200925289 九、發明說明 【發明所屬之技術領域】 本發明係關於一種使用作爲高爐用鐵原料之自熔性（ self fluxing)顆粒（在以下，僅稱爲「顆粒」）及其製造 方法，特別是關於一種適合於吹入多量之微粉碳（ pulverized coal)之高爐作業的自熔性顆粒及其製造方法 〇 【先前技術】 本發明人係由西元1 970年左右開始經過至1980年左右 ，完成可以藉由投入於使用作爲高爐用鐵原料之自熔性顆 粒之重組技術之開發，燒成（burning )在鐵礦石將配合 石灰石及白雲石（dolomite)來作爲CaO及MgO源且 〇3〇/8102質量比爲〇_8以上、Mg0/Si02質量比爲0·4以上之 配合原料予以造粒（pelletize)之生顆粒（raw pellet)而 ❹ 製造高溫之被還原性（reducibility )良好之自熔性顆粒（ ' 自熔性白雲石顆粒）之技術（參考專利文獻1、2 )。 -另一方面，本發明人係並行於前述自熔性顆粒之重組 技術之開發，推進高爐之裝入物分布控制技術之開發，完 成呈劃時代地改善高爐內之通氣性.通液性之焦炭中心裝 入技術（參考非專利文獻1 )。 藉由前述之自熔性白雲石顆粒之使用和焦炭中心裝入 技術之適用，而即使是在顆粒多配合高爐，吹入多量之微 粉碳’也可以進行穩定之作業，在本發明人之神戶製鐵所 -5- 200925289 之第3高爐，達成全顆粒操作技術（參考非專利文獻2 )。 但是，爲了應付於近年來之鋼鐵需要之急速增大，因 此，要求生鐵之更進一步之增產，高爐之生產性提升及成 爲高爐用原料之顆粒之增產係成爲吃緊（urgent)之課題 〇 但是，爲了提升高爐之生產性，因此，必須更加地改 善高爐內之通氣性。另一方面，顆粒係藉由格柵窯（ grate kiln )方式或直接格柵（straight grate )方式而進行 製造，但是，爲了增產顆粒，因此，必須在任何一種方式 之狀態下，也更加地改善格柵上之顆粒層之通氣性。 作爲用以一起改善高爐內之通氣性和格柵上之顆粒層 之通氣性之手段係認爲增大顆粒之平均粒徑。但是，顆粒 平均粒徑之增大係降低顆粒之被還原性（參考非專利文獻 3)，因此，有增加在高爐內之直接還原之比例而提高還 原材比之問題發生。 此外，作爲前述通氣性改善之手段係也認爲不增大顆 粒之粒徑，儘可能地使得顆粒之粒徑分布變窄，對於顆粒 之粒徑，進行均一化（參考非專利文獻3 )。但是，顆粒 之粒徑分布之狹窄化係降低顆粒之製造產率（yield ratio )，增大顆粒之製造成本，因此，向來係幾乎不檢討，更 加適合於近年來之微粉碳之多量吹入以及高度生產性之條 件下之高爐作業的自熔性白雲石顆粒之粒度分布係不明瞭 [非專利文獻1 ]松井們、「本公司之高爐操作技術之 200925289 進步和作爲焦炭中心裝入法之中心流操作思想」、：R & D 神戶製鋼技報、第55卷、第2號、西元2〇〇5年9月、p.9〜 17 [非專利文獻2]大山們、「對於神戶3高爐之全顆粒操 作之轉移：（神戶3高爐之全顆粒操作—其1)」、材料和 製程、第15卷、第1號、西元2002年3月1日、p.129〜13〇 [非專利文獻3]曰本鋼鐵協會編、「鋼鐵便覽（第Π卷 )製鐵·製鋼」、第3版、九善股份有限公司、日本昭和 54 年 10 月 15 日、p. 158 [專利文獻1]日本特公平3— 77853號公報 [專利文獻2]日本特公平3 - 77854號公報 【發明內容】 [發明所欲解決之課題] 於是，本發明之目的係提供一種可以改善高爐之通氣 性而提高生產性同時在顆粒之製造時來改善格柵上之顆粒 層之通氣性而增產顆粒的自熔性顆粒及其製造方法。 [用以解決課題之手段] 本發明係一種高爐用自熔性顆粒，其特徵爲：Ca0/Si02 質量比爲0.8以上、Mg0/Si02質量比爲0.4以上，且具有平 均粒徑爲10〜13mm且粒徑4mm以上、8mm未滿者爲6質 量％以下、粒徑15mm以上、20mm未滿者爲7質量％以下 的粒徑分布。 200925289 此外，本發明係一種高爐用自熔性顆粒之製造方法’ 其特徵爲：具備：在鐵礦石配合含有CaO和MgO之副原 料而調整Ca0/Si02質量比成爲0.8以上、MgO/Si〇2質量比 成爲0.4以上的原料配合步驟；造粒該配合之原料而成形 具有既定之粒徑分布之生顆粒之造粒步驟；以及’在1220 〜1 300°C加熱及燒成該生顆粒而成爲具有平均粒徑爲〜 13mm且粒徑4mm以上、8mm未滿者爲6質量％以下、粒徑 15mm以上、20mm未滿者爲7質量％以下、平均粒徑爲1〇 〜1 3 mm之粒徑分布之自熔性顆粒之燒成步驟。 [發明之效果] 如果藉由本發明的話，則可以藉由限制自熔性顆粒之 小粒徑部分及大粒徑部分之比例，成爲既定之比例以下， 對於顆粒之粒徑，進行均一化，而即使是在吹入多量微粉 碳之操作下，也改善高爐內之通氣性，提升高爐之通氣性 φ ’同時，在顆粒之製造時，改善格柵上之顆粒層之通氣性 增產自熔性顆粒。結果，可以維持由於多量微粉碳吹入 至高爐所造成之成本降低效果，並且，實現生鐵之更進一 步之增產。 【實施方式】 [發明之最佳實施形態] [本發明之高爐用自熔性顆粒之構造] 本發明之高爐用自熔性顆粒，其特徵爲：Ca0/Si02質 200925289 量比爲0.8以上、Mg〇/Si〇2質量比爲0.4以上’且具有平均 粒徑爲1〇〜13mm且粒徑4mm以上、8mm未滿者爲6質量％ 以下、粒徑15mm以上、20mm未滿者爲7質量％以下的粒 徑分布。 在以下，就構成前述本發明之各個要件而更加詳細地 進行說明。 (爐渣之組成） 因爲可以藉由一起提高規定自熔性顆粒之爐渣組成之 Ca0/Si02質量比及Mg0/Si02質量比，成爲既定値（〇.8及 0.4 )以上，而高度地維持在高溫還原時之顆粒之軟化· 熔落溫度，能夠提升高溫之被還原性之緣故。Ca0/Si〇2質 量比係最好是1 . 〇以上、甚至是1.2以上、特別是1 ·4以上。 此外，MgO/Si〇2質量比係最好是〇·5以上、甚至是〇.6以上 、特別是0.7以上。但是，在過度地提高CaO/Si〇2質量比 及MgO/Si02質量比之時，於顆粒之燒成時，Ca0及Mg〇 成分係不容易進行玻璃化’降低燒成顆粒之強度’同時’ 增加作爲CaO及MgO源之石灰石和白雲石之使用量’增 加成本，因此，CaO/Si〇2質量比係最好是2.0以下、甚至 是1.8以下、特別是1.6以下，MgO/Si02質量比係最好是 1 .1以下、甚至是1.0以下、特別是〇 · 9以下。 (粒徑分布） 在自熔性顆粒之平均粒徑過度小之時’被還原性變得 -9- 200925289 良好，高爐內之礦石層以及格柵上之顆粒層係皆降低通氣 性，另一方面，在過度大時，高爐內之礦石層以及格栅上 之顆粒層係皆改善通氣性，降低被還原性。於是，自熔性 顆粒之平均粒徑係成爲1〇〜13mm之範圍、最好是11〜 1 2mm之範圍。 接著，即使是平均粒徑滿足前述之規定範圍（10〜 13mm、最好是11〜12mm)，也在提高粒徑4mm以上、 8mm未滿之小粒徑之顆粒之比例以及粒徑15mm以上、 20mm未滿之大粒徑之顆粒之比例之時，擴大顆粒之粒度 分布，顆粒之塡充變得緻密，降低層空隙率（layer porosity)，因此，高爐內之礦石層以及格柵上之顆粒層 係皆降低通氣性。此外，在提高粒徑4mm以上、8mm未 滿之小粒徑之顆粒之比例時，於包含顆粒之礦石裝入至高 爐內之際’其小粒徑顆粒浸透至礦石層之底部，潛入至焦 炭層爲止（參考：松井們、「到達至高爐作業限度之非正 常現象及其控制」、材料和製程、財團法人日本鋼鐵協會 、西元2003年9月1日、第16卷、第16號、p.764〜767)， 降低焦炭層之通氣性’或者是在爐下部熔落其小粒之顆粒 之際，使焦炭惡化等。 於是，粒徑4mm以上、8mm未滿之小粒徑之顆粒之 比例係6質量％以下、最好是4質量％以下、更加理想是2質 量％以下’粒徑15mm以上、2〇mm未滿之大粒徑之顆粒之 比例係7質量°/〇以下、最好是5質量％以下、更加理想是3質 量％以下。 -10 - 200925289 前述之皆滿足爐渣組成及粒徑分布之自熔性顆粒係在 高溫之被還原性呈良好，同時，改善爐內之礦石層以及格 柵上之顆粒層之通氣性，因此，可以藉由使用該顆粒，而 維持乃至降低高爐之還原材比，並且，提高生產性，同時 ，能夠增產顆粒。 [本發明之高爐用自熔性顆粒之製造方法] 前述之本發明之高爐用自熔性顆粒係例如可以正如以 下而進行製造。 (原料配合步驟） 在成爲鐵原料之鐵礦石（顆粒進料），配合石灰石及 白雲石，來作爲含有CaO及M gO之副原料，進行調整而 使得Ca0/Si02質量比成爲0.8以上（最好是1.0以上、更加 理想是1.2以上、特別最好是1.4以上），MgO/Si〇2質量比 成爲〇·4以上（最好是〇.5以上、更加理想是0.6以上、特別 最好是0.7以上）。鐵礦石及副原料係由於需要而在事前 或配合後，藉由球磨機等，來進行粉碎，成爲配合原料之 粒度44μιη以下、80質量％以上。 (造粒步驟） 在該配合原料，添加適量之水分，使用圓盤造粒機（ pan pelletizer)或圓筒造粒機（drum pelletizer)來作爲 造粒機’進行造粒，形成生顆粒。生顆粒之粒徑分布係考 -11 - 200925289 慮由於後段之燒成所造成之收縮，藉由燒成後之自熔性顆 粒之粒徑分布（滿足本發明所規定之粒度分布之目標粒度 •分布）而設定平均粒徑移位至稍微大之側之粒徑分布。此 外，由於後段之燒成之所造成之粒徑之收縮量係以平均直 徑而成爲大約0.5〜1 mm程度。