US3704088A - Method of restricting oxidation of sponge iron - Google Patents

Method of restricting oxidation of sponge iron Download PDF

Info

Publication number
US3704088A
US3704088A US3704088DA US3704088A US 3704088 A US3704088 A US 3704088A US 3704088D A US3704088D A US 3704088DA US 3704088 A US3704088 A US 3704088A
Authority
US
United States
Prior art keywords
gas
mass
oxidation
sponge iron
iron
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Other languages
English (en)
Inventor
Horst Nagel
Wilhelm Thumm
Horst Garbe
William H Dailey
Egon Goedeke
Rolf Dadazynski
Bergen Enkheim
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Steel Company of Canada Ltd
GEA Group AG
Original Assignee
Steel Company of Canada Ltd
Metallgesellschaft AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Steel Company of Canada Ltd, Metallgesellschaft AG filed Critical Steel Company of Canada Ltd
Application granted granted Critical
Publication of US3704088A publication Critical patent/US3704088A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0086—Conditioning, transformation of reduced iron ores
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B2/00—Friction-grip releasable fastenings
    • F16B2/02—Clamps, i.e. with gripping action effected by positive means other than the inherent resistance to deformation of the material of the fastening
    • F16B2/18—Clamps, i.e. with gripping action effected by positive means other than the inherent resistance to deformation of the material of the fastening using cams, levers, eccentrics, or toggles

