CA1129834A - Spheroidal particles - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Recovery of industrial or sorted collector's waste containing at least one malleable, thin sectioned material such as copper, tin, lead, silver, aluminum or malleable alloys and/or plastic materials which are malleable at selected temperatures, such as thermoplastics and thermo-plastic rubbers, is accomplished in a dry process by first cutting and/or grinding to a suitable size and thereafter impacting in a manner to form the malleable materials into spheroids having apparent densities in proportion to their malleabilities. Thereafter, the spheriods are more easily and effectively separated by conventional means, such as gravity tables. The resultant polished spherized or shotted material is more effectively re-used and con-stitutes an upgraded product.

Description

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This invention relates to spheroidal particles, and more particularly to a mass of spheroidal particles, each havin~ a hammered surface structure and an interior less dense than its exterior.
This is a divi~ion of copending Canadian Patent Application Serial No. 312,904, filed Octobex 6, 1978.
In the art of reco~ering waste materials and, more particularly, mixed waste materials as well as industrial processing trim, rejects, scrap, punching trim, laminated waste and especially waste containing at least one thin sectioned product~ prior metals separating art has-en-countered difficulty in effecting separation by the usual properties of magnetism, density, and size.
Platelets contained in shredded waste do not respond well to the air floation and vibratory conveying actions of conventional separation "gravity tables."
Platelets may, after cutting, remain flat ox may be rumpled, folded, or rolled into tubes or other forms which give no constant and predictable "apparent density" or "apparent specific gravity" which is the property enabling separation to occur on the "gravity table" separators.
Furthermore conventional art can satisfactorily effect certain separations, such as separating shredded waste toothpaste tubes from residual.paste, plastic caps and iron closure clips, but such thin walled flake-like product is of very low value because it is so bulky to handle, so poor a heat exchanger that it melts slowly in remelt furnaces and oxidizes to a damaging degree in so doing because of the great surface area exposed to the heat and air. Beer motor oil, and soft drink cans similarly may be reclaimed from mixed wastes by hand sorting, but also represent high labor cost and low valued products because of similar reasons plus the fact that if tm/~

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they are not shredded and merely baled or briquetted, the contained moisture, residual product, dirt, ink enamel contamination, and foreign metal and non-metal contamin-ation lowers the value even Eurther.
In addition to the above mentioned, othe~ examples of waste having thin wal'ed components are: coaxial cable, heat exchanger tubing consisting of thin walled copper and aluminum and sometimes solder, printed circuit boards and other metal-plastic laminates, assorted electronic circuit assemblies, condensers, transformers, canned relays and condensers, and future mixed metal and plastic laminates currently being tested for solar heating systems.
Prior reclaimed metals separation art, using the dry process, consists essentially of the ~eneral steps of:
(1) gross manual separation ~2) reduction to ~ir~eyable size and polishing the discrete ~articles (3) magnetic separation of iron (this may occur at several locations) (4) particle sizin~ ~y grading screens and (S) speci~ic gravity separations.
Separations are based on magnetic rem~Ya1 of iron and on di$$erences of speci~ic gravity or density o$
whatever shaped particles are being separated. Because particle shapes vary so ~re~tly, we use the terms "apparent density" or "apparent specifi~ ~ravity". An air blast acts defferently on a flat platelet or short piece of fine wire than it does on a denser rouna sphere.
This makes possible the separation of fine wire or platelets or flakes from coarser wire and other denser cg/f~ - -.

