579391 A7 五、發明說明（I ) 本發明係有關於一種於電爐中生產液態熔煉鐵的方法 0 (請先閱讀背面之注意事項再填寫本頁) 在過去多年來已花費相當多的努力在發展還原/冶煉的 方法，以取代鼓風爐來生產液態熔煉鐵，特別是對於少量 產能的機構，並避免材料的製備，換言之，直接使用粉礦 和木炭。此類型的方法引人注目，因爲在基本上’相關之 昂貴設備的投資，如生產焦炭之設備及使礦石結塊的設備 均可省略。 直接還原方法（不需經由液態）使用木炭爲還原劑是 最經濟的，特別是對於沒有天然氣源的國家。然而，這些 方法的缺點是它們所生產的預還原鐵礦具有高的硫含量（ 0.3-0.6 wt·%硫）。 -線· 在這些方法中，那些使用微粒狀礦石（流體床或多重 爐床爐子技術）特別令人感興趣，因爲它們包含最少麻煩 的礦石形式。顆粒狀的預還原鐵礦亦可以粉狀的型態獲得 ’毫無困難的用於電子爐來生產鋼，使用冷或低溫（<3〇〇 °C )鼓風注入製程。 但大量使用此類型的預還原鐵礦顆粒以電爐來生產鋼 有兩個問題：一爲其引進大量的硫，且於電爐生產鋼之氧 化冶金環境下無法被消除；另一爲降低電爐的產率，因爲 它們從冷的環境下還原-冶煉，較從最初的原料（廢鐵^ 消耗更多的能量。這導致能源的過度耗損，其結果就曰 率的降低。 ， Ρ ’、疋產 這些缺點可用生產熔煉鐵取代鋼來加以避免。 畢*貫上 4 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 579391 A7 __ B7 _____ 五、發明說明（>) (請先閱讀背面之注意事項再填寫本頁) ，在大約1000°C下藉由從還原爐將預還原鐵礦顆粒（預還 原粉末）直接導入電爐來生產熔煉鐵，可將硫除去。且預 還原鐵礦顆粒於lOOOt下導入爐內可大量降低冶煉所需之 能量。熔煉鐵的生產需要還原介質來降低硫的含量將近90 %。藉由製造適合的礦渣，可獲得硫含量爲0.03-0.06%的 熔煉鐵，其爲達到標準等級的熔煉鐵，可使用於所有熔煉 鐵之傳統用途，特別是可用於當作以電爐生產純鐵之用。 所有的缺點都是正確的，特別是浪費在粉礦型式的還 原處理上，其總是使得預還原鐵礦含有很高的硫含量。在 後續的敘述中，“金屬粉礦”意謂著所有含部份氧化金屬 鐵之型式的產物。金屬粉礦代表鐵礦顆粒、所有型式之含 有部份氧化鐵之廢棄顆粒及特別是鼓風爐和電爐過濾器中 之粉狀顆粒、硏磨成片狀或顆粒狀（再加熱或滾軋所形成 之氧化鐵）、滾軋或機械加工的屑等等。 -線. 本型式用來生產熔煉鐵的細金屬顆粒之冶煉是在傳統 的電阻加熱熔渣爐中完成，其亦被誤稱爲潛弧爐（SAF) 。通常將粉礦藉由重力來導入此種型式的冷電爐。，然而 此種型式的電爐有功率上的限制。事實上，潛弧爐（SAF )之功率密度（表示爲MW/m2)較非電弧爐低約五分之一 。爲了獲得相當的產能水準，必須使用具有較一座電弧爐 的直徑大兩倍的潛弧爐。 除此之外，在電弧爐中，非噴射細分材料的冶煉導致 形成堆積，通常稱爲內襯（linings)或狹道（berms),並 粘附在爐壁上。本現象亦會發生在細的磨碎廢料、車製、 5 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） " - 579391 A7 ----—----- B7 _ 五、發明說明（巧） 碾磨上等等。 (請先閱讀背面之注意事項再填寫本頁) 過度使用這些材料會阻塞部份容器（vessel)的容積， 將阻礙正確的導引廢金屬，且操作者必須定期的將爐子適 當地過度加熱來完成清除熔煉鐵，此即爲能量產量損失的 原因°因此’若以重力方式將預還原金屬粉礦導入電爐， 而不需採取任何預防措施，則無可避免的將加速形成內襯 〇 丨線· 在正常操作電弧爐的情況下，使用泡沬化的熔渣。在 傳統廢金屬的冶煉中，泡沬化的熔渣的獲得是同時將碳及 氧氣以鼓風吹入’以於熔渣中形成一氧化碳氣體。當使用 的預還原材料富含碳（>2%碳）時，泡沬化的熔渣將自發 的形成’因爲預還原鐵礦同時提供氧氣及碳。而泡沬化的 熔渣具有低密度及隔絕熱的特性，其變成一種防止預還原 粉礦溶解的障礙物。預還原粉礦掉入熔渣中並快速聚集， 形成一個固體塊，因爲它不很緻密，並使內襯於牆壁形成 ，造成冶煉難以進行。 爲生產熔煉鐵，必需使用碳。碳可單獨投入，但較佳 的方法（以較經濟的方式）爲製造含有過量碳的預還原鐵 礦。過量的碳可以低的比率與鐵結合。然而，當生產含有 5-10%碳之預還原粉礦來製造熔煉鐵時，此碳將與自由碳 的顆粒相一致。不幸地，自由碳很難導入金屬中，除非它 被注射入熔融液中。事實上，無電弧爐（不像潛弧爐，其 實際的功能並非電弧，而是電阻加熱）在一個主要爲氧化 的氣氛中操作，其中碳的氧化將非常快速。若無採用特別 6 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公楚^ "〜 579391 A7 __B7_____ 五、發明說明（(|> ) 的預防措施，該未注射入的碳大部份將於瓦斯中消失，那 麼金屬將變得缺乏碳，而因此得到鋼。 (請先閱讀背面之注意事項再填寫本頁) 一個最佳化方法的優點在於從顆粒狀之預還原金屬粉 礦直接於電爐中生產熔煉鐵。 本發明的目的在於提出一個生產熔煉鐵的最佳化方法 Ο 依據本發明，該目的的達成是於電弧爐中生產液態熔 煉鐵，該電弧爐包括電極、配備一個爐床及包含一個由非 泡沫化之液態熔渣所覆蓋之底部（HEEL)。本方法包含下 列階段： a) 還原金屬粉礦，以形成包含過量自由碳之預還原金 屬粉礦。 b) 在惰性氣體的保護下，將預還原金屬粉礦之熱轉換 導入含有底部之電弧爐中。 _線· c) 以氣體攪動底部，此種方法可避免於表面形成硬殻 〇 d) 於電弧爐中將預還原金屬粉礦予以熔煉，以獲得液 態熔煉鐵。 該方法若用於非電弧爐則變爲一種很特殊的方法，包 括導入熱的預還原金屬粉礦（較佳爲直接在還原爐出口， 換言之，在溫度大於500°C下，及在一個特別的較佳實施 例中，其溫度介於800和1000°C之間），及在熔煉鐵的底 部覆蓋一層非泡沬狀的液態熔渣下實施。底部可以經由爐 床，以一個或多個長矛（lances)注入中性氣體（如氮氣、 7 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 579391 A7 ____B7_____— 一 f 五、發明說明（f ) 氬氣）及/或藉由注入含有氧氣的氣體來攪動。 很激烈的攪動可使金屬+熔渣熔液的溫度分布均勻’ 及更新熔渣層的表面，因此使其保持過熱並全部液化，並 有能力吸收預還原金屬粉礦而不會有固體化和形成不具滲 透性的硬殼層。 在本案例中，底部以中性或惰性氣體經由電弧爐爐床 予以攪拌，在已提出之方法中，惰性氣體流速較佳爲介於 50公升/分鐘公噸（升每分鐘每公噸於熔煉液中之液態金屬 )及150公升/分鐘公噸之間。在本發明之一特別較佳具體 實施例中，攪動速率爲介於80及120公升/分鐘公噸之間 。這些速率必須視底部的高度及注入點的數量與位置來調 整。在使用電弧爐的正常慣例中不需高的攪動速率。事實 上，以電弧爐生產鋼的傳統方法其範圍位於1至10公升/ 分鐘公噸，其僅用來使熔融液均質化及使冶金的結果及溫 度均勻。 爲保証攪動的最佳效能，金屬的底部必需有某一最小 高度，較佳的高度爲至少0.3公尺，以確保金屬熔融液活 潑的攪動。顯然地，底部最小的高度是隨著電弧爐的構造 及氣體注入裝置的位置（較佳爲多孔磚或偶數的噴嘴數） 而改變。 在本發明一特別的較佳具體實施例中，使用來注入攪 動氣體的裝置，安裝於近電弧爐爐床外側邊緣，換句話說 ，相對於熔融液底部的橫向位置。以如此的方式配置，殘 留或有向爐壁集結傾向之預還原金屬粉礦顆粒將被帶往最 _____8___ 木紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) 一aj- i線 579391 A7 __B7 _ 五、發明說明（k ) 熱、位於電極之間的中心位置。 底部的攪動以經由電弧爐爐床注入惰性氣體，或藉由 一個或多個注入口來注入含有氧氣的氣體來達成均可。使 用一種穿透的噴嘴將含有氧氣的氣體注入底部（在此之後 稱爲“主要的氧氣” （primary oxygen))，與含於熔煉鐵 中的碳反應而形成一氧化碳氣體氣泡。一氧化碳於液態金 屬中釋出而形成擾流，使得底部與熔渣的攪動更激烈。 當預還原金屬粉礦掉入爐內時，爲保護預還原金屬粉 礦，以惰性氣體的簾幕將其包覆，較適當氣體爲氮氣或氬 氣。惰性氣體的簾幕較佳爲具有環狀的形狀，其可在粉礦 到達熔渣層與底部之前，將分別被爐子進氣橫向衝走之顆 粒及預還原金屬粉礦的再氧化之可能性降至最低。較常用 來形成保護簾幕的氮氣較佳流量大約爲50 Nm3/h至200 Nm3/h，在60至100%之水準下用來保護傳輸速率大約爲 10至60 t/h之含有大約50%金屬化鐵之預還原金屬粉礦。 由這些値得到適當的成果決定於幾個因素，如爐子的構形 、粉礦掉入的高度及電弧爐中的擾流等等。 預還原金屬粉礦之較佳傳輸是在電弧爐位於電極之間 之中心區域完成。 依本發明之較佳實施例，木炭的較佳直徑爲2至20公 厘，在投入電弧爐之前，與完全還原之金屬粉礦混合。木 炭量的使用決定於預還原金屬粉礦中碳的含量。過剩的量 介於7至15%之間，較佳大約爲10%碳。以此方法，可獲 得含有3-3.5%碳、0.01-0.05%矽及0.03-0.06%硫的熔煉鐵 9 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) 丨裝 -線· 579391 A7 --___Β7__ _ 五、發明說明) ，其決定於木炭中之硫含量。 依據本發明其它較佳具體實施例，階段a)包含下列 步驟： al)金屬粉礦導入一個多重爐床的爐子，其包含數個 重疊的爐床，將其置於多重爐床之上面爐床， a2)金屬粉礦漸漸地導入較低之爐床， a3)將足夠量之碳還原劑導入一個或多個較低之爐床 來還原金屬粉礦，並保証有過量的自由碳。 a4)當加入之金屬粉礦與碳還原劑接觸後，將多重爐 床之爐子加熱以還原金屬粉礦，並藉由碳還原劑在適當的 溫度下產生氣體。 