EP0305510A1 - Systeme de centrifugation et de tri de substances particulaires - Google Patents

Systeme de centrifugation et de tri de substances particulaires

Info

Publication number
EP0305510A1
EP0305510A1 EP88903662A EP88903662A EP0305510A1 EP 0305510 A1 EP0305510 A1 EP 0305510A1 EP 88903662 A EP88903662 A EP 88903662A EP 88903662 A EP88903662 A EP 88903662A EP 0305510 A1 EP0305510 A1 EP 0305510A1
Authority
EP
European Patent Office
Prior art keywords
centrifuge
bowl
suspension
particles
colloids
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.)
Withdrawn
Application number
EP88903662A
Other languages
German (de)
English (en)
Inventor
Bruce E. Novich
Richard L. Pober
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.)
CPS Technologies Corp
Original Assignee
Ceramics Process Systems Corp
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
Priority claimed from US07/028,891 external-priority patent/US4781671A/en
Priority claimed from US07/036,325 external-priority patent/US4882088A/en
Application filed by Ceramics Process Systems Corp filed Critical Ceramics Process Systems Corp
Publication of EP0305510A1 publication Critical patent/EP0305510A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • 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
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
    • 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
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B9/00—General arrangement of separating plant, e.g. flow sheets
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/38—Treatment of water, waste water, or sewage by centrifugal separation
    • C02F1/385—Treatment of water, waste water, or sewage by centrifugal separation by centrifuging suspensions