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shapes of the same metal having higher apparent density.
Since this is not the goal o~ the recovery system, it becomes a handicap because the flakes and fine wires of copper may float along with larger but heavier, higher apparent density aluminum particles.
Prior art provided no method for efficiently making separations of all unlike shapes of different materials.
According to the present invention there is provided a mass of spheroidal particles each having a hammered sur~ace texture and an interior less dense than its exterior produced by the process of successively and repetitivel~ impactively accelerating a particulate feed material, i~lpactively decelerating the material and i~pactively reaccelerating the material by ~eans of at least one moving surface which throws the material through an air space against a contained target surface which is spaced from the moving surface by a minimum I
distance greater than the maximum individual dimensions of the feed ma$erial, the spheroidal particles havin~ relative apparent densities varying in proportion to their malleability.
The mixed shaped separation problems are eliminated by converting all materials which are to be separated on the gravity tab~es to roughly sperical lumps or spheroids and thereafter grading them to size. Thus, the gravity tables are comparing the apparent specific gravities of metals in comparative shapes and si~es and thus eliminate the dissimilar-ities caused by odd shapes. Added advantages consist in the fact that when fine wire is spherized, it no longer is inclined to plug the sizing and separator screens as it usually does. Aside from the advantages of processing the spherized material during separation/ there is an added valuable advantage in the fact that the end product(s3 are dense free-flowing easier melting/ polished metal shot which tm/' -3-3~
which brings a premium price on the market. ~ince the separations are much more efficient, the analysis also may be held to closer tolerances, giving further reas~n to command a premium market price.
Feed materials are processed in the same manner as used in prior art except that after reductlon to s~ze, the material may in some cases be ed directly to the spherl~er and then, after grading or sizing, to the ~ravity tables~
In case there is too much extraneous matter such as insulation, this may be removed on a gravity table before passing the metal to the spherizer. Sizing and separations of similarly sized fractions follow us with prior art.
Thus it should be emphasized that the use of the spherizing step may be variably introduced into the sequence of the operation depending upon the material mixture being processed. The use of spherizing be-Eore final separa~ion is the only critical feature of the sequence of the process.
The contributi~n to the art cf this process consists essentially in its ability to effect more efficient separations and to produce a better physical shape for form of the product based at least partly on the differences in ductility and/or malleability of different metals or alloys thereof.
~ t is essential to understand the uniqueness of mechanism and its action in producing a spheroid particle of metal or other malleable or ductile material in order to understand the process.
An interesting feature of the invention is that a thin particle is crumpled a little each time it is struck plus the fact that a free moving particle of irregular shape will align itself, as a dart does, with its least dense part in the rear, so that each blade blow crushes the most irregulàr part of the particleand thereby forms a roughly sperical or spheroided particle. This concept tm/l~ , ~7~ 33'~
seems to explain the resul-ts obtained; but since the explanation followed the discovery of the method and was suggested by another person, it is only submit-ted to help understand the process.
The degree of densification varies with the malle-ability of each metal or alloy. Platelets of sh~edded electrical assemblies containing spring bronze relay arms mixed with copper, aluminum, and brass terminal strips may be spherized. The hard bronze will respond least to the impacting while the soft copper will form the densest shot of spheres. Aluminum in most of its forms work hardens more than copper so it is inclined to form less dense spheres. Most brasses respond well but some hard brasses may be separated from softer grades.
The above generalizations change at elevated temperatures. A mill with a 42" diameter rotor can work heat particles to red heat if operated at high speeds (e.g. 1200 rpm). At such temperatures most metals are annealed tm~ ; -5-~ ~ ~J~ ~ 3 and become ductile and form dense spheriods. By control of temperature ~nd speedJ metals having dif;Eerin~ ~nneal-ing temperatures may be processed. For maximum flexibility, efficiency, and safety, it is advisable t~ provid~
temperature controls. This may be e~sily accomplished by circulation of he~ted or cooling air in suitable channels in the ~raming and control o~ throughput air volumes. ~he cooling air ma~ simply be circulated as coolant or may be used as a means of assisting in conveying the finished ~roduct. When elevated temperatures are desirable or a controlled non-oxidizing ~luid is pre~erred to ~ir, such may be re-circulated through the jacket ducts and then separated ~rom the end product at a cyclone and be re-ci~culated repeatedly. Added advantages result from use of "burned air!' as a carrier fluid when processing magnesium~containing products which are otherwise hazardous.
- ~Definitions , .. .
The following terms as used herein a~e defined as follows;
malleable material; Material which may be permanently formed or de$ormed by the blo~ o~ a tool or other impact~
spheroid: A shape roughly approximating a sphere such as a hammered particle~
sphe-rizer. A machine which beats or impacts other shapes into spheroidal shape. E~Go short pieces of cylindxical or square wire, shredded sheet, ~ragments of gxanulated aluminum or other metal casting or plate ! as ~ell as certain malleable plastic particles.
granulator~ A multi-pladed rotor turnin~ within a case . _ .
iikewise equipped with blades as well as a size controlling exit screen used to chop or cut plastics/ softer metals and the like into granules. A machine used to reduce X ~ 6 -cg ~

