GB2084055A - Particles of reclaimed materials - Google Patents

Abstract

Spheroidal particles are made from reclaimed industrial or sorted collector's waste which contains at least one malleable, thin-sectioned material such, for example, as copper, tin, lead, silver, aluminium or malleable alloys and/or plastics materials which are malleable at selected temperatures such, for example, as thermoplastics and thermoplastic rubbers. The particles have a hammered surface texture and an interior which is less dense than its exterior, and also have apparent densities proportional to their malleabilities. The particles have diameters not greater than one-half of one inch. <IMAGE>

Description

SPECIFICATION Particles of reclaimed materials In the recovery of waste materials and, more particu larly 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, the prior art has encountered difficulty in effecting separation by the usual properties of magnetism, density, and size.

The following terms as used herein are defined as follows: maleable material: Material which may be perma nently formed or deformed by the blow of a tool or other impact.

spherioid: A shape roughly approximating a sphere such as a hammered particle.

spherizer: A machine which beats or impacts other shapes into spheroidal shape, for example, short pieces of cylindrical or square wire, shredded sheet, fragments of granulated aluminium or other metal casting or plate, as well as certain malleable particles of plastics materials.

granulator: A multi-bladed rotor turning within a case likewise 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 to a desired granular size.

granules: Small particles which are conveyable by air or otherwise easily bulk-handled and fed. Sizes roughly range from a maximum dimension of 1" two a minimum of 1/16". Below that size it can be called a powder.

impacting: This term is used in an effort two avoid other connotations of the word "beating" which implies the existence of an anvil or other support.

The word "swat" would be more descriptive but perhaps unacceptable. 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 projected particle against a stationary or counter rotation target.

sizing: Grading on a stacked or other screen as to size. Reduction to size may be grinding in a granulator.

apparent density (also called apparent specific gravity): The specific gravity of a porous or hollow spheroid in contradistinction to the true specific gravity of the metal which forms the shape.

shot: A roughly spherical particle, usually solid in section. Shot results from melting metal and dropping it through an air space our a dense particle approaching shot can be formed in a spherizer when a red hot fully annealed particle is impacted suitably.

Its density then approaches true metal density.

specific gravity tables: These are well known in the semi-precious metals reclaiming trade and one form consists of an uphill conveying shaker table combined with an upflow of air through the screen bottomed conveying table which gives a simultaneous fluidized bed effect. These result in the heavierfractionsclimbing uphill and out while the lighter material flows downward and out a separate discharge port. The air lifting effect is erratic with non-spherical shapes and very effective with spher ical mixtures of similar size. The apparent specific gravity of a particle determines both its conveying and fluidizing response.

acceleration and deceleration: A just-fed particle is swatted or impacted and given the speed of the rotor or accelerated. Upon striking a rib on the case liner, it slows down and glances away as a decelerated particle. Because it is moving more slowly than the rotor, it is swatted from the read (which action crumples that part of it) and is thus reaccelerated.

This action is repeated at high frequency in a spherizer.

unsupported trajectory: Is herein used to ensure that the explanation of the action of processing particles in a machine with stationary (possibly counter-rotating) ribs and rotary blades is not confused with usual grinding, smearing or shearing action. By keeping the rotor members well-spaced from the stationary members, a bouncing and swatting sequence is obtained. 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 off rotor and stator, there would be little or no formation of spheroids. An overloaded machine blade just pushes a mass of feed material ahead of it and gives a grinding action not unlike that of a ball mill and produces dust.The use of an air path or unsupported trajectory is necessary for the desired hammering action which 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 depending on the diameter of rotor.

sweep air: Air or other gaseous transport fluid (as "burned air" or other controlled atmospheric) used to convey the particulate material-through or from the spherizer and to a cyclone or other 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 parti cles are conveyed; it may be any gas, gas mixture, or (in special cases) a liquid.

Platelets contained in shredded waste do not respond well to the air flotation and vibratory conveying actions of conventional separation "gravity tables". Platelets may, after cutting, remain flat or 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 reclaiming 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 labour cost and low valued products because of similar reasons plus the fact that if they are not shredded and merely baled or briquetted, the contained moisture, residual product, dirt, ink enamel contamination, and foreign metal and non-metal contamination all combine to lower the value even further.