Definitions

  • This invention relates to a centrifugation system for classifying particulate materials, to a system for obtaining sub-micron classification fractions from colloidal particulate feed materials, and to a method for facilitating the removal of those classified fractions from the centrifuge bowl.
  • the present invention relates to a system suitable for selective chemical reactions involving colloids during the separation process.
  • centrifuges and centrifugation systems for size classification is well known in the art. See, for example, U.S. Patent Nos. 2,085,538 and 2,097,420. Such art has been concerned primarily with the size classification of clay particles, which are used primarily for porcelain, china, and similar ceramic parts.
  • Ceramics have found a more wide-spread use in electronic components, cutting tools, and as structural substitutes for metal components.
  • the properties exhibited by such ceramic materials are determined primarily by the mic ostrueture of the sintered ceramic part.
  • current processing systems allow for a high variability in the processing parameters, which are dependent, to a large e tent, upon the characteristics of the starting ceramic po der.
  • Ceramic structures are typically manufactured from powders formed into a so-called "green body.” This green body is subsequently sintered at high temperature to yield the final ceramic material.
  • commercially available powders have large size distributions, typically from less than 0.5 microns to about 10 microns.
  • v the particle's settling of velocity
  • h the distance through which the particles settles
  • t the time required for the particles to settle through the distance h
  • r the particle radius
  • g the acceleration due to gravity
  • p the particle density
  • p the density of the medium
  • K the particle shape factor (2/9 for a sphere) , which takes into account both a particle's volume and its cross -sectional area .
  • t is the time required for a particle to settle through a distance x- j _ - X
  • T' ⁇ the rotating radius of the centrifuge to the end point of the particle's travel path
  • X ] _ the rotating radius of the centrifuge to the beginning point of the particles' travel path
  • ⁇ J the angular velocity of the centrifuge in radians/second
  • a slurry of particles is placed in a centrifuge bowl and centrifuged under those calculated conditions, such that the resulting overflow contains only particles finer than the upper limits of the desired increment and is decanted.
  • the overflow is then processed in a fashion similar to that used for the original slurry, such that actually all particles larger than the lowest size desired are spun out of suspension onto the centrifuge wall.
  • This second sediment consists of particles within the desired size range and is therefore retained.
  • TITUTE SHEET narrow size distribution powders Such powders would find widespread use and satisfy a variety of long-felt needs in forming high performance ceramics.
  • a further use for narrow size distribution powders is as fillers in conjunction with ferrite-ceramic compositions.
  • the present invention provides an improved method and system for centrifugally separating suspended colloids and for permitting selected chemical reactions involving colloids in the separation process.
  • this method comprises activating a centrifuge, introducing a fluid medium into the spinning centrifuge to form a static zone of fluid within the centrifuge bowl, and introducing a suspension of colloids into the spinning bowl at the location concentrically within the static zone .
  • the present invention provides a process for classifying commercially available broad distribution colloidal powders into precise, submicron size fractions.
  • a system includes providing an array of centrifuge units, each unit including a static zone within a bowl-type centrifuge as described above, providing a well -dispersed feed suspension to the array of units, and controlling, in real time, both the mass flow rate through and the rotation rate of each centrifuge unit within the array.
  • the present invention provides a method for facilitating the removal of the submicron classification fractions provided in the foregoing aspect.
  • the method includes using a substantial excess of dispersant in the feed slurry.
  • a plastic sedimentation cake is formed in the centrifuge bowl rather than a dilatant cake; accordingly, this plastic cake can be easily removed and thus provides for a centrifugation classification system that can be operated continuously, or at least semi-continuously, and efficiently .
  • Fig. 3 depicts an expanded vertical cross - section of the spinning apparatus in Fig. 2 at time showing the trajectories of colloids within the suspension;
  • Fig. 4 depicts a vertical cross-section of a spinning centrifuge bowl in accordance with the present invention, wherein the static zone includes both a separation zone and a reaction zone, the reaction zone including a reagent that reacts with the colloid, so that the larger colloids have reacted with the reagent following their separation;
  • Fig. 5 depicts a cross-section of a two-stage system according the present invention, showing idealized particle sizes and separation of particles by size;
  • Figs. 6 - 8 depict process schematics of a multi ⁇ stage, semi-continuous system for the classification of colloidal particulates in accordance with the present invention
  • Fig. 9 is a graphic representation of the particle size distribution of commercially available powder prior to classification
  • Fig. 10 is a graphic depiction of the particle size distribution of alumina powder obtained after a first step in the classification process in accordance with the present invention.
  • Fig. 11 is a graphic depiction of the particle size distribution of alumina obtained after a second step of the classification process in accordance with the present invention.
  • Fig. 12 is a graphic depiction of the particle size distribution of alumina obtained after a third step of the classification process in accordance with the present invention
  • Figs. 13 - 15 are photo-micrographs of SiAlON classified according to the present invention
  • Fig. 16 depicts a flow diagram of the centrifugal classification process in a simplified version