生顆粒之粒徑分布之設定 係可以藉由調整規定下限之粒徑（也就是在1 〇mm加入移 位部分）之種子筛網之篩孔（sieve opening)和規定上限 0 之粒徑（也就是在1 3mm加入移位部分）之過大尺寸篩網 之篩孔而容易地進行。可以藉由種子篩網之篩下（minus sieve )仍然直接地回復到造粒機，同時，過大尺寸篩網 之篩上（plus sieve)進行破碎（crushing)，回復到造粒 機，而不降低原料產率（製造產率），得到要求之粒徑分 布。此外，爲了得到本發明所規定之燒成後之顆粒之粒徑 分布，因此，向來必須加大種子篩網之篩孔，並且，縮小 過大尺寸篩網之篩孔，必然造成對於造粒機之回復量變多 φ ，所以，降低每1台造粒機之生顆粒生產能力，結果，有 必須增強或增設造粒機之狀態發生。 (燒成步驟） 正如前面敘述來成形而具有既定之粒徑分布之生顆粒 係藉由塡充於作爲燒成裝置之格柵窯或直接格柵之移動格 柵上，在該顆粒層，流通高溫氣體，而在經過乾燥、離水 (僅需要之狀態）及預熱之各個階段後，於前者，在旋轉 窯，於後者，仍然直接在移動格柵上，以1220〜1300 °c之 -12- 200925289 高溫氣體，來進行加熱及燒成而得到自熔 成之溫度係可以配合於使用之鐵礦石之I 質量比、MgO/Si02質量比等，而在前述 度地進行調整。 得到之自熔性顆粒係爐渣之組成滿足 Ca0/Si02質量比和Mg0/Si02質量比，同 之加熱燒成而由生顆粒開始進行收縮，由 布，移位至平均粒徑稍微小之側，槪略成 度分布，滿足本發明所規定之粒徑分布。 可以藉由正如前面之敘述，使用既有 備，僅在必要之狀態下，增強或增設造粒 度之設備成本之上升，容易地製造本發明 [實施例] 爲了驗證本發明之自熔性顆粒使用於 因此，正如下列之敘述所示，在各種粒徑 篩選（sieve)滿足本發明所規定之成分 熔性顆粒，就該各種粒徑範圍之每一種之 高溫荷重還原試驗，測定用以評價高溫之 還原率（後面敘述之間接還原率和直接還 使用該各種粒徑範圍之每一種之高溫還原 行具有各種粒徑分布之顆粒之高溫還原率 [高溫荷重還原試驗] 性顆粒。加熱燒 重類或 Ca0/Si02 之溫度範圍，適 本發明所規定之 時，藉著在高溫 生顆粒之粒徑分 爲前述之目標粒 之顆粒工廠之設 機，而不造成過 之自熔性顆粒。 高爐時之效果， 範圍之每一種， 組成之實機之自 顆粒而言，實施 被還原性之高溫 原率之總稱）， 率之實測値，進 之預測計算。 -13- 200925289 作爲實機之自熔性顆粒係使用在申請人之加古川製鐵 所內之顆粒工廠所製造之自熔性白雲石顆粒。將其成分組 成，顯示於表1。表1之「T.Fe」，係表示全Fe，並非僅 是表1之FeO之Fe部分，也是加入Fe203等之Fe部分之 [表1] 自熔性 白雲石 顆粒 成分α ff量％) CaO/Si02 質量比 Mg〇/Si02 質量比 T.Fe FeO Si02 CaO AI2O3 MgO 61.9 0.61 2.90 3.79 1.28 2.28 1.31 0.79 (各種粒徑範圍之顆粒之高溫還原率之測定） 藉由筛孔 20mm、15mm、12mm、10mm、8mm、4mm 之各篩而對於該顆粒進行篩選。在該顆粒，原本就不存在 超過20mm之顆粒，並且，4mm未滿之顆粒係在裝入至高 爐之即刻前，藉由篩網而除去之後，裝入至高爐。於是， 首先在藉由前述篩選而得到之4〜8mm、8〜1 0mm、1 〇〜 12mm、12〜15mm、15〜20mm之各種粒度範圍之每—種 顆粒，實施高溫荷重還原試驗。此外，例如「4〜8mm」 之表記係表示「4mm以上、8mm未滿」。 在此，高溫荷重還原試驗係正如下列之試驗條件所示 ’在石墨坦禍（graphite crucible)內，塡充既定量之試 料，施加一定之荷重，並且，在升溫條件下，流通還原氣 體，藉由排氣分析而算出在1000t、1100°c及1200。《：之各 個溫度到達時間點之還原率（間接還原率）以及由試料# -14- 200925289 充層之壓損急速上升時間點開始至試驗結束時間點（試料 塡充層之收縮結束時間點）爲止間之還原率（直接還原率 )，藉由這些還原率之値而評價高溫之被還原性。 [高溫荷重還原試驗之試驗條件] •石墨坩堝內徑：43mm •試料量：大約87g (塡充高度：大約33.5mm) .荷重：1 . Okgf/cm2 ( = 9.80665xl04Pa) •溫度：[室溫— 1 000°C]xl0°C/min、[ 1 000°C —熔落結束] X 5 °C /min •還原氣體：[30容量 ％CO+70容量 ％N2]x7.2NL/min 將試驗結果，顯示於表2及圖1和圖2。 [表2] 顆粒之粒徑 (mm) 範圍 4-8 8-10 10-12 12-15 15-20 平均 6 9 11 13.5 17.5 間接還原率 (%) 1000。。 52 44 40 33.8 25 1100。。 68 56 53 46 38 1200°c 75 70 65 60 54 直接還原率(％) 12 18.6 25 31.4 41.1 正如表2及圖1和圖2所示，得知顆粒之粒徑越大而越 加降低間接還原率，提高直接還原率。 藉由間接還原率和直接還原率而評價高爐之生產性者 係根據以下之理由。由高爐上部來裝入之原料（顆粒•燒 結礦等）係藉由產生於高爐下部之CO氣體而進行還原， -15- 200925289 同時，下降於高爐內。將此時之還原，稱爲間接還原。如 果能夠提高該間接還原相對於還原整體之比率的話，則在 爐下部，減少一部分熔解之裝入物和焦炭之直接反應。該 直接反應係藉由 FeO+C=Fe+CO-Akcal所表示而奪取 熱量之反應。將藉由此種反應所造成之還原，稱爲直接還 原。在增加該直接還原之比例時，由於在高爐內，進行焦 炭消耗量之增加以及焦炭之脆弱化（weakening )等，而 使得高爐作業，變得不穩定。因此，增加間接還原率係成 爲對於高爐作業成績提升之重要評價。 (具有粒徑分布之顆粒之高溫還原率之預測計算） 接著，假設各種粒徑分布，實際不進行高溫荷重還原 試驗，根據前述各種粒徑範圍之每一種之實測値，藉由預 測計算而求出具有各種粒徑分布之顆粒之高溫還原率（間 接還原率和直接還原率）。具體地說，具有前述假設之粒 徑分布之顆粒之高溫還原率（間接還原率和直接還原率） 係藉由以存在於前述假設之粒徑分布之各種粒徑範圍之顆 粒之質量比例，對於前述各種粒徑範圍之每一種之高溫還 原率（間接還原率和直接還原率）之實測値，進行加重平 均而求出高溫還原率。 將前述預測計算之結果，顯示於表3。此外，在同一 表，正如前面之敘述，4mm未滿（-4mm)者係藉由高爐 前之篩網而進行除去，並無裝入至高爐，因此，除去4mm 未滿（-4mm )以外，對於殘留之粒徑範圍，進行加重平 -16- 200925289 均而算出高溫還原率（間接還原率和直接還原率）。此外 ，顆粒平均粒徑係以存在於各種粒徑範圍之顆粒之質量比 •例，對於各種粒徑範圍之平均直徑（代表直徑）進行加重 平均而求出之値。 由表3而得知：比起平均粒徑位處於本發明之規定範 圍內且4mm以上、8mm未滿（4〜8mm)和15mm以上、 2 0mm未滿（15〜20mm )之比例超過本發明之規定範圍之 U No.l及Νο·2之比較例，當然平均粒徑位處於本發明之規 定範圍內且4mm以上、8mm未滿（4〜8mm)和15mm以 上、20mm未滿（15〜20mm )之比例也位處於本發明之規 定範圍內之發明例係即使是在1〇〇〇〜1 2 00 °C之任何一種溫 度，也使得間接還原率變高1〜2%程度，並且，直接還原 率也降低大約3%程度。 可以由該結果而確認：藉由不僅是單滿足先前技術（ 專利文獻1、2)所規定之成分組成，並且，粒徑分布也成 © 爲本發明之規定範圍，而可以明確地改善自熔性顆粒之高 溫之被還原性。 -17- 200925289200925289 IX. Description of the Invention [Technical Field] The present invention relates to a self fluxing particle (hereinafter, simply referred to as "particle") used as a raw material for iron for blast furnace, and a method for producing the same, and particularly A self-fluxing granule suitable for blowing a large amount of pulverized coal and a method for producing the same 〇 [Prior Art] The inventor of the present invention was started from about 1970 to around 1980, and completed. By investing in the development of a recombination technique using self-fluxing particles as a raw material for blast furnace iron, burning iron ore will be combined with limestone and dolomite as CaO and MgO sources and 〇3〇/ The 