Connect public, paid and private patent data with Google Patents Public Datasets

Method of substituting one ferrofluid solvent for another

Download PDF

Info

Publication number
US3531413A
US3531413A US3531413DA US3531413A US 3531413 A US3531413 A US 3531413A US 3531413D A US3531413D A US 3531413DA US 3531413 A US3531413 A US 3531413A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
particles
solvent
ferrofluid
surfactant
another
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.)
Expired - Lifetime
Application number
Inventor
Ronald E Rosensweig
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.)
Avco Corp
Original Assignee
Avco 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
Grant date

Links

Images

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/44Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION 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
    • B03DFLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00Flotation
    • B03D1/001Flotation agents
    • B03D1/004Organic compounds
    • B03D1/008Organic compounds containing oxygen
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION 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
    • B03DFLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00Flotation
    • B03D1/001Flotation agents
    • B03D1/004Organic compounds
    • B03D1/016Macromolecular compounds
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION 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
    • B03DFLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D2201/00Specified effects produced by the flotation agents
    • B03D2201/002Coagulants and Flocculants

Description

sePf- 29, 1970 R. E. ROSENSWEIG 3,531,413

METHOD OF SUBSTITUTING ONE FERROFLUID SOLVENT FOR ANOTHER Filed sept. 22, 1967 2 sheets-sheet 1 G ENERGY ff E a PARTncLE SEPARATION PARTCLE ATTRACTING ENERGY REPELLIN (VAN DER WAAL) ATTRACTING ENERGY REPELLING ENERGY VAN DER WAAL) INVENTOR.

RONALD E. ROSENSWEIG sept 29, 1970 l R. E. RosENswElcsA 3,531,413

METHOD OF SUBSTITUTING ONE FERROFLUID SOLVENT FOR ANOTHER Filed sept. 22, 1967 2 sheets-sheet 2 INVE R. RONALD E. ROSE WEIG United States Patent @ii 3,53lAl3 Patented Sept. 29, 1970 3,531,4ll3 METHD F SUBSTH'EUTENG @NE lFlERlRUFLlUlD SULVENT FR ANG'I'HER Ronald lE. Rosensweig, Lexington, Mass., assigner to Aveo Corporation, Cincinnati, Unio, a corporation of Delaware Filed Sept. 22, 1967, Ser. No. 669,938 int. Cl. Bllld 2]/0] US. Cl. 252-62.62 6 Claims ABSTRACT @E THE DISCLOSURE This invention covers a method of substituting one ferroiluid solvent for another. A typical class of ferrofluid contains magnetic particles with a polar surfactant adsorbed on the surface thereof suspended in a non-polar solvent. To substitute one solvent for another in accordance with the invention, a polar ilocculating solvent is introduced into the ferrofluid causing the particles with the adsorbed surfactant to tlocculate, and to settle out of solution.

The particles and solvent are separated. The particles are then redistributed within another solvent which may be the same as the original solvent or a different composition.

BACKGROUND OF THE INVENTION The invention relates to ferrouid and more particularly to methods of making ferrouids. Related information may be found in Pat. No. 3,281,403.

In general, ferrofluids contain submicron particles of magnetic material such as magnetite and ferrites. A surfactant or dispersing agent is adsorbed on the surface of these particles and acts as a coupling agent `between the particle and a solvent in which the particles are dispersed. Additional information on the structure of typical ferrolluids are found in an article entitled Magnetic Fluids by R. E. Rosensweig in the July 1966 issue of International Science and Technology.

Ferrotluids are generally made by grinding magnetic particles together with a surfactant and solvent over a prolonged period of time.

Not all surfactants or solvents are suitable grinding media. At times they are totally unsuitable and other times ineilicient.

Examples of magnetic material which are suitable for this purpose are magnetite (.FE3O4), manganese-zinc ferrite, v-FezOa, and any solid magnetic material that can be `formed in the proper particle size. Surfactants of the following general nature have been used to make ferrolluids. Carboxylic acids and their metallic salts, amines, succinic acid derivatives, condensation product of an amino ester of a fatty acid. The chain length should usually be eight carbon atoms or greater. Examples of solvents are aliphatic hydrocarbons such as heptane, octane, decane, mineral oil, kerosene etc., halogenated hydrocarbons such as carbon tetrachloride or trichlorethylene and aromatic solvents such as benzene, toluene and their non-polar derivatives. All of these solvents are suitable for grinding and are interchangeable.

