GB887492A - Separating mixtures of particles into fractions of particles of different specific gravities - Google Patents

Abstract

887,492. Sink-float separation. STAMICARBON N.V. Oct. 20, 1959 [Aug. 8, 1958], No. 25607/58. Class 82(2). In a sink-float separation process using a separating suspension of magnetisable particles, the separated fractions are rinsed on screens to remove adhering magnetisable particles, the resulting diluted suspension is supplied with the magnetisable particles therein in magnetised condition to a settling tank, overflow from said tank is thickened in a cyclone thickener, thickened discharge from the bottom of the settling tank and thickened discharge from the cyclone thickener are fed to a magnetic separator, and magnetisable particles recovered from said separator are re-used in the separation. As shown, raw coal is fed with water at A on to screen 1 and perforated plate 2 where it is respectively de-slimed and de-watered, and the resulting coal is then fed into vessel 4 from where it is introduced, together with a magnetite suspension, into cyclone washer 5. Washed coal, together with some magnetite, is passed from the overflow outlet of the cyclone to be wetscreened on screen 6, the underflow from which is received in tank 7 and the overflow passed across vibrating screen 8 on which the coal is rinsed with clarified water from sprays 9 and clean water from sprays 10. Diluted suspension from screen 8 is collected in tank 11 and washed coal discharged at C. Washed shales and middlings, together with some magnetite, issue from the bottom of cyclone 5 and are wetscreened on screen 12. The underflow from this screen enters tank 13, while the overflow is fed into vessel 15 via conduit 14. A magnetite suspension is fed into vessel 15 and the resulting mixture fed into cyclone 17. Middlings, together with some magnetite, pass from the overflow outlet of cyclone 17 to be screened on screens 18, 20 in a similar way to the coal issuing from cyclone 5. Shale issuing from the bottom of cyclone 17 is screened in a similar way on screens 24, 25. The undiluted suspension in tanks 7, 13 is led to tank 30 and thence pumped to vessel 4. The undiluted suspension in tanks 19, 28 is led to vessel 15 via conduit 14. Diluted suspension in tanks 11, 23, 29 is introduced into settling tank 32, the bottom fraction from which is pumped to screen 34 while the overflow is collected in receiver 35 and pumped to cyclone thickener 37. Clarified water issues from the overflow of cyclone 37 and is led to sprays 9, 21, 26, while the concentrated fraction from the bottom of cyclone 37 is fed to screen 34. The overflow and underflow from screen 34 are fed to magnetic separator 39, the magnetic fraction from which is returned to tanks 15, 30. Specifications 791,520, 791,857, 791,858, 791,859, 887,491 and 887,493 are referred to.