An apparatus for separating solid materials is described, which comprises a channel for receiving a liquid and the materials to be separated, the channel being provided with an agitation surface. Means for directing streams of fluid at the materials to be separated are provided, the streams of fluid urging the materials over and against the agitation surface to separate the materials. Heavier material is urged along the bottom of the channel to an exit under the action of the streams of fluid, and lighter material separated from the heavier material rises to the surface of the liquid. The agitation surface comprises a plurality of formations each extending across at least a portion of the width of the channel, each formation comprising an ascending surface and a descending surface, at least part of the ascending surface having a steeper slope with respect to the base of the channel than the descending surface. It has been found that the shallower descending surface of one formation followed by the steeper ascending surface of the next formation provides an improvement in agitation of the solid materials as they progress down the descending surface and start to progress up the ascending surface, keeps the transition from the descending surface to the ascending surface clear of a build-up of materials, and provides for the lighter materials to be urged upwards at a suitable angle to reach the surface for removal.

A method of recycling a filler included in artificial turf by sorting the filler into two or more materials, including: a first sorting operation of sorting the two or more materials based on a grain size; and a second sorting operation of sorting the materials, which are sorted by the first sorting operation and have grain sizes belonging to a predetermined range, based on specific gravity.

Processing of mineral material containing precious metal with one or more sulfide minerals and non-sulfide gangue minerals including acid-consuming carbonate may include preparation of a sulfide concentrate by flotation with the flotation or conditioning prior to flotation using a gas comprising carbon dioxide. Flotation may be at an acidic pH without prior decomposition of the acid-consuming carbonate and may be without addition of acid for pH adjustment.

Processing of mineral material containing precious metal with one or more sulfide minerals and non-sulfide gangue minerals including acid-consuming carbonate may include preparation of a sulfide concentrate by flotation with the flotation or conditioning prior to flotation using a gas comprising carbon dioxide. Flotation may be at an acidic pH without prior decomposition of the acid-consuming carbonate and may be without addition of acid for pH adjustment.