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material -to a desired granular size.
~ranules: Small particles which are airveyable or other-wise easily bulk handled and fed~ Sizes roughly range from a maximum dimension o~ 1" to a minimum of l/16". Below that si~e it can be called a powder.
impacting: This term is used in an ef~ort to avoid othex connotations of the word "beating" which implies the existance of an anvil or other support~ The word "swat"
would be more descriptive but perhaps unacceptableq The intent is to express both the blow of a moving surface as it strikes a free falling particle and also the collision of a pro~ected particle against a stationary or counter rotation target.
sizin~: Grading on a stacked or other screen as to size.
Reduction to size may be ~rinding in a granulator.
apparent _ nsity: (Also apparent specific ~ravity) The specific gravity ~f a porous or hollow spheroid as contrasted to the true specific gravity of the metal which forms the - shape.
shot: A roughly spherical particle - usuall~ solid in section. Shot results from meltin~ metal and droppin~ it throu~h an air space or a dense particle approaching shot can be Eormed in a spherizer when a red hot ~ully annealed particle is i~pacted suitably. Its density then approaches true metal density.
specif~ic gravity tables: Are weIl known by the semi-precious metals xecl~i~ing trade and one form consists of an uphill conveyin~ shaXer table combined with-an uPflow of air through the screen bottomed conyeying table which gives a simultaneous fluidized bed effect. These result in the heavier fractions climbiny uphill and out while the lighter material flows downward and out a separate Cg'b~

discharge port. The air lif-ting efEect is erratic wi-th non-spherical shapes and very effective with spherical mixtures of similar size. The apparent specific gravity of a particle determines both its conveying and fluidizing response.
acceleration and deceleration: A just-fed part~cle ~g swatted or impactea and given the speed of the rotor or accelerated. Upon stxiking a rib on the case liner, it slows down and glances a~ay a~ a decelorated particle.
Because it is moving more slowly than the rotor, it is swatted from the rear (which action crumples that part of it) and reaccelerated. This action i~ repeated at high frequency in a spherizer.
- unsupported traj~ctory: Is herein used to insure that the explanation of the action of processin~ particl2s in a machine with stationary (or possible counter-rotating~ ribs and rotary blades is not confused with usual ~rinding, smearing or shearin~ action. By keeping the rotor members well-spaced from the stationary-members, a bo~ncing and swatting sequence exists~ The use of closely adjusted rotor members would defeat the desired action and cause dust by grinding. If the particles were unable to bounce and glance o~f rotor and stator, there would be little or no formation of spheroids. An overloaded machlne blade just pushes a mass of ~eed material ahead o~ it and ~i~es a grinding action not unlike that of a ball mill and pro-duces dust. The use of an air path or unsuppoxted t~a~ec-tory is necessary for the desired hammerin~ action which cg/ ~