In addition to the above-mentioned, other examples of waste having thin walled components are: coaxial cable, heat exchanger tubing consisting of thin walled copper and aluminium and sometimes solder, printed circuit boards and other metal-plastic laminates, assorted electronic circuit assemblies, condensers, transformers, canned relays and condensers, and 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 general steps of: (1) gross manual separation (2) reduction to airconveyable size and polishing the discrete particles (3) magnetic separation of iron (this may occur at several locations) (4) particle sizing by grading screens and (5) specific gravity separations.

Separations are based on magnetic removal of iron and on differences of specific gravity or density of whatever shaped particles are being separated.

Because particle shapes vary so greatly, the terms "apparent density" or "apparent specific gravity" are used herein. An air blast acts differently on a flat platelet or short piece of fine wire than it does on a denser round sphere. This makes possible the separation of fine wire or platelets or flakes from coarser wire and other denser shapes of the same metal having higher apparent density. Since this is not the goal of 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 aluminium particles.

The present invention consists in 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 impactively accelerating a particulate feed material, impactively decelerating 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 apparent densities varying in proportion to their malleability.

Preferably, the diameter of each spheroidal particle does not exceed one-half of an inch.

Preferably, the apparent specific gravity (as defined above) of each spheroidal particle is less than the specific gravity of the contained metal.

Each metal spheroidal particle may have been heated and annealed while being impacted so as to be a completely annealed spheroid.

Said mass may contain a metal spheroidal particle which has been heated and impacted in a nonoxidizing gaseous fluid to give the resultant spheroid an impact-textured, unoxidized surface.

Said mass may contain a spheroidal particle whic'n is formed from a fragment of malleable wire.

Feed materials are processed in the same manner as hitherto except that, after reduction to size, the material may in some cases be fed directly to the spherizer and then after grading or sizing, to the gravity 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 before final separation is the only critical feature of the sequence of the process. The contribution to the art of this process consists essentially in its ability to effect more efficient separations and to produce a better physical shape or form of the product based at least partly on the differences in ductility and/or malleability of different metals or alloys thereof.

It is essential to understand the uniqueness of the mechanism and its action which results in the production of a spheroid particle of metal or other malleable or ductile material according to the present invention. In its simplest form (see Figure 1), a platelet or flake of thin malleable metal is fed into a confined area having a rotary paddle and a stationarty case or case liner the inner surface of which has at least one ridge or interrupting surface usually approximately parallel to the axis of rotation of the paddles. The paddle strikes the just-fed slowermoving platelet and throws it against the stationary surface ridge. The impact with the ridge slows the particle down so that, as it glances off the ridge, it is again struck by a faster moving paddle. This continues until the particle escapes through a suitable exit.The interesting feature is that the 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 irregular part of the particle and thereby forms a roughly spherical or spheroidal particle. This concept seems to explain the results obtained; but since the explanation followed the discovery of the method and was suggested by another person, it is only submitted to help understand the process.

The degree of densification varies with the malieability of each metal or alloy. Platelets of shredded electrical assemblies containing spring bronze relay arms mixed with copper, aluminium, 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.

Aluminium, in most of its forms, work-hardens more than copper with the result that 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 and become ductile and form dense spheroids. By control of temperature and speed, metals having differing annealing temperatures may be processed. For maximum flexibility, efficiency, and safety, it is advisable to provide temperature controls; this may be easily accomplished by circulation of heated or cooling air in suitable channels in the framing and control of throughput air volumes. The cooling air may simply be circulated as coolant or may be used as a means of assisting in conveying the finished product.When elevated temperatures are desirable or a controlled non-oxidizing fluid is preferred to air, such may be re-circulated through the jacket ducts and then separated from the end product at a cyclone and be re-circulated repeatedly. Added advantages result from use of "burned air" as a carrier fluid when processing magnesium-containing products which are otherwise hazardous.

The present invention will now be more particularly described with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a diagrammatic sectional view of a portion of an apparatus which can be employed to produce spheroidal particles according to the present invention, 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 direction of the arrows; Figure 4 is a fragmentary view of 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 Figure 7 is a diagrammatic representation of the apparatus and a method of use thereof.

A preferred form of apparatus is illustrated in Figures 2 and 3. This spherizing apparatus or "shot 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 feeder 5 which controls feed rate as well as preventing massive air inflow. The feed hopper 10 may be equipped with baffles to prevent particles from being thrown back by the rotor and is fitted with an air intake nozzle 12 which contains an air flow control damper 13. The hopper 10 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 19, 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 18. 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 support shell 24 and a wear-resisting liner 25. This liner is fitted with ribs 3 as shown in Figures 1 to 5 either by casting or by welding application. The liner may be a heavy rolled sheet or may be an assembly of sections which may be chill cast. Figures 2 and 3 illustrate two sectional rings formed into a liner. The shell 24 and liner 25 are fitted with outlet ports and grating 26 (Figures 4to 6).

