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WO2000031309A1 - Procede de recyclage de copeaux en materiau de grenaillage - Google Patents

Procede de recyclage de copeaux en materiau de grenaillage Download PDF

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Publication number
WO2000031309A1
WO2000031309A1 PCT/GB1999/003841 GB9903841W WO0031309A1 WO 2000031309 A1 WO2000031309 A1 WO 2000031309A1 GB 9903841 W GB9903841 W GB 9903841W WO 0031309 A1 WO0031309 A1 WO 0031309A1
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WO
WIPO (PCT)
Prior art keywords
swarf
particles
shot
crusher
pieces
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1999/003841
Other languages
English (en)
Inventor
Antonino Giorgio Cacace
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STELAX INDUSTRIES Ltd
Original Assignee
STELAX INDUSTRIES Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by STELAX INDUSTRIES Ltd filed Critical STELAX INDUSTRIES Ltd
Priority to AU13941/00A priority Critical patent/AU1394100A/en
Publication of WO2000031309A1 publication Critical patent/WO2000031309A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/02—Disintegrating by mills having rotary beater elements ; Hammer mills with horizontal rotor shaft
    • B02C13/04—Disintegrating by mills having rotary beater elements ; Hammer mills with horizontal rotor shaft with beaters hinged to the rotor; Hammer mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C21/00—Disintegrating plant with or without drying of the material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
    • B02C23/08—Separating or sorting of material, associated with crushing or disintegrating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/14—Treatment of metallic powder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C11/00—Selection of abrasive materials or additives for abrasive blasts
    • 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
    • C22B7/005—Separation by a physical processing technique only, e.g. by mechanical breaking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
    • C21D7/06—Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
    • 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

