AU612658B2 - Ferrohydrostatic separator - Google Patents

Description

1.25 zAXMAn~sj bdou wl1!!q l 5 jap:)qo ZAXMAfisOdoNWl~flHO 1 K1.5 1 11.25 OPI DATE 06/09/89 APPLN. ID 17855 88 AJPDTE PCT NME 619 r

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PCT/S.U88/00038 (51) Meac~yHapouan KJaccH~brncaqff (21) Homep mewzty~apo~J.EoI~ ny6aa'Wm: WO 89/07489 Hao~pe miuI 4: Al (2Z ,1aTa KeiEWlynapo)ANoA B03C I=3 uy6'Axawwa: 24 a rycra 1989 (24.08,89) (21) Hloiep xeaz~yi~apoj~noj1 aaswiic: PCT/SU88/00038 evich, Donetsk 3EJIEH 1 IYK BJzaAZIAip AaemeaIIJApBhI; Bopom~aoBrpaA 348021, xnaprair Pae- (22)AlIaT8 mezJ~yiapo~molI uo~amn: oRo, A. 5, jo. 8 (SUW [ZELENCHUK, Vladimir Ale- 17 4 eBpazs 1988 (17.02.88) xandrovich, Voroshilovgrad AJIHHOB An'emcaWi Hisaaom; BopomianwAspj 348005, yq. Xpamunumro, Az. 4, its. 95 (SU) (ALIPOV, Alexandr; (71) 3amgureu. rocYAAPCTDEHHbiR HPOERT- i Ivanovich, V'orosbilovgrad HO-ROHCTPYI(TOPCKHR HHCTHTYT -rpmI-I POMAM1YrJIEOBO1'AIIEHHE- [SU/SU]; Bopomi- I (74) Areu3T: TopI'oBO-rIPOMbIHIJEHHAR rIA.TIATA nxourpaA 348006, yn. BI!Jnpa UwrepKMwa, A- 30 (SU) CCCP- Mociria 103735, ya. Kyiu~meaa, A. 5/2 (SU) [GOSUDARSTVENNY PROEKTNO-KONSTRUK- [THE USSR CHAMBER OF COMMERCE AND TORSKY INSTITUT .,GIPROMASHUGLEOBOGA- INDUSTRY, Moscow SCHENIE-, Voroshilovgrad (81) Y"cA aae rocy~apcTRa: AT (enponeiicHr nareHT), (72)1Hao6perareaiu: BJIACOB Bniasuuip Hssxoniaenliq; AU, BE (eaponeficickig nam*HT, OH (elnponeficidi Ia- BOPOMsurOnrpaA 348003, ic~apraz repoeB CBAaHH- Teirr), DE (enponeiiciag naTeHT), FI, FR (eaponeirpaAa, A. 3, is. 271 (SU) [VLASOV, Vladi:rir Niko- cimfi IaTeHT), GB (elponieicxiurii areHT), HU, IT laevich, Voroshilovgrad (SUXi. rYBAPEBH- Bnia- (eiaponeicxnfi naminT), JP, LU (eeponeiiM na~reir), Amnip Himcaae]EIM; BopomHnIonrpaA 348040, iRiap- NL (eaponeficidi niamwr), SE (elaponecciiii naTeHr) TaJI A1pyxc6a, A. 13, Hil. 6 (SU) (GUBAREVCH, Vladimir Nikolaevich, Voroshilovgrad (SU)I. 3AC- KEBHtI Maxaan BaA AuiHP0BH'; Mispnfi 678170, Ony6Awinaa YJ1x. OfiyHCcoro, A. 7, xis. 39 (SU) [ZASKEVICH, C omuemom o eyapoa1w unoucxe Mikhail Vladimirovich, Mirny KPAB t

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HHmcoJaf AlmmrpHeMM'; 11011e=x 340003, rp. HnAL14a, g. 83, xii. 55 (SU) [KRAVCHENKO, Nikolai Dmitri- (54)nTtle: FERROHYDROSTATIC SEPARATOR (54) HaaMine uao~peremm 0EPPorHATPOCTATWIECKR~ CEIIAPATOP (57) Abstract A ferrohydrostatic separator comprises a magnetic system with two poles the profile of which is designed so as to form a magnetic field of an intensity varying over the4 height of the magnetic gap from the maximum value at the lower part of the poles to the minimum value at their upper part, a reservoir made of a non-magnetic material and filled with a 00 1 ferrom-agnetic liquid as well as a device for 0 feeding the mechanical mixture of non-magnetic materials and a device for removing the2 separated particles of the mechanical mixturr. 1.1 -0 the gap (N-S)between the poles are pla.ed0 elements of ferromagnetic material forming localF magnetic fields inside the column of the ferromagnetic liquid The vector of the magnetic force (Fix) of each of the local magnetic fields is directed at an angle to the velocity vectorN of particle movement in the mechanical 141 1~ (S7) P0*epaT: IepporX[DOCTaTgtec}CMI cerlaiaTOD BK5iiotqaeT marHATHYJO CI4CTemy C ,IByMR nomIocamI4 I'-S OM Kroi oTopblX #oPm~pyeT mrFHMTHoe nojie c 1g3meH Ome~cR no BYCOTe meyirlORnoCHOr'O Oa~opa HariD eHHOCTbIO OT ma(Ct4majvbH0v B Hz2&-He TiaC~v rIojiiocoB zlo MZHmmajib:HOn B BeIPXHe emKOCTb M3 HemapI-iITHOrO maepm c #epomarHHTH1l +U4,1ZIOCTbIO a Taiye YCTD09CTBO =H nozaqmi meame~r cmie- 014 HemarHZTHB1X MaTepzaJICB M4 YCTD0OCTBO =R yzanieHKws Da3zeiieH~b1X taCTMu rexaHvec~ox cmeCx4. 11j 3a3o~pe mexy rIonjocaM1 (N-S D~acnoIoxeHb 3zIemeHTbl M43 eDpomarHMTHOrO maTePl~aJa, 4IPM~pyoilulme JIOxaJlbHbie MPaH4THbie T1OJT BHYTP4 CTojiba #JppomarH4THQM 2if IOCTH BeXTop maPHTHOn~ CMib? (F 1 or mt'OIO3 jioICnbb~ix maPHMTH-bix nozier HarrDaB- JneH flozI yPJIom F BeKToDy CKODOCTM (W),BwKeHMH1 TqaCTKI4b mexaHMqec~ol cmeCM.

