusting raw materials for sintering to be charged into a sintering machine, comprising: Among the raw materials for sintering, at least a part of the carbonaceous material and at least a part of the quicklime are removed and the remaining raw materials for sintering are mixed and granulated; A method for preparing raw materials for sintering, characterized in that the removed carbonaceous material and quicklime are added after or during the granulation.

3. 3. The method for preparing a raw material for sintering according to claim 2, wherein the carbonaceous material added later includes a highly combustible carbonaceous material having a lower combustion start temperature than coke.

4. 3. The method for preparing raw material for sintering according to claim 2, wherein the entire amount of the carbonaceous material is added later.

5. 3. The method for preparing raw materials for sintering according to claim 1, wherein the entire amount of quicklime is added later.

6. A method for producing sintered ore, comprising firing a raw material for sintering obtained by the preparation method according to any one of claims 1 to 4 to produce sintered ore.

7. A method for producing sintered ore, comprising firing the raw material for sintering obtained by the preparation method according to claim 5 to produce sintered ore.

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