US 3797978 A
A process and apparatus for disintegrating a stream of molten ferroalloy into solidified spheroidal to spherical configurations for use as additives in metal producing furnace operations or the like.
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Description (OCR text may contain errors)
United States Patent [191 Young et a1.
APPARATUS FOR PRODUCING SIZED FERROALLOY PARTICLES Inventors: Claude Frank Young; Charles Martin Offenhauer, both of Niagara Falls. NY.
Assignee: Union Carbide Corporation, New
Filed: Jan. 19, 1972 Appl. No.: 219,099
Related US. Application Data Division of Ser. No. 28.594, April 15. 1970. Pat. No. 3.660544.
US. Cl 425/8, 264/8, 65/15,
65/21 Int. Cl. B29c 23/00 Field of Search 425/8, 332, 402; 264/8;
[ Mar. 19, 1974  7 References Cited UNITED STATES PATENTS 3.174.182 3/1965 Duncan 425/8 3.272.893 9/1966 1 Mogensen 264/8 3.358.323 12/1967 Chisholm l 425/8 3.532.775 10/1970 Brondyke et al. 264/8 X 1.210.097 12/1916 Perry et a1. 425/8 X 2.062.093 11/1936 Kann 425/8 2.439.772 4/1948 Gow 425/8 X Primary Examiner-Robert L. Spicer, Jr. Attorney, Agent, or FirmFrederick J. McCarthy, Jr.
ABSTRACT A process and apparatus for disintegrating a stream of molten ferroalloy into solidified spheroidal to spherical configurations for use as additives in metal producing furnace operations or the like.
6 Claims, 2 Drawing F lgures MOLTEN METAL PATENTEUIAR 1 9 1914 3.797, 978
SHEET 2 OF 2 MOLTEN METAL APPARATUS FOR PRODUCING SIZED FERROALLOY PARTICLES This is a division, of application Ser. No. 28,594 now U.S. Pat. No. 3,660,544, filed Apr. 15, 1970.
FIELD OF THE INVENTION This invention relates to a process and apparatus for producing substantially uniform ferroalloy sizes having a somewhat spheroidal configuration. The process consists in subjecting a molten metal to a centrifugal force sufficient to direct and disperse the molten metal into a radially defined zone wherein the dispersed metal particles contact and roll upon the surface within the zone so that the roll contact action, when added to the surface tension action of the metal, will be sufficient to draw each particle into a somewhat spheriodal to spherical shape. The molten to semi-molten ferroalloy particles are then discharged from the radial zone and quickly solidified into their adopted shapes. The ferroalloy particles or shots, so produced are relatively uniform in size, however, the size can vary depending upon the degree of centrifugal force imparted to the molten metal and the contour of the radially defined zone.
DESCRIPTION OF THE PRIOR ART Various methods are employed to produce small finless ferroalloy sizes for use as additives in metal alloy furnace operations. A uniformly sized ferroalloy charge is required to be relatively free of fines and fins so that when the charge reaches its final destination it can be fed into a metal producing furnace without fear that fines will explode or otherwise hamper the operational mode of the furnace.
One method for producing small sized ferroalloy charges is to cast them to the size desired. This method is expensive and still yields end alloys having fins which require another operation to remove. In addition, sizes between 8 Tyler mesh up to inch, and preferably V4 inch, are difficult to cast on a large scale basis.
Another method presently used is in casting alloy sizes in large chills and then crushing the alloy by conventional means to produce various alloy sizes. Due to the friability of the alloy, a considerable amount of fines and off-size particles are produced which decrease the net output quantity of a selected alloy size. Separating the selected size from the off-size elements requires another operation which adds additional time and expense to the overall production operation.
The disadvantage of present methods in producing an alloy size within a somewhat narrow range is in the large amount of off-size pieces that are co-produced. The present invention provides a method wherein the off-size pieces are greatly minimized and the selected alloy sizes are somewhat spheriodal to spherical in configuration. In addition no expensive crushing, casting or forming operation is required.
SUMMARY OF THE INVENTION Broadly, the process and apparatus of this invention comprises subjecting a stream of molten liquid within an insulated zone to a centrifugal force sufficient to direct and disperse the molten stream into a radially defined sinuous type passage wherein the molten to semimolten particles of the dispersed stream contact and roll upon at least one curvilinear surface of the passage.