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O$PaHUMlR ra6oH BernmKo6PHTAHHaI BCHrPHIR HTaMIU1 AlOHR Kopeffcla HAPOnHo-1eMoxpaTmecKaji Pecnry6nHKa Kopeitcxas Pecny6IK2 AMHXTCHWTeiH 11pM JIaHKa iliorceu6ypr MOHaxo Manar&CKap MaaPHTaHnsI HaeP.laHnabi HopiierHfl PYMb]HHRi CynaH CCHeran COMeTCtrni C0103 Toro CoenumeHrnJc WraTb Amemacmr FERROHYDROSTATIC SEPARATOR Technical Field This invention relates to ore concentration and, in particular, to ferrohydrostatic separators.

This invention can be most successfully used in nonferrous metallurgy for separation of non-magnetic non-ferrous scrap metals by density.

Background Art IO The present invention can also be used in mining and ore processing industries for mineral ore separation.

The trend fro lower content of a useful component in mined non-ferrous ores is becoming more evident at present and the growing demand for non-ferrous metals in the world market dictates 1 arger volumes of utilization of multicomponent scrap non-ferrous metals available in electrotechnical industry and some other fields, as well as scrap cables. But this scrap metal cannot be fully utilized because no industrially produced equipment is available in the world market to separate scrap metal by alloy types and, in this way, to make up for the shortage of non-ferrous metals.

Some Japanese and US companies are known to have adva.nced in developing production processes and techniques of separating fragmented scrap of non-ferrous metals by density using pilot ferrohydrostatic separators.

"Hittaki Seisaku", e Japanese company, has developed a pilot ferrohydrostatic separator to separate non-ferrous metals, such as aluminiun, zinc, and copper from automotive scrap, which comprises a reservoir filled with a ferromagnetic liquid made of kerosene and a dispersed phase which 0 consists of loadstone grains with a size of 100 A in a shell of oleic acid, and an electromagnetic system having a pole gap accomodating said reservoir. This reservoir is equipped with a feeding device supplying automotive scrap with particle size ranging from 6 to 25 mm. This separator was not effective when used to recover aluminium from scrap metal, which amointed to only 80 percent, while 20 percent 1 C ii 2 of aluminium was separated as a mixture with copper and zinc, thus yielding impure products.

The US Bureau of "ines has developed and tested a pilot ferrohydrostatic separator for recovery of non-ferrous metals from a mechanical mixture obtained by burining industrial and domestic waste materials.

Thi3 separator has a reservo-r placed in the pole gap of a .:agnetic system and filled with a ferromagnetic liquid which is a suspension of loadstone in kerosene with an ad- IO dition of 7-12% of oleic acid. The poles of the magnetic system are sloped with reference to the horizontal plane to provide a slope of the surface of the ferromagnetic liquid in the direction where separated particles of the mixture are removed. The separated also has a feeder of the mechanical mixture, which is secured on the reservoir, and a device for removal of separated particles of the mechanical mixture.

This separator was used to separate a nechanical mixture containing 58.5% Al, 14.8% Zn, and 19.7% Cu, as well as particles of lead, tin, and silicon oxide. The disadvantage of this prior art separator consisted in that the recovery of aluminium was inefficient, since the recovered aluminium contained 5.5% Cu and 10.7% Pb. This sub-standard product requires additional expenses for further separation, which makes the process much more expensive.

Known in the art is a ferrohydrostatic separator developed a-.d co.n.nercially produced in the USSR for rapid analysis of non-magnetic ores to determine their mineral composition and beneficiation ability. Practical exploitation of such separators proved they are very accurate as rapid analyzers. But this separator operates in cyles, and not continuously, and its output capacity is too low '(less than kg/h).

The method of separation of a mechanical mixture in a ferrohydraostatic separator consists in that a solid part-

N-

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7 I I 3 icle immersed in a ferromagnetic liquid is subjected, apart from the buoyancy force, to the hydrostatic pressure produced in the ferromagnetic liquid when acted upon by the nonuniform magnetic field established by the magnetic system of the separator.

The condition of separation of the mecElaical mixture composed of particles having different densities in a ferromagnetic liquid is compliance with the inequality: IO P I Pa

P

2 vhere Pa apparent density of the liquid; PI density of light particles; and 2 density of heavy particles.

The apparent density of the ferromagnetic liquid in a nomuniform magnetic field of the ceparator is given by the following equation:

JLQK

PJf O H _HradlHj g .aere: physical density of ferromagnetic liquid; K volume magnetic susceptibility of the ferromagnetic liquid; permeability of vacuum; H magnetic filed strength in the zone of location of a particle; grad H gradient of the magnetic field strength in the zone of location of a particle; g free fall acceleration.