Pentane is a suitable solvent but not useful as a grinding aid because it is very volatile.

Flocculation is used herein to denote the aggregation of individual particles into larger masses. These aggregations eventually grow large enough to deposit out of suspension.

It is an object of the invention to provide a method of substituting one solvent of a ferrofluid by another.

It is an object of the invention to provide a method of substituting one solvent of a ferroiluid by another by inducing particle flocculation to cause the magnetic particle to deposit out of solution.

It is another object of the invention to provide a means for formulating ferrolluids containing solvents that are not suitable as grinding or manufacturing aids.

It is yet another object of the invention to provide means for altering the particle concentration in a ferroiiuid particularly Where a ferrofluid surfactant is more volatile than the solvent.

It is still another object of the invention to induce flocculation for the purpose of substituting solvents by reducing the repelling forces overriding the Van der Waal forces of attraction.

In accordance with the invention a method of substituting one ferrofluid solvent for another ferrolluid comprises the steps of introducing a flocculation agent into the ferrofluid thereby causing the particles with adsorbed surfactant to come out of suspension. The particles are separated from the solvent and this is followed by resuspending them in another solvent.

The novel features that are considered characteristic of the invention are set forth in the appended claims; the invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specic embodiment when read in conjunction with the accompanying drawings, in which:

FIG. 1 shows a curve useful in explaining the forces acting on ferrofluid particles.

FIG. 2 is a schematic representation of a ferrouid structure.

FIG. 3 shows a second curve useful in explaining the forces acting on ferrofluid particles.

FIG. 4 depicts the relationship of the various components of a ferrofluid in which a flocculation solvent has been added.

FIG. 5 illustrates an alternate method of causing particles to flocculate.

Characteristically, magnetic particles in a ferrouid remain in suspension without changing the characteristics of the ferrofluid as a homogeneous medium under the influence of applied magnetic fields and magnetic field gradients. There are two contributing factors that maintain the magnetic particles in suspension. The rst relates to the size of the particles which typically are in the submicron region so that particle motion is maintained by thermal agitation. Secondly, the surfactant 0r dispersing agent acts to maintain the particles sufliciently remote from one another to overcome the force of attraction caused by Van der Waals forces.

The origin of the Van der Waal force is the attraction of a fluctuating electric dipole for a neighboring induced dipole. So long as the surfaces of adjacent particles are about one radius apart, the particles will not be strongly attracted toward each other and flocculation can be avoided. The function of the adsorbed coating or surfactant on the particles is to provide at least the minimum distance required for separation.

In FIG. 1 curve 21 represents the magnitude of Van der Waal energy as a function of distance separating two particles. Curve 20 represents the repelling energy generated by coatings of adsorbed surfactant on the surface of two adjacent particles. Curve 22 represents the algebraic sum of the attracting and repelling energies.

The repulsive force equals the negative rate of change of energy with distance dE (Prin (assuming the convention that positive force represents repulsion.) Clearly that repulsion occurs to the right of the apex 25 of curve 23 since the slope of the curve 23dE/dX or the rate of change of energy as a function of distance is negative.

Additionally, if the magnitude of energy at the apex exceeds the thermal energy per particle, the thermal fluctuations of the particles will now throw the particles close enough together to come within the attraction region, to the left of the apex.

Referring to FIG. 2 of the drawings, there is a schematic representation of two adjacent particles and 11 suspended within a non-polar solvent 12. Absorbed on each surface of the particles 10 and 11 are molecules 13 of a polar surfactant. It will Ibe noted that the molecules 13 contain a polar head 14 and a non-polar tail 15. The surfactant molecules 13 coat the surface of the particles, and in effect, form as an elastic boundary between the particles. When two particles such as 10 and 11 approach each other the coating is` compressed and provides an elastic repulsion greater than the attractive forces that would otherwise cause particles to come into contact until flocculation occurs and the solid material settles out.