  • 'swarf is intended to include at least the off cuts produced by turning, bo ⁇ ng, shaping, drilling and milling operations on steel or other metals where such off cuts can be processed by the methods outlined herein into particles which can be used as shot in at least some conventional shot blasting machinery
  • swarf comprising the off cuts from a variety of other metal working operations including some stamping and punching operations may also be suitable.
  • engineering steel is intended to include at least those low alloy steels which are commonly subjected to machining operations, including mild steel (a term which itself includes carbon steel), forging steel and axle or shaft steel It is the not the intention of the applicant that the scope of the present invention is necessarily restricted to the use of swarf composed of engineering steel
  • swarf produced by machining operations on a suitable grade of stainless steel or other metal including steel castings and free cutting steel may be suitable to be processed into shot by the techniques described herein
  • the invention is likelv to have its most common application to swarf composed of "engineering stee! " as discussed above
  • scrap steel swarf produced in the course of machining operations as discussed above is in the form of elongate- more or less springy pieces Typically, in their original state, these pieces vary randomlv between a few millimetres and many metres in length
  • chips is intended to refer to the original pieces which make up a mass of swarf.
  • particles is intended to refer to pieces which make up a mass of swarf which has been processed in one or other of the ways described herein so that the average size of the pieces is generally smaller and more uniform as compared to the size of the chips.
  • raw swarf there are present in raw swarf significant quantities of impurities such as the oils which are used in the machining operations, water, oxides, mill scale and dirt. It is well known that raw swarf is not in optimum condition either to be transported or to be fed to a furnace for remelting which is the usual method of recycling swarf. Consequently raw swarf is commonly subjected to a centrifuging operation to remove some of the oil and water and is also compacted into bundles before it is delivered to steel mills for remelting.
  • the raw swarf comprises swarf chips at least some of which are reduced in size to produce the mass of swarf particles.
  • the treatment of the swarf may thus include pieces of swarf to one or more size reduction operations, one or more grading or sorting procedures, or a combination of both.
  • at least some of the swarf chips are reduced in size to produce a mass of swarf pieces and at least some of the swarf pieces are reduced in size to produce the mass of swarf particles.
  • the swarf chips and/or the swarf pieces are reduced in size by passing the swarf through at least one hammer mill.
  • the swarf pieces or the swarf particles are subjected to a shaping operation in which they are rounded.
  • the swarf is advantageously but not necessarily essentially comprised substantially of engineering steel.
  • the method includes the step of using the swarf particles as shot in a shot blasting operation.
  • the scope of the invention includes shot comprising swarf particles produced by any of the inventive methods set out herein
  • Figure 1 is a block diagram showing in schematic form successive stages in a process for producing a product composing swarf particles which can be used as shot in a shot blasting operation
  • Figure 2 is a tracing of a photograph of an actual sample of typical swarf particles which are suitable for use as what is referred to herein as coarse grade shot
  • Figure 3 is a similar tracing of larger swarf particles produced in the process
  • Figure 4 is a tracing of swarf particles from the same batch as those shown in Figure 3 but after being conditioned as described herein
  • Figure 5 is a somewhat schematic sectional view of a crusher
  • Figure 6 is a plan view of a small part of the inner face of a grid of the crusher shown in Figure 5, developed so as to be viewed in the flat,
  • Figure 7 is an enlarged cross-sectional view on arrows A-A of a single perforation in the grid;
  • Figure 8 is a view, similar to Figure 6, of a grid with perforations in the form of tapered slots.
  • Figure 9 is a somewhat schematic side view of a grading apparatus,
  • Figure 10 is a view, similar to Figure 5. of a conditioning crusher used in a modification of the process shown in Figure 1
  • Figure 11 is a schematic view of the profiles of particles of conventional cast shot and of shot produced by the methods of the present invention DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
  • the swarf in the form of scrap steel chips is used
  • the swarf comprises off cuts of EN8 steel produced in the course of turning or other machining operations in a large scale machine shop
  • the selection of scrap steel swarf of this grade is made, in the present instance, principally on account of the reliability and convenience of supply and uniformity of quality It is advantageous but not essential if chip breaking tools are used in the machining operations in which the raw swarf is generated Use of such tools has the result that the chips are of substantially shorter average length than would otherwise be the case This facilitates handling and transportation of the raw swarf
