Patent US3887457A successfully refreshed from Google Patents.
US3887457A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic separation method
Assignee: MAGNETIC ENG ASS Inc
•
Filing: 1973-05-21
•
Granted: 1975-06-03
•
Expires: 1993-05-21
Abstract
Abstract A method of separating more-magnetic particles from lessmagnetic particles contained in a fluid medium submitted to a ferromagnetic matrix having a multiplicity of collection sites subject to an applied magnetic field of a predetermined intensity including: providing an applied magnetic field of predetermined field intensity in the matrix to induce high magnetic field gradients at the collection sites and to induce magnetic dipole moments in the more-magnetic particles to adhere the moremagnetic particles having induced magnetic dipole moments to the collection sites having high magnetic field gradients, some of the less-magnetic particles being entrapped between two or more more-magnetic particles or between one or more more-magnetic particles and a collection site; and periodically decreasing the intensity of the magnetic field below the predetermined intensity to reduce the induced high magnetic gradients at the collection sites, and to reduce the induced magnetic dipole moments in the more-magnetic particles below the level required for the moremagnetic particles to adhere to each other and to the collection sites to free entrapped less-magnetic particles, and then increasing the intensity of the magnetic field, at a rate of at least one cycle of the magnetic field per matrix transit period.
Inventors
- 👤 Peter G Marston
- 👤 Ionel Wechsler
- 👤 John J Nolan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:06
CPC Classifications
B; B03; B03C; B03C1/00; B03C1/02; B03C1/025; B03C1/031; B03C1/033; B03C1/0335; B03C1/027; B03C1/032; B03C1/034; B03C2201/00; B03C2201/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
239 words
An improved method of separating more-magnetic particles from less-magnetic particles contained in a fluid medium which reduces mechanical entrapment of less-magnetic particles by more-magnetic particles comprising: submitting a fluid medium containing both more-magnetic particles and less-magnetic particles to a ferromagnetic matrix having a multiplicity of collection sites; and simultaneously subjecting the more-magnetic particles and the less-magnetic particles, as they move through said matrix, to a time varying magnetic field whose intensity in said matrix varies, from a predetermined intensity sufficient to induce a high magnetic field gradients at sAid collection sites and to induce magnetic dipole moments in the more-magnetic particles to adhere the more-magnetic particles having induced magnetic dipole moments to said collection sites having high magnetic field gradients, some of the less-magnetic particles being entrapped between two or more more-magnetic particles or between one or more more-magnetic particles and a said collection site, to a lower intensity sufficient to reduce the high magnetic field gradients induced at said collection sites and reduce the induced magnetic dipole moment in said moremagnetic particles below the level required for said moremagnetic particles to adhere to each other and to said collection sites to free entrapped less-magnetic particles; said time varying magnetic field reaching said predetermined intensity at a collection site more than once and decreasing below that predetermined intensity at least once during each matrix transit period during which more-magnetic and lessmagnetic particles are simultaneously being fed to said matrix.
Claim 2
Dependent Claim
239 words
An improved method of separating more-magnetic particles from less-magnetic particles contained in a fluid medium which reduces mechanical entrapment of less-magnetic particles by more-magnetic particles comprising: submitting a fluid medium containing both more-magnetic particles and less-magnetic particles to a ferromagnetic matrix having a multiplicity of collection sites; and simultaneously subjecting the more-magnetic particles and the less-magnetic particles, as they move through said matrix, to a time varying magnetic field whose intensity in said matrix varies, from a predetermined intensity sufficient to induce a high magnetic field gradients at sAid collection sites and to induce magnetic dipole moments in the more-magnetic particles to adhere the more-magnetic particles having induced magnetic dipole moments to said collection sites having high magnetic field gradients, some of the less-magnetic particles being entrapped between two or more more-magnetic particles or between one or more more-magnetic particles and a said collection site, to a lower intensity sufficient to reduce the high magnetic field gradients induced at said collection sites and reduce the induced magnetic dipole moment in said moremagnetic particles below the level required for said moremagnetic particles to adhere to each other and to said collection sites to free entrapped less-magnetic particles; said time varying magnetic field reaching said predetermined intensity at a collection site more than once and decreasing below that predetermined intensity at least once during each matrix transit period during which more-magnetic and lessmagnetic particles are simultaneously being fed to said matrix.