Each particle of the mechanical mixture, placed in a ferromagnetic liquid, is subjected to: I. gravitational force .y V where V and D are the volume, and density of a spherical particle, V T d 3 or, for a particle having some other shape V d3/G, where de is an equivalent diameter; 2. hydrostatic pressure Fe dictated by the ponderomotive force of the magnetic field, acting on the liquid A>-s *^i I' i I i:: f! 4 .volume displaced by a particle TL d 3 P o K H gradH= e K K.HgradH; (2)

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3. buoyancy force T d 3 F V(3 g 3 a

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When a particle moves in a layer of t'.e ferromagnetic liquid, it meets with the hydrodynamic resistance force which is the function of the particle speed and acceleration, its density, dimensions and shape, and the viscosity of the ferromagnetic liquid. If the viscosity of the ferromagnetic liquid is characterized by Reynolds numbers Re 20-350, the hydrodynamic resistance can be found from the Newton-Rittinger equation Fv V'de' P, where V is the speed of the particle.

The Reynolds number Re V-de -f/q describes the flow of the liquid.

SWhen dealing with a mechanical mixture of non-ferrous scrap fragmented to less than I mm soze, the critical force acting on the particle is the viscous resistance given by the Stokes equation FV 3 7 Zq1*V-d where is the absolute viscosity coefficient.

When nonuniform magnetic field produced by the magnetic system of the separator is applied to the ferromagnetic liquid, the surface of this liquid assumes a position in compliance with the shape of the magnetic force lines at the interface of two media, namely liquid-air interface. The surface of the liquid becomes convex.

During separation of the mechanical mixture of nonferrous metals, particles whose density is lower than the 35 apparent density of the ferromagnetic liquid rise to the n, .i a- -r 5 surface of this liquid. And each particle on the surface of the liquid is subjected to a lateral component of the gravitational force FgZ, which pushes its towards the poles and holds it to the surface of the reservoir. The particles accumulate near the poles. The lateral component FgZ of the gravitational force is given by the 'following relationship: dH Fgz V p *g.sinp v -X.H (4) I0 where t- is the angle of the surface of the ferromagnetic liquid to the horizontal plane with reference to the axis Z.

Each particle in a column of the ferromagnetic liquid and on the surface thereof is exposed to the above described forces which make it move. The :novement of a particle can be described by a system of equations: d 2 x dF V 2 pax p -H .g.sino 4 2d 2 dx 2d dt -2 dH V2 f'g .P dt d=i V 2 Pay dt dy 2d d 2 Z *gsin H V2az dt 2 dZ 2d dt where: c is the slope of the surface of the ferromagnetic liquid to a horizontal plane with reference to the axis X; Paxa, ay, az are components of the apparent density.

For sim:plicity, the particle is assumed to be spherical and the megnetic field between the poles is plane parallel.

I I 6 No analytical solution of this system of e-uations exists because many of the components are variables and many of these are interconnected. Only a partial solution is possible for a particular magnetic system of a specific separator, a specific ferromagnetic liquid, and a specific mechanical mixture.

The mechanical mixture of non-ferrous scrap metals is separated in a layer of ferromegnetic liquid, which is limited in height. The thickness of this layer depends on IO the parameters of the magnetic field available between the poles of the magnetic system of the separator, magnetization of the ferromagnetic liquid, and its physical density Pf).

It should be remembered, when examining the gradient of the magnetic intensity between the poles, that this gradient reverses its sign in the pole gap below the zone of the minimal distance between tLe poles. The height of the layer depends on the manner in whih the magnetic field affects the ferromagnetic liquid and can be described by the following equation: H2 h J dH (f (6)

H

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There exists a condition providing a balanced state of the layer of the ferromagnetic liquid, which is achieved by fullilling the equality: FI- F 2 fgh, where: F I is magnetic force acting in the pole gap above the zone of the minimal distance between the poles;

F

2 is magnetic force acting in the pole gap below the zone of the minimal distance between the poles.

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I-2 I 7 The above magnetic forces are dictated by the following relationships: dE dH 2 I 2 F J-.oJ -2 0 dy -2 dy Proceeding from the above analysis of the relationships, the height of the column of the ferroagnetic liquid in the pole gap can be found from the following relation: I0 h =~L 0 .J [(dH 1 dH 2 /d]P f *g 1 (7) During separation of mechanical mixtures, when the magnetic intensity in the pole gap is not high and cannot provide a balanced state of the layer of ferromagnetic liquid, this layer can be maintained at a sufficient height by a device for removal of separated particles, which produces the required hydrostatic upthrust by a column of another liquid which does not mix with the ferromagnetic liquid.

The following condition should be observed: FI Pfgh 1

F

2 +Jw ghw The height of the upthrusting column of liquid can be found from the equation: dHI dH h [o P fg.h)] (8) d d y y Attempts to improve the quality of separation of a mechanical mixture of scrap non-ferrous metals have been made in a ferrohydrostatic separator (US, A, 2265458). This separator comprises a magnetic system featuring two poles shaped in such a way as to produce a magnetic field whose magnetic inteasity varies along the height of the pole gap and along the axis Y from amximum on the upper part and to minimum in the lower part thereof, and a reservoir made of a non-magnetic material and filled with a ferromagnetic i. [.1 $1 8 liquid located in the gap between the poles.

Magnetic elements are provided in the zone where the mechanical mixture is fed and in the zone where separated particles are discharged. Each such magnetic element is a triangular prism having one face secured to a pole, another face being the continuation of the pole face, and the third face being an inclined plane making an acute angle with the longitudinal axis X of the pole gap.