Definitions

  • ABSTRACT OF THE DISCLOSURE A system for reducing the oxidation of agglomerated sponge iron during storage or transit wherein the mass of iron is stored in an enclosure having a gas-permeable bottom and air, nitrogen-enriched air or nitrogen, treated to remove moisture and acidic constituents, is passed through the mass at a predetermined rate.
  • the present invention relates, in general, to a system for reducing the oxidation of iron and more particularly to a system for reducing the oxidation of agglomerated sponge iron during storage or transportation.
  • sponge iron when piled in a mass, such as it is during storage or transit, can oxidize, particularly in the presence of moisture, causing a rise in temperature of the mass to 80-100 C. or even to the point of ignition, endangering the storage or transit means, e.g. a ships hull.
  • Another object of the invention is to provide a method of limiting oxidation of sponge iron in lump or agglomerated form which is relatively inexpensive and free from the indicated disadvantages.
  • Still another object of the invention is to provide a system for the purpose described that does not deposit impurities on the iron.
  • the rate at which the gas is passed through the mass determines the rise in temperature of the mass, so that a rate can be selected to give virtually no rise in temperature or a rise only to the highest permissible limit.
  • the rate at which the gas should be passed through the mass is about 5-160 cubic meters per square meter-hour, depending on the height of the mass.
  • a dehumidifier is provided to remove moisture constituents present in the gas, prior to passage through the mass.
  • the dehumidifier may drop the temperature of the gas to about 20 C.
  • a heater is provided to bring the gas to about 30 C., the gas being then driven into the enclosure by a blower, at a water-vapor partial pressure as low as possible.
  • a lime filter is used to remove any acid constituents which may have been picked by the gas passing through the iron mass.
  • acid constituents such as CO S0 and S0 are removed by this filter.
  • the invention is based upon our surprising discovery that in spite of the fact that the oxidation-limiting gas may contain oxygen and eventually bring about more contact of iron surface with oxygen than a static system in which an ambient atmosphere lies in contact with sponge iron, the circulation of the gas through the mass materially limits oxidation.
  • the degree of oxidation is a function of temperature and, whereas a temperature buildup occurs in the static case, the displacement of the gas through the mass according to the invention prevents such buildup.
  • any steps which reduce the water vapor pressure in the gas supplied to the enclosed pile bring about a greater reduction in the tendency toward oxidation.
  • reduction of the H 0 vapor pressure can be effected by dehumidification using a cooler to bring the temperature of the gas below the dewpoint and condense water therefrom, absorption to remove water without changing the gas temperaure, or heating to reduce the relative humidity. Since a cooler is used to lower the temperature of the gas below the dewpoint, it is apparent that the gas circulated through the iron mass is at a temperature above the dewpoint (at most 45 C. as seen in curves b and d in FIG. 2), and that the water-vapor partial pressure is below that of the dewpoint at the gas temperature used.
  • FIG. 1 is a diagrammatic view of the apparatus according to the invention.
  • FIG. 2 is a graph illustrating results of the process according to the invention.
  • the enclosure 2 shown in FIG. 1 has cylindrical walls 2' and a perforated conical bottom end 2" supporting the sponge-iron mass.
  • a removable lid 3 is provided at the top of enclosure 2 for introducing agglomerated sponge iron therein.
  • the sponge iron forms a gas-permeable mass 1, which can be removed by means of a door 4 provided at the apex of the conical bottom 2".
  • a series of gas nozzles 5 are provided in an array along the inside walls of the conical bottom 2".
  • the nozzles 5, which introduce a gas such as air, nitrogen-enriched air or nitrogen, into the enclosure 2, are supplied by conduits 5' equipped with regulating valves 5".
  • the conduits 5' are supplied with warm gas at 30 C. from a heater 6 via a single conduit 6, the heater 6 being supplied by a blower 7.
  • the blower 7 and heater 6 form part of a recycling system which starts with the introduction of the aforementioned gas into the enclosure 2 via the nozzles 5.
  • the gas is passed through the mass 1 at a rate of 5 to 160 cubic meters per square meter-hour, depending on the height of the piled mass 1.
  • the required rate is 5 to 40 cubic meters per square meter-hour, preferably 8 to 25 cubic meters per square meter-hour.
  • the mass height is 3 to 8 meters, the requirement is 10 to 80 or preferably to 50 cubic meters per square meterhour. If the height of the mass exceeds 8 meters, the requirement is 20 to 160 or preferably 40 to 100 cubic meters per square meter-hour.
  • the gas After passing through the dehumidifier 9, the gas, which has been cooled to 20 C., is drawn through conduit 10' into a lime filter 10, where the acid constituents picked up from the mass 1 are removed.
  • FIG. 2 a graph representing some test results is shown.
  • the time in hours is plotted along the abscissa and the temperature, in the upper region of the iron mass, in degrees centigrade along the ordinate. Percentages recited relate to water content of the gas.
  • the curve a shows the rise in temperature of the mass when 5% water is present in the still atmosphere and no gas is passed through.
  • Curve b shows the temperature rise of the mass when 5% water is present and air is passed through at a rate of cubic meters per square meter-hour.
  • Curve 0 shows the temperature rise of the mass with a 0.19% water content and no air circulation.
  • a method of preventing oxidation of sponge iron comprising the steps of piling and enclosing agglomerated sponge iron to form a gas-permeable mass; passing a gas selected from the group consisting of air and nitrogenenriched air through said mass at a rate of 5 to 160 standard cubic meters per square meter-hour, and suflicient to prevent the temperature in said mass from rising above substantially 45C.; and dehumidifying said gas prior to passing it through said mass to maintain the water vapor partial pressure below that of the dewpoint at contact with said mass.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Fertilizers (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Drying Of Gases (AREA)
  • Gas Separation By Absorption (AREA)
US3704088D 1969-05-29 1970-05-22 Method of restricting oxidation of sponge iron Expired - Lifetime US3704088A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691927300 DE1927300B2 (de) 1969-05-29 1969-05-29 Verfahren zur verhinderung bzw. verringerung der reoxydation von eisenschwamm

Publications (1)

Publication Number Publication Date
US3704088A true US3704088A (en) 1972-11-28

Family

ID=5735474

Family Applications (1)

Application Number Title Priority Date Filing Date
US3704088D Expired - Lifetime US3704088A (en) 1969-05-29 1970-05-22 Method of restricting oxidation of sponge iron

Country Status (5)