The rotor assembly consists of a hub 27 which carries feed-acceleration fan blades 28 and support discs 29 having air recirculation holes 30 suitably disposed. The discs 29 carry blade support plates 31 which in turn replaceable wear-resisting impacting blades 32 which are the equivalent of the schematic moving plate 2 of Figure 1.

The rotor assembly is carried by drive shaft 33 supported by main bearing 34, and optionally by an outboard removable bearing 35 for larger machines as shown only in the schematic Figure 7.

Drive coupling 36 connects with drive motor 37 which is controlled by console 38 (Figure 7).

In Figure 7, the product discharged from 18 is ducted to blower-equipped cyclone 39 which discharges pressured air to secondary air inlet 17 and air inlet nozzle 12 with excess air discharged to vent.

Cyclone 39 drops the spherized metal mix into sizing screen 40 which supplies gravity tables 57-59 with material for separation using equipment standard to the known art.

Figure 1 shows liner plates 25 with ribs 3, 3b, 3c and 3dconsisting of either hardfacewelded ridges, weld attached matrices containing granular carbides or other abrasion-resistant ridges having crosssectional shapes generally approximating the forms of either, 3b, 3c, or 3d, however attached.

Figure 4 shows the sectional liner plates as viewed from inside the case to the right of the door opening and shows target ridges 3 which are generally parallel to the axes of the case in the forward liner while the rear liner exhibits angled ridges whose angles serve to aid in moving the circulating material toward the rear where the exit grating is located. The short reyerse-angled target ribs 3 assist in minimizing abrasive wear of the edge of that liner which abuts the rear wall 15 (not shown). The angles of these angled ridges are exaggerated but show that effective target deflecting is possible even with non-axial ridges.

Figure 5 is similar to Figure 4 except viewed from inside looking left at between 6-o'clock and 7-o'clock to show the exit grating 26 as well as straight and angles ribs 3. Figure 6 shows the same view as Figure 5 but with both the liner 25 and liner support 24 removed to show the crossover section of the reinforcing rings 16 which form the ducts for cooling and product removal sweep air which joins the air carrying the processed material through the grating 26 and convey the product 1 out 18 and to the cyclone 39 (see Figure 7).

Example! Radiators consisting of mixed fins and tubing of aluminium and copper are reduced to small fragments by known means such as "alligator" shears, "Cumberland" (or other) granulators and the like.

The resultant mixed metal leaflets are separated from the non-metallic carrier material and fed to a spherizer as herein above described. This machine processes the feed material as described below.

The rotary feeder 5 (Figures 2 and 3) drops the feed material 1 into hopper 10 where controlled air flow entering 12 sweeps it into the machine. Its residence time in the machine is controlled by air damper 13. As the fragments are bounced back and forth between blades 32 and the ribs 3 on the liner 25, they become generally spherical in shape and, in such denser form, exit through grid 26. An intense air eddy condition exists within the impacting area in the mill, which effect is adided by the fan-iike 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 grid 26, the dense spheres need more air flow to transport them up to a cyclonic separator. Such secondary air is provided by air entering inlet 17 where it exits through 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 time to give insufficient or incomplete spherizing.

The conveyed product is separated from its conveying air by cyclone 39 and dropped into a sizing screen 40 shown in Figure 7. Each discharge port supplies a gravity table final separation device. After separation, the dense spherized product it suitably packaged for sale or other conversion.

Copper separations may easily be obtained with less than 3% maximum aluminium content and, under close supervision, copper purity of 98/99% may be obtained.

Example II A mixed feed material composed of electronic waste material such as old radios, telephone switchboard and relay station equipment and the like is pulverized and granulated into a mixture of particles containing non-metal such as plastics material, glass, porcelain and carbon mixed with particulate and thin sheet metallic particles from "printed circuitry" containing iron, bronze, silver contacts, aluminium sheet chassis and/or condenser foil, 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 from its non-metailic content on gravity tables, the iron is removed by means of magnetic belts and the remaining mixture of metals run through a room temperature spherizerto avoid losing the solder.

