Chapter XXIII: Section 26: Concentrating and Separating

Sifting, riddling, and screening are treated of under Section 72. For concentrating ores many methods are in use, of which the water processes are the most important.

=475. Circular revolving concentrating table.= The lightest particles are discharged over the edge, and the heaviest remain in the centre.

The ordinary magneting machine, for separating particles of iron or
steel from mixed borings, &c., consists of a series of magnets drawn
through the material, and then through fixed brushes, which brush off
the iron particles adhering to the magnets.

=476. Separating dust from grain,= &c., by a current of air driven through the stream of material as it falls from hopper to hopper. See also Nos. 1268, 1270.

=477. Ore concentrator;= consists of an endless rubber belt with flanges (see No. 1082), having a slow longitudinal motion, and a rapid shaking motion, either sideways, as in the “Frue Vanner,” or endwise, as in the “Embrey” concentrator; a stream of water runs over the ore, the heavy particles settle on the belt, and the mud is washed off.

=478. Jig= for separating ores by motion of a piston in water, the heavy parts settle to the bottom and the light parts are removed at the top.

Filtration through various substances--as sand, charcoal, calcined
ores, &c., is employed to separate suspended matter from liquids.

Separation by subsidence in a tank, similar to No. 1571, is employed
for lime, &c.

Chemical deposition and evaporation are necessary in many cases.

Section 27.--CHOPPING, SLICING, AND MINCING.

=479. Has a disc cutter= with radial knives and slots; used for roots, &c.

=480. Disc cutter,= with small knives wedged in separate holes, through which the cuttings escape in shreds.

=481. Revolving cutter rollers.=

=482. Hand mincing compound knife.=

=483. Spiral tapered revolving cutter,= in a conical case, having projecting knives on its interior. The type of the common mincing machine.

=484. Two or more rectangular cutters,= with vertical reciprocating motion in a revolving pan for mincing.

=485. Single roller revolving cutter= machine.

=486. Revolving spiral cutters,= as used in the common lawn mower, in conjunction with a fixed straight knife or shear blade.

=487. Apple slicer and corer= (cutter for). The apple is passed down through the cutter and divided into sectors and central cylindrical core.

See also Section 24.