Referring to FIG. 4 of the drawings, the particles 10 and 11 are depicted in substantially the same environment as shown for FIG. 2, except for the fact that a occulating solvent depicted by molecules 16 has been added to the ferrofluid. The flocculating solvent is a polar solvent. Its effect on the ferroiiuid is to make the surfactant molecules less compatible with its fluid environment comprising the combination of ferrofluid solvent and lilocculating solvent. The tail sections of the surfactant molecules are repelled by the combination of solvents and tend to fold back on themselves toward the surface of the particles. Thus, the depth of coating is materially reduced.

The curves in FIG. 3 denote, as before, Van der Waal attraction, surfactant repulsion and the algebraic sum. Energy curve 23 in FIG. 3 reflects the shortened surfactant thickness as shown in FIG. 4. At no point does it go above the abscissa and therefore nowhere does the repulsion energy exceed the Van der Waal attraction energy.

Particles in their random movement through the combined solvent no longer encounter a repelling force in excess of the Van lder Waal attraction force. The particles adhere to each other, flocculate and deposit out of the combined solvent.

From this point it is a relatively simple matter to separate the particles from the combined solvent. A little of the flocculating and ferrofluid solvent remains on the particles. These solvents appear as a very small impurity when the particles are resuspended in the new solvent. No problems are encountered by these impurities as they are compatible with the new ferrofluid in these small quantities.

In the event the purpose in occulating the particles was to increase the concentration, it is now clearly obvious that the one need only add a reduced amount of solvent to the particles. On the other hand, if the purpose in occulating the particles was to substitute one solvent for another, this step is now clearly possible.

Typical formulations used in practicing the invention are provided in Table No. 1 which follows. The ferrofluid sCl/ents and flocculation solvents are fully interchangea e.

Another means for causing flocculation, called polymeric flocculation, is shown in FIG. 5. Flocculation is caused by linking of two-or more-particles 10, 11, 17

4 by a polymer molecule 18 as shown in FIG. 5. The particles that settle out of solution may be redispersed by supplying excess solvent to the particles to dissolve some of the entangling species.

The amount of flocculating agent that is required differs with each application. It is, however, determinable through routine procedures.

Observed iiocculating agents are polyisobutylene which works with aliphatic and chlorinated aliphatic solvents; polystyrene which may be used with aromatic solvents including toluene; and dimethylene siloxane polymers with the aliphatics.

Two important criteria of polymer occulation agents are: (i) they be miscible in the ferrouid solvent, and (ii) the molecule length shall be several times in the diameter of a particle since a linking of particles is an important consideration.

CONCLUSION In its broadest aspect, the invention covers the substitution of one ferrofluid solvent for another by introducing into the ferrofluid a flocculating agent. The agent can reduce the forces acting in opposition to the Van der Waal forces to the extent thatA the particles can be attracted to one another and deposit out of solution. Alternatively, the occulating agent can act to link particles causing occulation and ultimately the separation of particles and solvent. V

Secondarily, with respect to the former approach, the invention covers the concept of shrinking the thickness of the surfactant coating thus enabling the Van der Waal forces to bring and maintain adjacent particles together. Another aspect of the invention causes the coating to shrink and reduce its effective thickness by introducing into a ferrouid containing a polar surfactant and a nonpolar solvent, a polar flocculating agent.

The various features and advantages of the invention are thought to be clear from the foregoing description. Various other features and advantages not specifically enumerated will undoubtedly occur to those versed in the art, as likewise Will many variations and modifications of the preferred embodiment illustrated, all of which may be achieved without departing from the spirit and scope of the invention as deiined by the following claims.

What is claimed is:

1. A method of substituting one ferrouid solvent for another ferrouid solvent in a ferrofluid consisting essentially of suspended magnetic particles, a polar surfactant and a non-polar ferrofluid solvent comprising the steps of z (a) introducing a polar flocculation agent into the ferrofluid causing theiparticles with adsorbed surfactant to occulate and settle out of suspension;

(b) separating the original ferrofluid solvent and flocculation agent from the particles with adsorbed surfactant; and

(c) dispersing said occulated particles in another nonpolar ferrofluid solvent.