a5)藉由碳還原劑所產生之過量氣體在多重爐床中燃 燒，而產生的熱用來乾燥或預熱金屬粉礦。。 依據本發明另一較佳具體實施例，熔渣形成劑在階段 a)及/或階段b)時同時加入。這些較佳的熔渣形成劑是從 包含石灰、助熔石及氧化鎂的群組中選擇，與其之混合物 相同。 在階段a)後期之過量碳的含量介於7%至15%間是 有益的，較佳大約爲10%。 固體的碳還原劑係選自於木炭或液態或固態石油產物 。包含於碳還原劑之揮發性部份及部份的硫於多重爐床之 爐子內部時均會被消除。 部份的過量碳在階段d)期間會被消耗。 除此之外，過量自由碳於還原反應終止時可用來使熔 10 (請先閱讀背面之注意事項再填寫本頁) 訂·· ;線· 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 579391 A7 ___B7_ 五、發明說明（^) 煉鐵滲碳。 (請先閱讀背面之注意事項再填寫本頁) 依據本發明其它觀點，假如電弧能量由電弧電壓所限 制，係由於可獲得之“浸入”電弧的長度的緣故，電弧爐 的產能則可增加。 以自發性的方式輸入空氣進入電弧爐中，取代讓其“ 無用的燃燒”，並冒著金屬粉礦固體化並形成一個無法穿 透的硬殼的風險，從預還原金屬粉礦中使用過量的碳來得 到最大的能量效益，以增加電弧爐的產能是有益的。 明顯地，若某人欲增加電弧爐每小時熔煉鐵之產能， 就必須增加金屬粉礦導入電弧爐中之流動速率。而增加金 屬粉礦之流動速率亦同時增加形成硬殼的風險。 -線. 本目的是要藉由一種於上述電弧爐中生產液態熔煉鐵 方法來達到，其中包含一個或多個後燃燒矛（post-combustion lances)，其可附加一個或多個主要的氧氣注入 口-由燃燒器和及的上電弧的能源所組成。這些注射器傳 送後燃燒氣體噴出物，在一特別較佳具體實施例中，較佳 介於電極圓（circle of electrodes)上之（“電極節圓”） (“electrode pitch circle”)電弧之間。 以如此的方式配置後燃燒氣體噴出物的好處是，可將 熔渣推向電弧爐介於電極間的中心部份。其可以明顯的方 式來強化熔渣的攪動，並可使得過熱熔渣於接收金屬粉礦 的區域長久地維持劇烈攪動。在此區域過熱熔渣的高擾流 使得金屬粉礦的流動速率增加，而不會冒著形成硬殼的危 險。事實上，沒有後燃燒氣體的噴入，熔渣擾動的產生直 11 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ' 579391 A7 ____B7___ 五、發明說明) 接由藉由中性氣體經由電弧爐的爐床噴入底部，及或經由 一個或數個注射器將主要的氧氣噴入底部來造成擾動。事 實上將後燃燒氣體直接噴入熔渣層中，使得熔渣在電弧爐 中移動更易控制及定位，加速金屬粉礦的熔融，並使得未 熔融金屬粉礦黏附在爐壁上的危險降至最低。 本方法的另一個優點是兩個反應器操作的最適化。事 實上，包含過量自由碳之預還原熔融鐵的生產增加還原速 率及增加金屬化的水準。 爲了獲得過量自由碳，必需於還原階段添加適量的碳 還原劑。 過量自由碳在預還原鐵礦的另一優點在於還原反應器 的還原爐床中，其溫度非常高，因此，碳還原劑（碰巧是 木炭）被除去大部份的揮發性物質及硫。其証明在冶煉期 間，去除揮發物質的木炭比未去除揮發木炭更容易溶解於 鐵熔融液中。除此之外，當碳還原劑在還原反應器內部處 於高溫狀態時，硫的含量可大量降低。顯然在預還原鐵礦 顆粒熔融的期間，可用焦碳取代木炭以獲得較佳之碳溶解 度。然而，使用焦碳取代木炭將增加生產成本，而且無法 解決硫的問題。焦碳不包含揮發物質；然而，其包含大約 與木炭使用於生產時等量的硫。 過量的碳在融煉爐燒光，於顆粒熔煉期間可節省電能 0 碳還原劑僅可添加於多爐床爐子的上爐床，使得可使 用氣體殘餘的熱來烘乾及預熱顆粒或鐵礦，並完全燃燒一 12 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閲讀背面之注意事項再填寫本頁) 丨裝 訂· -線· 579391 A7 ____B7___ 五、發明說明（p) 氧化碳。並不需要一個分離的後燃燒階段，而且這些上爐 床的溫度愈高，則可降低自由碳中更多的硫。 (請先閱讀背面之注意事項再填寫本頁) 於本發明中未預期的優點，並未置於並列的兩個已知 方法’而是兩個方法的相互影響。 本發明其它特殊觀點及特性從下列具體實施例的優點 描述中將變得更爲淸晰，例如，在參考附錄中的略圖。其 顯不： 圖1 :依據本發明第一具體實施例生產液態熔融鐵之 電弧爐之剖面圖。 圖2:依據本發明第二具體實施例生產液態熔融鐵之 電弧爐之剖面圖。 圖3 :圖2電弧爐之平面。 圖1顯示依據本發明之第一具體實施例生產液態熔融 鐵之電弧爐之剖面示意圖。 其顯示一個電弧爐（10)包括一個容器（12)，以（ 14)覆蓋，穿過三個電極（16)。這些電極（16)，可產 生大約二十公分長的電弧及每一個功率大約爲4 MW。於 三個電極的中間（16)安裝一個裝置（18)，用來輸入預 還原金屬粉礦。該裝置（18) —方面包括一個導槽，將金 屬粉礦導入爐子（12)，另一方面，一個噴入噴嘴形成氮 氣簾幕（20)，當預還原金屬粉礦掉入爐子中時包覆在其 周圍。 預還原金屬粉礦的衝擊點(impact point)介於三個電極 (16)之間，換言之，在電弧爐（12)的最熱點。在衝擊 13 本紙張尺度適用中國國家標準（CNS)A4規格（210 x 297公釐） 579391 A7 ____B7 _ 五、發明說明q1 ) 非泡沬化熔渣（22)的瞬間浮在液態熔融液上，預還原粉 礦立刻聚集並快速熔化。 容器（12)的爐床（26)裝配數塊多孔性的磚塊（28 )，高速流動的攪動氣體（30)由此通過。藉由氣體（30 )的噴入製造擾流，穿透液態熔融液（24)，防止預還原 金屬粉礦結塊或形成硬殼。 圖2顯示依據本發明之第二具體實施例生產液態熔融 鐵之電弧爐之剖面圖。圖三爲該電弧爐之平面。 配有中心重力添料之本電弧爐（10’）安裝有三個後燃 燒矛（32)，附加三個主要的氧氣噴嘴（32，），介於電弧 (33)間，在電極圓上（“電極節圓”）組成一個具有功 率相當於電弧的燃燒器。來自於噴射器（32’）之主要氧氣 的噴出（34)是穿透噴流’且位於底部（24)。當氧氣穿 MS、液態金屬，氧氣和包含於熔融液中之碳反應，並釋放 碳氣體。一氧化碳的釋放於底部及漂浮之熔渣層產 生相當大的擾流。 胃/個後燃燒矛（32)噴出後燃燒氧氣的噴流（36) ，或二次氧氣進入熔渣層（22)。這些二次氧氣的噴流（ 36)較弱並且要的氧氣^賁流（34) &穿透力弱’丨吏得1 $自@部（24)之一氧化碳隨著主要的氧氣的注入而燃燒 。彳匕碳因此於熔渣層（22)的內部燃燒。其造成熔渣 。後燃燒氧氣的噴流（36)以如此的方式安裝（ «孤的相反方向）以便於將推動力傳輸予熔渣，以加 弓虽;的攪動，並把熔渣向後推向電弧爐的中心位置。熔 14 b氏¥_尺度適用準（CNS)A4規格（21() x 297公爱) (請先閱讀背面之注意事項再填寫本頁) t· •線· 579391 A7 _B7 五、發明說明（li) 渣的移動一方面因電弧（33)，另一方面因後燃燒氧氣噴 流所導致，以箭頭（38)表示於圖3。如此可加速預還原 粉礦的熔融，並因此防止這些粉礦結塊及推向爐壁，而黏 附於電弧爐之爐壁。 實施例1 : 已知電能，例如限制爲12MW，使用添加的自由碳及 氣體使得其= -熔融的速率至少爲金屬粉礦流動或（DRI)的速率 的兩倍； -或導入金屬化的金屬粉礦或（DRI)進入爐子，並 因此增加還原爐的產能，諸如此類技術的使用。 在多爐床爐子的案例中，每小時54或57噸DRI 60% 金屬化程度的產量，可確保爐子具有每小時50噸DRI90% 金屬化程度之生產力50%之生產力。 此外，表1最後一行顯示，添加額外自由碳形式的過 量碳於DRI中。 表1 :熔融的DRI導入l〇〇〇°C的爐子，進入含有3%碳的 熔融鐵中，隨著加熱至1500°C : DRI鐵的程 度（％) 金屬化的量 (%) DR1自由碳 (%) DRI流速（ t/h) 熔融鐵流速(_ 電能 (MW) 氧氣流速 (Nm3/h) 添加碳流速 (t/h) 80 90 8 50 40 12 0 0 80 90 8 125 100 12 3000 2.4 74 60 8 54 40 12 3600 2.6 71 60 12 57 40 12 3600 0 參考目錄 15 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） --------------裝--- (請先閲讀背面之注意事項再填寫本頁) 訂· 線- 579391 A7 五、發明說明（Γγ) 10 12 14 16 18 20 22 24 26 28 30 32 32， 33 34 36 38 電弧爐 容器 拱頂 電極 傳輸裝置 氮氣簾幕 熔渣層 液態金屬熔融液 爐床 多孔磚 惰性氣體 後燃燒矛 主要的氧氣噴射器 電弧 主要的氧氣噴流 後燃燒氧氣噴流 熔渣移動 (請先閱讀背面之注意事項再填寫本頁) 16 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐）579391 A7 V. Description of the invention (I) The present invention relates to a method for producing liquid smelted iron in an electric furnace. 