The molten liquid can be any material that solidifies at room temperature such as molten metal. The rolling contact action, together with the surface tension action of the molten to semi-molten liquid, is sufficient to influence the small particles into adopting a somewhat spheroidal to spherical configuration. Preferably, the molten to semi-molten particles should roll upon a rotating member having an inclined curvilinear surface and then be tangentially projected to the opposite surface of the passage having a declining curvilinear surface so that maximum circumferential contact between the spheroidially forming particles and the surfaces of the sinuous type passage can be obtained. To increase this contact action, the opposite surfaces of the passage may be counter-rotated with respect to each other thus subjecting the spheroidal to spherical particles to an increased spirally rotating motion, such motion derived from combining the radial motion due to the centrifugal force and the circular motion due to the counterrotating surfaces. It is this combination of radially directed contact force and circular imparted contact force, in addition to the relatively low surface tension force, that shapes the dispersed particles into spheriodal to spherical configurations.
The molten to semi-molten alloy particles, while still subject to the combined forces, are ejected from the peripheral outlet of the sinuous type passage and quickly quenched or solidified in their adopted spheroidal to spherical shapes. A receptacle or the like containing a quenching medium may be employed to catch and solidify the alloy shapes, such shapes being somewhat spheroidal to spherical in degree depending on the centrifugal force, the degree of the shape of the curvilinear surfaces, the number of peaks of the sinuous passage and the particular viscosity of the molten liquid used. A sinuous passage having at least one peak is required to insure that the dispersed particles will roll on at least one incline curvilinear surface thus providing sufficient contact force which can be added to the surface tension force to appropriately shape the particles. The inlet of the sinuous passage can be made adjustable so as to regulate at least the maximum size of the dispersed particles being forced through the passage.
DESCRIPTION OF THE DRAWING The invention will be more readily understood by reference to the drawing wherein:
FIG. 1 is an elevated sectional view taken through the center of the apparatus of this invention.
FIG. 2 is an isometric view of the rotating anvil of the apparatus showing the spiral path taken by the dispersed particles.
In FIG. 1 hot molten metal is axially fed upon rotating circular anvil 1 which is made from a material that can withstand the high temperature of the molten metal, such material being graphite, aluminum, magnesia, cast iron or any refractory metal that will not react with the molten metal. The anvil has a conically shaped projection 2, centrally disposed and extending upward. An inclined curvilinear surface 3 extends radially outward from projection 2 and before reaching the peripheral vicinity, the surface assumes a zero slope and then slopes slightly downward. A rotatable drum 4 has an axial opening 5 into which the molten metal is directed to contact projection 2. The undersurface 12 of drum 4 is curved with a mating curvilinear surface to that of surface 3 but extends radially outward further so that when axially disposed on top of anvil l a sinuous type passage 13 is defined. It is also possible to have anvil I extend further out than the drum so as to terminate the sinuous passage in an upward direction. The drum, like the anvil, can be made from any material that can withstand a high temperature environment without reacting with the molten metal being disintegrated into small particle sizes.
Motor 6 is used to rotate anvil 1 while motor 7 rotates drum 4 in a counter direction. Cone-shaped skirt 8 is used to protect the anvils rotating means from any misdirected metal particles.
Receptacle 9 may be a simple annular type receptacle or at least two arcuate receptacles which when juxtaposed will form an overall annular receptacle. This receptacle, containing a quenching or solidfying medium 14, is placed below and radially outward from peripheral outlet 15 of the sinuous passage so as to be in a position to catch the exiting spheroids l1.
Cylindrical shell 10, in addition to supporting drum 4, provides a protection barrier from misdirected alloy particles exiting from the sinuous passage.
In the operational mode, molten metal, such as ferroalloy, is fed into aperture in drum 4 and directed to contact projection 2. The rate of the metal feed is variable but must be slow enough to allow sufficient contact with rotating projection 2 so that the metal can be centrifugally projected and dispersed into the sinuous type passage 13 between drum 4 and anvil 1. With the anvil rotating, the dispersed metal particles are forced to roll and slide upon curvilinear surface 3 whereon each particle travels in a spiral path as exemplarily shown in FIG. 2. Each particle traveling in this spiral path is subjected to a radially applied centrifugal force A and a circular or rotating force B which is normal to force A and together the forces subject the particle to maximum circumferential contact with surface 3 of revolving anvil l. The molten spheroidally forming particles are then tangentially projected onto the curvilinear undersurface 12 of the drum where they continue to roll thus increasing the rolling contact acting thereon. A greater roll contact between the spheroidally formed particles and the drum can be obtained by rotating drum 4 in a counter direction to that of anvil 1.