8102 mass ratio is 〇8 or more, and the Mg0/SiO2 mass ratio is 0.4 or more. The raw material is pelletized raw pellets and the high temperature is self-melting with good reducibility. Technology of the granules ('self-fluxing dolomite granules) (refer to Patent Documents 1, 2). On the other hand, the present inventors developed the recombination technology of the self-fluxing particles in parallel, and promoted the development of the charge distribution control technology of the blast furnace, and completed the epoch-making improvement of the ventilation in the blast furnace. Center loading technique (refer to Non-Patent Document 1). By the use of the aforementioned self-fluxing dolomite particles and the application of the coke center loading technique, even in the case of multi-component blast furnace granules, a large amount of micronized carbon can be blown in, and the inventor of the present invention can be stably operated. In the third blast furnace of the Steel Works Institute-5-200925289, the full particle operation technique was achieved (refer to Non-Patent Document 2). However, in order to cope with the rapid increase in the demand for steel in recent years, the further increase in the production of pig iron is required, and the increase in the productivity of the blast furnace and the increase in the production of pellets for the raw materials for the blast furnace have become a problem of urgent. In order to improve the productivity of the blast furnace, it is necessary to further improve the ventilation in the blast furnace. On the other hand, the granules are produced by a grate kiln method or a straight grate method, but in order to increase the granules, it is necessary to improve them in any way. The air permeability of the granular layer on the grid. As means for improving the air permeability in the blast furnace together with the air permeability of the granular layer on the grid, it is considered that the average particle diameter of the particles is increased. However, the increase in the average particle diameter of the particles reduces the reducibility of the particles (refer to Non-Patent Document 3), and therefore, there is a problem that the ratio of direct reduction in the blast furnace is increased to increase the ratio of the raw material. In addition, it is considered that the particle size distribution of the particles is narrowed as much as possible, and the particle size of the particles is made uniform as much as possible (see Non-Patent Document 3). However, the narrowing of the particle size distribution of the particles reduces the yield ratio of the particles and increases the manufacturing cost of the particles. Therefore, the conventional system is hardly reviewed, and is more suitable for the infiltration of fine powder carbon in recent years. The particle size distribution of the self-fluxing dolomite particles in the blast furnace operation under the conditions of high productivity is unknown [Non-Patent Document 1] Matsui, "The company's blast furnace operation technology 200925289 progress and as the center of the coke center loading method Flow Operation Thoughts,: R & D Kobe Steel Technical Bulletin, Vol. 55, No. 2, September 2, 5, September, p. 9 to 17 [Non-Patent Document 2] Dasan, "For Kobe 3 Transfer of full-granule operation of blast furnace: (full-granular operation of Kobe 3 blast furnace - 1)", materials and processes, Volume 15, No. 1, March 1, 2002, p.129~13〇 [Non Patent Document 3] edited by Sakamoto Steel Association, "Steel Handbook (Vol. 2), Steel, Steel," 3rd Edition, Nine-Cho Corporation, Japan, October 15, 2014, p. 158 [Patent Document 1 Japanese Patent Publication No. 3-77853 [Patent Document 2] GENERAL 3 - 77854 SUMMARY OF THE INVENTION [Problems to be Solved by the Invention] Accordingly, it is an object of the present invention to provide an improved ventilating property of a blast furnace to improve productivity while improving granules on a grid during manufacture of granules. Self-fluxing