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
  • C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
  • C10B53/08—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form in the form of briquettes, lumps and the like
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L5/00—Solid fuels
  • C10L5/02—Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L5/00—Solid fuels
  • C10L5/02—Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin
  • C10L5/04—Raw material of mineral origin to be used; Pretreatment thereof
• • 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
  • C22B1/242—Binding; Briquetting ; Granulating with binders
  • C22B1/244—Binding; Briquetting ; Granulating with binders organic
• • 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
  • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
  • Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
• • 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

• ABSTRACT A novel composite briquette useful in producing iron is made by briquetting a reactive coal calcinate made as described in Work et a1.
• the briquette is distinguished by consisting of iron particles embedded and evenly distributed through a uniform solid carbonaceous structure.
• This invention has for its object an improvement in the manufacture of iron from iron oxide, which will reduce costs over prior-art methods.
• a calcinate produced as described in US. Pat. Nos. 3,140,241 and 3,140,242 is mixed and briquetted with a bituminous binder in sufficient quantity to produce a green briquette containing 12 to 25 percent by weight of binder based on calcinate and binder, together with a finely divided source of iron, the proportions of the ingredients being such that the total green briquette contains at least 50 percent by weight of calcinate plus binder and preferably at least 60 percent; the green briquettes are then heated to a briquette temperature of between about 450 to 575F for about 80 to 180 minutes in the presence of a gas containing at least of oxygen and preferably 15 to 21 percent to cure the briquettes, and the cured briquettes are then heated in the absence of oxygen to between about 1600 and 1800F for about 10 to 180 minutes and preferably 10 to 30 minutes to coke the briquettes while simultaneously reducing the iron to at least 90 percent metallic iron.
• the resultant briquettes are usefulin producing iron either in a cupola or a blast furnace; they have a sufficient excess of carbon to produce at least a part of the heat necessary to attain iron-melting temperatures in a cupola, and are useful in blast-furnace operation to I markedly increase production rates.
• the product of this invention differs from iron-containing carbonaceous briquettes made by prior-art techniques in that it consists of finely divided particulate metallic iron embedded and evenly distributed through uniform solid carbonaceous structure which is uniform in appearance and oxygen reactivity, in which it is impossible to differentiate the carbonaceous solid derived from the calcinate from the carbonaceous solid derived from the binder the two carbonaceous components have reacted so that they are indistinguishable under a light microscope, and react uniformly with ox- Y a DETAILED DESCRIPTION OF THE INVENTION
• This invention depends for its efficiency on the unique high reactivity of coal calcinate made in accordance with U. S. Pat. Nos. 3,140,241 and 3,140,242.
• the calcinate is so reactive that it will reduce iron oxide powder to iron oxide at temperatures in the 1600 to' 1800F range, below the sintering point of the iron produced, sothat the reduction of the oxide produces iron which has the same relationship to the briquette structure that the original iron oxide powder had.
• the briquettes formed are strong and can be mechanically handled Moreover, the chemical bond between binder and calcinate, which contributes to the unique character of the briquettes made in accordance with U. S. Pat. Nos.
• the calcinate used in making composite briquettes is made by grinding coal, preferably below the rank of anthracite, to a size consist amenable to fluidization.
• the coal may be predried, or dried in the first (cat'alyzation) step, where it is heated while suspended in a gas, either in fluid bed or gas transport, in the presence of oxygen which may come from the coal (U. S. Pat. No. 3,140,242) or from the gas (U.S. Pat. No.
• the catalyzed coal particles are shock-heated in one or more fluidized beds to tar-producing temperatures (about 500 to 900F, depending on the coal) for a sufficient time to remove substantially all of the tar-forming vapors.
• the resultant low-temperature char now free of condensible volatiles but still containing noncondensible volatiles, is then calcined to higher temperatures to reduce the volatile content to a sufficiently low level so that the calcinate can be briquetted without producing so much gas as to disrupt the briquettes below 5 percent of volatiles and preferably below 3 percent.
• the time and temperature are selected to get a char which will still react with the binder used for making the briquettes; to get this reactivity, the finished calcinate should contain at least about 1 percent of hydrogen. This result can be obtained by calcining at a temperature below 1800F, preferably at 1400 to 1600F, for a period of, about to 30 minutes.
• the highly reactive calcinate so produced is then cooled with nonreactive gases before exposure to air.
• this reactive calcinate is mixed with a bituminous binder, which is most preferably a pitch formed by air-blowing the tar distilled from the coal in the carbonization stage, using enough binder to thoroughly coat the particles, all as described in U. S. Pat. No. 3,140,241.
