Method of Gold Separation--1. Gravity Separation

The gravity separation working principle: Separate minerals according to the different relative density of the mineral (usually called specific gravity). The mineral particles of different density are treated by moving medium (water, air and heavy liquid) with the hydrodynamic and mechanical forces. And the loose stratification and separation conditions help to separate mineral particles of different density.

Gravity separation is an ancient and the most commonly used gold enrichment method. Placer gold is usually showed a single native gold in the form, whose particle size is generally greater than 16 t/m3 having big density contrast with gangue. So the gravity separation is the most important method for placer gold beneficiation.

But in vein gold separation, the gravity separation usually used with other gold separator equipment, which is not used as a part of the unite gold separation process. Generally, together with spiral chute and shaker, the jigger recovers a cleavage coarse free gold in advance for the next flotation and hydrogenated operations to get the qualified gold concentrate. This method is mainly used in small-scale gold mining separation and local groups gold separation, such as Gouliang, Dashuiqing gold mine in Inner Mongolia, China.
 
The main gold extraction machine for gravity separation includes chute, jigger and shaker. In addition to the conventional gravity separation equipment, Forui has developed the belt chute, Ross Chute, round jigger, placer gold centrifugal washer according to the characteristics of China's gold production on the basis of learning foreign advanced equipment. For example, in Shandong Province, Yinan gold field sets the soft cladding (blankets) chute in the grinding classification loop with gold recoveries up to 70%. Besides, the soft cladding chute is also applied to handle the flotation and the amalgamation tailings to improve gold recovery.

Amalgamation method can be divided into inner amalgamation and outer amalgamation according to their mode of production. The mixed mercury method is usually used to separate gold and heavy minerals in placer gold mines. As a part of unite vein gold production flow, the amalgamation method is usually used for the recovery of coarse-grained monomer gold together with flotation, gravity separation and cyaniding.