particles which increase the permeability of the layer to increase the particle size and a method for producing the same. [Means for Solving the Problem] The present invention is a self-fluxing particle for a blast furnace, characterized in that the mass ratio of Ca0/SiO 2 is 0.8 or more, the mass ratio of Mg0/SiO 2 is 0.4 or more, and the average particle diameter is 10 to 13 mm. Further, the particle size distribution is 7 mm or more, 8 mm or less, 8 mm or less, 15 mm or more, and 760 mass % or less. In addition, the present invention is a method for producing a self-fluxing granule for a blast furnace, which is characterized in that the iron ore is blended with a raw material containing CaO and MgO to adjust the mass ratio of Ca0/SiO2 to 0.8 or more, and MgO/Si〇 2 a mixing step of a raw material having a mass ratio of 0.4 or more; a granulation step of granulating the raw material to form a raw particle having a predetermined particle size distribution; and 'heating and firing the green granule at 1220 to 1 300 ° C When the average particle diameter is 133 mm or less, the particle diameter is 4 mm or more, the 8 mm is less than 6% by mass, the particle diameter is 15 mm or more, the 20 mm is less than 7 mass%, and the average particle diameter is 1 〇 to 1 3 mm. A firing step of self-fluxing particles of a particle size distribution. [Effects of the Invention] According to the present invention, it is possible to uniformize the particle diameter of the particles by limiting the ratio of the small particle diameter portion and the large particle diameter portion of the self-fluxing particles to a predetermined ratio or less. Even in the operation of blowing a large amount of micronized carbon, the air permeability in the blast furnace is improved, and the air permeability of the blast furnace is improved. Meanwhile, in the manufacture of the particles, the air permeability of the granular layer on the grid is improved to increase the self-fluxing particles. . As a result, it is possible to maintain the cost reduction effect caused by the infusion of a large amount of fine powder carbon into the blast furnace, and to further increase the production of pig iron. [Embodiment] [Best Embodiment of the Invention] [Structure of Self-fluxing Particles for Blast Furnace of the Present Invention] The self-fluxing particles for blast furnace of the present invention are characterized in that the Ca0/SiO 2 mass ratio of 200925289 is 0.8 or more. The mass ratio of Mg〇/Si〇2 is 0.4 or more′ and the average particle diameter is 1〇 to 13 mm, the particle diameter is 4 mm or more, the 8 mm is less than 6 mass%, the particle diameter is 15 mm or more, and the 20 mm is less than 7 mass. Particle size distribution below %. Hereinafter, each of the above-described requirements of the present invention will be described in more detail. (Composition of slag) Since the mass ratio of Ca0/SiO2 and the mass ratio of Mg0/SiO2 of the composition of the slag of the specified self-fluxing particles can be increased together, the predetermined enthalpy (〇.8 and 0.4) or higher can be maintained at a high temperature. The softening and melting temperature of the particles during the reduction can increase the reducibility of the high temperature. The Ca0/Si〇2 mass ratio is preferably 1. 〇 or more, or even 1.2 or more, particularly 1/4 or more. Further, the mass ratio of MgO/Si〇2 is preferably 〇·5 or more, or even 〇.6 or more, particularly 0.7 or more. However, when the mass ratio of CaO/Si〇2 and the mass ratio of MgO/SiO2 are excessively increased, the Ca0 and Mg〇 components are not easily vitrified when the particles are fired, and the strength of the calcined particles is lowered. Increasing the amount of limestone and dolomite used as a source of CaO and MgO increases the cost. Therefore, the CaO/Si〇2 mass ratio is preferably 2.0 or less, or even 1.8 or less, particularly 1.6 or less, and the MgO/SiO 2 mass ratio is It is preferably 1.1 or less, or even 1.0 or less, particularly 〇·9 or less. (particle