The magnetic elements produce local magnetic fields IO whose intensity gradients are directed towards the axis X of the pole gap.

When the mechanical mixture is fed into the surface of the ferroimagnetic liquid, the particles of this mixture are subjected, apart from the gravitational forces, buoyancy force, and hydrostatic pressure, to an additional magnetic force produced by these local magnetic fields. This for force prevents particles from accumulating on the surface of the ferromagnetic liquid near the poles and accelerates the movement of particles to the separation zone.

It is common knowledge that high-quality density separation of mechanical mixtures of scrap non-ferrous metals, which is characterized by a minimal proportion of low density particles in high density ones and visa versa, demands a sufficient length of the separation zone. In other words, the length of the pole gap in the direction of the axis X should be sufficient for heavy particles to precipitate at a certain rate. When the mechanical mixture consists of particles whose densities are only slightly different, the separation zone should be much longer. In the prior art separator, density 'separation of the mechnical mixture of particles occurs outside the zone of local magnetic fields. In consequence, particles of the mixture, which are floating on the surface in the separation zone, are pushed by lateral forces tovards the poles and held to the surface of the reservoir, where they accumulate, capturing heavy particles, I 9 and form flocculi. This formation of flocculi near the surface of the poles obstructs the movement of particles over the surface of ferromagnetic liquid, which seriously affects the efficiency and quality of separation of the mechanical mixture by density.

Moreover, in the separation zone, particles whose density is close to that of other si.milar particles and of the apparent density of the ferromagnetic liquid move in the layer of said li uid at very close levels. It is, therefore, IO extremely difficult to separate particles whose density is less than the apparent density of the ferromagnetic liquid.

As a result, separation of the mechanical mixture of particles having similar density is inefficient since the output of light particles always contains a measure of heavy ones and visa versa.

There is known a ferrohydrostatic separator (DE, 332110202) wherein a better quality of separation was achieved for mechanical nixtures of particles having very close densities.

This ferrohydrostatic separator co:miprises a magnetic system featuring two poles shaped in a way to produce a magnetic field whose intensity varies vertically from maximum in the bottom part of the poles to the minimal at the top part thereof, and a reservoir made of a non-magnetic material end filled with a ferromagnetic liquid disposed in the space between the poles. A partition is provided inside the reservoir to channel already separated .articles of the mechanical mixture. This partition is placed in the layer of the liquid and adapted to shift along one of the prism faces making an acute angle with the gravity vector of a particle. The prism has its bases secured on the lateral walls on the reservoir. Shifting the partition is necessary because t.e layer of the ferromagnetic liquid, in which low density particles move, is limited. The known separator also comprises a device for feeding the mechani- 10 cal mixture of scrap non-ferrous metals, which is located above the surface of the ferromagnetic liquid and secured on the poles, and a device for removal of density separated particles of the mnechanical mixture, which is associated with the reservoir. The poles of the magnetic system are inclined in the direction where light particles of the mixture move.

When a mechanical mi:ture of scrap non-ferrous metals is supplied to the surface of the ferromagnetic liquid, the particles of the source mixture are subjected to the horizontal component of the intensity gradient of the magnetic field and to the laterla component of the gravitational force Fg. The surface of the ferromagnetic liquid assumes a position which corresponds to the shape of magnetic force lines at the liquid-air interface. The surfauc becomes convex. In this case, the force Fg z acts on each particle whose density is less than the apparent density of the ferromagnetic liquid and holds these particles to the lateral surfaces of the reservoir. Light particles accumulate near the poles, capture heavy particles, and form flocculi. Formation of flocculi near the surface of the poles drastically reduces the cross-section area od -he pole gap in the plane perpendicular to its longitudinal axis.

This results in decrease of the output and may lead to a complete stop of the separator. Moreover, the known separator has one more disadvantage its output product is of a rather poor quality since light particles contain a certain proportion of heavy ones and visa versa.

One disadvantage consists in that the flow of particles whose density is greater than the apparent density of the ferromagnetic liquid contains light particles as it moves in the layer of this ferromagnetic liquid. These light particles are held by adhesion and viscosity and have no time to rise to the surface of the ferromagnetic liquid.

These light particles find their way, together with heavy /V i 7.

II particles, to the ready product, t::uc reducing its quality.

Separation of the mechanical ixture of scrap aluminium alloys, -here Dartcles have extremely close densities, e.g. the Al'Mg alloy with a density of 2.63 g/cm and Al-Si alloy with a density 2.67 g/cm3 was successful with the use of the known separator which produces good quality products ready for manufacturing hig-quality aluminuri alloys.

The employment of the partition made it )ossible to restrict the layer of th ferromagntic i quid where light CO particles whose density is cl c o ;hat of heavy narticles move.

Disclosure of -he Ivention The object of the invention is to create t ierrohvdrostatic separator wherein provision in the pole gap 3f additional magnetic forces intensifying movement of light and heavy particles in the directlon cf ah axes I and Z would increase effeativeness il separation i Aechanical mixture.

There is provided a forrochyd oac 2aarator comprising a magnetic system featuring at -eas t-,wc polec shaced to establish a magnetic field wihose intensity varies with the height of the pole gap from the maximum value at the bottom part of the poles to the minimal value at the top part thereof, a reservoir made of a non-magnetic material, filled with a ferromagnetic licuid, and arranged in the space between the poles, a device for feeding a mechanical mixture of non-magnetic materials, ih is disposed above the surface of the ferromagnetic licuid and secured on the poles, and a device for removing density separated partices of the mechanical mixture, 'hich is associated with the reservoir, in which, according to the inventio, elements made of a ferromagnetic material are placed in the pole gap to estabilish local magnetic fields inside a column of the ferromagnetic liquid, the magnetic force vector of each such local magnetic field being directed at an angle to the T IQ _1 2 _i i _I 12 motion of particles of the mechanical mixture.

