US3687284A - Reconditioning of suspensions used in the separation of minerals - Google Patents

Reconditioning of suspensions used in the separation of minerals Download PDF

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Publication number
US3687284A
US3687284A US84367A US3687284DA US3687284A US 3687284 A US3687284 A US 3687284A US 84367 A US84367 A US 84367A US 3687284D A US3687284D A US 3687284DA US 3687284 A US3687284 A US 3687284A
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Prior art keywords
suspension
fraction
cyclone
specific gravity
diluted
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US84367A
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English (en)
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Jan N J Leeman
Hubert H Dreissen
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Stamicarbon BV
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Stamicarbon BV
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/08—Subsequent treatment of concentrated product
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
    • B01D35/005—Filters specially adapted for use in internal-combustion engine lubrication or fuel systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/02—Froth-flotation processes

Definitions

  • the invention relates to a method for the reconditioning of suspensions which are rinsed off from products obtained in the course of the separation of minerals from tailings according to their specific gravity where a heavy medium comprising a suspension of magnetizable particles in a liquid is used.
  • This separation of the minerals from the tailings may be carried out in a float and sink bath or in a separator using centrifugal forces such as a cyclone washer.
  • the heavy medium used in the separation may consist of a suspension of finely divided magnetite, ferrosilicon or a mixture of these magnetizable materials in water.
  • magnetic separators which separate the suspension into at least two fractions, one comprising the bulk of the magnetizable particles and the other comprising the bulk of the contaminations and the bulk of the water.
  • the cleaned magnetic fraction is obtained in a more or less concentrated state.
  • the specific gravity at which the separation of the mineral is effected is relatively low, such as in the cleaning of coal
  • the specific gravity of the cleaned magnetic fraction is sufficiently high for this fraction to be used in the specific gravity separation system without first being subjected to a concentrating step.
  • a further concentrating of the cleaned magnetic fraction is necessary to raise its specific gravity to the value required for reuse.
  • the method of the present invention is adapted to regulate the concentration of magnetic particles in the suspension used in a heavy ore mineral separation process so that the suspension will have a specific gravity value compatible with its intended use in the specific gravity separation system.
  • the concentrating of the cleaned magnetic fraction may be carried out in densifiers, such as spiral densifiers, static concentrators or cyclone densifiers.
  • densifiers such as spiral densifiers, static concentrators or cyclone densifiers.
  • the use of cyclones for this purpose has the advantage as compared with other methods that the cyclones are cheaper in operation as they occupy less space and do not require mechanical devices for discharging the concentrates.
  • a cyclone densifier is an apparatus comprising a radially symmetrical vessel usually tapering towards one end and with a feed opening through which liquid medium containing suspended particles can be continuously supplied to create a vortex within the vessel and two opposed axial discharge openings through which fractions discharge from different parts of the vortex, one fraction (hereafter called the underflow) discharging through the apex opening and being more concentrated than the feed and the other fraction (hereafter called the overflow) discharging through the opening in the wider end of the vessel and being less concentrated than the feed.
  • the underflow fraction
  • the overflow discharging through the opening in the wider end of the vessel and being less concentrated than the feed.
  • the present invention provides a method of reconditioning a diluted suspension of fine magnetizable particles and contaminating solids in a liquid in which the magnetic fraction obtained from the magnetic separator is concentrated by means of a cyclone densifier and wherein the equipment for recovering the magnetizable particles discharged through the overflow of the cyclone may be of relatively small capacity.
  • the method according to the invention comprises the steps of magnetically separating the diluted, contaminated suspension into at least a first fraction which includes the bulk of the magnetizable particles and a second fraction which includes the bulk of the contaminating solids and the bulk of the liquid, then diluting said first fraction, concentrating the thus obtained diluted fraction in a cyclone densifier to a specific gravity exceeding that of said first fraction, magnetically separating at least the bulk of the magnetizable particles from the overflow of the cyclone densifier and combining the fraction containing such magnetizable particles with the concentrated underflow discharge from the cyclone densifier.