size distribution) When the average particle size of the self-fluxing particles is excessively small, the reducibility becomes -9-200925289, and the ore layer in the blast furnace and the granular layer on the grid all reduce the air permeability. On the other hand, when it is excessively large, the ore layer in the blast furnace and the granular layer on the grid improve the air permeability and reduce the reducibility. Therefore, the average particle diameter of the self-fluxing particles is in the range of 1 〇 to 13 mm, preferably in the range of 11 to 12 mm. Then, even if the average particle diameter satisfies the predetermined range (10 to 13 mm, preferably 11 to 12 mm), the ratio of the particles having a small particle diameter of 4 mm or more and 8 mm or less and the particle diameter of 15 mm or more are increased. When the ratio of the particles of the large particle size of 20 mm is insufficient, the particle size distribution of the particles is enlarged, the filling of the particles becomes dense, and the layer porosity is lowered, and therefore, the ore layer in the blast furnace and the particles on the grid Both layers reduce ventilation. In addition, when the ratio of the particles having a small particle diameter of 4 mm or more and 8 mm or less is increased, when the ore containing the particles is charged into the blast furnace, the small-sized particles penetrate into the bottom of the ore layer and sneak into the coke. Up to the level (Reference: Matsui, "Important phenomena and control of reaching the blast furnace operating limit", materials and processes, Japan Iron and Steel Association, September 1, 2003, Vol. 16, No. 16, p .764~767), to reduce the aeration of the coke layer or to deteriorate the coke when the particles of the small particles are melted in the lower part of the furnace. Therefore, the ratio of the particles having a small particle diameter of 4 mm or more and 8 mm or less is 6% by mass or less, preferably 4% by mass or less, more preferably 2% by mass or less, and the particle diameter is 15 mm or more and 2 mm or less. The ratio of the particles having a large particle diameter is 7 mass%/〇 or less, preferably 5% by mass or less, and more preferably 3% by mass or less. -10 - 200925289 The above-mentioned self-fluxing particles satisfying the slag composition and the particle size distribution are excellent in the reduction property at a high temperature, and at the same time, improve the air permeability of the ore layer in the furnace and the granular layer on the grid, and therefore, By using the granules, it is possible to maintain or even reduce the reduction ratio of the blast furnace, and to improve productivity, and at the same time, it is possible to increase the production of granules. [Method for Producing Self-Fusing Particles for Blast Furnace of the Present Invention] The above-described self-fluxing particles for blast furnace of the present invention can be produced, for example, as follows. (Materials mixing step) The iron ore (particle feed) to be an iron raw material is blended with limestone and dolomite as an auxiliary material containing CaO and MgO, and the Ca0/SiO2 mass ratio is adjusted to 0.8 or more. Preferably, it is 1.0 or more, more preferably 1.2 or more, and particularly preferably 1.4 or more), and the mass ratio of MgO/Si〇2 is 〇·4 or more (preferably 〇.5 or more, more preferably 0.6 or more, particularly preferably 0.7 or more). The iron ore and the auxiliary material are pulverized by a ball mill or the like before or after the mixing, and the particle size of the raw material is 44 μm or less and 80% by mass or more. (granulation step) An appropriate amount of water is added to the blended raw material, and granulation is carried out by using a pan pelletizer or a drum pelletizer as a granulator to form green pellets. Particle size distribution of raw particles -11 - 200925289 Considering the shrinkage caused by the firing of the latter stage, the particle size distribution of