This ferrohydrostatic separator provides a substantial improvement in the quality of separation of a mechanical mixture no matter how large or small is the difference between the density of particles therein.

The apparent density of the ferromagnetic liquid is much more important in the zone affected by a local magnetic field than in the separation zone. Particles of the mechenical mixture are subjected to the effect of additional magnetic forces produced by such local magnetic fields as they move inside a column of the ferromagnetic liquid or on the surface thereof. This interaction of p-rticles of the mechanical mixture with zones of higher apparent density can change the trajectory of particles and prolong their residence in the column of the ferromagnetic liquid.

WVhen flocs are formed on the surface of the ferromagnetic liquid, their motion is affected by additional magnetic forces produced by local magnetic _-elds and acquires a reciprocating direction along the axis Z, while moving along the axis X. This helps overcome tLe forces of the surface stress of the ferromagnetic liquid and forces of intermolecular interaction between the particles of the mechanical mixture. As a result, the flocs disintegrate, free heavy particles settling in the column of the ferromagnetic liquid, while light particles continue their movement on the surface of this liquid in the direction where separated particles are discharged from the reservoir.

When heavy particles of the mechanical mixture move through the column of the ferromagnetic liquid, they may carry down particles whose density is less than the apparent density of the ferromagnetic liquid in the separation zone and, going through zones of higher apparent density of this liquid, they may change their trajectory and move along these zones in the direction in which sink particles are removed from the reservoir. In this case, particles whose r 3 7 T 3 density is less than the apparent density of the ferromagnetic liquid in the separation zone are exposed to a higher hydrostatic pressure. This increased hydrostatic pressure separates light particles fro:n the heavy ones and they float on the surface of the ferromagnetic liquid and move together with other light particles in the discharge direction.

It is advisable that each element should be :ade as a rod, these rods being arranged at a uniform distance from one another and connected by non-imagnetic cross-pieces secured on the reservoir to form a plane directed parallel to the velocity vector of particles, of the mechanical mixture in the layer of the ferromagnetic liquid, one butt end of this plane is perpendicular to the rod axis and disposed in the mechanical mixture feed zone below t-e surface of the liquid, while the other butt end thereof is also perpendicular to the rod axis and located in the layer of the ferromagnetic liquid in the maximum intensity zone of the magnetic field.

The local magnetic fields with the intensity H and the gradient grad H much higher than in the separation zone are established in the zone between the rods and above them because the distances between these rods are too short.

These local magnetic fields act on the ferromagnetic liquid and produce areas with a much higher hydrostatic pressure in these zones as comipared to the separation zone. This area is equidistant in relation to the rods. The force of the hydrostatic pressure is dictated by the magnetic susceptibility of the rods and ferromagnetic liquid. Its magnitude is minimal near the butt end of the plane formed by the rods, which JA 30 is located below the level of the ferro.'aagnetic liquid and the mechanical mixture feed zone, and gradually grows to its maximum value in the direction of the other butt end of said plane, located in the maximu.:m intensity zone of the magnetic field.

Heavy particles and those light particles which had no 7 14 time to come to the surface change their traj .cCories under the action of the high hydrostatic pressure produced by the effect of local magnetic fields on the ferromagnetic liquid and directed at an angle to the gavity vector of the particles. These particles start moving above the rods. As the high hydrostatic pressure makes the particles move, light particles are separated from heavier ones and come to the surface of the ferromagnetic liquid, where they are discharged together with other light particles. This process IO contributes to more effective recovery of non-ferrous metals from a mechanical mixture thereof.

It is recommended that each element should be a part of a cone cut along the axis of symmetry thereof and having a spherical base secured by its plane on a pole, said elements being arranged along the generatrix t*f the pole curve, one after another at an equal distance from and displaced with respect to the element of the other pole, while the vertex of the cone is directed like the velocity factor of particles of the mechanical mixture over the surface of the ferromagnetic liquid. The arrangement of these elements and their shape permit establishment of local magnetic fields having higher i intensity H and intensity gradient grad H as compared to those in the separation zone. Each such local magnetic field interacts with the ferromagnetic liquid and changes the curve of the surface in the direction of the axis Z, while the level of the ferromagnetic liquid in the area around each element rises above the general level of the liquid in the separation zone. This particular interaction eliminates the lateral force F which holds particles of the mechanigz cal mixture to the side walls of the reservoir. This helps make the separator more efficient.

Flocs forming in the mechanical mixture feed zone are exposed to the action of local magnetic fields producing a moment of forces making them rotate about their axes and, S- 15 also, to the forces of hydrostatic pressure making them move in a crisscross fashion. As a result, the flocs are destroyed and particles whose density is higher than the apparent density of the ferromagnetic liquid in the separation zone sink to the bottom. This makes recovery of nonferrous metals from mechanical mixtures more effective.

It is desirable that in the ferrohydrostatic separator each pole should have a variable cross section along its longitudinal axis, ranging from the minimal section in the feed zone of the mechanical mixture of non-ferrous metals to the maximum section in the zone of discharge of separated particles of the mechanical mixture.

