GB809955A - Improvements relating to separating materials of different specific gravities such as coal - Google Patents

Abstract

809,955. Washing granular materials. SIMON-CARVES Ltd. Feb. 14, 1956 [March 8. 1955; Sept. 5, 1955], Nos. 6758/55 and 25387/55. Class 82(2) In a sink and float process and apparatus for separating solid materials employing liquid suspensions of different density, raw material is fed at 32 together with liquid suspension 13 into a bath 1 of the liquid suspension wherein a primary separation occurs, floats and some suspension being removed at 11, 34; suspension of a greater density than that in bath 1 is introduced to the bottom 10(7) of the separator whereby the sinks from bath 1 undergo a further separation, the floats from which (the middlings) are carried up the arm 4 by the suspension of intermediate density for discharge with the said suspension at 15, 33; while the secondary sinks are withdrawn from the bottom of the separator, e.g. by an elevator 8 for discharge at 9. Fig. 2 shows the separator and medium recovery circuit with cyclone thickener 31. The suspension source is vessel 28 whence it is raised via pump 29 to thickener 31. High density suspension from the thickener passes to vessel 35 and thence via valve 6 to entrance 7 (and 10 if desired) of the arm 5 of the separator; any overflow goes to vessel 61 where it meets the low density suspension from 31 which travels via rubber tube 63 and one side 65 of a splitter box. Tube 63 is governed by a lever 66 controlled either manually, or automatically according to the specific gravity of the suspension in vessel 35, to keep a predetermined density; liquid from the part 64 of the splitter box is led to vessel 35. Low density suspension leaves vessel 61 via control valve 68 to the inlet 13 of the separator; overflow passes by pipe 23 to the vessel 28. If desired, the suspension may be pumped direct to the separator (at 13) from the source 28 if the normally open valve 69 is closed and the normally closed valve 24 is opened. Suspension from exits 34, 33 of the separator is led to the source 28 direct. The products of the separation are washed with water at screens 37, 70, 71, the wash waters being led to screen 40 which removes fine material and then pumped to desliming case 43 for magnetic separation. The magnetized material falls to the bottom of case 43 whence it is raised by pump 46 to demagnetizer 47 and splitter box 49 governed by lever 50 controlled by the specific gravity of the medium in the lower part of 43. Part of the medium is returned from the splitter box to case 43, and part via pipe 51 to vessel 28, depending upon the position of lever 50. Overflow from 43 which is substantially medium-free water may be led to washing screens 37, 70, 71 via pipes 55, 56; while clean water is admitted to the separator at 53, being controlled by valve 54 according to the specific gravity of the bath in the separator. Magnetized material may if desired be led via valve 57 to the vessel 28