results from impacting or swatting the particles against one target surface at a time to cause spheroid formation.
A single surface impaction is not a beating or hammering on an anvil which would compact the inner structure of the spheroid.
blade: The replaceable hard alloy moving impact surface fitted to the tip of each paddle of the rotor - usually four to sixteen per rotor varying with diameter of rotor.
sweep air: Air or other gaseous transport fluid (as "burned air"
or other controlled at~ospheric) used to convey the ~arti ~ ate ~aterial through or from the spheriæer and to a cyclone or ~her collection device.
residence time: Time contained in processor.
target surface: Case liner or rib on liner against which an accelerated particle impinges or impacts.
carrier fluid: Medium, usually air, in which particles are conveyed. May be any gas, gas mixture, or in special cases a liquid.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagrammatic sectional view of an apparatus showing the manner in which the feed material undergoes spherizing;
Figure 2 is an elevational view of the apparatus with portions thereof broken away to illustrate the details of construction;
Figure 3 is a sectional view taken along line 3-3 of Figure 2 and viewed in the dire~tion of the arrows;
Figure 4 is a fragmentary view of the sectional liner plates as viewed from inside the case to the right of the door opening;
Figure 5 is a fragmentary view of the sectional liner plates as viewed from the inside looking left, Figure 6 is a view similar to Figure 5 with the liners removed; and tm//:, _9_ 3 L~
Figure 7 is a dia~ram~ltic r~presen~tion of the apparatus - and method forreproducing the mass of spheroidal particles according bo the present invention.
DETAILED DFSCRIPTION
A preferred form of apparatus is illustrated in E'igures 2 and 3. This spherizing apparatus or "shok mill"
consists of a case assembly provided with a feed assembly, a rotor assembly and drive means. The feed assembly (4) consists of a rotary feed ~5) which controls feed rate as well as prevents massive air inflow. The feed hopper (l0) may be equipped with baffles to prevent particles from being thrown back by the rotor and is fitted with an air intake nozzle 112) which contains an air flow control damper (13). The hopper (l0) is mounted on the door (6) which is equipped with hinges (8) and lock tabs (7) and held by lock bolts (9).
The case assembly consists of an outer shell (14), back plate (15), supports (l9), baseplate ~20), inner structural ribs (16) which also form temperature control cooling air ducts (see Figure 6) which supply air introduced at inlet nozzle (17~ for conveying the processed material when that air flow joins the inner air flow admitted at (12) and egresses through the product discharge port (lB).
A clean-out port (21) is provided under the grating to assist in removing the grating and removing foreign metal when a grade change is being made.
The case assembly is fitted with a removable liner tm/, ,~." -10-support shell (24) and a wear resisting liner (25~ This liner is fitted with ribs (3) as in Fiqures 1, ?~ 3/_4_ &_5!
either by casting or by welding application. The liner may be a heavy rolled shee~ or may be an assembly of sec~ions which may be chill cast~ Figurés 2 and 3 illustrate two sectional rings ~ormed i~to a liner. The shell (24) and liner (25) are fitted with outlet ports and grating (26) (also see section Figure 4, 5, 6)o The rotor assembly consists of a hub (27) which carries feed acceleration fan blades (28) and support discs (29) having air recirculation holes (30) suitable disposed.
The discs (29) carry blade support plates (31) which in turn carry wear resisting impacting blades ~32) which are the equivalent of the schematic moving impact plate (2? f Figure 1.
The rotor assembly is carried by d~i~e shaft (33) supportea by main bearing (34) and optionally by an out-board removable bearing (35~ indicated for larger machines, and shown only in the schematic drawing ~igure 7O
Drive coupling (361 connects with drive motor (37) which is controlled by console (38). Also see Figure 7.
In Figure 7, the product discharged from (18) is ducted to blower equipped cyclone (39~ which discharges pressured air to ease secondary air inlet (172 and air inlet nozzle (12) with excess air discharged to yent. Cyclone (39) drops the spherized metal mix into sizing scXeen (40 which supplies gravity tables (57~591 with ~aterial ~or separation using equipment standard to known art Figure 1 shows liner plates (25~ with ribs 3r 3b~
3c, & 3d consisting of either hardface welded rid~es, weld attached matrices containing granular carbides or other abrasion resistant ridges having crossectional shapes cg/ ~

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yenf~rally approximating the forms of either, 3b, 3c, or 3d, however attached.
Figure 4 shows the sectional liner plates as viewed rom inside -the case -to the ri~ht of the door openin~
and shows target ridges (3) which are generally par~llel to the axes of the case in the forward liner while the rear liner exhibits angled ridges whose angles ser~e to aid in moving tXe circulating material toward the rear where the exit grating is located. The short reverse angled 10 target ribs (3) assist in minimizing abrasive wear of the s edge of that liner which abuts the rear wall ~15), (not shown~. The angles of these angled ridges are exa~erated but show that effective tar~et deflecting is possible even with non-axial ridges.
Figure 5 is similar to Fi~ure 4 except vie~ed from inside looking left at 6:0Q to 7:00 to show the e~it grating - -(261 as well as straight and angles ribs (3)u Fi~ure 6 shows the sa~e view as ~igure 5 but with both the liner ~25~ and liner support (24~ removed to sho~ the crossoVer 20 section of the reinforcing rings (16) which f~rm the ductS
for cooling and product remova~ sweep air which joins the air carrying the processed materIal throu~h the grating - ~26~ and convey the product (1~ out (~8) and to the cyclone (39~ ~see Fi~u~e 7).
E~a,-m~lè 1 Radiators consisting of mixed ~ins and tubiny of aluminum and copper-are reduced to small ~ra~ments ~ kno~n means such as "a,lligator~ shears, "Cumberland'l tor other~
granulators and the like. The resultant mixed metal leaf-lets are separated from the non-metallic carrier material and fed to a spher}~er as herein above described. This machine processes the feed material as below described.