2. A method as defined in claim 1 in which the surfactant is a long chain molecule having a chain length of at least eight carbon atoms having a polar end group and a non-polar tail, said ferrofluid solvent is a non-polar organic fluid and said flocculating agent is a polar organic fluid soluble in the ferrofluid solvent.

3. A method as defined in claim 1 in which the surfactant is a member of the class consisting of carboxylic acids and their metallic salts, amines, succinic acid derivatives, condensation product of an amino ester of a fatty acid, said ferrouid solvent is a member of the class consisting of aliphatic hydrocarbons, halogenated aliphatic hydrocarbons and aromatic hydrocarbons, and said flocculating agent is a member of the class consisting of acetone, ethyl alcohol, dioxane, ethyl acetate and acetone.

4. A method of substituting one ferrouid solvent for another ferrofluid solvent in a ferroiluid consisting essentially of magnetic particles a surfactant adsorbed on said 6 particles and a non-polar ferrofluid solvent comprising the fluid solvent is an aromatic hydrocarbon and the occusteps of: lating agent is polystyrene.

(a) introducing a flocculating agent which is a miscible polymer particle linking agent having a 4molecular References Cited chain length at least twice the diameter of the mag- 5 UNITED STATES PATENTS netlc particles mto the ferrouid and occulatlng sald 2 590 997 4/ 1952 Mitchell 252-326 partlcles causmg said partlcles to settle out of suspension; 3,290,252 12/ 1966 Larsen 252-6254 (b) separating the ferrofluid solvent and polymer link- FOREIGN PATENTS ing agent from the particles with adsorbed surfactant; 10 974 627 11/1964 Great Britain and (c) dispersing said flocculated particles in another non- TOBIAS E LEVOW, Primary Examiner polar ferrouid solvent. 5. A method as defined in claim 4 in which the ferro- I' COOPER Assistant Exammer fluid solvent is an aliphatic hydrocarbon and the tioc- 15 U S C1 XR culating agent is selected from the group consisting of polyisobutylene and dimethyl siloxane. 252-6251, 62,56, 309, 327

6, A method as dened in claim 4 in which the ferro- Patent No. 3 531: 413 Dated September Z9, 1970 Inventor(s) Ronald E. Rosenweg It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column l, line 48, for "(FE O read{Fe O4) Column Z, line l5, after "ferroflud'read"solven Column 3, line 8, for "now" read not; Column 3, line 39, after "thickness" omitas; Column 3, line 57, after "that" omit--the.

SIGNED AND (l5-LED DEC im tSEAL) Attest:

M Flethg Ir- Eo y l :'i p nl L! OEE @omissionsor PatentaJ

US3531413A 1967-09-22 1967-09-22 Method of substituting one ferrofluid solvent for another Expired - Lifetime US3531413A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US66993867 true 1967-09-22 1967-09-22

Publications (1)

Publication Number Publication Date
US3531413A true US3531413A (en) 1970-09-29

Family

ID=24688351

Family Applications (1)

Application Number Title Priority Date Filing Date
US3531413A Expired - Lifetime US3531413A (en) 1967-09-22 1967-09-22 Method of substituting one ferrofluid solvent for another

Country Status (1)

Country Link
US (1) US3531413A (en)

