Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
  • C22B1/24—Binding; Briquetting ; Granulating
  • C22B1/2406—Binding; Briquetting ; Granulating pelletizing
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B13/00—Making spongy iron or liquid steel, by direct processes
  • C21B13/008—Use of special additives or fluxing agents
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• the present invention relates to a process for making iron sponge from iron ores containing 95 percent or more of iron oxide, for use in producing various types of steels.
• Processes are known for melting cast iron with lame]- lar graphite, or with modular graphite, or malleable cast iron, in cupola furnaces, reverberatory furnaces or electric furnaces.
• a mixture is added in the furnace of cast iron scrap, steel scrap, returns, and pig iron.
• Armco iron Another known iron used for making high-quality steel is Armco iron, which has been in use for making such high-grade and other steels for a long time.
• a material of superior purity is iron sponge. Its impurities are only small quantities of silica, alumina, and traces of calcium and magnesium oxides, which pass into the slag. With regard to the accompanying elements, such as carbon, silicon, manganese, phosphorus and sulfur, only carbon is present. For trace elements, such as copper, titanium, chromium, aluminum, arsenic and lead, only minimal amounts are to be found, for example, less than 0.01 percent by weight in each case.
• iron sponge can be made from iron ores containing 95 percent by weight or more of iron oxide
• the melts may be used for making, for example, modular cast iron, black-malleable cast, over-eutectoid cast steel, the carbon content of which above 0.9 percent is separated in the raw castings as modular graphite; also other steel brands may be made, e.g. silicon construction steels.
• iron oxides are ground to fine grain-size and mixed with equally fine ground silicon carbide, and then made into lumps or pellets in a known manner.
• the iron ores used at least percent should be ground to a size less than 40 82
• the silicon carbide is used in an amount of 0.1 10 percent by weight, preferably 0.5 6 percent by weight, calculated on the total amount, and having a grain size of 10 p. 2 mm, preferably 10 ,u, 400 t.
• This silicon carbide is added in adequate grain size to the iron ore to be pelletized, which after pelletizing, may be roasted and reduced.
• the extremely fine distribution of unmeltable silicon carbide in the iron sponge has the effect that, as the latter is melted and silicon carbide is dissolved therein, the distribution in the melt occurs very evenly and the iron oxide entrained in the iron sponge is more readily reduced.
• a starting block of 900 kg modular iron was placed into the 3,5 to furnace and covered with reformed material. After melting down, a refill took place with the use of new, clean stacks of sheet until the furnace was filled. Then a substantial specimen of slag was taken off from the surface. After the specimen had cooled down, its weight was 800 g. After grinding, 300 g of mostly spherical metallic occlusions could be drawn out with a magnet. In the balance of 500 g, 16.34 percent Fe and 6.12 percent Mn were found.
• example 1 The melting test of example 1 was repeated while using the same ratios of weight. But instead of the stacks of sheets, 500 kg iron sponge and 0.9 percent of metallurgical silicon carbide, calculated on the total filling of 3.5 to were separately and consecutively added to the melt. In this manner, about 28 kg silicon carbide with about 20 kg pure silicon were introduced, (about 0.55 percent Si). The amount of iron oxide introduced by the sponge iron, is 33 kg. Already to the naked eye the color of the slag showed to be lighter. After cooling, 315 g of slag were weighed, from which only 2 g metallic occlusions could be withdrawn by means of a magnet. The remaining 313 g stag contained 2.73 Fe and 4.54 percent Mn.
• the analysis of the added sponge is: 92.2 percent by weight total iron, of which 86.6 percent metallic, 0.7% A1 2.5% SiO 1.0% CaO, 6.7% FeO, corresponding to 5.4% metallic iron, 0.85% C, 2% silicon carbide, (Metallurgical quality 90% SiC).
• the 900 kg iron sponge introduced the following slag-forming compounds: 58 Kg FeO, 23 kg SiO 6.0 kg A1 0 kg CaO, 1.0 kgMgO and, additionally, from the metallurgical silicon carbide, 1 kg SiO
• the silicon carbide addition is 17 kg with about 12 kg pure silicon.
• these 99 kg slag forming compounds are composed of 58% FeO, 23% SiO 6% A1 0 10% CaO, 1% MgO. In reality, the following amounts were found in the slag: 6.0% Fe, corresponding to 8% FeO, 1% Mn, 68% SiO 17% CaO, 12% A1 0 and 1.2% MgO. Instead of the theoretically expected FeO content of 58 percent, the slag contained only 8%.
• the SiO content derives from the reduction power of the 17 kg silicon carbide resulting in CaO and 25 kg SiO
• the result is 48 kg SiO
• the amount (by weight) of the slag decreases to 87 kg, due to the FeO removed by reduction. Therefore, the above 48 kg correspond to 55% SiO
• Added SiO results from the worn furnace lining and adhering sand from the reformed material increase the difference to 68 percent.
• a process for making iron sponge from iron ores containing at least 95% by weight of iron oxide comprising, pulverizing the iron ore to extremely fine grain size, mixing the pulverized iron ore with fine-grained silicon carbide, pelletizing the so obtained mixture, and subjecting the same to direct reduction.
• silicon carbide is used in an amount of 0.1-10 percent by weight calculated on the total weight and in a grain size between 10 p. and 2mm.
• silicon carbide is used in an amount of 0.5 6 percent by weight calculated on the total weight and in a grain size of 10 p. to 400 11..

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• Mechanical Engineering (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Carbon And Carbon Compounds (AREA)
• Manufacture Of Iron (AREA)
• Treatment Of Steel In Its Molten State (AREA)

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Citations (2)

• 1974
  • 1974-01-09 DD DD175916A patent/DD109663A5/xx unknown
  • 1974-02-20 JP JP2037574A patent/JPS5342008B2/ja not_active Expired
  • 1974-02-21 FR FR7405911A patent/FR2219230B1/fr not_active Expired
  • 1974-02-21 NL NL7402391A patent/NL7402391A/xx not_active Application Discontinuation
  • 1974-02-22 BE BE141286A patent/BE811456A/xx not_active IP Right Cessation
  • 1974-02-22 SE SE7402398A patent/SE424091B/xx unknown
  • 1974-02-22 GB GB816874A patent/GB1466475A/en not_active Expired
  • 1974-02-25 CA CA193,339A patent/CA1018360A/en not_active Expired
  • 1974-02-25 US US445413A patent/US3899320A/en not_active Expired - Lifetime
  • 1974-02-25 IT IT48661/74A patent/IT1004334B/it active

Patent Citations (2)

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