0 (Please read the notes on the back before filling this page). In the past years, considerable efforts have been devoted to the development. Reduction / smelting methods to replace blast furnaces to produce liquid smelted iron, especially for institutions with small capacity, and avoid material preparation, in other words, use ore and charcoal directly. This type of method is compelling because investment in essentially 'relevant' expensive equipment, such as equipment for producing coke and equipment for agglomerating ore, can be omitted. The direct reduction method (without going through the liquid state) using charcoal as the reducing agent is the most economical, especially for countries without a natural gas source. However, these methods have the disadvantage that the pre-reduced iron ore they produce has a high sulfur content (0.3-0.6 wt ·% sulfur). -Line · Among these methods, those using particulate ore (fluid bed or multiple hearth furnace technology) are of particular interest because they contain the least troublesome ore form. Granular pre-reduced iron ore can also be obtained in powder form ’It is used in electronic furnaces to produce steel without difficulty, using cold or low temperature (<300 ° C) blast injection process. However, the use of this type of pre-reduced iron ore particles in electric furnaces to produce steel has two problems: one is to introduce a large amount of sulfur, which cannot be eliminated under the oxidative metallurgical environment of steel production by electric furnaces; the other is to reduce the production of electric furnaces. Rate, because they reduce-smelt from the cold environment, consume more energy than the original raw materials (waste iron ^). This leads to excessive energy consumption, and the result is a reduction in the rate. Disadvantages can be avoided by the production of smelted iron instead of steel. Bi * Consistently 4 paper sizes are applicable to Chinese National Standard (CNS) A4 (210 X 297 mm) 579391 A7 __ B7 _____ V. Description of the invention (>) (Please Read the precautions on the back before filling this page). At about 1000 ° C, the pre-reduced iron ore particles (pre-reduced powder) are directly introduced into the electric furnace from the reduction furnace to produce molten iron, which can remove sulfur. The introduction of iron ore particles into the furnace at 100 t can greatly reduce the energy required for smelting. The production of smelted iron requires a reducing medium to reduce the sulfur content by nearly 90%. By making suitable slag, the sulfur content can be obtained The smelting iron of 0.03-0.06%, which is to reach the standard grade of smelting iron, can be used for all traditional uses of smelting iron, especially for the production of pure iron by electric furnace. All the shortcomings are correct, In particular, it is wasted on the reduction process of the fine ore type, which always makes the pre-reduced iron ore contain a high sulfur content. In the following description, "metal fine ore" means all types containing partially oxidized metal iron. Metal ore represents iron ore particles, all types of waste particles containing some iron oxide, and especially powder particles in blast furnace and electric furnace filters, honed into flakes or granules (reheated or rolled) Iron oxide formed), rolled or machined swarf, etc. -line. This type of smelting of fine metal particles used to produce smelted iron is completed in a traditional resistance heating slag furnace, which has also been misnamed It is a submerged arc furnace (SAF). Pulverized ore is usually introduced into this type of cold electric furnace by gravity. However, this type of electric furnace has power limitations. In fact, the power density of the submerged arc furnace (SAF) ( Expressed as MW / m2) is about one-fifth lower than that of non-electric arc furnaces. In order to obtain a comparable level of production capacity, a submerged arc furnace with a diameter twice as large as that of an electric arc furnace must be used. The smelting of the sprayed fine material leads to the formation of piles, often called linings or berms, and adheres to the furnace wall. This phenomenon also occurs in finely ground waste, turning, 5 paper The scale is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) "-579391 A7 ---------------- B7 _ 5. Description of the invention (clever) Milling and so on. (Please first Read the notes on the back and fill in this page) Excessive use of these materials will block