  • the invention is based on the discovery that by diluting the feed to the cyclone densifier, the percentage of magnetizable particles discharging though the underflow opening of the cyclone is increased, and, furthermore, the specific gravity and volume of the undert'low are so high that the magnetic fraction which is recovered from the overflow by magnetic separation can be added to such underflow without first being concentrated.
  • the method of the present invention enables the use of very finely divided magnetizable particles, which do not settle at an acceptably high rate in the separating devices.
  • the grain size of the magnetizable particles may be substantially smaller than 60 t. So called atomized ferrosilicon is preferably used due to its spherical shape. However, finely ground ferrosilicon, magnetite or mixtures of these materials may be used.
  • the extent to which the first fraction can be diluted in any given case prior to the introduction of such fraction into the cyclone densifier depends on the nature of the magnetizable material, on the characteristics of the cyclone densifier used, and, of course, on the extent of concentration which is required in the separation process.
  • the feed concentration For attaining a given specific gravity value for the underflow, the feed concentration must be lower for some magnetizable materials than for others. The appropriate feed concentration, however, can be determined by simple tests.
  • a conical cyclone densifier was fed at a pressure of 1.1 atmospheres with a suspension of ferrosilicon (specific gravity of solids 6.75) in water at a concentration of 750 grams per liter; the underflow had a specific gravity of 3.9 and contained percent of the magnetizable material.
  • a magnetite suspension specifically gravity of solids 5.0
  • concentration corresponding with a specific gravity of 1.4
  • the mineral material to be separated for example, raw iron ore having a grain size of 95 inch, is supplied with water through a launder 1 onto a desliming screen 2. On this screen the raw material is rinsed with water by means of sprayers 3. Particles smaller than 0.5 mm pass through the screen and are discharged as underflow through a conduit 4 for further treatment, such as froth flotation.
  • the deslimed ore having a grain size larger than 0.5 mm is fed through a conduit 5 to a tank 6, in which it is mixed with a separating suspension.
  • the separating suspension is supplied from a tank 7 by means of a pump 8 through a conduit 9 to the mixing tank 6.
  • the suspension consists of atomized ferrosilicon, 95 percent of which is smaller than 40 u.
  • the specific gravity of the suspension is about 3.2.
  • the specific gravity of the separating medium has to be so high, on the one hand, because it is diluted in the mixing tank 6 by the incoming wet ore and, on the other hand, because of the high specific gravity of the tailings which are to be separated from the ore.
  • the mixture of raw iron ore and separating medium is fed by means of a pump 10 and a conduit 11 to a hydrocyclone washer 12, where it is separated into an ore fraction and a tailings fraction.
  • the clean ore fraction is discharged from the cyclone 12 through a conduit l3 and supplied to a draining screen 14.
  • the suspension oozes out of the ore mass and is collected in a reservoir 15.
  • the ore passes over a washing screen 16 where the suspension still adhering to the ore particles is sprayed off by means of sprayers 17.
  • the thus diluted suspension passing through screen 16 is collected in a reservoir 18, whereas the cleaned ore is discharged at 19.
  • the tailings fraction is discharged from the cyclone washer 12 through a conduit 20 and supplied to a draining screen 21.
  • the suspension drained from the tailings is collected in a reservoir 22.
  • Suspension still adhering to the tailings is sprayed off on washing screen 23 by means of sprayers 24.
  • the diluted suspension passing through screen 23 is collected in a reservoir 25, whereas the tailings are discharged at 26.
  • the undiluted suspension collected in the reservoirs 15 and 22 may be reused without furthertreatrnent and is passed through a conduit 27 to the storage tank 7.
  • the diluted suspension collected in the reservoirs 18 and 25 not only contains the ferrosilicon particles but also those particles of the separated fractions which have a size smaller than the mesh of screens 16 and 23.
  • This diluted suspension flows through a conduit 28 to a diluted media tank 29. From this tank 29, the diluted suspension is pumped by means of a pump 30 through a conduit 31 to a magnetic separator 32. In this magnetic separator a concentrated ferrosilicon suspension is recovered, which may have a specific gravity of about 2.7. This fraction flows through a conduit 33 to a collecting tank 34.