  • Such swarf is optimally in a condition known as 'shovelling' grade
  • shovelling grade swarf composes many chips of substantial length which m practice become entangled with each other and form large bundles Swarf which is composed of many such bundles is known as 'bushy " grade swarf
  • the raw swa r . is usefully subjected to a centnfuging operation to remove some of the entrained o- and v. - ⁇ er This may be earned out at the locality where the raw swarf is generated and is an advantage in carrying out the present invention but is not essential
  • the swarf in the present example is first passed through a trommel 10, a known device composing a cyhndocal god which rotates about its longitudinal axis This axis is inclined to the hoozontal so that swarf which is fed into one end of the trommel (typically by a front end loader) passes through the trommel under gravity as the trommel rotates Round holes are formed in the god
  • the trammelling of the swarf loosens any bundles of bushy swarf and frees unwanted large objects such as bars and bolts which may damage the crushers or other equipment which is used to treat the swarf after it has passed through the trommel
  • the smaller chips which were sorted from the raw swarf in the trommel 10 are also fed to the intermediate crusher 20.
  • the swarf is further broken down into pieces the great majority of which typically do not exceed 20 mm in length.
  • these pieces are fed by a belt conveyor to a storage bin 26 and thence by another belt conveyor to a rotary kiln 28.
  • the kiln 28 the oil and water in the swarf are removed.
  • the kiln is of the forced draught, gas fired type.
  • the kiln desirably operates under a mildly reducing atmosphere at a temperature of 500-800° C since it is considered preferable to vapoose rather than burn the oil off.
  • the kiln temperature is preferably automatically controlled.
  • the gases from the kiln are fed to an afterburner where combustibles in the gases are burned off.
  • the heat from the gases may be recovered and returned to the kiln so that very little additional fuel is required for the overall process of removing the moisture and oil from the swarf.
  • the waste gases from the afterburner are scrubbed and cleaned before being discharged to atmosphere.
  • the kiln, afterburner and scrubber are of conventional construction and need not be described in detail here.
  • the swart " is fed in the present example to a vibrating table 30 where it is spread out to facilitate cooling to about 100° C
  • the swarf still contains a lot of dust made up principally of iron oxides and the residue (soot) of the vaporised oil.
  • the swarf is fed by means of a conventional bucket elevator to a final stage crusher 34
  • the pieces of swarf are further reduced in size to produce a product comprising steel particles the greatest dimension of the majooty of which does not exceed 8 mm.
  • Most dust still adherent to the pieces of swarf is knocked off in the crusher 34. This dust is extracted by an extractor fan.
  • This fan is also able to remove very fine particles of swarf which would not be useful when the product is used as shot in a shot blasting operation.
  • the swarf is fed by a belt conveyor to a grading apparatus 38 shown in Figure 9.
  • this is a three stage trommel, comprising four cylindrical grids 39, 40, 42, 44, each of 1.25 metres diameter, 1.5 metres axial length and 3 mm thickness.
  • the grids are disposed end to end along their common longitudinal axis which, like the axis of the trommel 12, is inclined to the horizontal at an angle equal in this case to 3.6°. Holes, which in this case are round, are formed in each grid.
  • the trommel rotates at a speed of 18 rpm.
  • the swarf discharged from the final stage crusher 34 is fed into the upper end 35 of the grading trommel and, as the trommel rotates, gravitates first through the initial grid 39 the holes in which are of 1mm diameter.
  • the purpose of this grid is to remove any dust, soot and any other very fine impurities remaining in the swarf as well as swarf particles of less than 1 mm nominal size. These are considered to be too small to be of use as shot.
  • the matter removed by the grid 39 is collected and dumped.
  • the swarf particles remaining in the grading trommel pass to the first stage grid 40 the holes in which, in the present case, are of 2 mm diameter. They then pass into the second stage grid 42 which has holes which are of 3 mm diameter, and finally through the third stage grid 44 which has holes of 4 mm diameter. Fine particles of swarf (i.e. particles of 1-2 mm nominal size) which can be used as shot are first separated by the first stage grid from the larger particles. Similarly, particles of 2-3 mm nominal size are separated from the larger particles by the second stage grid 42 and particles of 3-4 mm nominal size are separated from any larger particles by the third stage grid 44.
  • the graded swarf particles drop through the holes in the respective grid as the swarf passes therethrough.
  • the particles which are too large to pass through the holes in the third stage grid are discharged from the lower end 45 of the grading trommel.