the volume of some vessels, which will prevent the correct introduction of scrap metal, and the operator must periodically overheat the furnace properly to complete the smelting Iron, which is the reason for the loss of energy production ° Therefore, 'If the pre-reduced metal powder ore is introduced into the electric furnace by gravity without taking any precautionary measures, it will inevitably accelerate the formation of the lining. When operating an electric arc furnace, Foaming of the slag with. In the smelting of traditional scrap metals, foamed slag is obtained by blowing carbon and oxygen into the blast at the same time 'to form carbon monoxide gas in the slag. When the pre-reduced material used is rich in carbon (> 2% carbon), the foamed slag will spontaneously form because the pre-reduced iron ore provides both oxygen and carbon. The foamed slag has the characteristics of low density and heat insulation, and it becomes an obstacle to prevent the dissolution of the pre-reduced fines. The pre-reduced powder ore falls into the slag and quickly aggregates to form a solid block because it is not very dense and causes the lining to form on the wall, making smelting difficult. To produce smelted iron, carbon must be used. Carbon can be invested separately, but the preferred method (in a more economical way) is to make prereduced iron ore containing excess carbon. Excess carbon can be combined with iron at a low ratio. However, when producing pre-reduced fines containing 5-10% carbon to make smelted iron, this carbon will be consistent with free carbon particles. Unfortunately, free carbon is difficult to introduce into metals unless it is injected into the melt. In fact, arc-free furnaces (unlike submerged arc furnaces, whose actual function is not electric arcing, but resistance heating) operate in a predominantly oxidizing atmosphere where the oxidation of carbon will be very rapid. If there is no special 6 paper size applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 Gongchu ^ " ~ 579391 A7 __B7_____ V. The precautionary measures of the invention description (| >), the uninjected carbon Most of it will disappear in the gas, then the metal will become lack of carbon, and thus get steel. (Please read the precautions on the back before filling this page) The advantage of an optimization method is that it reduces the metal from the granular pre-reduction The ore is directly produced in the electric furnace by smelting ore. The purpose of the present invention is to propose an optimized method for producing smelted iron. According to the present invention, this object is achieved by producing liquid smelted iron in an electric arc furnace, which includes an electrode, Equipped with a hearth and containing a bottom (HEEL) covered by non-foamed liquid slag. The method includes the following stages: a) Reduction of metal powder to form a pre-reduced metal powder containing excess free carbon. B ) Under the protection of inert gas, the heat conversion of the pre-reduced metal powder ore is introduced into the electric arc furnace containing the bottom. _Line · c) Agitate the bottom with gas. This method can avoid the formation of a hard shell on the surface. D) The pre-reduced metal ore is smelted in an electric arc furnace to obtain liquid molten iron. This method becomes a very special method if it is used in non-arc furnaces, including the introduction of hot pre-reduced metal powder (preferably directly at the outlet of the reduction furnace, in other words, at a temperature greater than 500 ° C, and in a special In a preferred embodiment, the temperature is between 800 and 1000 ° C), and the bottom of the molten iron is covered with a layer of non-foamed liquid slag. The bottom can be injected with neutral gas (such as nitrogen, 7) through the hearth with one or more lances. This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) 579391 A7 ____B7_____ — f 5. Description of the invention (f) Argon) and / or agitated by injecting a gas containing oxygen. Very intense agitation can make the temperature distribution of the metal + slag melt uniform and refresh the surface of the slag layer, so that it remains overheated and fully liquefied, and has the ability to absorb pre-reduced metal powder ores without