JP4205242B2 - Granulation method of sintering raw material - Google Patents

Description

【０００９】
図７に核粒子２０に付着した微粉の模式図を示すが、図４の本発明法と図５の従来法で造粒し焼結に供する前の混合原料を採取して核粒子に付着した粉層の厚みを測定した。
測定に当たって造粒物１３の疑似粒子の５〜１０ｍｍを造粒物から取出し、乾燥した後に熱可塑性の樹脂に埋め込み研磨して粒子の四方の付着粉層２１の厚みを顕微鏡を用いて測り比較すると、本発明法であるピソライト鉱石の核粒子に付着した粉層の厚みは平均値で７９０μｍであったのに対して、従来法で混合造粒したピソライト鉱石への付着粉の厚みは４２０μｍと少なかった。
すなわち、ピソライト鉱石が魚卵状を呈し粒子外面が他の鉱石と比較して凹凸が少なく、且つ平均粒径が大きく飽和水分値が高いため造粒性が悪い。造粒性が悪いと、全焼結原料を一次ミキサー３に装入して混合造粒すると、粒子外面の凹凸が大きく飽和水分が低い造粒性の良い原料、たとえば返鉱核粒子などから優先的に微粉が付着し、微粉の絶対量が不足してピソライト鉱石には微粉が付着し難いと考えられる。
【００１０】
さらに、焼結工場の原料フロー工程である原料ホッパーから切り出した焼結原料を一次ミキサー３にて水分を添加しながら混合造粒し、混合造粒して得られた造粒物を二次ミキサー５に装入し、更に返鉱１１を加えて混合造粒した焼結原料を焼結機に装入して焼結が行われるが、焼結鉱工場を想定した四方を耐火物で形成した内寸法３００ｍｍ角の焼結鍋で一次、二次ミキサー３，５を想定して混合造粒した焼結原料を装入層厚を７００ｍｍと一定にし、ガスバーナーにより原料表面に着火し下方から吸引負圧が１１００ｍｍＡｑで吸引してラボテストを行った。
【００１１】
また、鍋試験原料配合を実際の焼結工場で操業する配合を想定して配合設計をした。その配合設計を前記した表１で配合した。
飽和水分の高いピソライト鉱石と逆に飽和水分の低い返鉱１１を一次ミキサー３、二次ミキサー５と別けて混合造粒することによって、返鉱１１に付着する粉を抑制し、抑制した分だけピソライト鉱石の付着粉層の増加が図られ、ピソライト鉱石の過溶融を防止する。
すなわち、返鉱は凹凸の多い粗い粉であるため、凹部に微粉が詰まり、この微粉が更に造粒性を高めるためと、飽和水分が低いため少ない水分でも十分に造粒が進むと考えられる。このように低水分域でも充分に造粒が進行する返鉱をピソライト鉱石と分離して造粒することで、ピソライト鉱石への付着粉の増大を図るものである。
【００１２】
次に、前述の第１表に示す焼結に供する各原料を配合してラボテストを行い焼結特性を調査した結果について説明する。本発明法である焼結工程を前述の図４に示し比較法として図５に全原料を一次ミキサー３に入れて混合造粒を行った。なお、ピソライト鉱石を２４（重量）％と他の鉱石３８．８７（重量）％と副原料である生石灰、石灰石、珪石、蛇紋岩と燃料であるコークスを外数で４（重量）％と３．７（重量）％、二水準でそれぞれ計り取って一次ミキサー３を想定した直径１ｍで高さ５０ｃｍのペレタイザーを１２ｒｐｍで回転させ、造粒水分の８０％を一次ミキサー３で添加し５分間混合造粒を行った。
次いで一次ミキサー３で混合造粒した造粒物１２と返鉱１１を加えて造粒水分の残りの２０％を加え、５分間回転させ二次ミキサー５を想定した直径１ｍで高さ５０ｃｍのペレタイザーを１２ｒｐｍで５分間回転させ混合造粒して焼結原料としての造粒物１３を鍋試験に供した。