When the poles are made in this manner, the density of magnetic force lines varies in the pole gap and so does the strength of the magnetic field ranging from maximum values in the mechanical mixture feed zone to thp minimal values in the zone where light particles of this mechanical mixture are removed. This results in that the surfaces of the-poles form a uniform gap along the longitudinal axis thereof but have a va-fing magnetic potential. The difference in the magnetic potential of the pole surfaces in the mechanical mixture feed zone and in the separated particle discharge zone is produced by a different degree to which the metal of the poles is saturated in these zones. As a resutl, the magnetic field strength H in the pole gap is distributed so that a specific gradient of magnetic strength (grad H) is produced with the vector being directed opposite to the vector of motion of the particles of the mechanical mixture over the surface of the ferromagnetic liquid. The effect of the strength H and its gradient (grad H) on the ferromagnetic liquid layer consists in production of a horizontal component of the hydrostatic pressure force Fix, which is directed parallel to the vector of the particles of the niechanical mixture moving over the surface of the ferromagnetic liquid. This horizontal component acts on the particles

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kw I _r ;1 16 of the mechanical mixture and contributes to their timely removal from the feed zone. It also imparts motion to particles of the mixture, both in the layer of the liquid and on the surface thereof, from the feed zone towards the zone where separated particles are discharged. This, on the one hand, makes separation process more effective and, on the other hand, improves the efficiency of the separator as a whole.

The ferrohydrostatic separator, made according to the IO invention, is used to separate fragmented cable scrap and, generally, waste in lead sheaths (metal mixtures: copperlead, aluminum-lead). It permits recovery of the light product, which is either aluminum or copper, with impurities of heavy product of not more than I percent; and recovery of the heavy product, lead in this case, with admixture of the light product of not more than 2 percent.

When dealing with scrap domestic radioelectronic equipment, which is a mixture of rmeals: aluminum, copper,, and tin-lead solder, the ferrohydrostatic separator permits recovery of aluminum with less than 1% additions of copper and tin-lead solder and of copper-tin-lead product with less than 2% aluminum admixture. Separation of mechanical mixtures of non-ferrous metals by this method offers products which can be used to manufacture high-quality alloys.

Other objects and advantages of this invention will become more apparent from the following concrete embodiment and accompanying drawings, in which: Brief Description of the Drawings Fig.I shows schematically an isometric view of a ferrohydrostatic separator designed for separation of a mechanical mixture of high-density particles, according to the invention; Fig.2 shows an enlarged schematic view of elements establishing local magnetic fields, according to the invention; ,y.u ua- pjeature re dictated by the ponaeromotive force of the magnetic field, acting on the liquid

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17 Fig.3 shows a section taken along line III-II of the schematic of Fig.I; Fig.4 shows a top view of a reservoir arranged between the poles N-S; Fig.5 shows an isometric view of a ferrohydrostatic separator designed for separation of a mechanical mixture of low-density particles, according to the invention.

Best Mode of Carrying Out the Invention A ferrohydrostatic separator designed for separation IO of a mechanical mixture of non-magnetic materials, e.g.

domestic radioelectronic equipment or fragmented cable scrap and lead-sheathed waste with fragment size of up to 40 umm and nade according to the invention comprises a magnetic system I (Fig.I) having two poles N-S of a variable section, whose shape establishes a magnetic field having its strength H varying with the height of the pole gap, ranging from the maximum strength at the lower part of the poles to the minimal strength at the top part thereof, and also varying along the generatrix of the pole curve, ranging from the maximum strength in the mechanical mixture feed zone to the minimal strength in the zone where separated particles of the mixture are discharged from the separator. It also comprises a reservoir 2 made of a non-magnetic material, which contains a ferromagnetic liquid 3, arranged in the space between the poles, a device 4 for feeding the mechanical mixture of non-ferrous metals, which is positioned above the surface of the ferromagnetic liquid 3, and a device 5 for discharging separated particles of the mechanical mixture.

The magnetic system I comprises two excitation windings 6, each mounted on a yoke 7 secured by brackets 8 on a frame 9 installed on a foundation. The poles N-S of the magnetic system I are also secured on the yoke 7.

The device 4 for feeding the mechanical mixture of non-ferrous metals comprises a hopper 10 rigidly secured on i the poles N-S by a bracket II, and a vibrating chute 12 18 cinematically connected with the reservoir 2. The hopper is located above the vibrating chute 12.

For better understanding, heavy particles of the mechanical mixture are indicated as dark circles, while light particles as clear transparent circles.

The device 5 for discharging separated particles of the mechanical mixture is a flat element 13 secured on the side walls of the reservoir 2 in the zone most distant from the mechanical mixture feed zone. The butt end of the flat element 13 extends beyond the butt of the reservoir 2 to form a passage 14 for discharging heavy particles and a passage 15 for discharging light particles.

Elements made of a ferromagnetic material are arranged in the gap between the poles N-S to establish local magnetic fields inside a column of the ferromagnetic liquid. The magnetic force vector of each local magnetic field is directed at an angle to the vector of velocity V of particles of the mechanical mixture. To exert action on high-density particles of the mechanical mixture, each element is made as a rod 16 (Fig.2). These rods 16 are spaced apart uniformly from one another. All rods 16 are connected to one another by non-magnetic cross-pieces 17 secured on the reservoir 2 (Fig.3) to form a plane extending parallel to the direction of the velocity vector of heavy particles. One end of this plane is perpendicular to the axis of the rod 16 and is located in the mechanical mixture feed zone below the surface of the ferromagnetic liquid, while the other butt end thereof, which is also perpendicular to the axis of the rod 16, is located in the zone of the maximum strength of the magnetic field.