the self-fluxing particles after firing (the target particle size satisfying the particle size distribution specified by the present invention) Distribution) The particle size distribution in which the average particle diameter is shifted to the slightly larger side is set. Further, the amount of shrinkage of the particle diameter due to the firing of the succeeding portion is about 0.5 to 1 mm in terms of the average diameter. The particle size distribution of the green particles can be set by adjusting the sieve opening of the seed sieve of the particle size of the specified lower limit (that is, adding the displacement portion at 1 〇 mm) and the particle size of the specified upper limit of 0 (also It is easy to carry out by adding the sieve of the oversized screen to the displaced portion at 13 mm. It can still be directly returned to the granulator by the seed sieve of the seed sieve, while the over sieve of the oversize screen is crushed and returned to the granulator without lowering. The raw material yield (manufacturing yield) gives the desired particle size distribution. In addition, in order to obtain the particle size distribution of the particles after firing as specified in the present invention, it is necessary to increase the mesh size of the seed sieve, and to reduce the size of the mesh of the oversized screen, which inevitably results in a granulator. The amount of recovery is increased by φ, so that the production capacity of the pellets per granulator is lowered, and as a result, it is necessary to enhance or increase the state of the granulator. (Burning step) The green particles having a predetermined particle size distribution as described above are distributed on the moving grid of the grid kiln or the direct grid as a firing device, and are distributed in the particle layer. High temperature gas, after various stages of drying, leaving water (only required) and preheating, in the former, in the rotary kiln, in the latter, still directly on the moving grid, to 12-20~1300 °c -12 - 200925289 The temperature at which the high-temperature gas is heated and calcined to obtain self-melting can be adjusted in accordance with the I mass ratio of the iron ore used, the MgO/SiO 2 mass ratio, and the like. The composition of the obtained self-fluxing particle slag satisfies the Ca0/SiO2 mass ratio and the Mg0/SiO2 mass ratio, and is similarly heated and fired to start shrinking from the green particles, and is displaced from the cloth to the side having a slightly smaller average particle diameter. The degree of distribution is such that the particle size distribution specified in the present invention is satisfied. The present invention can be easily fabricated by using the existing equipment and increasing or increasing the cost of equipment for granulating only in a necessary state. [Examples] In order to verify the self-fluxing particles of the present invention Therefore, as shown in the following description, a high-temperature load reduction test for each of the various particle size ranges is determined in various particle sizes to satisfy the molten particles of the components specified in the present invention, and the measurement is used to evaluate the high temperature. The reduction rate (the high-temperature reduction rate of the particles having various particle size distributions [high-temperature load reduction test] particles is described later in the high-temperature reduction of each of the various particle size ranges. Or the temperature range of Ca0/Si02, as defined by the invention, is set by the particle factory of the above-mentioned target particles in the particle size of the high-temperature raw particles, without causing self-fluxing particles. The effect, the range of each, the real machine of the composition, the general name of the high temperature rate of the reduction of the reduction, the rate of the actual measurement, into Forecast calculation. -13- 200925289 The self-fluxing granules used as the actual machine