  • the respective graded particles drop onto belt conveyors which take the particles to magnetic separators 46, 46', 46" of known kind where, in each case, any non magnetic material is removed from the swarf. From the magnetic separation stations the swarf particles are taken by belt conveyor to bagging stations 48, 48', 48" for bagging and ultimate use as fine, medium and coarse size shot blasting material.
  • Figures 2 illustrates the typical appearance of swarf particles which are intended for use as coarse size shot 56, as such particles emerge from the magnetic separator 46".
  • the size of these particles may be judged from the scale, which in Figure 2 (as in Figure 3 and 4), is graduated in millimetres They have been found to function well as shot despite they fact that they vary somewhat in shape and mass
  • the appearance of the particles emerging from the magnetic separators 46, 46' is similar but their size is correspondingly smaller It has been found by testing that the particles which emerge from all of the magnetic separators 46, 46', 46" function satisfactooly as shot when used in conventional shot blasting machinery of the wheelabrator type shown schematically at 49
  • a shot mixture was prepared by mixing a quantity of the fine grade particles with a quantity of commercially available spheocal cast steel shot which was known to work satisfactorily in the machinery being used
  • the initial mixing ratio was 1 part by weight of fine grade particles to 1 part bv weight of cast steel shot It was found that no damage was caused to the machinery when the initial shot mixture descobed above was used Shot is of course recycled through conventional shot blasting machinery and, as use progressed, it was also found that the fine grade particles in the shot mixture became progressively more rounded and resembled more closely the pellets which made up the cast shot Thereafter, further quantities of the fine grade particles were added to the mixture as it was reused m the conventional way Ultimately, so much of the fine grade particles had been added to the mixture that very little remained of the cast shot originally present Further sets of tests which were substantially identical to the tests in the first set were earned out using the medium grade and coarse grade particles as shot, with similar results
  • the above descobed methods of progressively adding the three grades of swarf particles to conventional shot were adopted out of caution
  • shot blasting machines have been charged with shot comprised purely of fresh swarf particles of each grade
  • the qual of the shot blasting has been satisfactory No damage has been caused to the machinery in these tests and no evidence of excessive wear has appeared in the machinery to date
  • the swarf which is discharged from the end of the grading trommel 38 comprises oversize particles, I e particles of greater than 4 mm nominal size
  • Figure 3 illustrates the appearance and size of typical such oversize particles 58 It should be understood that the particles, in the dimension perpendicular to the drawing, are generally flatter than may appear from the drawing In the condition illustrated the particles 58 are too large to be used as shot in the machinery which has been used to date However, it may well be that the particles 58 may be suitable for use as shot in other shot blasting machinery If this is found to be the case, the particles can be passed through a magnetic separator 46"' and bagged at a
  • the crusher 1 10 comprises a hammer assembly including a rotatable shaft 1 12 driven by a motor (not shown) A seoes of radially disposed arms 1 14 are mounted on the shaft Each arm is provided with a forked outer end carrying a hammer 116 The hammer composes a cyhndocal body 1 18 having teeth 120 on its outer face and a central passage 122 A pin 124 is mounted between the outer ends of the arm and passes with substantial clearance through the passage 122 By this means the hammer is free to rotate on the arm and moreover is capable of a substantial degree of movement in the radial direction on the arm
  • the crusher further comprises an upper casing 136 which overlies the
  • Baffles may be mounted in the duct to prevent unwanted entrainment of smaller pieces of swarf with the dust which is extracted by the fan
  • a separator such as a cyclone may also be mounted in the duct 142 to separate the solids from the air
  • a l ⁇ nd ⁇ cal g d 126 is located below the hammer assembly
  • the god partiallv surrounds the hammer assembly and is positioned so that when the hammers are in their extreme outer positions on the am s 1 14 there is clearance between the hammers and the inner face 128. This clearance is typically of about 30 mm in the first stage crusher but reduces to about 15 mm in the intermediate crusher and 4 mm in the final stage crusher.
  • the grid is provided with many perforations 130.
  • the perforations are in the form of cylinders or slots which in the present case are advantageously tapered as described below although the invention may also be performed with perforations of parallel sided form.
  • the ends of the perforations at the inner face 128 of the grid are of smaller cross sectional size than the ends at the outer face 132.
  • the perforations are in fact frusto-conical, having longitudinal axes of symmetry 134.
