Gold Extraction Method--1.3 Chute Extraction 1.4 Spiral Concentrator

1.3 Chute Extraction
The chute gold extraction method is an ancient method of gravity separation and is still used today.The main equipment for the chute extraction is gold chute. The chute is an long and narrow wooden (or steel) chute with a inclination of 3° to 4° (maximum of 14° to 16°).
The separation principle: After entering the chute from the slot head, the ore slurry of different density separates layers under the combined force effects of the flow force, mineral particles gravity (centrifugal force), the friction between mineral particles and the tank bottom, the high density concentrates settle to the bottom of the tank and the low density particle ore is tailings. With intermittent operation, the chute will stop feeding materials and discharge the concentrate when a certain amount conentrate heeps on the bottom. There are coarse particle chute and slime chute, the former is suitable for dealing with coarse material, the latter is suitable for the treatment of fine grade material. There are bedding and baffle on the bottom of the coarse particle gold extraction chute.  The course particle chut is mainly used for the placer gold extraction, works on land (chute length: around 15m) or gold dredger(chute length: 4-6m).

1.4  Spiral Concentrator
The spiral concentrator is the main gold extraction machine in spiral concentration gold process.
Working principle: The spiral concentrator using gravity, the friction force, the combined effect of the centrifugal force and flow, so that the mineral particles can be separated according to the specific gravity, particle size and shape.
Characteristics: The whole chute is bent into a spiral status in the vertical direction.
Extraction process: The slurry feeded from the top of the chute flow down along the chute with spiral line movement. and the mineral particles are separated in the flow process. The low density particle is distributed in the outer edge of the spiral grooves, the high density fine particles is distributed in the inner edge of the helical groove. Stratified heavy product discharged from the discharge under the inside bottom of the tank and the light product is discharged from the end of the spiral groove.

The spiral concentrator has simple structure, need no transmission mechanism and the drawback is that this gold extraction machine cannot effiently separate the gold ores whose particle size is more than 6mm or below 0.05 mm effective. So users usually use it for placer gold extraction.