Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C1/00—Refining of pig-iron; Cast iron
• • 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
  • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
  • C22B7/001—Dry processes
  • C22B7/003—Dry processes only remelting, e.g. of chips, borings, turnings; apparatus used therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B1/00—Shaft or like vertical or substantially vertical furnaces
  • F27B1/08—Shaft or like vertical or substantially vertical furnaces heated otherwise than by solid fuel mixed with charge
• • 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 OF THE DISCLGSURE A process for combining fine metal particles with a molten metal mass by placing a quantity of molten metal in a mixing vessel, adding the fine particles and any desired alloying material, stirring the mixture until the additives have been dissolved into the molten mix, placing the mix in a holding furnace for subsequent mixing with a molten metal discharge from a cupola for forming a casting mixture for pouring in a mold.
• blast furnace pig iron suitable for economical use in cupolas to furnish molten cast iron for making castings sells for about $60 per ton; that baled scrap sheet sells for $36 per ton; and that commercial chips and shavings in bulk sells for about $23 per ton.
• the metal in the chips and shavings is just as suitable for making castings as the pigs or other larger pieces of metal although it may require some alloying agents or additives to attain the particular composition which is being used for casting.
• the reason for the much lower price for substantially the same metal when in small particles is that it is so difficult and wasteful to convert the smaller particles to the molten form ready for casting.
• the small particles When small particles are charged into a cupola, even along with pigs or other large pieces, the small particles will either be blown out or burned out to a large extent by the hot gas blasts maintained in the cupola. They also form thick scum or slag on top of the body of molten metal in the cupola. Both the small particles and the scum restrict the flow of gases through the charge and greatly reduce the efficiency and melting rate of the cupola.
• the present invention also provides a convenient process for introducing such additives or alloying ingredients as may be desired with assurance that they will be fully incorporated in the final molten metal to be cast.
• the quality of the particular metal being made from particulate material can be brought up to the quality of the metal being melted in the cupola or can even be formed into a superior quality of metal for other uses.
• a body of molten metal is drawn off from a metal melting furnace, such for example as a cupola which is supplying molten metal such as cast iron or the like, for making castings, and deposited in a mixing vessel of suitable shape and suitably coated for dumping metal which solidifies therein.
• the vessel is only partly filled with molten metal, leaving space for additional material which will be added.
• the metal in the vessel outside the cupola will be in a quiet state so that fine material, when added, will not be blown out or burned up.
• the amount of particulate metal which is added at a given temperature and the amount and temperature of the molten metal will be in such ratio that when the particulate metal is thoroughly stirred into the molten metal there will be formed a thick mush which fuses all solid particles into the molten metal to form a coherent body of metal which will not break up when exposed as a solid pig in the gas blasts of a cupola.
• a first advantage of using this ratio is that the mixture in the vessel will quickly solidify to the point where it can be dumped from the mixing vessel as a pig to be used wherever needed like commercial pig metal. Another advantage of using such a ratio is that it avoids the cost of melting excess metal whose heat is lost when cooled in the mix.
• the ratio of solid particulate material to liquid metal will obviously vary according to the size of the solid particles, the temperature of the particles when added, and the temperature of the molten metal; but, as an example, it has been found that when using a commercial grade of cast iron chips and turnings at room temperature with molten cast iron at approximately 2800 F. it is possible to obtain thorough incorporation and fusion and rapid solidification by using about one part of solid particles to about two parts of molten metal, 30% solid to 70% liquid having been found to give especially good results with the particular materials used. It is estimated that molten metal which was at about 2800 F. in the cupola will be at about 2600 F. to 2650 F. in the mixing vessel :by the time the solid metal particles are introduced into the vessel.
• the mixture in the relative amounts just specified will be at a temperature of about 1900" F. and will quickly solidify to a body or pig which can be dumped from the mixing vessel. If larger particles are used it will be possible to use a large ratio of solid material in a given quantity of liquid metal.
• the desired amounts of alloying ingredients are added so as to be stirred in at the same time. They will be fully incorporated because there is no blast to blow them away, as would be the case if the attempt should be made to add them in a cupola.
• the type of materials to be added is very diverse but such additives are well known and it is not necessary to specify the kind and amount since such small quantities are used that the ratios of the present invention are not materially affected. Examples of such additives for cast iron are silicon, manganese, chromium, tungsten, nickel, carbon and the like.
• additive alloying ingredient to be used is not a part of the present invention, such additives are mentioned because the present invention provides for their successful and efficient incorporation into the mixture without substantial loss so that the composition of the mixture pig and the final mixture of molten metal for casting can be very accurately predetermined.
• a continuous line of such vessels is feasible because the time of solidification is so short and can be so accurately predetermined that the metal will regularly be ready to dump by the time the vessels travel a predetermined distance from the cupola. It is readily possible to provide automated means along the line for dumping, coating, stirring and the like.
• the metal temperatures and ratios may be such that the mixture will remain molten so as to be poured at about 2100 F. to 2500 F. into a hold- 4 ing furnace from which the molten metal can be directly taken for pouring into molds to make castings or added to the molten metal in a cupola from which molten metal is taken for making castings.
• thepresent invention provides for the efficient, convenient, and economical use of low cost particulate material to make high cost casting material and at the same time provides for economical use of the off-peak capacity of cupolas which are used to supply molten metal for casting.
• the heating cost of using a cupola to supply molten metal during off-peak periods is not great because it is more economical to run the cupola regularly near its peak production rate than it is to operate it in on-ofi cycles.
• the added labor cost is not great because the cupola operators are commonly almost idle during off-peak periods.
• the cupola could be run on commercial casting pig or on a reserve accumulated supply of pig metal (or molten metal from a holding furnace) from the present process to convert further quantities of particulate material into high priced material suitable for casting.
• Step 1 (2) placing a predetermined amount of fine particulate material in the mixing vessel, wherein the amount laced therein is controlled by the amount and temperature of molten metal placed in the mixing vessel in Step 1,

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Materials Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Geology (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

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Citations (4)

• 1965
  • 1965-10-23 US US50422965 patent/US3366470A/en not_active Expired - Lifetime
• 1966
  • 1966-10-10 GB GB4522366A patent/GB1157978A/en not_active Expired
  • 1966-10-20 FR FR80762A patent/FR1502136A/fr not_active Expired

Patent Citations (4)

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