  • Figure 8 illustrates a grid with perforations in the form of elongate slots 150 comprising walls 152 which are tapered.
  • a sectional view on aoows B-B in Figure 8 would depict the same as what is shown in Figure 7.
  • the slots 150 are disposed in parallel columns in the grid, the slots in one column being offset or staggered from those in an adjacent column. Swarf which enters the crusher is broken down into smaller pieces by the hammers as they rotate. The pieces are driven through the grid when they are reduced to a size which enables them to pass through the perforations.
  • the degree of initial size reduction in the primary crusher is limited in that, if the perforations in the grids are too small, oil and dirt in the swarf tend to clog the perforations and block them up completely. This ultimately causes the crusher to stall as too much resistance is offered by the uncrushed swarf which builds up in the crusher. This can also happen if, again due to size and number of perforations, the rate of passage of the crushed swarf through the perforations in any of the crushers is too slow.
  • the size and shape of the perforations 130 is dependent on what is fed to the crusher in question.
  • the perforations 130 typically are elongate, in the present case being of size 100 mm by 25 mm.
  • the applicant has found that the smallest practical size for the perforations in the primary crusher using swarf from turning operations is 50 x 25 mm. Perforations of smaller size lead to blockage and stalling of the crusher for the reasons given above.
  • the primary crusher is the most vulnerable to this problem because of the large bundles of bushy swarf which require a considerable amount of hammeong before they are further broken down
  • the crusher is the intermediate crusher 20 as discussed above, the perforations will typically be round and have a diameter (indicated at Dl ) of 20 mm at the inner face 128 and a diameter (indicated at D2) of 24 mm at the outer face 132 of the god
  • the intermediate crusher is not prone to stalling on account of the presence of bundles of bushy swarf as these have been broken down in the pomary crusher
  • the swarf in the intermediate crusher is still wet and dirty, there remains a tendency for the perforations to become blocked
  • the perforations are advantageously cylindocal and the smallest practical size thereof is about 20 mm diameter
  • the crusher is the final stage crusher 34 as discussed above which receives cleaned swarf composing relatively small pieces
  • the perforations will again typically be round and in the present example diameter Dl is 8 mm and diameter D2 is 12 mm
  • the perforations in the final stage crusher can be smaller than m the upstream crushers because there is no danger that they will become blocked from wet dirt as the swarf has passed through the drying kiln and most of the oil, water and other dirt has been removed.
  • Shot particles having a rounded shape are likely to produce better results or be more efficient to use in some circumstances.
  • the kinetic energy of a piece of shot in a shot blasting operation is " ⁇ mv 2 where m is the mass and v is the velocity of the piece of shot.
  • a spherical piece of shot is likely to have a greater velocity than a piece which is less round.
  • a relatively flat or long piece of shot may be subject to an aerodynamic effect which reduces its kinetic or "cleaning " energy.
  • a swarf particle of rectilinear shape will be rounded to some extent when it is impacted by the hammer in a hammer mill and this rounding effect will be increased in proportion to the number of times that the swarf particle is impacted. That this rounding does in fact take place is demonstrated when the swarf particles are used as shot.
  • some percentage of the swarf particles catapulted by the machinery- impact a work piece. The impact is analogous to the impact of the hammers on the particles in a hammer mill as described above.
  • the crusher 80 composes a hemi- cylindrical lower casing 82 located below a rotary hammer assembly comprising an a ⁇ ay of radially disposed arms 1 14' each of which caoies at its outer end a hammer 1 16 "
  • the lower casing is made up of six curved segments 84 of equal angular size, each subtending about 30° at the centre of curvature of the lower casing.
  • the crusher 80 comprises an upper casing 138' which overlies the hammer assembly and is provided with a first aperture 136 " through which swarf particles from the final stage crusher 34 are fed into the crusher 80 The first aperture is located directly above the hammer assembly
  • the major part of the lower casing 82 is unperforated.
  • one of the segments 84 being the last of the segments traversed by the hammers 1 16 ' as rotate in an anticlockwise sense as viewed in Figure 10. constitutes a god 126 " comp sing perforations 130'.
  • the perforations are of tapered cylindrical form, being of smaller cross sectional size at the inner face 128' of the grid than at the outer face 132'.
  • the diameter of the perforations 130' is 2 mm at the inner face 128' but may be 3 mm or 4 mm (or other suitable size) in circumstances which will be discussed.
  • Each segment 84 shown here is a casting, 6 mm thick and having a 70 cm radius of curvature.