  • Fig. 17 is a scanning electron micrograph of 0.4 to 0.7 micron size particles classified in accordance with the present invention.
  • a fluid medium distinct from the colloidal suspension is first introduced into the centrifuge bowl.
  • time t2
  • larger particles collect to form a layer 22 against outer wall 15.
  • the static zone can be employed as a chemical reactor, as shown in Fig. 4, wherein larger particles are brought into contact with the reagents during settling.
  • the static zone 44 includes a separation zone 42 and a reaction zone 43. To establish these zones, one may. for example, successfully ⁇ ⁇ - ⁇ -'f ⁇ T HE T place in the spinning bowl first a fluid reagent (to form zone 43) and then a second fluid (which may be distinct from the fluid reagents) to form zone 42. The suspension is then provided through a feed, as described above in connection with Fig. 2, so as to form a dynamic zone 41.
  • the larger, but not the smaller particles may be caused to react with the fluid reagents.
  • the method of the present invention permits a wide range of reagents to be employed.
  • the reagents may be introduced as an additional fluid component, separated from the zone by an immiscible boundry zone, or the reagent may itself form a static fluid zone used as above.
  • Employing the static zone as a reactor provides excellent flexibility in reacting components, because of the variable residence time, particle concentration, and size fractionation.
  • the prior art would predict that an inaccuracy occurs as the sediment layer accumulates on the centrifuge wall.
  • the distance particles travel to reach the outer wall diminishes with the accumulation of the sediment on the centrifuge wall, and some fine particles, which would otherwise go into the overflow, should then hit the wall and remain there.
  • the prior art would predict that this inaccuracy is unavoidable (unless the wall is continuously scraped or the operating conditions of speed and flow rate are changed) , because the calculated minimum diameter of the particles within a cut constantly decreases with sediment built up. Nevertheless, we have found that this is not the case, and the relative lack of variation in separation accuracy with accumulation of sediments on the centrifuge wall tends to confirm the validity of our model of the separation process, although we do not wish to be constrained to any particular theory.
  • continuous flow centrifugation may be used to classify each unit volume of dispersion as it is introduced to the system.
  • a centrifuge basket rotating at a constant angular velocity can be filled with liquid, forming a wall of fluid.
  • the slurry is then introduced as the calculated feed rate determined by the largest particle size desired:
  • V the volume of the centrifuge basket.
  • Concentrated suspensions caled powder cuts very different from theoretical due to the numerous particle interactions; these interactions disturb the particle's velocity, sometimes causing larger particles to be carried over with fine particles in the supernatant.
  • the following examples are illustrative of centrifugation using the aforedescribed static zone:
  • Example 1 Into a spinning centrifuge of the bowl type having apacity were added approximate amounts of the following: 100 ml 1/2 weight percent Corcat P600 (a cationic amino based polymeric flocculent obtained from Cordova Chemical Company, Michigan) ; and 240 ml deionized water. This liquid mixture was used to form a static zone. A feed suspension was then introduced, comprising: 10 vol . % A16 alumina powder (available from Aluminum Company of America, Pittsburgh, Pa) 89 vol . % deionized water; and
  • Example 1 The procedure of Example 1 was followed as above, but with the substitution of a halogenated hydrocarbon (such as Freon TF , available from E. I. DuPont De Nemours and Company, Wilmington, Delaware) used to form the static zone.
  • a halogenated hydro-carbon such as Freon TF , available from E. I. DuPont De Nemours and Company, Wilmington, Delaware
  • the halogenated hydro-carbon is immiscible with water and has a higher density than does water. so the system is stable both thermodynamical1y and mechanically.
  • the particles are stable in the aqueous zone, but not in the hydrocarbon zone, so the particles flocculate when they enter the hydrocarbon zone.
  • the system works with acid because as the LD-45 is neutralized, its dispersing powder is also reduced.
  • the foregoing description and examples have generally described a single centrifuge including a static zone.
  • a preferred embodiment of the present invention comprises two or more separate centrifugation steps to produce particles of decreasing sizes.
  • the overflow product from one centrifugation stage is used as the feed input for the succeeding centrifugation stage. Residence time and centrifugal acceleration are the fundamental parameters determinative of particle size separation.
  • centrifugation process is useful for any type of fluid or material, including, but not limited to ceramics, including oxides such as alumina, glasses such as cordierite , SiAlONS, and the like. Depending on the particles type chosen, the skilled artisan can chose an appropriate liquid and dispersant.
  • Typical liquid media include water (either deionized or tap) , alcohols (such as ethanol or isopropanol ) , and other organic solvents such •as methylethyl ketone .
  • Typical dispersants include inorganic acids (such as nitric acid) . inorganic bases (such as ammonia) , organic acids (such as para- hydroxynebenzoic acid) , organic bases (such as triethanolamine) , and polymeric dispersants, which can be
  • Fig. 5 depicts a cross-sectional view of a two-stage system in accordance with the present invention. This figure shows a cross - sectional view of particle distributions in the two-stage classification system. For simplicity, only three particle sizes are shown.
  • the first stage feed 101 contains particles of all three sizes. Two smaller size fractions are removed from suspension as overflow 102 from stage one, forming a second stage feed 103, and leaving the larger size particles in the first stage sediments 104. The smallest size particles are removed from suspension as stage two overflow 105, leaving the intermediate size particles in stage two sediments 106.