Cited By (43)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3635819A (en) * 1970-06-15 1972-01-18 Avco Corp Process for cleaning up oil spills
US3764540A (en) * 1971-05-28 1973-10-09 Us Interior Magnetofluids and their manufacture
US3855137A (en) * 1972-03-03 1974-12-17 Exxon Research Engineering Co Hydrocarbon gels
US3917538A (en) * 1973-01-17 1975-11-04 Ferrofluidics Corp Ferrofluid compositions and process of making same
DE2529053A1 (en) * 1974-08-23 1976-03-04 Ibm magnetic ink
US3951785A (en) * 1975-01-29 1976-04-20 Avco Corporation Classification by ferrofluid density separation
US4025448A (en) * 1975-12-29 1977-05-24 Union Carbide Corporation Superparamagnetic wax compositions useful in magnetic levitation separations
US4094804A (en) * 1974-08-19 1978-06-13 Junzo Shimoiizaka Method for preparing a water base magnetic fluid and product
US4107063A (en) * 1977-03-02 1978-08-15 International Business Machines Corporation Water based selectable charge magnetic inks
US4108767A (en) * 1975-09-02 1978-08-22 Georgia-Pacific Corporation Separation of an aqueous or water-miscible liquid from a fluid mixture
US4356098A (en) * 1979-11-08 1982-10-26 Ferrofluidics Corporation Stable ferrofluid compositions and method of making same
US4381244A (en) * 1980-03-24 1983-04-26 General Electric Company Ferrofluid
US4416751A (en) * 1980-03-24 1983-11-22 General Electric Co. Process for producing a ferrofluid
US4445940A (en) * 1982-11-30 1984-05-01 Georgia-Pacific Corporation Process to remove corrosion deposits using aqueous-base ferromagnetic fluids
US4565793A (en) * 1975-09-03 1986-01-21 Exxon Research And Engineering Co. Composite zeolitic magnetic material
US4576725A (en) * 1983-07-13 1986-03-18 Toyota Jidosha Kabushiki Kaisha Magnetic fluid incorporating fine magnetic powder and method for making the same
US4579173A (en) * 1983-09-30 1986-04-01 Exxon Research And Engineering Co. Magnetized drive fluids
US4599184A (en) * 1984-02-01 1986-07-08 National Research Institute Process for producing ferromagnetic liquid
US4701276A (en) * 1986-10-31 1987-10-20 Hitachi Metals, Ltd. Super paramagnetic fluids and methods of making super paramagnetic fluids
EP0249229A2 (en) * 1986-06-12 1987-12-16 BASF Aktiengesellschaft Superparamagnetic solid particles
US4741850A (en) * 1986-10-31 1988-05-03 Hitachi Metals, Ltd. Super paramagnetic fluids and methods of making super paramagnetic fluids
US4770183A (en) * 1986-07-03 1988-09-13 Advanced Magnetics Incorporated Biologically degradable superparamagnetic particles for use as nuclear magnetic resonance imaging agents
US4855079A (en) * 1986-10-31 1989-08-08 Hitachi Metals, Ltd. Super paramagnetic fluids and methods of making super paramagnetic fluids
US4938886A (en) * 1988-02-08 1990-07-03 Skf Nova Ab Superparamagnetic liquids and methods of making superparamagnetic liquids
US4946623A (en) * 1986-11-07 1990-08-07 Commissariat A L'energie Atomique Process for the production of a ferromagnetic composition, ferromagnetic liquid crystal obtained by this process and apparatus using said liquid crystal
US4951675A (en) * 1986-07-03 1990-08-28 Advanced Magnetics, Incorporated Biodegradable superparamagnetic metal oxides as contrast agents for MR imaging
US5069216A (en) * 1986-07-03 1991-12-03 Advanced Magnetics Inc. Silanized biodegradable super paramagnetic metal oxides as contrast agents for imaging the gastrointestinal tract
US5143637A (en) * 1990-02-20 1992-09-01 Nippon Seiko Kabushiki Kaisha Magnetic fluid composition
US5171424A (en) * 1990-10-22 1992-12-15 Ashland Oil, Inc. Magnetic separation of old from new cracking catalyst by means of heavy rare earth "magnetic hooks"
US5190635A (en) * 1989-04-03 1993-03-02 Ashland Oil, Inc. Superparamagnetic formation of FCC catalyst provides means of separation of old equilibrium fluid cracking catalyst
US5198098A (en) * 1990-10-19 1993-03-30 Ashland Oil, Inc. Magnetic separation of old from new equilibrium particles by means of manganese addition
US5219554A (en) * 1986-07-03 1993-06-15 Advanced Magnetics, Inc. Hydrated biodegradable superparamagnetic metal oxides
US5240628A (en) * 1990-12-21 1993-08-31 Nok Corporation Process for producing magnetic fluid
DE4309333A1 (en) * 1993-03-17 1994-09-22 Silica Gel Gmbh Superparamagnetic particles, process for their production and use thereof
US5676877A (en) * 1996-03-26 1997-10-14 Ferrotec Corporation Process for producing a magnetic fluid and composition therefor
EP0977212A2 (en) * 1998-07-31 2000-02-02 International Business Machines Corporation Method for producing nanoparticles of transition metals
US6068785A (en) * 1998-02-10 2000-05-30 Ferrofluidics Corporation Method for manufacturing oil-based ferrofluid
US20030209057A1 (en) * 1996-09-03 2003-11-13 Tapesh Yadav Color pigment nanotechnology
US20050152073A1 (en) * 2002-02-11 2005-07-14 International Business Machines Corporation Magnetic-field sensor device and method of formation
US7282710B1 (en) 2002-01-02 2007-10-16 International Business Machines Corporation Scanning probe microscopy tips composed of nanoparticles and methods to form same
US7341757B2 (en) 2001-08-08 2008-03-11 Nanoproducts Corporation Polymer nanotechnology
EP1967267A1 (en) 2007-02-07 2008-09-10 Samsung Electronics Co., Ltd. Microfluidic valve filler and valve unit including the same
US7708974B2 (en) 2002-12-10 2010-05-04 Ppg Industries Ohio, Inc. Tungsten comprising nanomaterials and related nanotechnology