Country Link
US (1) US3704088A (OSRAM)
AU (1) AU1391670A (OSRAM)
DE (1) DE1927300B2 (OSRAM)
GB (1) GB1297070A (OSRAM)
NL (1) NL7006977A (OSRAM)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4066401A (en) * 1975-05-05 1978-01-03 Arie Solomon Long term storage apparatus
US4128966A (en) * 1975-11-17 1978-12-12 Applied Research Commodities Ind., Inc. Inflatable terrarium assembly with controlled environment
US4287152A (en) * 1980-02-07 1981-09-01 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Method of for retarding dye fading during archival storage of developed color photographic film
US4317797A (en) * 1980-08-25 1982-03-02 The United States Of America As Represented By The Secretary Of The Navy Resin purger
US4362484A (en) * 1980-11-07 1982-12-07 Ecobric Foundry Limited Apparatus for hot briquetting of ferrous or non-ferrous metallic particles
US9238253B2 (en) 2010-09-10 2016-01-19 Nu-Iron Technology Llc Processed DRI material

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4066401A (en) * 1975-05-05 1978-01-03 Arie Solomon Long term storage apparatus
US4128966A (en) * 1975-11-17 1978-12-12 Applied Research Commodities Ind., Inc. Inflatable terrarium assembly with controlled environment
US4287152A (en) * 1980-02-07 1981-09-01 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Method of for retarding dye fading during archival storage of developed color photographic film
US4317797A (en) * 1980-08-25 1982-03-02 The United States Of America As Represented By The Secretary Of The Navy Resin purger
US4362484A (en) * 1980-11-07 1982-12-07 Ecobric Foundry Limited Apparatus for hot briquetting of ferrous or non-ferrous metallic particles
US9238253B2 (en) 2010-09-10 2016-01-19 Nu-Iron Technology Llc Processed DRI material

Also Published As

Publication number Publication date
GB1297070A (OSRAM) 1972-11-22
DE1927300B2 (de) 1973-04-12
AU1391670A (en) 1971-11-11
DE1927300A1 (de) 1970-12-03
NL7006977A (OSRAM) 1970-12-01

Similar Documents

Publication Publication Date Title
US3704088A (en) Method of restricting oxidation of sponge iron
US3285711A (en) Inert flue gas system
EP0976842A2 (en) Box annealing furnace, method for annealing metal sheet using the same, and annealed metal sheet
US2625298A (en) Fire prevention system for fuel tanks
US880783A (en) Process of regenerating water in reservoirs containing aquatic animals.
PL102910B1 (pl) Sposob odzyskiwania cieklego dwutlenku siarki z gazow spalinowych
JPH0622654B2 (ja) ハロゲン化炭化水素系ガスの吸着除去方法
DE3376255D1 (en) Process for the removal of air contaminants from waste gases, especially from flue gases, by condensation
US2315481A (en) Method and apparatus for degasifying liquids
US3723059A (en) Method of restricting the oxidation of sponge iron
US2130163A (en) Process of making gas
JPH11347351A (ja) 排煙脱硫装置
JPS6435348A (en) Gas analyzer
JPS5630707A (en) Manufacture of ferromagnetic metal powder, ferromagnetic metal powder and magnetic recording medium
US2906372A (en) Sulfuric acid mist removal
US1417066A (en) Process for enriching metallurgical gases containing sulphur dioxide
US3069829A (en) Method and apparatus for dehydrating gas
GB897543A (en) Improvements in or relating to the removal of hydrogen cyanide from gas or aqueous solutions
DD158744A5 (de) Adsorber zur gasreinigung
US1396028A (en) Process of recovering the solids of waste pulp liquors
CN116392935A (zh) 一种快速温变箱防凝露方法
US1996769A (en) Process for the manufacture of stable sodium hypochlorite and product thereof
JPS61254893A (ja) 放射性気体廃棄物の処理方法および処理装置
US1464732A (en) Cooling and stabilizing charcoal
JPS55137006A (en) Semipermeable membrane dehumidifier