  • Figs. 6-8 are schematic diagrams of a multi-stage con ⁇ tinuous system for the classification of particulates in accordance with the present invention.
  • "raw" powder 201 is passed through screen oven 203, and weighing device 204, and finally feed to dispersion device 205, preferably a Sweco mill (available from Sweco, Inc. , Los Angeles, California) with media.
  • Dispersion device 205 preferably a Sweco mill (available from Sweco, Inc. , Los Angeles, California) with media.
  • Liquid 206 is passed through filter 207 and driven by pump
  • the preferred liquid for use with alumina is isopropryl alcohol or water, and a preferred dispersant such as Narlex LD-45 210 is fed to filter 211, pump 212, and totalizer 213, and subsequently into mixing device
  • Setpoint controller 214 communicates with totalizer
  • Providing a well-dispersed feed slurry, including the liquid medium dispersant and colloidal powder, is a critical step in the classification process.
  • the particles are not comminuted so as to avoid increasing irregularities in particle shape.
  • Powder, liquid, and dispersant are added to the dispersion device in a selected order at appropriate stages. It is preferred that the powder be added in staged order of addition to liquid and dispersant already in the dispersion device; however, although more difficult ' to obtain, a well- dispersed slurry can be obtained by mixing all components at once and agitating for a prolonged period of time. Dispersing is conducted for a pre-determined time, typically for about 6 hours , under controlled conditions (generally relating to speed and temperature conditions). Monitoring devices 218 and 219 periodically measure parameters indicative of the dispersion quality of the mixture, and samples of the mixture are returned to the dispersion device 205 from the particle size test stage 222 via line 223.
  • the stock suspension in tank 220 is moved by pump 224 to classifier feed tank 225.
  • the output of pump 224 is monitored by monitoring device 226 and by controller 227.
  • the suspension input to the classifier feed tank 225 is stirred and diluted with dilution fluid from tank 229 via pump 228.
  • the output of pump 228 is monitored by monitoring device 230 and regulated by controller 231.
  • a preferred dilution fluid for alumina is water, which is typically added at a ratio of about 3 parts of dilution liquid to one part of stock.
  • the diluted suspension is referred to as classifier feed suspension.
  • This classifier feed suspension is then pumped by pump 232 to first stage classifier 233, shown in Fig. 7.
  • the output of pump 232 is monitored by device 234 and regulated by controller 235.
  • Monitoring device 234 is a commercially available unit which measures density and temperature and mass flow rate. Typical flow rates into the first stage are approximately 0.4 kilograms per minute.
  • Classifiers 223, 236, 237, and 238 are commercially available centrifuge devices modified with a tachometer and commercially available set point contollers 239, 240, 241, and 242. Classifiers are typically operated at a maximum speed of approximately 6000 rpra .
  • An exemplary centrifuge device is available from International Equipment Company, Needham Heights, Mass, as model K, in which a solid basket rotor #1357A can be used. However, it will be evident to the skilled artisan that other components may be substituted and adjustments, made accordingly.
  • each centrifuge is activated and filled with liquid (for example, solely water when water is used as the liquid medium for alumina) prior to the introduction of a feed dispersion, as discussed above regarding the static zone.
  • liquid for example, solely water when water is used as the liquid medium for alumina
  • classifier 233 is activated, then "primed" with water before feed is pumped from tank 225. After feed is introduced, classifier 233 is operated at a speed and feed rate conditions calculated to yield the desired particle size in the centrifuge basket. The centrifuge is operated for a pre -determined time, or until such sufficient separation is observed.
  • the classifier is then shut down, and bowl waste is removed by pump 243 along line 244 to holding tank 248; classifiers 236, 237, and 238 likewise have bowl waste removed via lines 245 to 247 to holding tank 248.
  • the bowl waste can contain significant amounts of material concentrated in a particular size fraction.
  • Wet powder 249 is then removed from the centrifuge basket.
  • coarses particles smaller than the minimum size desired in the first stage basket ("fines") are drained from overflow into tank 250 from which they are pumped by pump 251 to second stage classifier 236.
  • This flow rate is controlled by a feed regulation system com ⁇ posed of pump 251(a), which is monitored by device 252(a) and regulated by setpoint controller 253(a); the second stage 236, third stage 237, and fourth stage 238 classifiers operate in a similar fashion.
  • fines from overflow tanks 254 and 255 are pumped to classifiers 237 and 238 by pumps 251(b) and 251(c), respectively, monitored by devices 252(b") and 252(c) , and regulated by setpoint controllers 253(b) and 253(c) .
  • each succeeding classifier stage separates out a range of particles having a smaller mean diameter than the range of the preceding stage. Each succeeding stage must therefore operate at a lower mass flow rate and higher rpm range than the previous stage.
  • the last stage classifier is fitted with an in-line static mixer 267, in which the fines suspension is mixed with a flocculent to facilitate the fines recovery.
  • classifier stages thus operate in a cascaded fashion, with each succeeding stage classifying the fines of the previous stage, and with holding tanks 250, 254, and 255 functioning as accumulators to buffer output rates to feed rates.
  • holding tanks 250, 254, and 255 functioning as accumulators to buffer output rates to feed rates.
  • the actual number of stages may vary depending on the application.
  • the particles which are so small as to remain in suspension after passing through a par ⁇ ticular classifier can be flocculated out and the liquid remaining can be recycled through the process.
  • Fig. 8 One method for accomplishing this is illustrated in Fig. 8.