The somewhat spheroidal to spherical particles 11 are then ejected at peripheral outlet 15 in a downward direction into a receiving receptacle 9. A quenching medium of any non-reactive gas or liquid, such as water, oil, molten salt, molten glass or any combination thereof, quickly solidifies the particles into their adopted shapes. A jet of cold air disposed in the vicinity between the passage outlet and the receptacle may also be used to effect solidification of the particles. A screen-like net or mesh liner within the receptacle may be employed for facilitating the removal of the particles. It is also possible to employ a revolving type mesh liner which could be used to direct the particles to a preselected section in the receptacle where a conveyor, inclined radially outward through a suitable opening in the lower portion of the cylindrical shell, would continuously remove the particles and direct them into a collection container.
Since conical projection 2 continuously contacts the molten metal feed thereby being subject to wear. it may be made replaceable by providing a threaded or geometrically shaped lower portion which can be threaded or inserted into a mating recess in the center of the anvil.
The degree of the curvilinear passage, as to slope and the number of peaks, is variable and depends on the degree of sphere required for the solidified alloy. The peripheral outlet of the passage may terminate with a positive slope thereby directing the exiting alloy particles in an upward direction.
Molten ferroalloys suitable for use with this apparatus include ferrosilicon, ferromanganese, ferrochrome, ferrochrome silicon, magnesium ferrosilicon, silicomanganese and the like.
EXAMPLE Using an apparatus similar to that shown in the drawing, several heats of molten 50 percent ferrosilicon, each weighing about 30 pounds, was poured into the central opening of a graphite drum to contact a rotating conical protrusion of a graphite anvil. The conical protrusion broke the stream of ferrosilicon into small particles and discharged them into a sinuous passage similar to that shown in the drawing. The ferrosilicon particles were made to spirally roll and slide upon the revolving anvil and then were tangentially projected to contact and roll upon the under curvilinear surface of the drum. The particles under the force of surface tension and roll contact action were influenced into adopting a somewhat spheroidal to spherical shape by the time they reached the peripheral outlet of the passage. They were then discharged from the sinuous passage and caught in a plurality of circular receptacles positioned below and concentrically outward from the passage outlet. The receptacles were filled with water which immediately quenched the caught ferrosilicon particles into their adopted shapes, such shapes being somewhat spheroidal to spherical in configuration.
The solidified particles were then subjected to a screen analysis test and found to contain 92 percent by weight sized between 8 Tyler mesh and Mpjnch.
The term somewhat spheroidal is intended to mean the shape of discrete particles, such as shots or pellets, which may have protrusions disfiguring a true spheroidal shape. These protrusions occur from the solidification of the particles prior to the particles assuming a true spheroidal to spherical shape. Although the particles depart from a true spheroidal to spherical shape, they are still commercially usable as long as they fall within a particular size range.
It is to be understood that a higher percentage of uniformly shaped particles can be obtained by rotating the drum of the apparatus of this invention in a counter direction to that of its mating rotating anvil and/or by extending the radial length of the sinuous passage so formed by the drum and anvil since either or both of these modifications will increase the spiral path upon which the particles will roll thereby subjecting the particles to a greater circumferential contact with the surfaces of the passage. This increased circumferential contact, due to the increased radial and circular rolling motion imparted to the particles, will aid in influencing the particles to adopt a more spheroidal shaped configuration.
What is claimed is:
1. An apparatus for disintegrating molten liquids into somewhat spheroidal to spherical configuations comprising a rotatable circular drum having a centrally located opening through which the liquid can flow; a power driven rotatable circular anvil concentric with and located below said drum; said drum and said anvil being rotatable in opposite directions; said anvil having a conically shaped center projection directly under the opening in the drum and a curvilinear upper surface extending radially outward from said projection which mates with and is spaced apart from a similar curvilinear lower surface on said drum; said curvilinear surfaces forming a sinuous passage having at least one peak through which the liquid can be centrifugally passed; and a circumferential receiving receptacle containing a quenching medium positioned radially outward from, concentric with and below the peripheral outlet of said sinuous passage so as to be in a position to catch the exiting spheroidal configurations from the outlet.
2. The apparatus of claim 1 wherein the circumferential receptacle is filled with a quenching material selected from a group consisting of water, oil, liquid salt, liquid silicon, liquid glass and mixtures thereof in any and all proportions.
3. The apparatus of claim 1 wherein the conical shaped projection at the center of the anvil is replacable.
4. The apparatus of claim 1 wherein at least one of the surfaces of the sinuous passage is made from at least one material selected from a group consisting of graphite. alumina, magnesia, and cast-iron.
5. The apparatus of claim 1 wherein the peripheral outlet of the sinuous passage is downwardly directed.
6. The apparatus of claim 1 wherein the opening of the inlet sinuous passage is adjustable.
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