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. The rotary ~eed~r (5) Fi~ures 2 and 3 drops the feed material (l) into hopper (lO) where controlled air flow entering (12) sweeps it into the machine. Its residence time in the machine is controlled by air damper.(131. ~s the ~ragments are bounced back and forth between blades (32) and the ribs (3) on ~he liner (25), they becorne ~en-erally spherical in shape and in such denser form exit through grid (26). An intense air eddy condition exists within the impactin~ area in the mill which ef~ect is aided by the fan like action of the wide blade support plates (31) and the holes (30) which interconnect the chambers : formed by the rotor discs ~29).
Upon dropping or being mildly blown through the ~rid (26), the dense spheres need more air flow to transport them up to a cyclonic separator. Such secondary air is provided by air enterin~ inlet (17) where it exits throu~h outlet (.18~, mixed with sweep air which entered through (12~. If an excess of sweep air were passed through the inside of the case, it could reduce residence ti~e to giye insuf~icient or incomplete spherizing~
The con~eyed product is separated from its con-veying air by cyclone (~9). and dropped into a Sweco sizing screen (40~ shown in ~i~ure ~. Each discharge port sup~lies a gravity table final separation. device~ AfteE separation~
the dense spherize.d produce is suitably packaged for sale or other conversiQn.
Copper separations may eas1l~ be obta~ined ~ith less than 3% maximum aluminum content and, under close super-vision, copper purity of 98~99~ may be obtained.
- Example II
. A mixed feed material compos~d of electronic waste - material such as old radios, telephone switchboard and cg/~

relay station equipment and the like is pulverized and granulated into a mixture of particles containiny non-metal such as plastic, glass, porcelain and carbon mixed with , particul~te and thin sheet me-tallic particles f~om "printed circuitry" containin~ iron, bronze, silver contac-ts, alum~
inum sheets chasis and/or condenser ~oil, plus copper wire and copper foil, as well as a fair amount of soldered wire ends and soldered terminals of copper or brass.
This feed mix after size reduction is freed of its non-metallic content on gravity tables, the iron is removed by means of magnetic belts and the remaining mixture of metals run throu~h a room temperature spherizer to avoid losing the solder.
The spherized mix is graded into sizes and each size subdivided by gravity tables using the well-known fluid-ized bed and conveying vibration screen method. Spherized pellets of leaded copper, copper and bronze may be separ-ated from less dense spheriods of brass, hard bronze, and aluminum. Subse~uent passes over more closel~ adjusted gravity screens can separate these fractions. Even copper coated aluminum wir~'can be separated fro~ co~per wire and aluminum wire. Silver contacts and soldered terminals may be separated from the copper ~raction in closel~ ad-justed fxactionatin~ of spheroids using s~eci~ic ~raVity tables due to the fact that the malleabilities and work hardening properties dif~er.
Example III
In Example III, fragmented scrap br~ss tubing and sheet is separated from an antimony-bismuth-lead allot used in bending brass tubing in the manufacture of wind instruments.
While this separation can be accomplished by other simpler means, it serves as an example of separating ductile brass cg/ ~

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from a non-ductile metal which under high speed impaction is converted to dust and thus separated in a cyclonic separator followed by a bay collector for the metal dust.
Example IV
When a spherizer is Eed shredded, particula~e, hard bronze sprin~ me~al and operated at hi~h surface velocity and temperature, the particles reach or approach "red heat"
and become annealed enough to become malleable and form-able into spheroids. The change in physical form rendexs lD the material more easily handleable and enhances its market value. Separation follows the same general steps as in Example 1.
Example V
Heavily lacquered aluminum containers and enameled aluminum magnet wire often are problems to recoyer~ Ma-terial to be reclaimed is precut to feedable size and spherized at a temperature hot enough to burn off the in-sulation and lacquers. The lacquer pigment is ~reed from the metal in the spheriæer~ burnished and separated in suitable dust collectors without need for the usual grind~
ing and polishing with a carrier medium as in a series of granulators. Wire which was unrecoverable by con~entional means has been spherized and reclaimed in up~raded farm.
- Used toothpaste tubes and aluminum cans ~lso ma~ be xe-covered without "burning o~"~in a furnace and baling.
Exam ~
- A particulate mixture of cured thérmosettiny plastic such as phenolic molded parts mixed with a particulate thermoplastic material of similar specific gravity such as granulated polyvinyl chloride is obtained by ~rinding up plastic waste~
When this mix is fed through a spherizer at a temper-cg ~ ~