solidification and Forms a non-permeable hard shell. In this case, the bottom is stirred by the arc furnace hearth with a neutral or inert gas. In the proposed method, the flow rate of the inert gas is preferably between 50 liters per minute metric ton (liters per minute per metric ton in the smelting liquid Liquid metal) and 150 liters per minute metric ton. In a particularly preferred embodiment of the invention, the agitation rate is between 80 and 120 liters per minute metric ton. These rates must be adjusted depending on the height of the bottom and the number and location of injection points. High agitation rates are not required in the normal practice of using electric arc furnaces. In fact, the traditional method for producing steel by electric arc furnaces, which ranges from 1 to 10 liters per minute metric ton, is only used to homogenize the melt and to make the metallurgical results and temperature uniform. In order to ensure the best performance of agitation, the bottom of the metal must have a certain minimum height, preferably at least 0.3 meters, to ensure active agitation of the molten metal. Obviously, the minimum height of the bottom varies with the configuration of the electric arc furnace and the position of the gas injection device (preferably a porous brick or an even number of nozzles). In a particularly preferred embodiment of the present invention, the device used to inject the agitating gas is installed near the outer edge of the hearth of the electric arc furnace, in other words, in a lateral position relative to the bottom of the melt. Configured in this way, residual or reduced pre-reduced metal powder ore particles that tend to build up towards the furnace wall will be brought to the most _____8___ wood paper size applicable to China National Standard (CNS) A4 (210 X 297 mm) (please first Read the notes on the back and fill out this page) AJ-I line 5739391 A7 __B7 _ V. Description of the invention (k) It is hot and located at the center between the electrodes. The agitation at the bottom can be achieved by injecting an inert gas through the electric arc hearth, or by injecting a gas containing oxygen through one or more injection ports. A penetrating nozzle is used to inject a gas containing oxygen into the bottom (hereinafter referred to as "primary oxygen"), and reacts with carbon contained in the smelted iron to form a carbon monoxide gas bubble. Carbon monoxide is released in the liquid metal to form a turbulent flow, which makes the bottom and slag agitate more intensely. When the pre-reduced metal powder ore falls into the furnace, in order to protect the pre-reduced metal powder ore, it is covered with a curtain of inert gas, and a more suitable gas is nitrogen or argon. The curtain of the inert gas preferably has a ring shape, which can re-oxidize the particles which are washed away by the furnace inlet gas and the pre-reduced metal powder ore before the powder ore reaches the slag layer and the bottom. Minimized. Nitrogen, which is more commonly used to form a protective curtain, preferably has a flow rate of about 50 Nm3 / h to 200 Nm3 / h, and is used to protect the transmission rate of about 10 to 60 t / h at a level of 60 to 100%, which contains about 50%. Pre-reduced metal powder of metalized iron. The proper results obtained from these maggots depend on several factors, such as the configuration of the furnace, the height at which the fine ore falls, and the turbulence in the electric arc furnace. The preferred transport of the pre-reduced metal powder is done in the central area of the electric arc furnace between the electrodes. According to a preferred embodiment of the present invention, the preferred diameter of the charcoal is 2 to 20 mm, and it is mixed with the fully reduced metal powder before being put into the electric arc furnace. The amount of charcoal used depends on the amount of carbon in the pre-reduced metal powder. The excess is between 7 and 15%, preferably about 10% carbon. In this way, smelted iron containing 3-3.5% carbon, 0.01-0.05% silicon, and 0.03-0.06% sulfur 9 can be obtained. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (please first Read the notes on the back and fill in this page) 丨 Installation-line · 579391 A7 --___ Β7__ _ 5. Description of the invention), it depends on the sulfur content in charcoal. According to other preferred embodiments of the present invention, stage a) includes the following steps: a) the metal powder ore is introduced into a furnace with multiple hearths, which includes several overlapping hearths, which are placed above the hearths of the multiple hearths A2) The metal powder ore is gradually introduced into the lower hearth, a3) A sufficient amount of carbon reducing agent is introduced into one or more lower hearths to reduce the metal powder ore, and an excess of free carbon is guaranteed. a4) After the added metal powder ore is brought into contact with the carbon reducing agent, the furnace of the multiple hearth is heated to reduce the metal powder ore, and the carbon reducing agent is used to generate a gas at an appropriate temperature. a5) The excess gas generated by the carbon reducing agent is burned in a multiple hearth, and the heat generated is used to dry or preheat the metal powder ore. . According to another preferred embodiment of the present invention, the slag forming agent is added at the same time in stage a) and / or stage b). These preferred slag forming agents are selected from the group consisting of lime, fused stone and magnesia, and are the same as their mixtures. It is beneficial in the late stage a) that the excess carbon content is between 7% and 15%, preferably about 10%. The solid carbon reducing agent is selected from charcoal or liquid or solid petroleum products. Both the volatile part of the carbon reducing agent and part of the sulfur are eliminated inside the furnace of the multiple hearth. Part of the excess carbon is consumed during phase d). In addition, excess free carbon can be used to melt at the end of the reduction reaction (please read the precautions on the back before filling out this page). · · · Line · This paper size applies Chinese National Standard (CNS) A4 specifications ( 210 X 297 mm) 579391 A7 ___B7_ 5. Description of the invention (^) Carburizing iron. (Please read the notes on the back before filling this page.) According to other viewpoints of the present invention, if the arc energy is limited by the arc voltage, the capacity of the arc furnace can be increased due to the length of "immersion" arc available. Input air into the electric arc furnace in a spontaneous manner, instead of letting it "uselessly burn", and risking the solidification of the metal fines and forming an impenetrable hard shell, using excessive amounts from the pre-reduced metal fines Carbon is beneficial for maximum energy efficiency to increase the capacity of the electric arc furnace. Obviously, if someone wants to increase the capacity of the electric arc furnace to melt iron per hour, it is necessary to increase the flow rate of the metal powder into the electric arc furnace. Increasing the flow rate of metal fines also increases the risk of hard crust formation. -Line. This objective is to be achieved by a method for producing liquid smelted iron in the above-mentioned electric arc furnace, which comprises one or more post-combustion lances, which can be attached with one or more main oxygen injections Inlet-Composed of burner and arcing energy. The combustion gas ejections delivered by these syringes are, in a particularly preferred embodiment, preferably between arcs on an electrode circle ("electrode pitch circle"). An advantage of the post-combustion gas ejection arrangement in this manner is that the slag can be pushed toward the center portion of the electric arc furnace between the electrodes. It can obviously strengthen the agitation of the slag, and can keep the superheated slag in the area receiving the metal powder ore vigorously and agitated for a long time. The high turbulence of the superheated slag in this area increases the flow rate of the fine metal ore without risking the formation of a hard crust. In fact, there is no injection of post-combustion gas, and the slag disturbance is generated. This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) '579391 A7 ____B7___ V. Description of the invention) Neutral gases are sprayed into the bottom via the hearth of the electric arc furnace, or the main oxygen is sprayed into the bottom via one or several