  • a dilute nonmagnetic fraction is separated off in the magnetic separator 32, which fraction is discharged through a conduit 35 into a tank 36.
  • the suspension is fed by means of a pump 37 and through a conduit 38 to a clarifying cyclone 39.
  • the clarified overflow from this cyclone discharges via a conduit 40 into a reservoir 41 from which it is partly returned to the cleaning system through a conduit 42 leading to the sprayers 17 and 24 and partly to the collecting tank 34 through a conduit 43 as described hereinafter.
  • the magnetic particles recovered in this separator may be fed through a conduit 46 into the dilute medium tank 29 as shown in the drawing or returned to the collecting tank 36.
  • the tailings from this separator are discharged through a conduit 47.
  • the magnetic fraction from the magnetic separator 32 which has a specific gravity of about 2.7 is diluted in the collecting tank 34 by the addition of clarified water through conduit 43.
  • the amount of water is controlled by means of a valve 48 in such a way that the medium in the tank has a specific gravity of about 1.86 which corresponds with 1,000 g ferrosilicon in one liter suspension or about 15 percent by volume of solids in the suspension.
  • the medium from the collecting tank 34 is supplied by means of a pump 49 through a conduit 50 into a cyclone densifier 51.
  • the concentrated apex underflow discharge of this cyclone has a specific gravity of about 3.8 and is led though a conduit 52 into an overdense medium tank 53.
  • the overflow of the cyclone contains about 250 g/l ferrosilicon and is fed through a conduit 54 into a magnetic separator 55.
  • a magnetic fraction is recovered which has a specific gravity of about 2.35 and is discharged through a conduit 56. This fraction is combined with the concentrated fraction flowing through line 52 and introduced into the tank 53. The specific gravity of the combined medium in this tank amounts to about 3.5.
  • the nonmagnetic fraction from the magnetic separator 55 is fed through a conduit 57 into tank 36.
  • the overflow of the cyclone 51 mainly contains the finest particles of the magnetizable material and the apex discharge the coarser particles of this material, these fractions have to be combined so that the suspension recirculated to the gravity separation process will irliclude the whole size range of the magnetizable partic es.
  • the specific gravity of the suspension obtained by combining these fractions is decreased whereas, on the other hand, the capacity of the secondary separation unit 55 has to be increased to handle the greater amount of suspension discharged through the overflow of the cyclone densifier.
  • the suspension in the overdense medium tank 53 is pumped by means of a pump 58 and a conduit 59 to the medium storage tank 7.
  • a pump 58 and a conduit 59 to the medium storage tank 7.
  • the specific gravity of the suspension returned through line 59 to the gravity separation system has to be in excess of that in the specific gravity separation system.
  • the concentration of the input of the cyclone densifier 51 falls below a certain critical value, which may be 5 percent of solids by volume, the specific gravity of the combined fractions introduced through line 52 into the tank 53 will fall below the value required for the separation process. This decrease in concentration may be caused by the fact that the amount of ore being treated has decreased considerably so that less magnetizable particles are rinsed off and passed over the magnetic separator 32 into the tank 34.
  • a splitter box 60 is provided in conduit 52, which splitter box is adjusted by means of a specific gravity control device 61 in such a way that the medium is recirculated through a conduit 62 to the tank 34 when the concentration of the feed to the cyclone densifier falls below a certain value.
  • the present invention provides a method for reconditioning a suspension of fine magnetizable particles as well as regulating the concentration of the suspension within a range whereby the suspension may be employed at nearly optimum efficiency in a separation process.
  • the invention is not restricted to the separation of iron ore as described in the example.
  • Other minerals such as lead-zinc ore, uranium ore, tungsten ore, magnesite, etc., may be separated by using the method according to this invention.
  • WE CLAIM WE CLAIM:
  • a method of reconditioning a diluted suspension of fine magnetizable particles and contaminating solid particles in a liquid which comprises the steps of magne call se arati t edilut dsus nsioni to at least a first rac ion w icii includes th bulk oi the magnetizable particles and a second fraction which includes the bulk of the contaminating solid particles and the bulk of the liquid, diluting said first fraction, concentrating the thus obtained diluted fraction in a cyclone densifier to a specific gravity exceeding that of said first fraction, magnetically separating at least the bulk of the magnetizable particles from the overflow of the cyclone densifier and combining the fraction containing such magnetizable particles with the concentrated discharge from the cyclone densifier.