  • Floc ⁇ culent, for example water and nitric acid (or water and Corcat P600, as mentioned above) from a tank 268 is filtered through device 256, then pumped via pump 257 through the in-line static mixer 267 into the last stage classifier 238.
  • the flow rate is monitored by device 258 and regulated by set point controller 259.
  • the liquid passing out of the classifier, now particle free, is collected in overflow tank 260 and sent by pump 261 to holding tank 262. Thereafter, the liquid passes through filter 263 and is sent by pump 264 through the molecular seives 265 and 266 where water is removed, thereby leaving liquid which is ready to be pumped back to reuse or recycle as liquid 206, as shown in Fig. 6.
  • Example 4 A four-stage classifying system was first primed with one residence volume of water.
  • Alumina 60 weight per cent
  • A-16 Superground available from Aluminum Company of America, Pittsburgh, Pa. was mixed with water (39.25 weight percent) and a dispersant (Narlex LD-45, 0.75 weight percent suspension basis) . This mixture was milled, filtered, and pumped into the classifier feed tank. The starting size distribution range is shown in
  • Fig. 9 The feed suspension was then pumped at 1.0 kg/min into the first stage classifier, which was operated at 973 rpm , which thereby resulted in the removal of particles larger than 1.2 microns from the feed stream. The particles were collected in a bowl.
  • the suspension containing particles smaller than 1.2 microns was pumped at 0.85 kg/min into the second stage classifier operating at 1268 rpm.
  • the actual size distribution achieved is shown in Fig. 10.
  • Liquid containing particles smaller than 0.8 microns was pumped at 0.760 kg/min into the third stage classifier, which was operated at 1942 rpm.
  • the actual size dis ribution of these particles is shown in Fig. 11. Particles smaller than 0.5 microns were pumped at a rate of 0.506 kg/min into the fourth stage classifier, which was operated at 2700 rpm.
  • Fig. 12 shows the actual size range of these particles.
  • Particles smaller than 0.3 microns which remained in suspension were pumped through a static T-mixer with a dilute nitric acid solution to bring the suspension screen pH to 3 +. 1.
  • the resulting flocculated suspension was introduced into a fifth stage classifier at 0.45 kg/min which was operated at 2700 rpm, wherein all remaining particles were removed.
  • the type of system just described could be scaled up to classify a large volume of material rapidly, for commercial production, i.e. , up to about one metric ton per hour.
  • Fig. 9 is a photomicrograph of the particles from the 2.0 to 3.0 micron fraction, demonstrating the relatively narrow size ranges.
  • Fig. 10 depicts the classified SiAlON particles from the 0.1 to 3.0 micron cut. The very fine particles of Fig. 11 are less than 0.1 micron.
  • the present process provides the ability to classify colloidal particles into submicron classification fractions.
  • classification fractions are dilatant rather than plastic, and therefore are not easily removed from the centrifuge bowl.
  • a plasticizer or lubricant such as a humectin, is not desireable because such agents may tend to cause flocculation , thereby ruining the dispersion of the colloids, and such agents may also segregate non-uniformly during the classification process .
  • a polymeric dispersant include those that are commercially available, such as that designated Narlex LD-45, and as discussed above ,(preferably used in combination with alumina powders classified in water), and those designated Darvan C and Darvan 821 A, both available from R. T. Vanderbilt Company, Norfolk, Conn.
  • the amount of the dispersant added will vary with the type of dispersant and the particular powder composition. In any case, the amount of dispersant should be effective to impart plasticity to the classified cake, but not at such a high concentration as to interfere with flow or dispersion characteristics of the slurry as it is classified, especially regarding viscosity .
  • Example 6 A two stage classifying system was first primed with one residence volume of water.
  • Alumina 60 weight %) A-16 Superground (available from Aluminum Company of America, Pittsburgh, Pa) was mixed with water (39.25 weight %) and a dispersant (0.75 weight % of Narlex LD-45, weight % suspension basis) .
  • This mixture was milled, filtered, and then pumped into the classifier feed tank.
  • the feed suspension was then pumped at 0.85 kg/min into the first stage classifier, which was operated at 1268 rpm and which resulted thereby in the removal of particles larger than 0.8 microns from the feed stream. These particles were collected in a bowl.
  • the suspension containing particles smaller than 0.8 microns was pumped at 0.760 kg/min into the second stage classifier, which was operated at 1942 rpm.
  • Example 7 A stock suspension of the apprximate amount of the following materials was made and milled for twenty-four hours on a roller mill:
  • a feed suspension was made, starting with 1.0 kg of the stock suspension and diluted with 2.2 kg of distilled water and 800 grams of the LD-45 dispersant. This feed suspension was milled for about 30 minutes, filtered, and then pumped into a classifier feed tank similar to that in the above-described classification system, which is depicted in a simplified form in Fig. 16.
  • the feed suspension was pumped at 0.3 kg/min into a first classifier, which was operated at 3120 rpm.
  • the fines overflow from the first classifier was pumped at a rate of about 0.17 kg/min into a second classifier which was operated at 4000 rpm.
  • the fines overflowing from this classifier were discarded.
  • Adding the additional dispersant causes an increase in solution viscosity from 1.1 to 2.4 cps, measured at 100 sec
  • the equation (1) described above predicts the particle size cut in the second bowl. This equation predicts an average equivalent spherical diameter particle size fraction of about 0.4 to 0.8 microns, which was then verified by scanning electron microscopy, as depicted in Fig. 17.
  • the narrow size range powder collected in the bowls was not dilatant. Rather, it was plastic and could easily be scooped out of the bowl.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Analytical Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Centrifugal Separators (AREA)
  • Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
  • Colloid Chemistry (AREA)