The spherized mix is graded into sizes and each size subdivided by gravity tables using the wellknown fluidized bed and conveying vibration screen method. Sperized pellets of leaded copper, copper and bronze may be separated from less dense spheroids of brass, hard bronze, and aluminium.

Subsequent passes over more closely adjusted gravity screens can separate these fractions. Even copper coated aluminium wire can be separated from copper wire and aluminium wire. Silver contacts and soldered terminals may be separated from the copper fraction in closely adjusted fractionating of spheroids using specific gravity tables due to the fact that the malleabilities and work-hardening properties differ.

Example III Fragmented scrap brass tubing and sheet is separated from an antimony-bismuth-lead alloy 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 from a non-ductile metal which, under high speed impaction, is converted to dust and thus separated in a cyclonic separator followed by a bag collector for the metal dust.

Example IV When a spherizer is fed with shredded, particulate, hard bronze spring metal and operated at high surface velocity and temperature, the particles reach or approach "red heat" and become annealed enough to become malleable and formable into spheroids. The change in physical form makes it possible to handle the material more easily and enhances its market value. Separation follows the same general steps as in Example 1.

Example V Heavily lacquered aluminium containers and enamelled aluminium magnet wire often are difficult to recover. Material to be reclaimed is precut to feedable size and spherized at a temperature hot enough to burn off the insulation and lacquers. The lacquer pigment is freed from the metal in the spherizer, burnished and separated in suitable dust collectors without need for the usual grinding and polishing with a carrier medium as in a series of granulators. Wire which was unrecoverable by conventional means has been spherized and reclaimed in upgraded form. Used toothpaste tubes and aluminium cans also may be recovered without "burning off" in a furnace and baling.

Example Vl A particulate mixture of cured thermosetting plastics material(s) such as phenolic molded parts mixed with a particulate thermoplastic plastics material(s) of similar specific gravity such as granulated polyvinyl chloride is obtained by grinding up waste of plastics materials.

When this mix is fed through a spherizer at a temperature just adequate to render the PVC deformabie but not tacky, it forms beads while the hard thermoset particles are milled to dust if given adequate residence time. The warm rubbery PVC is easily separated from the thermoset dust, for exam ple, in suitable cyclones or on simple sizing screens.

This separation is made possible by using the malleability of the thermoplastic material at the specific or selected temperature where mal lea bi lity is acquired and is characteristic of each given material. Similarly, heated polystyrene or methacry lic resins can be separated from brittle thermoset materials or, if cold and brittle themselves, may be shattered to dust and separated from ductile or tough materials at room temperature such as certain nylons, polyolefins or polycarbonates.

While the general type of apparatus used to produce spheroidal particles according to the pre sent invention is illustrated in Figures 2, 3 & 7, it must be understood that any mechanism which employs a moving surface and a stationary surface in a non-contacting relationship - separated by at least the maximum dimension of a particulate feed material (preferably by a distance equal to from 2 to 10 times the maximum dimension of the particulate feed materials) where the difference in surface speeds of the two surfaces is within the range from 5000 to 20,000 SFM (and where means for feeding, containing, and withdrawing the product are pro vided) will be suitable.

The particular mechanism described is described as running in a continuous rather than as a batch treatment. It is obvious that the machine can dis charge into a storage container and recycle the same batch of material repeatedly 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 a con tinuous operation is usually preferable.

The method carried out by the described appar atus consists in projecting and impacting a feed material or mixed feed containing at least one malleable component to form it into spheroid shape.

Said generally spherical shaped particle is uniform and easily separable from a mixture of non malleable particles.

It is especially effective to form all contained feed material into spheroids because, if spherized to the ultimate or true density of each material, spherical shapes composed of different materials are easily and precisely separated on efficient "gravity tables".

The spherizing method disclosed herein for the production of spheroidal particles according to the present invention, however, opens up a new con cept: the use of the fact that no two metals work-harden to exactly the same degree at the same temperature (unless the temperature is above the annealing temperature of both metals) and conse quently do not compact to an extent such as to equal their ultimate density. Differences in the resulting apparent Density or ASO determine the ease of separation on gravity tables. It just so happens that, in general, the heaviest metals are intrinsically more malleable than the lighter ones, and work-harden less.Thus, aluminium, for example, in addition to being intrinsically lighter, forms even lighter spher oids with lower apparent specific gravity; this makes its separation from copper even easier than it would be if dense aluminium spheres of true specific gravity resulted, as melted shot.