Claim 3
Dependent Claim
239 words
An improved method of separating more-magnetic particles from less-magnetic particles contained in a fluid medium which reduces mechanical entrapment of less-magnetic particles by more-magnetic particles comprising: submitting a fluid medium containing both more-magnetic particles and less-magnetic particles to a ferromagnetic matrix having a multiplicity of collection sites; and simultaneously subjecting the more-magnetic particles and the less-magnetic particles, as they move through said matrix, to a time varying magnetic field whose intensity in said matrix varies, from a predetermined intensity sufficient to induce a high magnetic field gradients at sAid collection sites and to induce magnetic dipole moments in the more-magnetic particles to adhere the more-magnetic particles having induced magnetic dipole moments to said collection sites having high magnetic field gradients, some of the less-magnetic particles being entrapped between two or more more-magnetic particles or between one or more more-magnetic particles and a said collection site, to a lower intensity sufficient to reduce the high magnetic field gradients induced at said collection sites and reduce the induced magnetic dipole moment in said more-magnetic particles below the level required for said more-magnetic particles to adhere to each other and to said collection sites to free entrapped less-magnetic particles; said time varying magnetic field reaching said predetermined intensity at a collection site more than once and decreasing below that predetermined intensity at least once during each matrix transit period during which more-magnetic and less-magnetic particles are simultaneously being fed to said matrix.
Claim 4
Dependent Claim
239 words
An improved method of separating more-magnetic particles from less-magnetic particles contained in a fluid medium which reduces mechanical entrapment of less-magnetic particles by more-magnetic particles comprising: submitting a fluid medium containing both more-magnetic particles and less-magnetic particles to a ferromagnetic matrix having a multiplicity of collection sites; and simultaneously subjecting the more-magnetic particles and the less-magnetic particles, as they move through said matrix, to a time varying magnetic field whose intensity in said matrix varies, from a predetermined intensity sufficient to induce a high magnetic field gradients at sAid collection sites and to induce magnetic dipole moments in the more-magnetic particles to adhere the more-magnetic particles having induced magnetic dipole moments to said collection sites having high magnetic field gradients, some of the less-magnetic particles being entrapped between two or more more-magnetic particles or between one or more more-magnetic particles and a said collection site, to a lower intensity sufficient to reduce the high magnetic field gradients induced at said collection sites and reduce the induced magnetic dipole moment in said more-magnetic particles below the level required for said more-magnetic particles to adhere to each other and to said collection sites to free entrapped less-magnetic particles; said time varying magnetic field reaching said predetermined intensity at a collection site more than once and decreasing below that predetermined intensity at least once during each matrix transit period during which more-magnetic and less-magnetic particles are simultaneously being fed to said matrix.
Claim 5
Dependent Claim
15 words
The method of claim 1 in which said applied magnetic field is periodic and stationary.
Claim 6
Dependent Claim
14 words
The method of claim 2 in which said applied magnetic field periodically reverses polarity.
Claim 7
Dependent Claim
16 words
The method of claim 1 in which said slurry to undergo separation includes an iron ore.
Claim 8
Dependent Claim
18 words
The method of claim 4 in which the more-magnetic particles include magnetite and the less-magnetic particles include silica.
References Cited (Backward Citations)
US1417189A
Cited
US1564732A
Cited
US1605117A
Cited
US3279602A
Cited
US3294237A
Cited
US3375925A
Cited
US3552564A
Cited
US3627678A
Cited
US3676337A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |