page_title: Blast furnace
section_title: Modern process
hierarchical_section_title: Blast furnace / Modern process
caption_attribution_description: English: Blast furnace 1: Iron ore + Calcareous sinter 2: coke 3: conveyor belt 4: feeding opening, with a valve that prevents direct contact with the internal parts of the furnace 5: Layer of coke 6: Layers of sinter, iron oxide pellets, ore, 7: Hot air (around 1200°C) 8: Slag 9: Liquid pig iron 10: Mixers 11: Tap for pig iron 12: Dust cyclon for removing dust from exhaust gasses before burning them in 13 13: air heater 14: Smoke outlet (can be redirected to carbon capture &amp; storage (CCS) tank) 15: feed air for Cowper air heaters 16: Powdered coal 17: cokes oven 18: cokes bin 19: pipes for blast furnace gas This technology image could be recreated using vector graphics as an SVG file. This has several advantages; see&#160;Commons:Media for cleanup for more information. If&#160;an&#160;SVG&#160;form&#160;of&#160;this&#160;image is available, please upload it and afterwards replace this template with {{vector version available|new image name}}. Français&#160;: haut fourneau 1&#160;: minerai de fer + calcine 2&#160;: coke 3&#160;: convoyeur à bande 4&#160;: gueulard, muni d'une valve évitant l'entrée d'air extérieur 5&#160;: couche de coke 6&#160;: couche de calcine + minerai 7&#160;: air chaud (environ 1&#160;200°C) 8&#160;: laitier 9&#160;: fonte brute liquide 10&#160;: réservoir pour le laitier 11&#160;: réservoir pour la fonte 12&#160;: cyclone pour dépoussiérer des gaz d'échappement 13&#160;: tour de préchauffage de l'air (Cowpers) 14&#160;: cheminée (peut être redirigé vers un réservoir de stockage du CO2) 15&#160;: entrée d'air 16&#160;: charbon 17&#160;: four à coke 18&#160;: soute à charbon 19&#160;: tuyaux de collecte du gaz de haut fourneau Русский: Доменная печь 1&#160;: железная руда + известняк 2&#160;: кокс 3&#160;: лента конвейера 4&#160;: колошник с аппаратом, предотвращающим уход доменного газа в атмосферу 5&#160;: слой кокса 6&#160;: слои известняка, оксида железа, руды 7&#160;: горячий воздух (с температурой около 1200°C) 8&#160;: шлак 9&#160;: жидкий передельный чугун 10&#160;: шлаковый ковш 11&#160;: чугуновоз 12&#160;: циклон для очистки доменного газа от пыли перед сжиганием его в регенераторах 13 13&#160;: регенераторы (кауперы) 14&#160;: дымовая труба 15&#160;: подача воздуха в регенераторы (кауперы) 16&#160;: порошок угля 17&#160;: коксовая печь 18&#160;: резервуар для кокса 19&#160;: газоотвод для горячего колошникового газа 中文: 高爐 1&#160;: 燒結礦、石灰石 2&#160;: 石炭 3&#160;: 輸送帶 4&#160;: 投入口 5&#160;: 燒結礦、礦石、石灰石 6&#160;: 石炭 7&#160;: 熱風管 8&#160;: 礦渣 9&#160;: 溶銑 10&#160;: 礦渣車 11&#160;: 混洗車 12&#160;: 氣體分離器 13&#160;: 熱風爐 14&#160;: 煙囪 15&#160;: 冷風 16&#160;: 微粉炭 17&#160;: 粉碎機 18&#160;: 分配器 19&#160;: tuyaux de collecte du gaz de haut fourneau עברית: תנור רם 1: עופרת ברזל ואבן גיר מרוסקת 2: קוק 3: מסוע 4: פתח הזנה, עם שסתום המונע מעבר ישיר לחלל התנור 5: שכבת קוק 6: שכבה של עפרת ברזל ואבן גיר מרוסקת 7: אוויר חם (1200 מעלות לערך) 8: סיגים 9: ברזל גולמי נוזל 10: מערבלים 11: פתח ניקוז ברזל גולמי 12: ציקלון לניקוי חלקיקים מן הגזים החמים בטרם בעירתם ב-13 13: מחמם אוויר 14: פתח פליטת עשן 15: הזנת אוויר חם מתנורי קאופר 16: אבקת פחם 17: תנור קוק 18: אכסון קוק 19: צנרת גזים חמים
context_page_description: A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. Blast refers to the combustion air being "forced" or supplied above atmospheric pressure.
  In a blast furnace, fuel, ores, and flux are continuously supplied through the top of the furnace, while a hot blast of air is blown into the lower section of the furnace through a series of pipes called tuyeres, so that the chemical reactions take place throughout the furnace as the material falls downward. The end products are usually molten metal and slag phases tapped from the bottom, and waste gases exiting from the top of the furnace. The downward flow of the ore along with the flux in contact with an upflow of hot, carbon monoxide-rich combustion gases is a countercurrent exchange and chemical reaction process.
  In contrast, air furnaces are naturally aspirated, usually by the convection of hot gases in a chimney flue. According to this broad definition, bloomeries for iron, blowing houses for tin, and smelt mills for lead would be classified as blast furnaces.
context_section_description: Modern furnaces are equipped with an array of supporting facilities to increase efficiency, such as ore storage yards where barges are unloaded. The raw materials are transferred to the stockhouse complex by ore bridges, or rail hoppers and ore transfer cars. Rail-mounted scale cars or computer controlled weight hoppers weigh out the various raw materials to yield the desired hot metal and slag chemistry. The raw materials are brought to the top of the blast furnace via a skip car powered by winches or conveyor belts.
  There are different ways in which the raw materials are charged into the blast furnace. Some blast furnaces use a "double bell" system where two "bells" are used to control the entry of raw material into the blast furnace. The purpose of the two bells is to minimize the loss of hot gases in the blast furnace. First, the raw materials are emptied into the upper or small bell which then opens to empty the charge into the large bell. The small bell then closes, to seal the blast furnace, while the large bell rotates to provide specific distribution of materials before dispensing the charge into the blast furnace. A more recent design is to use a "bell-less" system. These systems use multiple hoppers to contain each raw material, which is then discharged into the blast furnace through valves. These valves are more accurate at controlling how much of each constituent is added, as compared to the skip or conveyor system, thereby increasing the efficiency of the furnace. Some of these bell-less systems also implement a discharge chute in the throat of the furnace (as with the Paul Wurth top) in order to precisely control where the charge is placed.
  The iron making blast furnace itself is built in the form of a tall structure, lined with refractory brick, and profiled to allow for expansion of the charged materials as they heat during their descent, and subsequent reduction in size as melting starts to occur. Coke, limestone flux, and iron ore (iron oxide) are charged into the top of the furnace in a precise filling order which helps control gas flow and the chemical reactions inside the furnace. Four "uptakes" allow the hot, dirty gas high in carbon monoxide content to exit the furnace throat, while "bleeder valves" protect the top of the furnace from sudden gas pressure surges. The coarse particles in the exhaust gas settle in the "dust catcher" and are dumped into a railroad car or truck for disposal, while the gas itself flows through a venturi scrubber and/or electrostatic precipitators and a gas cooler to reduce the temperature of the cleaned gas.
  The "casthouse" at the bottom half of the furnace contains the bustle pipe, water cooled copper tuyeres and the equipment for casting the liquid iron and slag. Once a "taphole" is drilled through the refractory clay plug, liquid iron and slag flow down a trough through a "skimmer" opening, separating the iron and slag. Modern, larger blast furnaces may have as many as four tapholes and two casthouses. Once the pig iron and slag has been tapped, the taphole is again plugged with refractory clay.
  The tuyeres are used to implement a hot blast, which is used to increase the efficiency of the blast furnace. The hot blast is directed into the furnace through water-cooled copper nozzles called tuyeres near the base. The hot blast temperature can be from 900 °C to 1300 °C (1600 °F to 2300 °F) depending on the stove design and condition. The temperatures they deal with may be 2000 °C to 2300 °C (3600 °F to 4200 °F). Oil, tar, natural gas, powdered coal and oxygen can also be injected into the furnace at tuyere level to combine with the coke to release additional energy and increase the percentage of reducing gases present which is necessary to increase productivity.
caption: Blast furnace placed in an installation Iron ore + limestone sinterCokeElevatorFeedstock inletLayer of cokeLayer of sinter pellets of ore and limestoneHot blast (around 1200 °C)Removal of slagTapping of molten pig ironSlag potTorpedo car for pig ironDust cyclone for separation of solid particlesCowper stoves for hot blastSmoke stackFeed air for Cowper stoves (air pre-heaters)Powdered coalCoke ovenCokeBlast furnace gas downcomer
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