• the mixture is formed into briquettes, which are cured by heating in the presence of an oxygen-containing gas, preferably containing at least 5 percent and preferably percent or more, of oxygen; generally, the gas is supplied at 400F to induce an exothermic reaction in the briquettes, which apparently causes the binder to react with the calcinate and raise the briquette temperature to about 550F.
• an oxygen-containing gas preferably containing at least 5 percent and preferably percent or more, of oxygen
• the gas is supplied at 400F to induce an exothermic reaction in the briquettes, which apparently causes the binder to react with the calcinate and raise the briquette temperature to about 550F.
• briquettes are formed in which the material derived
• It can be used to produce iron by feeding into a cupola, where combustion of the hydrocarbonaceous material will produce some of the heat necessary to melt the iron; or it can be fed into a blast furnace to add its iron to the product, and give up its hydrocarbonaceous portion as a source of heat and reductant for iron ore fed into the furnace.
• the green briquettes, as made up, will contain at least 50 percent, and preferably at least 60 percent, of total briquette weight of hydrocarbonaceous material comprising from 12 to 25 percent of binder and 88 to 75 percent of calcinate, the balance being the iron-containing material.
• the iron-containing material may be iron ore i.e., hematite, magnetite, or other oxide or iron bearing material.
• blast-furnace dust which is a mixture of iron oxide, carbonaceous material and ash; it may be mill scale, which is largely iron oxide; it may be finely shreaded steel scrap, which inevitably is so heavily oxidized that it cannot be conveniently remelted in a cupola; or it may be any other finely divided source of iron such as basic oxygen-fumace dust.
• the source of iron oxide is very much heavier than the calcinate-binder matrix, so that the volume ratio of calcinate-binder to iron source is always much higher than the weight ratio.
• the highest levels of iron-containing material 40 to 50 percent by weight
• the amount of binder in the mixture will also depend on the desired strength.
• the green briquettes are cured as described in U. S. Pat. No. 3,140,241, by exposing them to gas containing from 5 to 21 percent of oxygen, preferably at least 15 percent.
• the gas flowing about the briquettes is heated to about 400F (375 to 450F); this induces an exotherm in the briquettes which brings their interior temperature to between about 450 and 575F, and preferably about 550F.
• About to 180 minutes in the curing oven complete the merger of calcinate and binder into a uniform mass which encloses the ironbearing material.
• the cured shapes are then calcined for about 10 to 180 minutes, and preferably 10 to 30 minutes, to a range of l600 to 1800F about 100 to 200F- higher than that generally used in making form coke.
• the atmosphere used should be free of carbon dioxide, which will react rapidly with the green briquettes, and contain as little water vapor as possible; a neutral flame from propane is desirable.
• this coking gas may be tempered with a portion or all of the off-gas from the coking vessel which has been cooled and cleaned of tarand solids generated in the coking vessel.
• the hot coked shapes are cooled by passage of some of this same cooled cleaned off-gas over and through the bed of hot briquettes.
• the briquettes consist of a uniform matrix of carbonaceous material, having dispersed therein unmelted particles of iron, in essentially the form in which the original iron-bearing material was charged to the original green briquettes. It is impossible to see any lines of demarcation between the original calcinate and original binder. The iron particles are embedded in this matrix. On oxidating the carbonaceous material burns uniformly, like a single substance would.
• the iron content of the iron-bearing substance is analyzed by the standard method of the Metal Powder Producers Association, coded as MPIF 7-61, which enables the determination of the total iron content, the sum of the iron that is free or metalized or of zero valence and the iron that is combined bearing a valence of plus 2 or plus 3. This same method also enables the determination of free or metallic iron in the same substance.
• this total iron content of the iron-bearing substance may be as high as percent, as is sometimes the case with shredded auto bodies, or it may be zero as is the case with virgin ores.
• the amount of free or metallic iron in relation to the total iron content is the degree or percent of reduction. That ratio is always greater than percent in briquettes made in accordance with the instant invention.
• the quality of the final coked briquettes is measured, for all practical purposes, by two specific characteristics.
• the first measure is the resistance to crushing or crushing strength which is determined by the force necessary to crush or destroy a form coke specimen when the force is applied between the parallel plates of any suitable hydraulic or mechanical device designed to apply force.
• this figure is expressed as total force and is specific to the size and shape of the briquette being testedfln the case of regular cylinders, 1 inch square in cross section between the parallel bases, the force necessary to crush is expressed in units of force per square inch.
• the second measure is the tendency to produce personnel dust.
• the shaking machine such as a standard wrist shaker, is used.
• the Burell machine listed in the A. H. Thomas Catalogue for 1968 as number 8900 has been employed. This device was set at maximum amplitude.