比較材としては本発明法と全く同一の原料を用い配合も同一で、全原料を計り取り、一次ミキサー３、二次ミキサー５で混合造粒時間を一定にして比較試験に供した。
なお、飽和水分の測定方法としては、図示していないが、各種原料を混合した混合物を濾紙を敷いたロートに入れ、原料表面を被うまで水を添加し、その後ロート下方から水が自然落下しなくなるまで置き、その時の総重量を測り原料を１１０℃の乾燥機に入れて絶乾させ絶乾重量を求め飽和水分を算出した。本試験における造粒水分は飽和水分の６０％を使用した。
【００１３】
前述のラボテスト結果を図１〜図３に示す。図１に示す如く焼結特性である生産性、歩留まりは、本発明法である、ピソライト鉱石と、返鉱と前記ピソライト鉱石より飽和水分が低く吸収可能な水分量が少ないリオドセ鉱石及びカラジャス鉱石とを除くその他の鉱石や、副原料を一次ミキサー３にて優先的に混合造粒して、二次ミキサー５で、前記混合物と、返鉱とピソライト鉱石より飽和水分が低く吸収可能な水分量が少ない前記リオドセ鉱石及びカラジャス鉱石とを加えて混合造粒して焼結に供すると、コークスの添加量に関わらず生産性、歩留まりは向上し、焼結時間は短縮されることが判明した。
【００１４】
また、多孔質なピソライト鉱石は通常の鉱石と比較してフラックスと反応しやすく、過剰な融液を生成するため、一次ミキサー３でピソライト鉱石の粒子に微粉を付着させて付着粉層の増大を図ったことが図２の通気性の改善で見られる。
このことは、ピソライト鉱石は他の鉱石に比べて粗粒であるため核粒子となり易いことと推定される。
更に、ピソライト鉱石は他の鉱石に比べて平均粒径が大きくしかも、飽和水分も高いため、原料ホッパーから一次ミキサー３に至る間に混合造粒に必要な水分の一部を予め噴霧添加すると、添加した水との馴染みが良くなり一次ミキサーでの付着粉層の増大が図られ、通気性改善にはより好ましい。
また、図３に焼結鉱の品質である被還元性（ＲＩ）が従来に比べて向上し、焼結鉱の冷間強度（Ｓｉ）も良好になっている。
【００１５】
図８には鉱石の平均粒径と飽和水分の関係を図示しているが、ピソライト鉱石は平均粒径が大であるのに比し飽和水分が他の鉱石より高い。これは、ピソライト鉱石より飽和水分の低い他の鉱石、例えば豪州産のヘマタイト鉱石やインド産鉱石、更にブラジル鉱石などの一部は返鉱と同様に二次ミキサー５で混合造粒するとピソライト鉱石を用いた焼結原料であっても通気性を悪くしないことを示唆している。従って、ピソライト鉱石と比較して飽和水分が低く吸収可能な水分量が少ないリオドセ鉱石及びカラジャス鉱石は返鉱と同様に二次ミキサー５で混合造粒することが好ましい。
なお、実施の形態としてピソライト鉱石としてローブリバーを示したが、他の鉱石銘柄であっても同様な作用が得られる。
【００１６】
【実施例】
前述の第１表の銘柄を表記した配合割合で配合し、返鉱１１を除いた銘柄に燃料であるコークスを添加して一次ミキサー３である回転ドラムへ各ホッパーから切り出し装入し、水を添加して混合造粒を行い、混合造粒物をベルトコンベアで二次ミキサー５に送り、この時点で最大粒径４ｍｍ以下の返鉱１１を装入して造粒物１２と合わせて、さらに水分を加えながら混合造粒物を得て焼結原料としての造粒物１３として焼結ホッパーへ供給し焼結機にて焼結鉱を得た。
