Patent GB-600183-A (GB)
Title: Improvements in or relating to concentration of ores
IPC: B03B5/52
Filed: 1942-06-17
Abstract: 600,183. Concentrating ores &c. BUTLER BROS. June 17, 1942, No. 8318. Convention date, Feb. 11. [Class 82(ii)] In a process for concentrating minerals containing substantial quantities of particles of all ranges up to the maximum size be treated, the minerals are subjected to an hydraulic classification causing fine low density material to be separated and leaving a product containing coarse low density and both coarse and fine high density material which is subjected to a hydraulic concentration in a separate apparatus in which a mass of solid particles is subjected to an upward percolation of water having a force insufficient to produce a teetering of the mass and in which mechanical agitation causes localised lifting and releasing effects, to separate coarse and fine high density material from a product containing coarse low density material and some fine high density material, the latter being transformed into a product substantially free from coarse low density material, a sufficient quantity of the transformed product being introduced into the first classifying operation to maintain the density of the mass therein. In one type of plant for carrying out the process described, Figs. 1, 2, the ore &c., after screening and treatment in a preliminary classifier 20 of conventional form, is passed to a feed-box 29 of a concentrator 30 in which a screw conveyer 34 works the ore upwards to a discharge 45, water being supplied through separately controlled inlets 41 to a number of compartments of a tank 38 extending under the lower part of the inclined trough 32 and communicating therewith through perforations 43. The flights 34 carry lifting bars 37 which work the coarser tailings to the surface. Light material together with some fine ore &c. is carried by the water over a weir 33 which extends half-way across the lower end of the trough at the side to which the material is worked by the flights 34 and bars 37, the other side of the lower end having a baffle 46 at a higher level. The material discharged over the weir 30 may be passed to a screen 49 from which the undersize may be returned to the classifier 20. In a second form shown in Fig. 6, the product passing through the screen 17 is fed to a feed-box 57 of an inclined trough 58 having an adjustable weir 59 at the lower end for the discharge of fine sand and water and reciprocating rakes 63 which move the heavy material up the trough, water being supplied through boxes 61 under the upper part of the trough. The product from the outlet 60 is fed to a feed-box 65 of a second trough 66 having similar raking means, the water supply boxes extending farther down the trough and an adjustable baffle 72 the bottom of which is submerged, being provided near the weir 77. The coarse light material together with some fine light and heavy material is discharged over the weir to a screen 79; the undersize may be returned to the classifier 58, and the oversize may be sent to waste or ground and returned to the classifier. U.S.A. Specification 1,156,543 is referred to. The Specification as open to inspection under Sect. 91 also describes another form of apparatus shown in Fig, 9 (Cancelled) in which the material is fed to a series of three classifiers 81, 82, 83 comprising conical vessels having water inlets at the bottom to which adjustable water supplies are admitted tangentially. The material carried with the water from the classifiers 81, 82 is passed by launders 89, 95 to shaking screens from which the undersize is passed to the feed-boxes 92, 98 of the classifiers 82, 83, the oversize being either sent to waste or ground and returned to the classifiers. The concentrates are withdrawn through outlets 102. Adjustable baffles 103 are suspended in the classifiers 81, 82, 83. This subject matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specification 556,502.