In order to act on particles of the mixture on the surface of the ferromagnetic liquid, each element is made as a part of a cone 18 (Fig.4) slit along the axis of symmetry and having a spherical "base secured by its plane on the pole N or S. The cones 18 are arranged along the generatrix ATvj 19 of the curve of the pole N or S and spaced. evenly apart, each next cone 18 being shifted with respect to the elements of the other pole. The vertex of the cone is directed as the velocity vector of particles moving over the surface of the ferromagnetic liquid.

The ferrohydrostatic separator made according to the invention operates as follows.

VWhen power is applied to the excitation windings 6 (Fig.I), a non-uniform magnetic field is established in the pole gap, which acts on the ferromagnetic liquid. This magnetic field has one strength gradient grad H whose vector is directed towards the minimal distance between the poles N-S along the axis Y and another strength gradient grad H whose vector is directed towards the mechanical mixture feed zone along the axis X. The ferromagnetic liquid acquires an apparent density pa which is .iictated by the following relationship: o .K Pa j f H grad H, g where Pf physical density of the ferromagnetic liquid; k volume magnetic susceptibility of the ferromagnetic liquid; J-o permeability of vacuum; H strength of the magnetic field in the zone where the particles of mechanical mixture are located; grad H gradient of strength of the magnetic field in the zone where particles are located; g free fall acceleration.

The mechanical mixture of source material is supplied to the hopper 10 (Fig.I), then to the vibrating chute 12, and to the surface of the ferromagnetic liquid. Particles of the mechanical mixture in the layer of the ferromagnetic 20 liquid 3 are exposed to the action of the vertical component 'PF. (Fig.3) and horizontal component F 1 P of the hydrostatic pressure force Fl, which makes particles move.

Particles of the mechanical mixture,. whose density is less that the apparent density Pa of the ferromagnetic liquid, come to the surface of this liquid, while particles whose density is larger than the apparent density pa of the ferromagnetic liquid sink under the gravity force F g into the layer of the ferromagnetic liquid 3.

IO Local magnetic fields established between and above the rods 16 are characterized by the strength H and strength gradient grad H, which are higher than those in the separation zone. These local magnetic fields produce zones of higher apparent density Pa in the ferromagnetic liquid 3.

Particles of the mechanical mixture sinking into the liquid come across zones of higher apparent density. Since the hydrostatic pressure forces F I in these zones are higher, particles change their trajectories and start moving in the direction of the passage 14, supported by these zones. When particles of the mechanical mixture, whose density is higher than the apparent density Pa of the ferromagnetic liquid, carry particles of lesser apparent density in the separation zone, the latter are still separated by the action of increased forces P 1 of hydrostatic pressure and emerge on the surface of the ferromagnetic liquid 3.

Floating particles of the *mechanical mixture are exposed to the horizontal component F1x of the hydrostatic pressure force F 1 and move al.ng the generatrix of the shape of the poles N-S in the direction of the passage 15. A local magnetic field is established around each cone I8 (Fig.4) to act on the ferromagnetic liquid 3 and change its surface shape in the direction of the axis Z. The surface of the ferromagnetic liquid 3 in the separation zone becomes somewhat elevated above the general level. Particles moving along the generatrix of the poles N-S are additionaly exposed to the 21 action of lateral forces Fg due to the elevated level of gz the ferromagnetic liquid 3. Their trajectory is changed, which prevents flocs from being formed near the side walls of the reservoir 2.

The device 5 for discharge of separated particles of the mechanical mixture removes separates heavy and light particles in respective collectors of separated products (not shown in figures).

The herein disclosed ferrohydrostatic separator should IO advisably be used to separate mechanical mixtures of nonferrous metals whose density does not exceed 5 10 kg/m.

To separate mechanical mixtures of non-magnetic materials, e.g. fragmented aircraft and automotive scrap, such as aluminum scrap with fragment size of up to 120 mm and density of I.5I103 kg/m 3 and higher, it is advisable to use the ferrohydrostatic separator shown in This separator comprises a magnetic system 19(Fig.5) featuring two variable-section poles N-S whose shape-produces a magnetic field with its strength varying along the height of the pole gap, from the maximum value at the lower part of the poles to the minimal value at the top thereof, and along the generatrix of the pole curve, from the maximum value in the mechanical mixture feed xone to the minimal value in the discharge zone. The separatnr also comprises a reservoir 20 made of a non-magnetic material and filled with a ferromagnetic liquid 3, which is disposed in the pole gap, a device 21 for feeding the mechanical mixture of non-ferrous .etals, which is positioned above the surface of the ferromagnetic liquid 3, and a device 22 for removal of separated particles of the mechanical mixture. The magnetic system 19 is provided with two excitation windings 23, each such winding being mounted on a yoke 24 secured by brackets 25 on a frame (not shown). The poles N-S of'the magnetic system 19 are secured on the yoke 24. The device 21 for feeding the mechanical mixture of non-ferrous metals K l-Pr 0 22 comprises a hopper 26 rigidly secured on the poles N-S by means of a bracket 27, and a vibrating chute 28. The hopper 26 is positioned above the chute 28.