are self-fluxing dolomite granules manufactured by the granule factory in the applicant's Kakogawa Steel Works. The components are composed and shown in Table 1. "T.Fe" in Table 1 indicates total Fe, not only the Fe portion of FeO of Table 1, but also the Fe portion of Fe203 or the like [Table 1] Self-fluxing dolomite particle component α ff amount %) CaO /Si02 Mass ratio Mg〇/SiO2 Mass ratio T.Fe FeO Si02 CaO AI2O3 MgO 61.9 0.61 2.90 3.79 1.28 2.28 1.31 0.79 (Measurement of high temperature reduction rate of particles in various particle size ranges) With mesh holes of 20 mm, 15 mm, 12 mm, The sieves were screened for each of 10 mm, 8 mm, and 4 mm. In the granules, particles of more than 20 mm were not originally present, and the granules which were less than 4 mm were removed by the screen immediately before being charged into the blast furnace, and then charged into the blast furnace. Then, a high-temperature load reduction test was first carried out for each of the particle sizes of 4 to 8 mm, 8 to 10 mm, 1 〇 to 12 mm, 12 to 15 mm, and 15 to 20 mm which were obtained by the above-mentioned screening. Further, for example, the expression "4 to 8 mm" indicates "4 mm or more and 8 mm is not full". Here, the high-temperature load reduction test is as shown in the following test conditions. 'In the graphite crucible, the sample is filled with a certain amount of load, a certain load is applied, and under the temperature rising condition, the reducing gas is circulated. Calculated by exhaust gas analysis at 1000t, 1100°c and 1200. ": The reduction rate (indirect reduction rate) of each temperature arrival time point and the time point from the rapid rise of the pressure loss of the filling material from the sample #-14- 200925289 to the end of the test (the end time of the shrinkage of the sample filling layer) The reduction rate (direct reduction rate) up to the end is evaluated by the reduction rate of the high temperature. [Test conditions for high-temperature load reduction test] • Graphite crucible inner diameter: 43 mm • Sample amount: approximately 87 g (charge height: approximately 33.5 mm). Load: 1. Okgf/cm2 (= 9.80665xl04Pa) • Temperature: [room temperature — 1 000°C]xl0°C/min, [1 000°C—end of melting] X 5 °C /min • Reduction gas: [30 vol% CO + 70 vol% N2] x 7.2 NL / min The results are shown in Table 2 and Figures 1 and 2. [Table 2] Particle size (mm) Range 4-8 8-10 10-12 12-15 15-20 Average 6 9 11 13.5 17.5 Indirect reduction rate (%) 1000. . 52 44 40 33.8 25 1100. . 68 56 53 46 38 1200°c 75 70 65 60 54 Direct reduction rate (%) 12 18.6 25 31.4 41.1 As shown in Table 2 and Figures 1 and 2, it is known that the larger the particle size, the more the reduction is reduced. Rate, increase the direct reduction rate. The productivity of the blast furnace is evaluated by the indirect reduction rate and the direct reduction rate for the following reasons. The raw materials (particles, burnt ores, etc.) charged from the upper part of the blast furnace are reduced by the CO gas generated in the lower part of the blast furnace, and -15-200925289 is simultaneously lowered in the blast furnace. The reduction at this time is called indirect reduction. If the ratio of the indirect reduction to the reduction as a whole can be increased, a direct reaction of a portion of the molten charge and coke is reduced in the lower portion of the furnace. This direct reaction is obtained by the reaction of FeO+C=Fe+CO-Akcal to take heat. The reduction caused by such a reaction is called direct reduction. When the ratio of the direct reduction is increased, the increase in coke consumption and the weakening of coke in the blast furnace cause the blast furnace operation to become unstable. Therefore, increasing the indirect reduction rate is an important evaluation for the improvement of the blast furnace operation. (Predictive calculation of high-temperature reduction rate of particles having a particle size distribution) Next, assuming various particle size distributions, the