| (19) |
 |
|
(11) |
EP 0 431 965 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
21.08.1991 Bulletin 1991/34 |
| (43) |
Date of publication A2: |
|
12.06.1991 Bulletin 1991/24 |
| (22) |
Date of filing: 07.12.1990 |
|
|
| (84) |
Designated Contracting States: |
|
AT BE CH DE FR GB IT LI NL SE |
| (30) |
Priority: |
07.12.1989 ZA 899361
|
| (71) |
Applicant: DE BEERS INDUSTRIAL DIAMOND DIVISION
(PROPRIETARY) LIMITED |
|
Johannesburg,
Transvaal (ZA) |
|
| (72) |
Inventor: |
|
- Roos, Edwin Harm
Florida Hills,
Florida,
Transvaal (ZA)
|
| (74) |
Representative: Senior, Alan Murray et al |
|
J.A. KEMP & CO.,
14 South Square,
Gray's Inn
London WC1R 5LX
London WC1R 5LX (GB) |
|
| |
|
|
|
Remarks: |
|
The title of the invention has been amended (Guidelines for Examination in the EPO,
A-III, 7.3). |
|
| (54) |
Magnetic separation of material using eddy currents |
(57) Non-magnetic, conductive particles are separated from one another on the basis of
their respective electrical conductivities. This is achieved by irradiating the particles
with microwave or radio frequency electromagnetic radiation and simultaneously subjecting
the particles to a magnetic field. The eddy currents induced in the particles by the
electromagnetic irradiation interact with the magnetic field to cause movements of
the particles which are dependent on their conductivities.