得られた焼結鉱の品質である、冷間強度、低温還元粉化性、還元粉化性それぞれ良好で、問題となっている通気性についても改善され、通気性の向上に伴い焼結時間が短縮され生産性が向上した。従って、本発明においては、各原料ホッパーからゲーサイトを含むピソライト鉱石と他の鉱石と副原料と燃料を切り出し、水を添加しながら一次ミキサー３で混合造粒し、二次ミキサー５にて返鉱１１と前記一次ミキサー３で混合造粒した造粒物４とを混合造粒する方法と、各原料ホッパーからゲーサイトを含むピソライト鉱石と他の鉱石と副原料と燃料を切り出し、水を添加しながら一次ミキサー３で混合造粒し、二次ミキサー５にて返鉱１１と前記ピソライト鉱石より飽和水分の低い鉱石と前記一次ミキサー３で混合造粒した造粒物４とを混合造粒する方法と、さらに、前記原料ホッパーから一次ミキサー３に至る間に混合造粒に必要な水分の一部を前記ピソライト鉱石に噴霧添加する方法を採用している。
【００１７】
【発明の効果】
本発明による焼結原料の造粒方法は、以上のように構成されているため、次のような効果を得ることができる。すなわち、各原料ホッパーからピソライト鉱石と副原料と燃料又は他の鉱石を切り出し、水を添加しながら一次ミキサーで混合造粒し、二次ミキサーにて返鉱と前記一次ミキサーで混合造粒した造粒物を混合造粒することにより、焼結反応時に生成する溶融液とピソライト核粒子との接触を遮断する付着粉層を増大させ、ペレタイザー等の事前処理設備、既設造粒設備の大掛かりな改造等を必要とせずに、かつ、強度、生産性を低下させずにピソライト鉱石を多量配合した焼結鉱を製造することが可能となる。
また、各原料ホッパーから、ピソライト鉱石と、返鉱と前記ピソライト鉱石より飽和水分が低く吸収可能な水分量が少ないリオドセ鉱石及びカラジャス鉱石とを除く他の鉱石と、副原料と、燃料を切り出し、一次ミキサーで水を添加しながら混合造粒し、二次ミキサーにて返鉱と前記ピソライト鉱石より飽和水分が低く吸収可能な水分量が少ないリオドセ鉱石及びカラジャス鉱石とを前記一次ミキサーで混合造粒した造粒物とを混合造粒することにより、更にピソライト鉱石の粒に微粉層を形成させて通気性の阻害要因を排除して生産性が向上する。
また、原料ホッパーから一次ミキサーに至る間に混合造粒に必要な水分の一部を予めピソライト鉱石に噴霧添加することによって、鉱石に水を十分なじますことができ、付着粉の形成を促進させることができる。
【図面の簡単な説明】
【図１】 本発明法と従来法を比較した焼結の生産性を示す特性図である。
【図２】 本発明法と従来法を比較した焼結の通気性を示す特性図である。
【図３】 本発明法と従来法を比較した焼結の品質を示す特性図である。
【図４】 本発明法を説明する原料の混合造粒工程図である。
【図５】 従来法を説明する原料の混合造粒工程図である。
【図６】 焼結工程の概略を説明する構成図である。
【図７】 核粒子に微粉が付着した様子を示す模式図である。
【図８】 平均粒径と飽和水分の関係を説明する特性図である。
【符号の説明】
１ 原料ホッパー
２ ベルトコンベア
３ 一次ミキサー
４ ベルトコンベア
５ 二次ミキサー
６ ベルトコンベア
７ 給鉱ホッパー
８ 焼結機
９ ノズル
１０ 原料
１１ 返鉱
１２，１３ 造粒物
１４，１５ 水[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to mixed granulation of a powder material of a sintering raw material, and in particular, relates to a novel improvement for mixing and granulating the pisolite ore that is a raw material charged into a sintering machine while preventing overmelting. .