'he dealing with mechanical mixtures of low density, it is necessary to reduce the strength and its gradient (grad H) of the magnetic field. In this case, in order to provide conditions for maintaining a column,with a height h, of the ferromagnetic liquid required for high-quality separation of mixtures, this liquid is subjected to the action 1O of the hydrostatic column of water or other liquid which does not mix with the ferromagnetic liquid. The height h of the hydrostatic column of this liquid can be found from the equation The device 22 for removal of separated particles of the mechanical mixture is a hollow V-shaped duct 29 rigidly secured to the reservoir 20 and associated therewith. The hollow duct 29 is filled with water 30, a layer of ferromagnetic liquid floating on the water surface facing the reservoir 20. The space of the duct 29 is divided by a 31 into two passages 32 and 33. The passage 32 accomodates any known transportation means (not shown) to remove heavy particles of the mechanical mixture. The passage 33 accomodates any known trancs oration means (not shown) to remove light particles of the mechanical mixture.

made of ferromagnetic material are placed in the gap between the poles N-S. Each element is a rod 34. All rods are connected by non-magnetic cross-pieces 35 so as to form a plase parallel to the velocity vector of heavy particles. In order to exert action on the oarticles of the mixon the surface of the ferromagnetic liquid, each element is made as a part of a cone 36 slit along the axis of symmetry thereof and having a spherical base secured on the pole N or S. Each element 36 is arranged similarly to the elements 18 (Fig.4). This separator operates exactly as the of Figs.I-4.

L

f-U "u 1 1 23 Industrial Applicability In separation of fragmented cable scrap and leadsheathed waste (copper-lead and aliminium-lead mixtures), the ferrohydrostatic separator forming the subject of the present invention permits recovery of the light product representing aluminium or copper with inclusion of the heavy product not in excess of 1% and separation of the heavy product representing lead with inclusion of the light product not in excess of 2%.

In separation of domestic radioelectronic equipment scrap comprising a mixture of aluminium, copper and tinlead solder, the proposed ferrohydrostatic separator permits recovery of aluminium with inclusion of copper and tin-lead solder not in excess of 1% and separation of the copper-tin-lead product with inclusion of aluminium not J.n excess of The results obtained in separating mechanical mixtures of non-ferrous metals allow producing high-grade alloys from the recovered products.

Claims (6)

1. A ferrohydrostatic separator comprising a magnetic system featuring at least two poles N S shaped to establish a magnetic field whose intensity H varies with the height of the pole gap from the maximum value at the bottom part of the poles to the minimum value at the top part thereof, a reservoir of a non-magnetic material with a ferromagnetic liquid arranged in the space between the poles, a device for feeding a mechanical mixture of non-magnetic materials, which is disposed above the surface of the ferromagnetic liquid and secured on the poles N S, a device for removing separated particles of the mechanical mixture, which is associated with the reservoir, characterized in that elements made of a ferromagnetic material are placed in the gap between the poles N S and on the poles N S to establish local magnetic fields inside a column of the ferromagnetic liquid, the magnetic force vector Fla, F 1 g of each local magnetic field being directed at an angle to the velocity vector V of particles of the mechanical mixture.

2. A ferrohydrostatic separator as claimed in claim 1, characterized in that each element arranged in the gap between the poles is made as a rod provided at a uniform distance from one another, and all the rods are connected by non-magnetic cross-pieces secured on the reservoir to form a plane directed parallel to the velocity vector V of particles of the mechanical mixture in the layer of the ferromagnetic liquid, one butt end of said plane perpendicular to the axis of the rod being disposed in the mechanical mixture feed zone below the surface of the ferromagnetic liquid, while the other butt end thereof perpendicular to the axis of the rod is located in the layer of the ferromagnetic liquid in the zone of maximum intensity H of the magnetic field.

3. A ferrohydrostatic separator as claimed in claim 1 or claim 2, characterized in that each and every element is a part of a cone, cut along the axis of symmetry thereof and having a spherical base secured by its plane on the pole N S and arranged along the generatrix of the curve of the pole N S at an equal distance with respect to one another and displaced with respect to the element of the other pole, while the vertex of the cone is directed like the velocity vector V of particles of the mechanical mixture over the surface of the ferromagnetic liquid. STA/1548w t nKN~ ~1 _11- 25

4. A ferrohydrostatic separator as claimed in claim 1 or claim 2, characterized in that each of the poles N S has a variable cross section along the interpole gap, ranging from the minimum section in the feed zone of the mechanical mixture to the maximum section in the zone of discharge of separated particles of the mechanical mixture.

A ferrohydrostatic separator as claimed in claim 3, characterized in that each of the poles N S has a variable cross-section along the interpole gap, ranging from the minimum section in the feed zone of the mechanical mixture to the maximum section in the zone of discharge of separated particles of the mechanical mixture.

6. A ferrohydrostatic separator substantially as hereinbefore described with reference to the accompanying drawings. DATED this SIXTEENTH day of APRIL 1991 0 Gosudarstvenny proektno-konstruktorsky institut-Gipromashugleobogaschenie Patent Attorneys for the Applicant SPRUSON FERGUSON STA/548w ,II STA/1548w S., lg. I uua3ru~ur;aanuPan~-- .r~4-rx lliY~ -26 PERROHYDROSTATIC SEPARATOR ABS TRACT The ferrohydrostatic separator comprises a magnetic syste, having two poles shaped to establisj a magnetic field w.hose intensity (II) varies with the height og the pole gap from the maximum value at the bottom part of the poles to the minimum value at the top part thereof, IO a reservoir of a non-magnetic material filled with a ferromagnetic liquid a device for feeding a mecha- nical mixture of non-magnetic materials, and a device for removing separated particles of the mechanical mixture. Located in the gap between the poles are elements made of a ferromagnetic material and establishing local magnetic fields inside a column of the ferromagnetic liquid The magnetic force vector (Fix) of each local magnetic field is directed at an angle to the velocity vector of particles of the mechanical mixture. i