• dust is considered as the dry fine powder that passes the 325 mesh USS sieve.
• the jar is removed from the test rig and opened.
• the cloud that arises is classified as dusty, slightly dusty" or non-irritating to the nose and throat".
• This dusting characteristic is also measured by the ASTM Tumbler Test", D-294, modified to turn 700 revolutions in 28 minutes instead of 1,400 revolutions in 56 minutes.
• Example II A mix of 20 grams of auto body scrap from a bodyshredding works was made with a green-briquette mix consisting of 87 grams of calcinate from an Illinois No. 6 coal (bituminous A) by the process of U. S. Pat. No. 3,140,241 and 13 grams of binder from this same source (air-blown to 150F softening point).
• the auto body scrap was highly oxidized, and was in fine shreds about one-half inch in average length. This mix was formed into cylinders 1 inch in diameter and inch high.
• a sample of the cylinders was dissolved in toluene and washed free of calcinate and binder. The residue was easily separated with a strong magnet and analyzed for free and cornheretofore described. The average crushing strength was 4,300 psig,
• the analyses for iron before and after devolatilization at 1,700F were as follows:
• Example III A mix of 34 pounds of calcinate produced from 11- linois No. 6 coal, 6 pounds of oxidized binder pitch produced concurrently with this calcinate and 10 pounds of mill scale, ground to pass a VB inch square hole, was made in the integral pug mill mixer attached to a Komarek-Greaves 10 inch diameter roll briquette press. Green briquettes were produced at a compression force of 10,000 pounds per inch of linear roll width or 40,000 pounds of total force. These briquettes were cured in air in a 1 foot wide moving basket oven at 450F gas temperature for minutes. They were coked in a vertical shaft kiln 9 inches in inside diameter and 9 feet high at 1650F, using combustion gas tempered with nitrogen and containing no oxygen. The cured briquettes were held at 1650F for 30 minutes in passage through the kiln. Analyses of these coke specimens were as follows:
• the method of producing carbonaceous iron-bean ing briquettes which comprises (A) preparing a reac tive calcinate by the steps of catalyzing coal particles in the presence of oxygen at a temperature of from 250F to just below temperatures at which substantial amounts of tar-forming vapors are evolved, shock-heating to higher temperatures in one or more fluid beds to remove substantially all of the tar-forming vapors, heating the char thus freed of tar formers to a higher temperature below l800F to reduce volatiles to below percent while retaining at least 1 percent of hydrogen in the material, and cooling the thus produced highly reactive calcinate, (B) mixing and briquetting the reactive calcinate with a bituminous binder and an ironbearing particulate material to produce a mixture containing at least 50 percent by weight of binder plus calcinate, in which the binder is l2 to 25 percent of the total binder plus calcinate, (C) curing the so produced briquettes by heating for 80 to l80

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Geochemistry & Mineralogy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Carbon And Carbon Compounds (AREA)

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  • BE BE790753D patent/BE790753A/xx unknown
• 1971
  • 1971-11-01 US US00194559A patent/US3725034A/en not_active Expired - Lifetime
• 1972
  • 1972-06-19 AR AR242711A patent/AR197387A1/es active
  • 1972-10-11 ZA ZA727253A patent/ZA727253B/xx unknown
  • 1972-10-12 CA CA153,743A patent/CA972164A/en not_active Expired
  • 1972-10-12 AU AU47687/72A patent/AU462742B2/en not_active Expired
  • 1972-10-24 AT AT906772A patent/AT330818B/de not_active IP Right Cessation
  • 1972-10-24 IT IT30871/72A patent/IT969853B/it active
  • 1972-10-27 GB GB4975072A patent/GB1364614A/en not_active Expired
  • 1972-10-30 LU LU66393A patent/LU66393A1/xx unknown
  • 1972-10-30 SE SE7214029A patent/SE375802B/xx unknown
  • 1972-10-30 CS CS727291A patent/CS204971B2/cs unknown
  • 1972-10-30 NL NL7214698A patent/NL7214698A/xx unknown
  • 1972-10-30 FR FR7238402A patent/FR2158344B1/fr not_active Expired
  • 1972-10-31 ES ES408161A patent/ES408161A1/es not_active Expired
  • 1972-10-31 BR BR7645/72A patent/BR7207645D0/pt unknown
  • 1972-10-31 DE DE2253454A patent/DE2253454C3/de not_active Expired
  • 1972-10-31 RO RO72682A patent/RO60674A/ro unknown
  • 1972-11-01 JP JP47108948A patent/JPS4852615A/ja active Pending
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