[0002]
[Prior art]
In general, as shown in FIG. 6, the raw material cut out from the raw material hopper 1 is supplied to the first stage primary mixer 3 by the first belt conveyor 2, and water is added at the nozzle 9 in the primary mixer 3. While mixing the raw materials, the raw materials are fed to the next stage belt conveyor, and further, the mixed raw materials are supplied to the second stage secondary mixer 5 by the second belt conveyor 4, and then the granulated raw materials are supplied to the third belt conveyor. 6 is stored in the feed hopper 7 and then supplied to the sintering machine 8 to produce sintered ore.
[0003]
However, a high-quality ore of hematite (hematite) or magnetite (magnetite) has been used as a sintering raw material, but pisolite ore that has recently shown an egg-like shape containing a lot of goethite (Fe2O3 · H2O). The usage of is increasing. This pisolite ore has many problems in maintaining productivity in the sintering process, and technical development corresponding to this is desired.
In addition, the pisolite ore contains 4% or more of crystallization water, and the pisolite ore that has dissociated the crystallization water at 300 ° C. becomes porous. In the sintering process at 1200 ° C. or more, the porous pisolite ore is a normal ore. It reacts more easily with flux compared to, and produces an excessive melt. It has been found that this excessive melt deteriorates the air permeability of the sintered layer and decreases the productivity. Therefore, as a technology for using large amounts of pisolite ore, pisolite ore contains a large amount of crystallization water, so cracks and pores are generated during sintering and the quality of the sinter is deteriorated. A method of pre-granulating with a pelletizer using serpentine, a high melting point material, etc., and forming a protective layer, adjusting the composition of the granulated adhered powder so that a melt is generated at 1300 ° C. or higher There are melting point liquid phase sintering methods and the like.
[0004]
[Problems to be solved by the invention]
Since the conventional method for granulating a sintered raw material is configured as described above, the following problems exist.
In other words, none of the pretreatment methods can be achieved with existing granulation equipment alone, and it is necessary to significantly modify the equipment and introduce new equipment. Further, in the normal granulation process, since the graniteability of the pisolite ore is poor, a sufficient protective layer of adhering powder cannot be formed, resulting in a decrease in strength and productivity.
[0005]
The present invention has been made to solve the above-described problems. Particularly, in order to prevent overmelting of the pisolite ore, the pelletizer and the like require a large amount of modification of the pretreatment equipment and the existing granulation equipment. Provides a granulation method for sintering raw materials that increases the adhesion powder layer that blocks the contact between the melt generated during the sintering reaction and the pisolite core particles, and suppresses the strength and productivity reduction caused by the large amount of pisolite ore The purpose is to do.
[0006]
[Means for Solving the Problems]
Granulation process of the sintering raw material according to the present invention, from the raw material hopper, and Pisoraito ore containing goethite, and return ores and the Pisoraito absorbable amount of water saturation water is lower than the ore is less CVRD ores and Carajas ore Excluding other ores, auxiliary materials, and fuel, a part of moisture necessary for mixing granulation is sprayed and added to the pisolite ore in advance from the raw material hopper to the primary mixer, and water is added by the primary mixer. mixing granulation while adding, at the secondary mixer, and the return ores, said a Pisoraito ore than the saturated water can absorb low amount of water is less the CVRD ores and Carajas ore was mixed granulated with the primary mixer This is a method of mixing and granulating a granulated product.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a method for granulating a sintering raw material according to the present invention will be described with reference to the drawings.
First, in order to investigate the mixing granulation property of the sintering raw material in advance, the raw material was designed with the mixing raw materials shown in Table 1 below, and the mixing shown in FIG. 4 (method of the present invention) and FIG. 5 (conventional method). A granulation test was performed. That is, in FIG. 4, the raw material 10 and the water 14 are put in the primary mixer 3 and granulated, and the granulated product 12, the return mineral 11 and the water 15 are put in the secondary mixer 5 and granulated, and then granulated. Item 13 is obtained.
On the other hand, in FIG. 5, all raw materials 10A are put in the primary mixer 3 together with water 14 and granulated, and the resulting granulated product 12 is granulated by the secondary mixer 5 to obtain the final granulated product 13. Have gained.