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2590997A (en) * 1949-08-01 1952-04-01 Gulf Research Development Co Method for separating colloidally dispersed iron particles from organic liquids
GB974627A (en) * 1960-09-13 1964-11-11 California Research Corp Dispersions of ferromagnetic metals
US3290252A (en) * 1963-07-16 1966-12-06 Chevron Res Cobalt concentration from cobalt sol by extraction

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2590997A (en) * 1949-08-01 1952-04-01 Gulf Research Development Co Method for separating colloidally dispersed iron particles from organic liquids
GB974627A (en) * 1960-09-13 1964-11-11 California Research Corp Dispersions of ferromagnetic metals
US3290252A (en) * 1963-07-16 1966-12-06 Chevron Res Cobalt concentration from cobalt sol by extraction

Cited By (58)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3635819A (en) * 1970-06-15 1972-01-18 Avco Corp Process for cleaning up oil spills
US3764540A (en) * 1971-05-28 1973-10-09 Us Interior Magnetofluids and their manufacture
US3855137A (en) * 1972-03-03 1974-12-17 Exxon Research Engineering Co Hydrocarbon gels
US3917538A (en) * 1973-01-17 1975-11-04 Ferrofluidics Corp Ferrofluid compositions and process of making same
US4094804A (en) * 1974-08-19 1978-06-13 Junzo Shimoiizaka Method for preparing a water base magnetic fluid and product
DE2529053A1 (en) * 1974-08-23 1976-03-04 Ibm magnetic ink
US3951785A (en) * 1975-01-29 1976-04-20 Avco Corporation Classification by ferrofluid density separation
US4108767A (en) * 1975-09-02 1978-08-22 Georgia-Pacific Corporation Separation of an aqueous or water-miscible liquid from a fluid mixture
US4565793A (en) * 1975-09-03 1986-01-21 Exxon Research And Engineering Co. Composite zeolitic magnetic material
US4025448A (en) * 1975-12-29 1977-05-24 Union Carbide Corporation Superparamagnetic wax compositions useful in magnetic levitation separations
US4107063A (en) * 1977-03-02 1978-08-15 International Business Machines Corporation Water based selectable charge magnetic inks
US4356098A (en) * 1979-11-08 1982-10-26 Ferrofluidics Corporation Stable ferrofluid compositions and method of making same
US4381244A (en) * 1980-03-24 1983-04-26 General Electric Company Ferrofluid
US4416751A (en) * 1980-03-24 1983-11-22 General Electric Co. Process for producing a ferrofluid
US4445940A (en) * 1982-11-30 1984-05-01 Georgia-Pacific Corporation Process to remove corrosion deposits using aqueous-base ferromagnetic fluids
US4576725A (en) * 1983-07-13 1986-03-18 Toyota Jidosha Kabushiki Kaisha Magnetic fluid incorporating fine magnetic powder and method for making the same
US4579173A (en) * 1983-09-30 1986-04-01 Exxon Research And Engineering Co. Magnetized drive fluids
US4599184A (en) * 1984-02-01 1986-07-08 National Research Institute Process for producing ferromagnetic liquid
EP0249229A3 (en) * 1986-06-12 1990-04-11 Basf Aktiengesellschaft Superparamagnetic solid particles
EP0249229A2 (en) * 1986-06-12 1987-12-16 BASF Aktiengesellschaft Superparamagnetic solid particles
EP0460714A3 (en) * 1986-06-12 1992-01-15 Basf Aktiengesellschaft Preparation process for polar and apolar superparamagnetic fluids
US4810401A (en) * 1986-06-12 1989-03-07 Basf Aktiengesellschaft Superparamagnetic solid particles
EP0460714A2 (en) * 1986-06-12 1991-12-11 BASF Aktiengesellschaft Preparation process for polar and apolar superparamagnetic fluids
US4770183A (en) * 1986-07-03 1988-09-13 Advanced Magnetics Incorporated Biologically degradable superparamagnetic particles for use as nuclear magnetic resonance imaging agents
US5219554A (en) * 1986-07-03 1993-06-15 Advanced Magnetics, Inc. Hydrated biodegradable superparamagnetic metal oxides
US4951675A (en) * 1986-07-03 1990-08-28 Advanced Magnetics, Incorporated Biodegradable superparamagnetic metal oxides as contrast agents for MR imaging
US5069216A (en) * 1986-07-03 1991-12-03 Advanced Magnetics Inc. Silanized biodegradable super paramagnetic metal oxides as contrast agents for imaging the gastrointestinal tract