Abstract

Des particules colloïdales peuvent être séparées d'une suspension (13) au moyen d'une centrifugeuse comportant un volume de fluide statique (44) constitué avant l'introduction de la boue de départ. On obtient ainsi une fraction de tri plus précise. Un système de tri, comportant un certain nombre de centrifugeuses de ce type (233, 236, 237, 238) agencées en cascade, permet d'obtenir de multiples fractions de tri submicroniques dans les cas où la matière de départ est un coulis bien dispersé de particules colloïdales et où le débit et la vitesse de rotation dans et à travers chacune des centrifugeuses sont régulés en temps réel. De telles fractions de tri submicroniques présentent souvent une rhéologie de dilatance et, par conséquent, sont très difficiles à éliminer du bol plein de centrifugeuse. La présente invention décrit un procédé pour faciliter l'élimination de tels gâteaux dilatants grâce à l'emploi d'une quantité excédentaire de dispersant qui est efficace pour disperser les colloïdes et donner un gâteau plastique plutôt que dilatant, tout en ayant également peu d'incidence sur la rhéologie de dispersion.
EP88903662A 1987-03-23 1988-03-23 Systeme de centrifugation et de tri de substances particulaires Withdrawn EP0305510A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US2875787A 1987-03-23 1987-03-23
US07/028,891 US4781671A (en) 1987-03-23 1987-03-23 System for classification of particulate materials
US28757 1987-03-23
US28891 1987-03-28
US07/036,325 US4882088A (en) 1987-03-23 1987-04-09 Slurry for centrifugal classification of colloidal particles
US36325 1993-03-24

Publications (1)

Publication Number Publication Date
EP0305510A1 true EP0305510A1 (fr) 1989-03-08

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EP (1) EP0305510A1 (fr)
JP (1) JPH01503525A (fr)
KR (1) KR890700383A (fr)
AU (1) AU1627688A (fr)
WO (1) WO1988007400A1 (fr)

Families Citing this family (5)

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CN102015920B (zh) * 2008-04-17 2014-09-17 尤尼明公司 由矿物或岩石材料形成的具有受控的粒度分布的阻热膜用粉末
JP2009261781A (ja) * 2008-04-28 2009-11-12 Mitsubishi Electric Corp 遠心脱水装置
CN101797530B (zh) * 2009-02-06 2014-08-20 昆山纳诺新材料科技有限公司 离心分离装置及离心分离固体粒子的制备方法
WO2015198461A1 (fr) * 2014-06-27 2015-12-30 サイチ工業株式会社 Centrifugeuse pour séparer des particules ayant des différences de densité
CN115501689B (zh) * 2022-09-21 2024-01-23 中复神鹰碳纤维股份有限公司 一种分散于浆液中的微米级颗粒连续分级及收集方法

