Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/62—Record carriers characterised by the selection of the material
  • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
  • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
  • G11B5/706—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material
  • G11B5/70626—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances
  • G11B5/70642—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides
  • G11B5/70652—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides gamma - Fe2 O3
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G49/00—Compounds of iron
  • C01G49/02—Oxides; Hydroxides
  • C01G49/06—Ferric oxide [Fe2O3]
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/62—Record carriers characterised by the selection of the material
  • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
  • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
  • G11B5/706—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material
  • G11B5/70626—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances
  • G11B5/70642—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides
  • G11B5/70647—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides with a skin

Definitions

• the invention relates to a process for the direct production of finely divided ferromagnetic ferric oxide from ferric halides in the vapor phase.
• fern'c oxide can be obtained by hydrolysis of the corresponding halide in a hydrogen-oxygen flame. In this process in general an excess of oxygen is used and the ferric oxide obtained is paramagnetic.
• ferric oxide iron pentacarbonyl has also been already used as the starting material and this was burned alone or together with other combustible substances.
• the preparation of magnetic fenic oxide has also already been described by processing iron carbonyl compounds with a deficit of oxygen, relative to the composition of ferric oxides.
• the ferric oxide obtained according to the process of the invention, in contrast to the products of the processes previously known, is ferromagnetic even for almost stoichiometn'c composition, referred to Fe O Because of its finely divided nature it is pre-eminently suitable as magnetogram-carrier, further for the preparation of magnetic solid solutions by pressing or also as agent for nondestructive testing of industrial materials. Likewise, of course, due to its extremely finely divided state and its activity, it can also be incorporated for purposes of which the utilization of the magnetic properties is not itself or not primarily the object, and it can serve, for example, as filler or also as pigment or polishing agent.
• the process according to the application is not limited in the selection of water-forming gases for the flame to pure oxygen or pure hydrogen, although the latter is, however, preferably used, rather the production of the flame can take place through the utilization of hydrogencontaining and hydrogen-forming gases or gas mixtures such as illuminating gas, methane or the like, While air can be used advantageously as oxygen-carrier.
• the water-forming gases are mixed homogeneously together with the volatile ferric halides before bringing them to the flame, whereupon the reactive mixture is expediently led to the flame in laminar flow.
• the flame burns autark (self-sufficiently) in relation to all components required for the formation of Fe O by bydrolysis, so that there is no dependence on the uncontrolled entrance of oxygen from the environment of the flame.
• autark self-sufficiently in relation to all components required for the formation of Fe O by bydrolysis
• the particles at first separated from the aerosol state thus act, so to say, as an inoculating agent or condensation nucleus for the further separation of the portions not yet coagulated, inasmuch as they are kept in suspension in as long a path as possible.
• the coagulation is further favored by the fact that the particles are moved especially in relation to one another.
• the gas stream containing the aerosol is whirled up in chambers of large volume or moved through long, purposely bent tubes up to 60 m. and more in length, in such a way that a preferably turbulent flow is developed and the suspended particles remain for some time, for example longer than 3 seconds, preferably 5 seconds or more, in the coagulation space.
• the final separation of the solid from the gaseous react-ion products then takes place in auxiliary equipment, itself known, especially in cyclones.
• filters or electrical separators it is possible also to use filters or electrical separators.
• the advantage of the method of operation according to the invention lies primarily in the fact that it is possible to use even cyclones alone as the separation instrument, because, due to the previously described coagulation, the actual separation equipment is no longer burdened with the coagulation.
• a gas mixture containing hydrogen, air, and nitrogen in the volume relationship 2.2 to 2.2 to 4 is mixed with sufficient vaporized ferric chloride so that the charge comes to g. FeCl /m. gas mixture.
• This homogeneous mixture is led to a tubular burner 24 mm. in diameter of such a type that every hour 2.2 m. hydrogen, 2.2 m. air, and 4 111. nitrogen (all measured at standard condition of temperature and pressure) are passed through.
• a suthciently high rate of outflow e.g. 520 cm./sec. a flash back of the flame is prevented.
• the ferric chloride hydrolyzes practically quantitatively into Fe O which is separated from the reaction gases after coagulation.
• the finely divided product is colored light yellowish brown and is strongly ferromagnetic.
• the rate of outflow is given according to a temperature of 20 C.
• a gas mixture containing hydrogen. and air in the volume relationship 1.1 to 12.0 is mixed with vaporized ferric chloride to come to a charge of 120 g. FeCl /m gas mixture and burnt in the same burner as in the foregoing example.
• the rate of outflow was ca. 810 cm./sec.
• the finely divided product is colored light yellowish brown and is practically non-ferromagnetic.
• Process for the preparation of finely divided ferromagnetic ferric oxide by decomposition of iron compounds in the gaseous phase characterized by the steps of first homogeneously mixing a volatile ferric halide with waterforming gases, the gaseous mixture containing oxygen and hydrogen in at least sufllcient amount for the formation of water for the complete hydrolysis of said ferric halide and hydrogen in excess of that amount, burning said mixture in a self-sufficient flame thereby completely bydrolyzin g the halide to ferromagnetic oxide and thereafter separating the oxide from the products of combustion.
• the method of forming finely divided magnetic ferric oxide comprising mixing vapors of ferric chloride with hydrogen, oxygen and nitrogen in relative amounts such that upon burning Water vapor is formed, the amount of oxygen being at least the stoichiometric equivalent of the ferric iron, the amount of hydrogen being in excess of the stoichiometric equivalent of the oxygen and the amount of nitrogen being suflicient to maintain a flame temperature of less than 1000 C., to form a homogeneous gaseous mixture, causing said mixture to flow from a burner by laminar flow at a rate at the burner in excess of the rate of flame propagation through said mixture, burning said mixture as it flows from the burner in a self-sufficient flame, thereby forming a flame containing water vapor as a combustion product and causing said ferric chloride to be hydrolyzed to ferric oxide by reaction with said water vapor, flowing the combustion products formed by said burning with the ferric oxide suspended therein in turbulent flow for at least three seconds, and thereafter separating the ferric oxide from said combustion products
• the method of forming finely divided ferro-magnetic oxide comprising forming a gaseous mixture containing relatively by volume 2.2 parts of hydrogen, 2.2 parts of air and 4 parts of nitrogen, mixing ferric chloride vapors with said gaseous mixture in relative amount of grams per cubic meter and forming a homogeneous mixture, flowing said homogeneous mixture from a burner tube having an outlet diameter of 24 mm. at a volume rate per hour of 1008 grams of FeCl 2.2 m of H 2.2 m. of air and 4 m. of N and at a linear rate at the mouth of the burner of 520 cm./sec., burning said homogeneous gaseous mixture, and separating ferric oxide from the combustion products formed from said burning.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Dermatology (AREA)
• General Health & Medical Sciences (AREA)
• Inorganic Chemistry (AREA)
• Compounds Of Iron (AREA)
• Silicon Compounds (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=7038241

Family Applications (1)

Country Status (5)

Cited By (5)

Citations (6)

• 1956
  • 1956-12-31 DE DED24600A patent/DE1034163B/de active Granted
• 1957
  • 1957-10-21 CH CH5178957A patent/CH372648A/de unknown
  • 1957-11-01 NL NL222078A patent/NL222078A/xx unknown
  • 1957-12-10 US US701708A patent/US2950955A/en not_active Expired - Lifetime
  • 1957-12-30 GB GB40290/57A patent/GB836275A/en not_active Expired

Patent Citations (6)

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