high-temperature load reduction test is not actually performed, and the actual measurement 値 according to each of the above various particle size ranges is obtained by predictive calculation. The high temperature reduction rate (indirect reduction rate and direct reduction rate) of particles having various particle size distributions. Specifically, the high-temperature reduction ratio (indirect reduction ratio and direct reduction ratio) of the particles having the aforementioned particle size distribution is determined by the mass ratio of the particles in various particle diameter ranges existing in the above-mentioned assumed particle size distribution. The high-temperature reduction rate (indirect reduction rate and direct reduction rate) of each of the above various particle diameter ranges was measured and averaged to obtain a high-temperature reduction rate. The results of the aforementioned prediction calculations are shown in Table 3. In addition, in the same table, as described above, 4mm underfill (-4mm) is removed by the screen in front of the blast furnace, and is not loaded into the blast furnace. Therefore, except for 4mm less than (-4mm), For the residual particle size range, the high-temperature reduction rate (indirect reduction rate and direct reduction rate) was calculated by weighting the average -16-200925289. Further, the average particle diameter of the particles is obtained by weighting and averaging the average diameter (representative diameter) of the various particle diameter ranges in the mass ratio of the particles existing in various particle diameter ranges. It is known from Table 3 that the ratio of the average particle diameter is within the range specified by the present invention and that the ratio of 4 mm or more, 8 mm is less than (4 to 8 mm), 15 mm or more, and 20 mm is less than (15 to 20 mm) exceeds the present invention. In the comparative examples of U No. 1 and Νο. 2 in the predetermined range, the average particle size is within the range specified by the present invention and is 4 mm or more, 8 mm or less (4 to 8 mm), and 15 mm or more and 20 mm or less (15~). Inventive examples in which the ratio of 20 mm) is also within the range specified by the present invention makes the indirect reduction rate 1 to 2% higher even at any temperature of 1 Torr to 1 00 ° C, and The direct reduction rate is also reduced by about 3%. It can be confirmed from the results that the composition of the components specified in the prior art (Patent Documents 1 and 2) is not only singularly satisfied, and the particle size distribution is also within the prescribed range of the present invention, and the self-melting can be clearly improved. The high temperature of the particles is reduced. -17- 200925289
直接 還原率 (%) 29.9 30.3 27.3 1200。。 64.8 65.3 66.5 it m 鹏 逝 酲 1100。。 50.9 51.3 1 53.0 1000°C 36.5 36.3 38.5 平均 粒徑 (mm) 12.16 12.29 11.50 粒之粒徑分布(質量％) 15-20mm [17.5mm] 11.2 CN (Ν 12-15mm [13.5mm] 46.3 46.7 1 31.3 10-12mm [11mm] 25.2 24.4 47.7 8-10mm [9mm] οό 17.2 顒 4-8mm [6mm] 寸 -4mm [2mm] 卜 (N Η 粒徑範圍 [平均] 比較例 比較例 發明例 6 CN m -18- 200925289Direct reduction rate (%) 29.9 30.3 27.3 1200. . 64.8 65.3 66.5 it m Peng died 酲 1100. . 50.9 51.3 1 53.0 1000°C 36.5 36.3 38.5 Average particle size (mm) 12.16 12.29 11.50 Particle size distribution (% by mass) 15-20mm [17.5mm] 11.2 CN (Ν 12-15mm [13.5mm] 46.3 46.7 1 31.3 10-12mm [11mm] 25.2 24.4 47.7 8-10mm [9mm] οό 17.2 颙4-8mm [6mm] inch-4mm [2mm] 卜 (N Η particle size range [average] Comparative example Comparative example invention example 6 CN m - 18- 200925289
【圖式簡單說明】 圖1係顯示高溫荷重還原試驗之顆粒平均粒徑和間接 還原率之關係之曲線圖。 圖2係顯示高溫荷重還原試驗之顆粒平均粒徑和直接 還原率之關係之曲線圖。 -19-BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the relationship between the average particle diameter of particles and the indirect reduction rate in a high-temperature load reduction test. Fig. 2 is a graph showing the relationship between the average particle diameter of the particles and the direct reduction rate in the high-temperature load reduction test. -19-