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  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Cyclones (AREA)
  • Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US84367A 1969-11-19 1970-10-27 Reconditioning of suspensions used in the separation of minerals Expired - Lifetime US3687284A (en)

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GB5671469 1969-11-19

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US (1) US3687284A (enrdf_load_stackoverflow)
CS (1) CS166265B2 (enrdf_load_stackoverflow)
GB (1) GB1225887A (enrdf_load_stackoverflow)
SE (1) SE354792B (enrdf_load_stackoverflow)
ZA (1) ZA707261B (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3877999A (en) * 1974-06-03 1975-04-15 Gen Electric Hydration-disintegration of cobalt-rare earth alloy containing material
US3878000A (en) * 1974-06-03 1975-04-15 Gen Electric Recovery of cobalt-rare earth alloy particles by hydration-disintegration in a magnetic field
US4470901A (en) * 1982-07-28 1984-09-11 Bethlehem Steel Corp. System for controlling separating gravity in dense-media cyclone
US4775464A (en) * 1981-10-22 1988-10-04 Prominco S.R.L Process for separating materials of different specific gravities through a closed loop system utilizing a liquid medium of different densities
US4802976A (en) * 1988-01-04 1989-02-07 Miller Francis G Method for recovering fine clean coal
US5236089A (en) * 1991-01-30 1993-08-17 The Broken Hill Proprietary Company Limited Method of beneficiating coal
US20080202988A1 (en) * 2007-01-24 2008-08-28 Seminis Vegetable Seeds, Inc. Liquid density separation system
US20110225879A1 (en) * 2008-10-15 2011-09-22 Ath Regeneration Limited Separation system and method
WO2017087498A1 (en) 2015-11-16 2017-05-26 Cidra Corporate Services Inc. Utilizing engineered media for recovery of minerals in tailings stream at the end of a flotation separation process

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA522159A (en) * 1956-02-28 L. Bosqui Francis Process for classifying magnetized or magnetizable solids
US2781906A (en) * 1951-07-04 1957-02-19 Stamicarbon Process and apparatus for the separation of mixtures of solid particles
US2889925A (en) * 1955-10-14 1959-06-09 Stamicarbon Process and apparatus for treating suspensions
GB822856A (en) * 1956-08-04 1959-11-04 Stamicarbon Process for separating magnetisable particles from contaminating non-magnetisable particles, present in suspension
US2932395A (en) * 1953-11-21 1960-04-12 Stamicarbon Process of separating mixtures of particles

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA522159A (en) * 1956-02-28 L. Bosqui Francis Process for classifying magnetized or magnetizable solids
US2781906A (en) * 1951-07-04 1957-02-19 Stamicarbon Process and apparatus for the separation of mixtures of solid particles
US2932395A (en) * 1953-11-21 1960-04-12 Stamicarbon Process of separating mixtures of particles
US2889925A (en) * 1955-10-14 1959-06-09 Stamicarbon Process and apparatus for treating suspensions
GB822856A (en) * 1956-08-04 1959-11-04 Stamicarbon Process for separating magnetisable particles from contaminating non-magnetisable particles, present in suspension

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3877999A (en) * 1974-06-03 1975-04-15 Gen Electric Hydration-disintegration of cobalt-rare earth alloy containing material
US3878000A (en) * 1974-06-03 1975-04-15 Gen Electric Recovery of cobalt-rare earth alloy particles by hydration-disintegration in a magnetic field
US4775464A (en) * 1981-10-22 1988-10-04 Prominco S.R.L Process for separating materials of different specific gravities through a closed loop system utilizing a liquid medium of different densities
US4470901A (en) * 1982-07-28 1984-09-11 Bethlehem Steel Corp. System for controlling separating gravity in dense-media cyclone
US4802976A (en) * 1988-01-04 1989-02-07 Miller Francis G Method for recovering fine clean coal
US5236089A (en) * 1991-01-30 1993-08-17 The Broken Hill Proprietary Company Limited Method of beneficiating coal
US20080202988A1 (en) * 2007-01-24 2008-08-28 Seminis Vegetable Seeds, Inc. Liquid density separation system
US20110225879A1 (en) * 2008-10-15 2011-09-22 Ath Regeneration Limited Separation system and method
AU2009305211B2 (en) * 2008-10-15 2013-12-19 Recycoal Switzerland S.A. Separation method
US9039793B2 (en) * 2008-10-15 2015-05-26 Recycoal Switzerland S.A. Separation system and method
WO2017087498A1 (en) 2015-11-16 2017-05-26 Cidra Corporate Services Inc. Utilizing engineered media for recovery of minerals in tailings stream at the end of a flotation separation process
EP3377230A4 (en) * 2015-11-16 2019-07-24 Cidra Corporate Services LLC USE OF MEDIATED MEDIA FOR OBTAINING MINERALS IN AN AFTER STREAM AT THE END OF A FLOTATION DETECTION METHOD
US12005460B2 (en) 2015-11-16 2024-06-11 Cidra Corporate Services Llc Utilizing engineered media for recovery of minerals in tailings stream at the end of a flotation separation process

Also Published As

Publication number Publication date
CS166265B2 (enrdf_load_stackoverflow) 1976-02-27
ZA707261B (en) 1971-07-28
SE354792B (enrdf_load_stackoverflow) 1973-03-26
GB1225887A (enrdf_load_stackoverflow) 1971-03-24

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