GB626861A - Improvements in and relating to the separation of materials of different densities by means of a dense suspension - Google Patents

Abstract

626,861. Washing granular materials. BOLIDENS GRUVAKTIEBOLAG. June 20, 1946, No. 18604. Convention date, June 21, 1945. [Class 82(ii)] In a process for separating materials of different densities by means of a dense suspension in a separating device 101 and in which the heavy medium for the suspension is supplied by the material itself, the dense suspension is taken from a closed circuit grinding system containing one or several other separating devices 105, wherein is formed the fine particle fraction of the material from the first separating device 101, which has not been in effect separated, and possibly also the coarse fraction of higher density which has not been freed in the first separating device from lower density material. Raw material is fed to the device 101 containing a dense suspension, from which the lighter and fine particle fraction is led through the line 111 to washing screens 113, 114, the washer gangue being rejected at 115 whilst the screened suspension and fines are led via line 121 to the closed grinding circuit comprising a grinding mill 103 and size-classifier or classifiers 105. Wash water from the screen 114 may also be admitted to the grinding circuit via line 141. The heavy fraction (values) from the separator 101 is removed at 123a by a rake, but in general some or all of such heavy fraction is led via line 123 to the grinding mill 103 where it is ground or mixed with the fines and wash water to form heavy suspension which is led to the classifier 101 via the line 131. Particles removed at 129 from the size-classifier 105 may be subjected to further recovery treatment if desired. In a modification, Fig. 2, (not shown), the closed grinding circuit includes in addition a classifier 251 similar to the primary classifier 101, the dense suspension being led to the classifier 101 from a point below the surface of the liquid in the classifier 251 via the line 231.