US4855079A (en) * 1986-10-31 1989-08-08 Hitachi Metals, Ltd. Super paramagnetic fluids and methods of making super paramagnetic fluids
US4741850A (en) * 1986-10-31 1988-05-03 Hitachi Metals, Ltd. Super paramagnetic fluids and methods of making super paramagnetic fluids
US4701276A (en) * 1986-10-31 1987-10-20 Hitachi Metals, Ltd. Super paramagnetic fluids and methods of making super paramagnetic fluids
US4946623A (en) * 1986-11-07 1990-08-07 Commissariat A L'energie Atomique Process for the production of a ferromagnetic composition, ferromagnetic liquid crystal obtained by this process and apparatus using said liquid crystal
US5049307A (en) * 1986-11-07 1991-09-17 Commissariat A L'energie Atomique Process for the production of a ferromagnetic composition, ferromagnetic liquid crystal obtained by this process and apparatus using said liquid crystal
US4938886A (en) * 1988-02-08 1990-07-03 Skf Nova Ab Superparamagnetic liquids and methods of making superparamagnetic liquids
US5190635A (en) * 1989-04-03 1993-03-02 Ashland Oil, Inc. Superparamagnetic formation of FCC catalyst provides means of separation of old equilibrium fluid cracking catalyst
US5143637A (en) * 1990-02-20 1992-09-01 Nippon Seiko Kabushiki Kaisha Magnetic fluid composition
US5198098A (en) * 1990-10-19 1993-03-30 Ashland Oil, Inc. Magnetic separation of old from new equilibrium particles by means of manganese addition
US5171424A (en) * 1990-10-22 1992-12-15 Ashland Oil, Inc. Magnetic separation of old from new cracking catalyst by means of heavy rare earth "magnetic hooks"
US5240628A (en) * 1990-12-21 1993-08-31 Nok Corporation Process for producing magnetic fluid
DE4309333A1 (en) * 1993-03-17 1994-09-22 Silica Gel Gmbh Superparamagnetic particles, process for their production and use thereof
US5676877A (en) * 1996-03-26 1997-10-14 Ferrotec Corporation Process for producing a magnetic fluid and composition therefor
US6056889A (en) * 1996-03-26 2000-05-02 Ferrotec Corporation Process for producing a magnetic fluid and composition therefor
US20030209057A1 (en) * 1996-09-03 2003-11-13 Tapesh Yadav Color pigment nanotechnology
US8058337B2 (en) 1996-09-03 2011-11-15 Ppg Industries Ohio, Inc. Conductive nanocomposite films
US7387673B2 (en) 1996-09-03 2008-06-17 Ppg Industries Ohio, Inc. Color pigment nanotechnology
US8389603B2 (en) 1996-09-03 2013-03-05 Ppg Industries Ohio, Inc. Thermal nanocomposites
US6068785A (en) * 1998-02-10 2000-05-30 Ferrofluidics Corporation Method for manufacturing oil-based ferrofluid
CN1328735C (en) * 1998-07-31 2007-07-25 国际商业机器公司 Method for producing nano-size particles from transition metals
EP0977212A2 (en) * 1998-07-31 2000-02-02 International Business Machines Corporation Method for producing nanoparticles of transition metals
US6262129B1 (en) * 1998-07-31 2001-07-17 International Business Machines Corporation Method for producing nanoparticles of transition metals
EP0977212A3 (en) * 1998-07-31 2000-07-05 International Business Machines Corporation Method for producing nanoparticles of transition metals
US7341757B2 (en) 2001-08-08 2008-03-11 Nanoproducts Corporation Polymer nanotechnology
US7282710B1 (en) 2002-01-02 2007-10-16 International Business Machines Corporation Scanning probe microscopy tips composed of nanoparticles and methods to form same
US20070256480A1 (en) * 2002-01-02 2007-11-08 Black Charles T Scanning probe microscopy tips composed of nanoparticles and methods to form same
US20050152073A1 (en) * 2002-02-11 2005-07-14 International Business Machines Corporation Magnetic-field sensor device and method of formation
US7726008B2 (en) 2002-02-11 2010-06-01 International Business Machines Corporation Method of forming a magnetic-field sensor having magnetic nanoparticles
US7708974B2 (en) 2002-12-10 2010-05-04 Ppg Industries Ohio, Inc. Tungsten comprising nanomaterials and related nanotechnology
EP1967267A1 (en) 2007-02-07 2008-09-10 Samsung Electronics Co., Ltd. Microfluidic valve filler and valve unit including the same
US8281815B2 (en) 2007-02-07 2012-10-09 Samsung Electronics Co., Ltd. Microfluidic valve filler and valve unit including the same