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ature just adequate to render the PVC deformable but not tacky, it forms beads while the hard thermoset particles are milled to dust i~ ~iven adequate residence time~ The warm rubbery PVC is easily separated fro~ the thermoset dust - in suitable cyclones or on simple sizing scxeens.
This separation is made possible by usin~ the malleability of the thermoplastic material at the speci~ic or selected temperature where malleablility is acquired and is characteristic of each given material. Similarly, heated polystyrene or mathacrylic can be separated from brittle thermoset materials or! i~ cold and brittle them-selves, may be shattered to dust and separated fro~ ductile or tough materials at room temperature such as certajin nylons~ polyolefins or polycarbonates~
~hile the general type o~ apparatus is typically presented in Figures 2 t 3 & 7~ It must be understood that any mechanism which`employs a ~oving surface and a station- ~-ary surface in a non-contacting relatiQnship - separated by at least the maximum dimension of a particulate ~eed material (preferably by a greater separation e~ual to ~rom

2 to 10 times the particulate feed mater~als maximum dimen-sion) where the difference in surace speeds o~ the two surfaces is oVer 5,000 S~M (and~where meanS fox ~eedingr containing, and withdrawing the product are pro~ided~ co~es within the scope of the herein tau~ht art.
The particular mechanism described i5 described as running in a continuous rather than as a batch txeatment.
It is obvious that the machine can discharge into a stor-age container and recycle the same batch of materiaL xepeat-edly until a desired degree of treatment is obtained and thus constitute a "batch" process. Therefore the process is capable of either batch or continuous operation although cg~

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a con~inuous operation is usually preferable. Either arrangement is consi~ered as taught by this subject process.
~ he process carried out by the described appara-tus consists in projec~ing and impactin~ a feed material or mixed Eeed containiny at leask one malleable component ~o form it into spheroid shape. Said generally spherical shaped particle is uniform and easily separable from a mix-ture of non-malleable par~icles.
It is especially effective to form all contained feed material into spheroids because, if spherized to each material's ultimate or true density, spherical shapes com-posed of differen.t materials are easily and precisçly separated on efficient "gravity tables".
The spherizing process, however, opens a new concept:
the use of the fact that no two metals ~ork harden to ex-actly the same de~ree at the same temper~ture (unless the temperature is above the annealing temperature of both metals) and consequen.tly don't compact equally to their ultimate density~ Diferences in the resulting Apparent Density or ~SO determine the ease of separation on gravity tables. It just so happens that in gene~al the heaviest .metals are intrinsically more malleable than the lighter and work harden less. Therefore aluminum~ for example, in addition to being in.trinsically lighter~ forms even lighter spher~ids with.lower apparent specific ~ravlt~, This makes its separation fro~ copper eyen easier than it - would be if dense aluminu~ spheres of.true speci~ic graVity resulted ~ ~s melted shot~
Because of the uniqueness of the process and of the purity of the products obtaInable, this process consti-tutes a valuable addition to the art of metals se~ration and recovery.