Family Cites Families (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2467402A (en) * 1949-04-19 Recovery of proteins from castor
US1062216A (en) * 1908-03-06 1913-05-20 Francis J Arend Apparatus for separating solids and liquids and washing or otherwise treating the separated solids.
US1082386A (en) * 1910-05-06 1913-12-23 Edward Goodrich Acheson Method of treating amorphous bodies and produce thereof.
US1154575A (en) * 1914-03-11 1915-09-21 Willis W Jourdin Centrifugal separator.
US1749057A (en) * 1926-11-11 1930-03-04 Arthur L Armentrout Apparatus for separating solids from liquids
US1933119A (en) * 1930-06-23 1933-10-31 Merco Centrifugal Separator Co Centrifuge method and apparatus
US1951108A (en) * 1930-07-12 1934-03-13 William J Reilly Centrifugal amalgamator
US1939143A (en) * 1931-11-17 1933-12-12 Drayton A Silver Gold saving machine
US2013668A (en) * 1932-01-15 1935-09-10 Merco Centrifugal Separator Co Material treatment method, apparatus, and system
US2022926A (en) * 1932-11-04 1935-12-03 Schlank Michael Machine for the separation of gold or other concentrate from sand or other material
US2097531A (en) * 1934-06-20 1937-11-02 Merco Centrifugal Separator Co Process applicable to starch manufacture
US2085537A (en) * 1935-01-18 1937-06-29 Bird Machine Co Conditioning of freshly quarried clay
US2085538A (en) * 1936-07-10 1937-06-29 Bird Machine Co Resolution of suspensions of finely divided solids into substantially uniform solids fractions of varying average particle size
US2097420A (en) * 1937-06-26 1937-10-26 Bird Machine Co Centrifugal fractionation of finely divided solids into substantially uniform solids fractions of varying average particle size
US2524816A (en) * 1946-02-21 1950-10-10 Bird Machine Co Method of improving kaolin and products thereof
US2889982A (en) * 1952-11-25 1959-06-09 Kaiser Aluminium Chem Corp Process of purifying caustic aluminate liquors
US2905643A (en) * 1954-06-14 1959-09-22 Thiele Kaolin Co Method of dewatering clay
US2869779A (en) * 1955-04-25 1959-01-20 Shell Dev Method of withdrawing a mixture of feed liquor and carrier liquid from a centrifuge
US3328282A (en) * 1962-02-28 1967-06-27 Pennsalt Chemicals Corp Separation of components of liquidsolid mixtures
DK120629B (da) * 1963-06-12 1971-06-21 Separator Ab Fremgangsmåde til ved separering af opslemninger at regulere koncentrationen af det afgående koncentrat, samt anlæg til udøvelse af fremgangsmåden.
US3334516A (en) * 1964-03-16 1967-08-08 Millipore Corp Continuous fluid purity monitor
US3487003A (en) * 1967-01-16 1969-12-30 Great Canadian Oil Sands Removal of clay from the water streams of the hot water process by flocculation
US3519400A (en) * 1967-01-25 1970-07-07 Atomic Energy Commission Method of centrifugal separation and recovery of chemical species utilizing a liquid medium
US3536253A (en) * 1969-02-24 1970-10-27 Atomic Energy Commission Zonal centrifuge
US3677405A (en) * 1970-09-25 1972-07-18 Pennwalt Corp Liquid and sludge treatment
US3819110A (en) * 1971-06-22 1974-06-25 V Baturov Method for suspension separation and apparatus for accomplishing same
US3916585A (en) * 1973-10-24 1975-11-04 Norton Co Sintered abrasive containing oxides from the system ceria, alumina, zirconia
DE2811887C2 (de) * 1978-03-18 1991-07-18 Westfalia Separator Ag, 4740 Oelde Antrieb für eine kontinuierlich arbeitende Schneckenzentrifuge
US4414106A (en) * 1981-04-01 1983-11-08 E. I. Du Pont De Nemours & Co. Method and apparatus for improving sedimentation field flow fractionation channels
US4421651A (en) * 1982-05-28 1983-12-20 Iowa State University Research Foundation, Inc. Method of recovering adsorbed liquid compounds from molecular sieve columns
JPS5982633A (ja) * 1982-11-02 1984-05-12 Sumitomo Chem Co Ltd 親油性表面を有する磁気記録用研磨剤
ZA839064B (en) * 1982-12-06 1985-07-31 Broken Hill Pty Co Ltd Centrifugal separation method and apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8807400A1 *

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KR890700383A (ko) 1989-04-24
WO1988007400A1 (fr) 1988-10-06
AU1627688A (en) 1988-11-02
JPH01503525A (ja) 1989-11-30

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