[0008]
[Table 1]

[0009]
FIG. 7 shows a schematic diagram of the fine powder adhering to the core particles 20. The mixed raw material is collected and adhered to the core particles before being granulated and sintered by the method of the present invention of FIG. 4 and the conventional method of FIG. 5. The thickness of the powder layer was measured.
In measurement, 5 to 10 mm of the pseudo particles of the granulated product 13 are taken out from the granulated product, dried, embedded and polished in a thermoplastic resin, and the thickness of the adhered powder layer 21 on all four sides of the particle is measured and compared. The average thickness of the powder layer attached to the core particles of the pisolite ore according to the present invention was 790 μm, whereas the thickness of the powder attached to the pisolite ore mixed and granulated by the conventional method was as small as 420 μm. It was.
That is, the graniteability is poor because the pisolite ore has an egg-like shape and the outer surface of the particle is less uneven than the other ores, the average particle size is large, and the saturated moisture value is high. When the granulation property is poor, when all the sintered raw materials are charged into the primary mixer 3 and mixed and granulated, it is preferential from the raw materials with good granulation properties such as irregularities on the outer surface of the particles and low saturated moisture, such as returning ore core particles. It is considered that the fine powder adheres to the pisolite ore due to insufficient absolute amount of fine powder.
[0010]
Furthermore, the granulated product obtained by mixing and granulating the sintered raw material cut out from the raw material hopper, which is the raw material flow process of the sintering plant, while adding water with the primary mixer 3, and the granulated product obtained by mixing and granulating the secondary mixer Sintered raw material charged into No. 5 and further mixed with the returned ore 11 and mixed and granulated is charged into the sintering machine, and sintering was performed. Sintered raw material mixed and granulated with a 300mm square inner pot assuming primary and secondary mixers 3 and 5, the charge layer thickness is kept constant at 700mm, the raw material surface is ignited by a gas burner and sucked from below A lab test was conducted with a negative pressure of 1100 mmAq.
[0011]
In addition, the composition was designed assuming a composition in which the pot test raw material composition was operated in an actual sintering factory. The blending design was blended in Table 1 above.
Contrary to the high-saturated pisolite ore, the low-saturated water return ore 11 is separated from the primary mixer 3 and the secondary mixer 5 and mixed and granulated, so that the powder adhering to the return ore 11 is suppressed and the amount of the suppression is reduced. The adhesion powder layer of pisolite ore is increased to prevent overmelting of pisolite ore.
That is, since the return ore is a coarse powder with many irregularities, the concave portions are filled with fine powder, and the fine powder further enhances the granulation property, and since the saturated water is low, granulation proceeds sufficiently even with a small amount of water. In this way, the returned ore, which is sufficiently granulated even in a low moisture region, is separated and granulated from pisolite ore, thereby increasing the amount of powder adhering to pisolite ore.
[0012]
Next, a description will be given of the result of examining the sintering characteristics by blending each raw material to be used for sintering shown in Table 1 and conducting a laboratory test. The sintering process which is the method of the present invention is shown in FIG. 4 described above, and as a comparative method, all the raw materials are put in the primary mixer 3 in FIG. In addition, 24 (wt)% of psolite ore, 38.87 (wt) of other ores, quick lime, limestone, quartzite, serpentinite, and coke as fuel are 4 (wt)% and 3 .7 (weight)%, measured at two levels, respectively, rotating a pelletizer with a diameter of 1 m and a height of 50 cm assuming a primary mixer 3 at 12 rpm, adding 80% of granulated water with the primary mixer 3 and mixing for 5 minutes Granulation was performed.
Next, the granulated product 12 and granulated product 11 mixed and granulated by the primary mixer 3 are added, the remaining 20% of the granulated water is added, and the pelletizer is rotated for 5 minutes and assumes a secondary mixer 5 with a diameter of 1 m and a height of 50 cm. The mixture was granulated by rotating at 12 rpm for 5 minutes, and the granulated product 13 as a sintering raw material was subjected to a pan test.