syringes to cause disturbances. In fact, the post-combustion gas is directly injected into the slag layer, which makes it easier to control and locate the slag movement in the electric arc furnace, accelerates the melting of the metal powder ore, and reduces the risk of the unmelted metal powder sticking to the furnace wall. lowest. Another advantage of this method is the optimization of the operation of the two reactors. In fact, the production of pre-reduced molten iron containing excess free carbon increases the rate of reduction and increases the level of metallization. In order to obtain excess free carbon, an appropriate amount of carbon reducing agent must be added during the reduction stage. Another advantage of excess free carbon in the pre-reduced iron ore is that the temperature in the reduction hearth of the reduction reactor is very high, so the carbon reducing agent (which happens to be charcoal) is removed most of the volatile substances and sulfur. It proves that during the smelting, volatile charcoal is more easily dissolved in the molten iron than volatile charcoal. In addition, when the carbon reducing agent is in a high temperature state inside the reduction reactor, the sulfur content can be greatly reduced. Obviously, during the melting of the pre-reduced iron ore particles, coke can be used in place of charcoal to obtain better carbon solubility. However, replacing charcoal with coke will increase production costs and will not solve the problem of sulfur. Coke does not contain volatile materials; however, it contains approximately the same amount of sulfur as charcoal was used in production. Excess carbon is burned out in the melting furnace, which can save electricity during pellet smelting. 0 Carbon reducing agent can only be added to the upper hearth of the multi-hearth furnace, so that the residual heat of the gas can be used to dry and preheat the pellets or iron. Mine, and completely burned-12 This paper size is applicable to Chinese National Standard (CNS) A4 specifications (210 X 297 mm) (Please read the precautions on the back before filling this page) 丨 Binding · -Line · 579391 A7 ____B7___ V. DESCRIPTION OF THE INVENTION (p) Carbon oxide. There is no need for a separate post-combustion stage, and the higher these upper hearth temperatures, the more sulfur in free carbon can be reduced. (Please read the notes on the back before filling this page) The unexpected advantages in the present invention are not placed in the two known methods side by side 'but the mutual influence of the two methods. Other special viewpoints and characteristics of the present invention will become clearer from the description of the advantages of the following specific embodiments, for example, in the appended drawings. It shows: Fig. 1: A sectional view of an electric arc furnace for producing liquid molten iron according to a first embodiment of the present invention. Fig. 2 is a sectional view of an electric arc furnace for producing liquid molten iron according to a second embodiment of the present invention. Figure 3: Plane of Figure 2 electric arc furnace. Fig. 1 shows a schematic sectional view of an electric arc furnace for producing liquid molten iron according to a first embodiment of the present invention. It shows that an electric arc furnace (10) includes a container (12), covered with (14), and passes through three electrodes (16). These electrodes (16) can produce arcs of about twenty centimeters long and each of them has a power of about 4 MW. A device (18) is installed in the middle (16) of the three electrodes to input the pre-reduced metal fines. The device (18) includes a guide groove for introducing metal powder ore into the furnace (12), and an injection nozzle forming a nitrogen curtain (20), which is packed when the pre-reduced metal powder ore falls into the furnace. Covered around it. The impact point of the pre-reduced metal powder is between the three electrodes (16), in other words, at the hottest point of the electric arc furnace (12). At impact 13 this paper size applies the Chinese National Standard (CNS) A4 specification (210 x 297 mm) 579391 A7 ____B7 _ V. Description of the invention q1) The non-foaming slag (22) floats on the liquid melt instantly, The pre-reduced