GB1113601A - Improvements in or relating to mineral separation - Google Patents

Abstract

1,113,601. Centrifugal separators; separating solids. COAL INDUSTRY (PATENTS) Ltd. I Oct., 1965 [2 Oct., 1964; 29 Jan., 1965], Nos. 40283/64 and 4100/65. Headings B2H and B2P. An apparatus for classifying minerals, e.g. raw coal, comprises a cylindrical separating chamber 2 provided with a tangential inlet I for dense medium and mineral particles, with an axially arranged conduit 3 for discharging dense medium and mineral particles of relatively low specific gravity and with an axially positioned circular opening 4 in one end of the chamber for discharging dense medium and mineral particles of relatively high specific gravity, means being provided for controlling the flow of dense medium discharged through the opening 4. The dense medium may be a suspension of magnetite in water. The dense medium and the particles of relatively high specific gravity discharging through the annular orifice 4 enter and involute or, as shown, annular chamber 5 having a tangential outlet conduit 6 tangentially connected to the inlet of a vessel 7 having an axial outlet 8 which may be provided with a replaceable orifice plat whose size can be chosen to alter the discharge quantity. in a modification. Fig. 3 (not shown), the conduit 6, which may be flexible, terminates at an overflow means 10 at a level higher than the annular chamber 5, the quantity discharged being varied by raising or lowering the overflow means 10. In a frrth?r modification. Figs. 4 and 5, the conduit 6 is connected to a hydrocyclone 11 in which further classification takes place. The specific gravity of each of the fractions separated may be altered by admitting dense medium or water through a conduit 15 into the conduit 6 to adjust the specific gravity of the separating medium in the hydrocyclone. Alternatively, dense medium or water may be injected through a tangential inlet into the chamber 5 or through a second connection into the hydrocyclone. Instead of a hydrocyclone, the second separating vessel of the type disclosed in Fig. I or in Fig. 3 (not shown) with the same discharge arrangements may be provided or it may be the apparatus disclosed in Specification 1100343. In a still further modification, the pipe 3 instead of passing through the opening 4 extends from the middle zone of the chamber 2 upwards through the other end of the chamber.