As the comparative material, the same raw materials as in the method of the present invention were used and the blending was the same. All raw materials were weighed and subjected to a comparative test with the mixing granulation time kept constant in the primary mixer 3 and the secondary mixer 5.
Although not shown in the figure as a method for measuring saturated moisture, a mixture of various raw materials is placed in a funnel with filter paper, water is added until it covers the raw material surface, and then water falls naturally from below the funnel. Then, the total weight at that time was measured, the raw material was put into a dryer at 110 ° C. and dried completely, the dried weight was determined, and the saturated moisture was calculated. The granulated moisture in this test was 60% of saturated moisture.
[0013]
The above laboratory test results are shown in FIGS. Productivity, yield a sintering characteristics as shown in FIG. 1 is a present invention method, and Pisoraito ore, the return ores and the Pisoraito ore from CVRD ore saturated moisture is less capable of absorbing water content lower and Carajas ore Ore and other raw materials other than the above are mixed and granulated preferentially in the primary mixer 3, and in the secondary mixer 5, the amount of water that can be absorbed is lower than that of the mixture, and the return or pisolite ore. It has been found that when a small amount of the above-mentioned riodose ore and carajas ore is added and mixed for granulation and subjected to sintering, productivity and yield are improved regardless of the amount of coke added, and the sintering time is shortened.
[0014]
In addition, porous pisolite ore is easier to react with the flux than ordinary ore, and generates an excessive melt. Therefore, the primary mixer 3 attaches fine powder to the pisolite ore particles to increase the adhered powder layer. This is seen in the improvement in air permeability shown in FIG.
This is presumed that the pisolite ore is coarser than other ores and therefore tends to be a core particle.
Furthermore, since the pisolite ore has a larger average particle size than other ores and has a high saturated water content, when a part of the water necessary for mixing granulation is sprayed and added in advance from the raw material hopper to the primary mixer 3, Familiarity with the added water is improved, and the adhered powder layer in the primary mixer is increased, which is more preferable for improving air permeability.
Further, in FIG. 3, the reducibility (RI), which is the quality of the sintered ore, is improved as compared with the conventional one, and the cold strength (Si) of the sintered ore is also improved.
[0015]
FIG. 8 shows the relationship between the average particle size of the ore and the saturated moisture, but the pisolite ore has a higher saturated moisture than the other ores compared to the large average particle size. This is because other ores with lower saturated moisture than pisolite ore, such as Australian hematite or Indian ore, and some Brazilian ore are mixed and granulated by secondary mixer 5 in the same way as return ore. This suggests that even the sintered raw material used does not deteriorate the air permeability. Therefore, it is preferable to mix and granulate the riodose ore and carajas ore with a low saturated water content and a small amount of water that can be absorbed as compared with the pisolite ore by the secondary mixer 5 in the same manner as the return ore .
In addition, although the lobe river was shown as pisolite ore as embodiment, the same effect | action is acquired even if it is another ore brand.
[0016]
【Example】
Mixing the brands listed in Table 1 above in the blending ratio, adding coke as fuel to the brands excluding the return ore 11, cutting and charging from each hopper into the rotary drum as the primary mixer 3, and water. Add and perform mixed granulation, send the mixed granulated product to the secondary mixer 5 with a belt conveyor, and at this time, load the return ore 11 having a maximum particle size of 4 mm or less together with the granulated product 12, A mixed granulated product was obtained while adding moisture, and supplied to a sintering hopper as a granulated product 13 as a sintering raw material, and a sintered ore was obtained by a sintering machine.