fines immediately aggregated and quickly melted. The hearth (26) of the container (12) is equipped with a plurality of porous bricks (28), and the agitation gas (30) flowing at a high speed passes therethrough. The turbulence is produced by the injection of gas (30), which penetrates the liquid molten liquid (24) to prevent the pre-reduced metal powder ore from agglomerating or forming a hard shell. Fig. 2 shows a sectional view of an electric arc furnace for producing liquid molten iron according to a second embodiment of the present invention. Figure 3 shows the plane of the electric arc furnace. The electric arc furnace (10 ') equipped with a center gravity feed is equipped with three post-combustion spears (32), plus three main oxygen nozzles (32,), between the arc (33), on the electrode circle (" The electrode pitch circle ") forms a burner with power equivalent to an arc. The main oxygen spray (34) from the ejector (32 ') is a penetrating jet' and is located at the bottom (24). When the oxygen passes through the MS, the liquid metal, the oxygen reacts with the carbon contained in the melt and releases carbon gas. The release of carbon monoxide on the bottom and the floating slag layer caused considerable turbulence. The stomach / post-combustion spear (32) ejects a jet of post-combustion oxygen (36), or secondary oxygen enters the slag layer (22). These secondary oxygen jets (36) are weaker and the required oxygen ^ stream (34) & weak penetrating power. 丨 get 1 $ from @ 部 (24) one of the carbon oxides burns with the injection of the main oxygen . The dagger carbon thus burns inside the slag layer (22). It causes slag. The post-combustion oxygen jet (36) is installed in such a way («opposite to the opposite direction) to facilitate the transmission of the propelling force to the slag to add bowing; agitation, and push the slag backwards towards the center of the arc furnace . Fusion 14 b's ¥ _ Applicable standard (CNS) A4 specifications (21 () x 297 public love) (Please read the precautions on the back before filling out this page) t · • line · 579391 A7 _B7 V. Description of the invention (li The movement of the slag is caused by the arc (33) on the one hand and the post-combustion oxygen jet on the other hand, which is shown in Fig. 3 by the arrow (38). This speeds up the melting of the pre-reduced fines and therefore prevents them from agglomerating and pushing towards the furnace wall and sticking to the furnace wall of the electric arc furnace. Example 1: Known electrical energy, for example, limited to 12MW, using free carbon and gas added so that = = the rate of melting is at least twice the rate of metal powder flow or (DRI);-or the introduction of metallized metal Fine ore (DRI) enters the furnace and therefore increases the capacity of the reduction furnace, such as the use of such technologies. In the case of a multi-hearth furnace, an output of 60% metallization of 54 or 57 tons of DRI per hour can ensure that the furnace has a productivity of 50% of DRI90% metallization and 50% productivity per hour. In addition, the last row of Table 1 shows that excess carbon in the form of additional free carbon is added to the DRI. Table 1: Melted DRI is introduced into a furnace at 1000 ° C and enters into molten iron containing 3% carbon. With heating to 1500 ° C: the degree of DRI iron (%) the amount of metallization (%) DR1 free Carbon (%) DRI flow rate (t / h) Molten iron flow rate (_ electrical energy (MW) oxygen flow rate (Nm3 / h) carbon flow rate (t / h) 80 90 8 50 40 12 0 0 80 90 8 125 100 12 3000 2.4 74 60 8 54 40 12 3600 2.6 71 60 12 57 40 12 3600 0 Reference list 15 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) ----------- --- Install --- (Please read the precautions on the back before filling this page) Order and line-579391 A7 V. Description of the invention (Γγ) 10 12 14 16 18 20 22 24 26 28 30 32 32, 33 34 36 38 Arc furnace vessel dome electrode transfer device Nitrogen curtain slag layer Liquid metal molten liquid hearth Porous brick Inert gas After burning spear Main oxygen injector Arc After main oxygen jet After burning oxygen jet slag movement (please read the back first (Please note this page before filling out this page) 16 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)