Similar Documents

Publication Publication Date Title
Rosensweig et al. Viscosity of magnetic fluid in a magnetic field
Oberteuffer Magnetic separation: A review of principles, devices, and applications
US5683615A (en) Magnetorheological fluid
Huang et al. Suppression of spin polarization in graphene nanoribbons by edge defects and impurities
Fermigier et al. Structure evolution in a paramagnetic latex suspension
Anton et al. Application orientated researches on magnetic fluids
Promislow et al. Aggregation kinetics of paramagnetic colloidal particles
US5985168A (en) Magnetorheological fluid
Šafařı́k et al. Use of magnetic techniques for the isolation of cells
US4957644A (en) Magnetically controllable couplings containing ferrofluids
US5705085A (en) Organomolybdenum-containing magnetorheological fluid
Tao Super-strong magnetorheological fluids
US4315827A (en) Low-vapor-pressure ferrofluids and method of making same
US5670077A (en) Aqueous magnetorheological materials
US5906767A (en) Magnetorheological fluid
US4356098A (en) Stable ferrofluid compositions and method of making same
US3926789A (en) Magnetic separation of particular mixtures
Marshall Clay mineralogy in relation to survival of soil bacteria
Moskowitz et al. Magnetic properties of magnetotactic bacteria
US6451207B1 (en) Magnetic cell separation device
Halsey Electrorheological fluids
Bossis et al. Magnetorheology: fluids, structures and rheology
Rosensweig Ferrohydrodynamics
Phulé et al. Synthesis and properties of novel magnetorheological fluids having improved stability and redispersibility
Felt et al. Rheology of a magnetorheological fluid