  • a second aperture is provided in the casing 138' immediately adjacent the segment grid 126'. This aperture is closed by a trapdoor 85 and is discussed further below.
  • the hammers 1 16' have a profile which, viewed in the axial direction, is bell shaped and comprises a wide outer portion 86 which has flat leading and trailing faces 88, 90 and tapers to a narrow portion 92 at the inner end of which there is provided a passage through which a pin 124' passes with clearance for attaching the hammer 1 16' to the outer end of the arm 1 14'.
  • the outer face 94 of the hammer is smooth and rounded.
  • the hammers 1 16' are free to swing on the arms 114' and are capable of a substantial degree of movement in the radial direction on the arms.
  • the geometry of the arrangement is that, when an arm 114' which carries a hammer 116' is aligned with any of the segments 84 comprising the lower casing, in the extreme outer position of the hammer on the arm, there is clearance (of 2 mm in this example) between the outer face 94 of the hammer and the inner face 128' of the segments 84.
  • the swarf particles 56 discharged from the final stage crusher 34 enter the conditioning crusher through the aperture 136'.
  • the hammers 1 16' Under the action of the hammers 1 16' they are driven (anticlockwise in the drawing) around the shell of the crusher 80 and traverse first the unperforated segments 84 of the lower casing. Before the swarf particles reach the grid 126' there is no route by which any of them can escape. In any case most of the swarf particles are larger than the perforations in the grid 126', so they cannot escape through the grid even when they reach it. The bulk of the swarf particles thus continue to be driven round the crusher 38 as long as the trapdoor 85 is kept closed. In the course of this movement they are thus impacted, on average, many times by the hammers.
  • the swarf particles are tough and the impacts cause the bulk of the swarf particles in the conditioning crusher to be become progressively more rounded in shape.
  • Figure 4 illustrates the shape of particles 58' which originally had a shape typified by that of the particles 58 but which have been conditioned in the conditioning crusher Their greater roundness is evident
  • the conditioning crusher is not intended or designed to reduce the size of the swarf particles except to the extent of rounding them in shape This is why the faces 88, 90, 94 of the hammers 116' are smooth
  • Some of the smaller swarf particles are doven through the perforations in the god These will also have been rounded and can be earned by a belt conveyor 96 to a storage bin and subsequently passed through the grading trommel
  • the trapdoor 85 is opened, in the present case by an air cylinder (not shown), and the rounded swarf particles remaining in the conditioning crusher are doven by the hammers out of the second aperture from where they drop onto a belt conveyor 98 and are ultimately passed through the grading trommel 38 in the manner already described
  • the nature of the action of the conditioning crusher is better suited to treating batches rather than a continuous feed of swarf particles
  • the particles can be rounded to the point where their shape is close to that of conventional cast pellets
  • the hammer assembly of the conditioning crusher here described rotates at 500-900 rpm
  • the swarf particles in a batch which is held in the crusher for 15 seconds potentially undergo 1225 impacts
  • a batch of shot typically circulates once in two minutes
  • the particles of shot would take 147000 seconds to impact a work piece 1225 times
  • More than one of the segments 84 adjacent the trapdoor 85 mav incorporate gods and the size of .he perforations m each grid can be selected so that swaif " particles of different size can be doven through each god
  • a typical batch advantageously comprises up to 200 kg of swarf particles which were discharged from the end of the final stage crusher An output of 1 -2 tonnes per hour of satisfactorily rounded swarf particles is achieved using a 350 motor to drive the hammer assembly in the crusher 80
  • the swarf particles discharged from the crusher 34 need to be conditioned, they may be passed first through the grading trommel. In that case only the oversize particles 58 might then need to be conditioned and subsequently recycled through the grading trommel.
  • the swarf particles are considerably tougher than the brittle high carbon steel of which conventional cast steel pellets are made. Consequently the cast pellets are more likely than the swarf particles to be broken up impacts. This is another reason why the appearance of the swarf particles becomes close to that of the cast pellets in the course of use.
  • One advantage of the shot prepared by the methods of the present invention is that it produces little dust in use.
  • a second advantage is that it is cheap to produce.
  • the raw material (swarf) is cheap and the plant for processing it is cheaper than the plant for producing cast steel shot.
  • the process for producing cast steel shot involves the use of a steel melting furnace which consumes a considerable quantity of energy and generates a considerable amount of pollutants including dust, slag and greenhouse gases.
  • the process of the present invention is more environmentally friendly.