Because of the uniqueness of the method described above and of the purity of the products obtainable, a valuable addition to the art of metalsseparation and recovery is made by the present invention.

Because either annealed or work-hardened metal shot can be produced by control of speed, residence time, and temperature, the product (spheroidal particles) is useful; moreover, it is easily identified by its surface texture, even in its porour or low specific gravity, spherical, work-hardened form, it is easily poured and fed into shape-forming cold pressing dies or remelting furnaces.

In their 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 constitute a new and useful raw material suited to automatic shape-making operations as well as for remelting.

Although this process has been in commercial operation for a few months, there has been insufficlient time to establish critical speeds and all temperature effects. A simple primitive test with a modified fan-like device established that the method was workable. Bigger units were immediately put to work at higher and higher surface speeds. Representative speeds employed and found effective are 10,000/ 15,000 surface feet per minute, although slower speeds (e.g. 5,000 SFM) may be adequate for certain separations and higher speeds (e.g. up to 20,000 SFM) may be necessary for others. 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 problem arises.

Preferred blade clearances appear to be from 1/2" to 2" when processing feed material passing 1/2" to 1" screens in the granulators, although a detailed study is yet to be made. It is interesting to note that the patent literature is full of described equipment having close blade clearance and used to make metallic dusts, but none mentions the use of wide separation of blade-to-rib to make shot-like spheroids. Neither is mention made of the use of elevated temperatures.

One limitation of the method should be kept in mind; very soft metals like tin-lead solders tend to plate or burnish onto other metals if severely impacted, especially at elevated temperatures. Also to be borne in mind is the fact that brittle metals such as certain zinc alloys, "type metal" alloys containing antimony, and alloys of bismuth, silicon and the like, make break into dust and may thus be separated and collected as dust from mixtures of spheroided malleable metals such as aluminium and/or copper.

The final duct collection equipment is known art for other industries, but the process for impacting the malleable fraction in a device of the described type to make dense spheroids which separate from metal dusts is new art. Use of the described impacting device to selectively make dusts of those particles having a given degree of friability is also new art. it does not just grind everything in the mixture to dust as do machines having no control of grinding intensity.

It should be pointed out that the spheroidal particles according to the present invention are obtained by the swatting and bouncing 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 which is perhaps enhanced by the presence of metal oxide films on the metals being processed. In any event, a mild steel blade 32 will not last for many hours even when processing shredded copper foil which has already been separated from its supporting printed-circuit boards in earlier granulation and separation steps.

It is considered quite probable that the disintegration equipment used in the well known equipment for "micronizing" of friable powders using compressed air to accelerate and convey particulate material to and against a target would, if tested with malleable materials, likewise form spheroidal products. Such systems, however, would probably not be economically competitive with the system (described above with reference to the drawings) when used with the heavier, larger, bulkier, and irregular types of metallic feed materials encountered in metals reclamation.

It is expected that the combination of the ability to spherize malleable metals by means ofthe method described herein - which also has the abilityto shatter brittle metals and even, if specifically designed for the purpose, form particulate granules of lathe turnings composed of steel, gray iron and the iike-with its shattering action on brittle materials, may well lead to broad usage for salvaging much of the small part mixed metal waste not presently reused.

The apparatus, and the method(s) of operation thereof which produce(s) the spheroidal particles according to the present invention, is/are described and claimed in co-pending Patent Application No.

39310 of 1978.

Claims (7)

1. A mass of spheroidal particles each of said particles having a hammered surface texture and an interior less dense than its exterior produced by the process of successively and repetitively impactively accelerating a particulate feed material, impactively decelerating 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 apparent densities (as defined above) varying in proportion to their mallea bility.

2. Aspheroidal particle as claimed in Claim 1, wherein its diameter does not exceed one-half of one inch.

3. A spheroidal particle as claimed in Claim 1 or Claim 2, wherein the particle is metal and wherein the apparent specific gravity thereof (as defined above) is less than the specific gravity of the contained metal.

4. A spheroidal particle as claimed in any one of the preceding Claims, wherein said particle is metal and has been heated and annealed while being impacted, thereby becoming a completely annealed spheroid.

5. A spheroidal particle as claimed in any one of the preceding Claims, wherein the particle is metal and has been heated and impacted in a nonoxidizing gaseous fluid to give the resultant spheroid an impact textured, unoxidized surface.

6. A spheroidal particle as claimed in any one of the preceding Claims, wherein said particle is formed from a fragment of malleable wire.

7. A spheroidal particle substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.