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Because either annealed or work hardened metal shot can be produced by control of speed, residence time, and temperature, the produck itself is new, unique and useful. It is easily identified by its surface texture, even in its porous or low specific ~ravity, spherical, work hardened form, it is easily poured and fed into shape ~orm-ing cold pressing dies or remelting furnaces.
In its annealed form with higher or even ultimate density (if melted or hot forged in the spherizer), the particles are easily identified under the microscope by their impacted surfaces. These denser, annealed spheres comprise a new and useful raw material suited to automatic shape-making operations as well as for remeltingO
Although this process has been in commercial oper-ation for a few months, there has been insufficient time to establish critical s~eeds and all tem~erature ef~ects.
simple primi~ive test with a mod~fied fan-like device established that the method was workable4 Bi~er units -~
were immediately put to work at higher and higher sur~ace speeds. Representative s~eeds employed and ~ound effective are lO,OQ0/15,00Q surface feet per minute, although slower speeds (eOg. S,Q00 SPM) may be adequate for certain separ-ations. Also to be mentioned is the observation that when the "blades" (32) are fitted with less than 1~4' clearance from the liner ribs ~3), a dust forming ~roblem arises. Preferred blade clearances appear to be from 5~"
to 1 1~4" when processing feed material passing 1~2" to 1" screens in the granulators although a detailed study i5 yet to be made~ It is interesting to note that the patent literature is full o~ described equipment having close blade clearance and used to make metallic dusts, but none mention use of wide separation of blade-to-rib to make X ~ 18 -cg~ ~ -3g~
shot-like spheroids. Neither is mention made of the use of elevated temperatures.
One limitation of the process should be kept in mind; very soft metals like tin-lead solders tend to plate or burnish on~o other metals if severely impacted, especially at elevated temperatures.
Also bear in mind that brittle metals 5uch as certain zinc alloys, "type metal" alloys containing antimony, and alloys of bismuth, silicon and the like, may break into dust and thus be separated and collected as dust from mixtures of spheroided malleable metals such as aluminum and/or copper. The ~inal dust collection equipment is known art for other industries, but the process for im-pacting the malleable fraction in a device o th~ described type to make dense spheroids which separate from metal dusts is new art. Use of the described impar~ing device to selectively made dusts of those particles havin~ a given degree of friability is also new art. It does not just grind everything in the mixture tb dust as do usual machines haviny no control of grinding intensity~
It should be pointed out specifically that the ~rocess consists in the swatting and bounciny of ductile material fragments instead of cutting same. The impacting surfaces (2) or "blades" (32) are made of hard alloy not because they must cut, as in a granulator, but because they must resist a special type of high speed wear whlch is perhaps enchanced by the presence of metal oxide fil~s on the metals being processed. In any eVent,a mild steel blade (32~ will not last many hours even when processin~
3Q shredded copper foil rom which its printed circuit boards has already been removed in earlier granulation and separ-ation steps.

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It is considered quite probable that the disinte-gration equipment used in the well known equipment for "micronizing" of friable powders using compressed air to accelerate and convey particulate material to and agains-t a targets would, if tested with malleable materials likewise form spheroidal products. Such systems, however, would be probably be economically non-competitive with the present invention when used with the heavier, larger, bulkier, and irregular types o metallic feed materials encountered with metals reclamationO
It is expected that the combination of the ability to spherize malleable metals by means of this process; -which also has the ability to shatter brittle metals : :
and even, if specifically designed for the purpose, form particulate granules of lathe turnings composed of steel, gray iron and the like ~ with its shatterin~ action on brittle materials, may well lead to broaa usage for sal-~ ~ 20 -cg//~"

vaging much of the small part mixed metal was-te not presently reused.
A new line of products consisting of controllable specific gravity spheroids of assorted metals is presented.
The process for making same is described and an apparatus for accomplishing the process are given .tn detailed drawings. 'rhese are additions to the art of metals separations and recovery but also contribute new products which are raw materials capable of being used for other new products. The above-described apparatus and process are also described and are claimed in applicant's above-identified parent Application Serial No. 312,904.

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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1, A mass of spheroidal particles each having a hammered surface texture and an interior less dense than its exterior produced by the process of successively and repetitively impact-ively accelerating a particulate feed material, impactively de-celerating the material and impactively reaccelerating the material by means of at least one moving surface which throws the material through an air space against a contained target surface which is spaced from the moving surface by a minimum distance greater than the maximum individual dimensions of the feed material, said spheroidal particles having relative ap-parent densities varying in proportion to their malleability.

2. The spheroidal particle of Claim 1 wherein its diameter does not exceed one-half inch.

3. A metal spheroidal particle according to Claim 1 wherein the apparent specific gravity thereof is less than the specific gravity of the contained metal.

4. A metal spheroidal particle according to Claim 1 which has been heated and annealed while being impacted so as to be a completely annealed spheroid.

5. A metal spheroidal particle according to Claim 1 which has been heated and impacted in a non-oxidizing gaseous fluid to give the resultant spheroid an impact textured, unoxidized surface.

6. The spheroidal particle of Claim 1 which is formed from a fragment of malleable wire.