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  • Crushing And Pulverization Processes (AREA)

Abstract

L'invention se rapporte à un procédé qui permet de recycler des copeaux en grenaille pour alimenter des grenailleuses. Les copeaux, en particulier les copeaux constitués d'acier industriel, sont séparés des gros objets dans un trommel [10] et nettoyés de leurs contaminants. Les copeaux sont passés dans un four rotatif [28] pour en éliminer l'huile et l'eau. Les copeaux sont composés au départ de pièces de différente taille non triées, lesquelles pièces sont passées dans au moins un broyeur [18, 20, 34, 80] pour en réduire progressivement la taille, puis dans une trieuse [38] pour séparer les pièces de taille différente en groupes dont au moins un comprend des pièces pouvant servir de grenaille. Dans au moins un desdits broyeurs [80], les copeaux en pièces peuvent être soumis à une opération de formage qui leur confère une forme arrondie.
PCT/GB1999/003841 1998-11-19 1999-11-17 Procede de recyclage de copeaux en materiau de grenaillage Ceased WO2000031309A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU13941/00A AU1394100A (en) 1998-11-19 1999-11-17 Method of recycling swarf into shot blasting material

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NZ332870 1998-11-19
NZ33287098 1998-11-19

Publications (1)

Publication Number Publication Date
WO2000031309A1 true WO2000031309A1 (fr) 2000-06-02

Family

ID=19927018

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/003841 Ceased WO2000031309A1 (fr) 1998-11-19 1999-11-17 Procede de recyclage de copeaux en materiau de grenaillage

Country Status (2)

Country Link
AU (1) AU1394100A (fr)
WO (1) WO2000031309A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
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WO2006029063A3 (fr) * 2004-09-07 2006-08-24 Unist Inc Systeme de distribution de liquide de graissage et de refroidissement pour machine
US9616540B2 (en) 2011-02-08 2017-04-11 The University Of Utah Research Foundation System and method for dispensing a minimum quantity of cutting fluid
CN107597584A (zh) * 2017-09-01 2018-01-19 江苏华宏科技股份有限公司 一种全自动钢刨花粉碎压块流水线
CN108839375A (zh) * 2018-07-20 2018-11-20 江苏华宏科技股份有限公司 一种破碎料热压成型线
CN110014159A (zh) * 2019-05-22 2019-07-16 宁波中物东方光电技术有限公司 一种具有提高金属粉末球形度功能的激光制粉设备
CN113664727A (zh) * 2021-08-18 2021-11-19 苏州捷丹耀科技有限公司 一种具有多级电磁分离装置的高精度打磨设备及控制方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109261321A (zh) * 2017-07-18 2019-01-25 李朝和 一种粉碎机器
CN107597372A (zh) * 2017-08-23 2018-01-19 惠州市正耀科技有限公司 建筑材料边角料及废品料碎取再生利用处理方法及系统

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DE2000378A1 (de) * 1969-01-09 1970-09-10 Gkn Screws Fasteners Ltd Koernungspartikeln fuer Stahlsandstrahlprozesse
US4023738A (en) * 1975-02-06 1977-05-17 Aida Engineering, Ltd. Apparatus for producing fine iron particles
US4377259A (en) * 1980-03-21 1983-03-22 Reclamet, Inc. Chip and turnings separator and crusher
US4424891A (en) * 1981-06-22 1984-01-10 Reclamet, Inc. Equipment for reclaiming the waste products of machining
EP0079796A2 (fr) * 1981-11-17 1983-05-25 Metal Sciences Limited Procédé de préparation de matériau pulvérulent métallique
US4683664A (en) * 1983-03-23 1987-08-04 Giovanni Codenotti Apparatus for drying metal turnings or scrap
FR2648057A1 (fr) * 1989-06-13 1990-12-14 Becker Arnaud Procede de regulation de la densite de dechets metalliques broyes et dispositif pour la mise en oeuvre de ce procede

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006029063A3 (fr) * 2004-09-07 2006-08-24 Unist Inc Systeme de distribution de liquide de graissage et de refroidissement pour machine
US9616540B2 (en) 2011-02-08 2017-04-11 The University Of Utah Research Foundation System and method for dispensing a minimum quantity of cutting fluid
US9931724B2 (en) 2011-02-08 2018-04-03 University Of Utah Research Foundation System and method for dispensing a minimum quantity of cutting fluid
CN107597584A (zh) * 2017-09-01 2018-01-19 江苏华宏科技股份有限公司 一种全自动钢刨花粉碎压块流水线
CN107597584B (zh) * 2017-09-01 2024-03-22 江苏华宏科技股份有限公司 一种全自动钢刨花粉碎压块流水线
CN108839375A (zh) * 2018-07-20 2018-11-20 江苏华宏科技股份有限公司 一种破碎料热压成型线
CN110014159A (zh) * 2019-05-22 2019-07-16 宁波中物东方光电技术有限公司 一种具有提高金属粉末球形度功能的激光制粉设备
CN110014159B (zh) * 2019-05-22 2024-01-19 宁波中久东方光电技术有限公司 一种具有提高金属粉末球形度功能的激光制粉设备
CN113664727A (zh) * 2021-08-18 2021-11-19 苏州捷丹耀科技有限公司 一种具有多级电磁分离装置的高精度打磨设备及控制方法

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