The quality of the obtained sintered ore, cold strength, low-temperature reduced powdering property, reduced powdering property are good, and the problem of air permeability has been improved. Has been shortened to improve productivity. Therefore, in the present invention, pisolite ore containing goethite, other ores, auxiliary materials and fuel are cut out from each raw material hopper, mixed and granulated with the primary mixer 3 while adding water, and returned with the secondary mixer 5. A method of mixing and granulating the ore 11 and the granulated product 4 mixed and granulated by the primary mixer 3, and cutting out pisolite ore containing goethite, other ores, auxiliary materials and fuel from each raw material hopper, and adding water While mixing with the primary mixer 3, the secondary mixer 5 mixes and granulates the return ore 11, the ore having a lower saturated water content than the pisolite ore, and the granulated product 4 mixed and granulated with the primary mixer 3. Further, a method of spraying and adding a part of moisture necessary for mixing granulation to the pisolite ore during the period from the raw material hopper to the primary mixer 3 is adopted.
[0017]
【The invention's effect】
Since the method for granulating a sintered raw material according to the present invention is configured as described above, the following effects can be obtained. That is, pisolite ore, auxiliary material and fuel or other ore are cut out from each raw material hopper, mixed and granulated with a primary mixer while adding water, and returned to the secondary mixer and mixed and granulated with the primary mixer. By mixing and granulating the granules, the adhesion powder layer that blocks the contact between the melt generated during the sintering reaction and the pisolite core particles is increased, and large-scale remodeling of pretreatment equipment such as pelletizers and existing granulation equipment Thus, it is possible to produce a sintered ore containing a large amount of pisolite ore without reducing the strength and productivity.
Also, cut out from each raw material hopper, and Pisoraito ore, and other ores, except the return ores and the Pisoraito ore than the saturated water can absorb low amount of moisture is small CVRD ores and Carajas ore, and auxiliary raw material, fuel, mixing granulation while adding water in the primary mixer, mixing granulation and return ores and the Pisoraito absorbable amount of water saturation water is lower than the ore is less CVRD ores and Carajas ore in the secondary mixer the primary mixer By mixing and granulating the granulated material, a fine powder layer is further formed on the particles of the pisolite ore, and the factor of impeding air permeability is eliminated, thereby improving the productivity.
Also, by adding a part of the water necessary for mixing granulation to the pisolite ore in advance from the raw material hopper to the primary mixer, water can be sufficiently applied to the ore, which promotes the formation of adhered powder be able to.
[Brief description of the drawings]
FIG. 1 is a characteristic diagram showing the productivity of sintering by comparing the method of the present invention with a conventional method.
FIG. 2 is a characteristic diagram showing the breathability of sintering comparing the method of the present invention with the conventional method.
FIG. 3 is a characteristic diagram showing the quality of sintering comparing the method of the present invention with the conventional method.
FIG. 4 is a mixing granulation process diagram of raw materials for explaining the method of the present invention.
FIG. 5 is a mixing granulation process diagram of raw materials for explaining a conventional method.
FIG. 6 is a configuration diagram illustrating an outline of a sintering process.
FIG. 7 is a schematic view showing a state in which fine powder adheres to a core particle.
FIG. 8 is a characteristic diagram illustrating the relationship between average particle size and saturated moisture.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Raw material hopper 2 Belt conveyor 3 Primary mixer 4 Belt conveyor 5 Secondary mixer 6 Belt conveyor 7 Feeding hopper 8 Sintering machine 9 Nozzle 10 Raw material 11 Return ore 12, 13 Granulated material 14, 15 Water

Claims (1)

From each raw material hopper, and Pisoraito ore containing goethite, and other ores, except the return ores (11) and said Pisoraito absorbable amount of water saturation water is lower than the ore is less CVRD ores and Carajas ore, and auxiliary raw material In addition, a part of the water necessary for mixing granulation is sprayed and added to the pisolite ore in advance while cutting out the fuel and reaching the primary mixer from the raw material hopper, and mixed granulation while adding water in the primary mixer (3) And
At the secondary mixer (5), wherein the return ores (11), wherein the Pisoraito absorbable amount of water saturation water is lower than the ore less the CVRD ores and Carajas ore, mixing granulation in the primary mixer (3) A granulated method of a sintering raw material, characterized by mixing and granulating the granulated product (12).

Images