Gold Cyanide Leaching Process

Specifications

Processing plant

At present, the dressing methods are mercury mixing gold leaching process and cyanidation gold leaching process. Mercury mixing gold leaching process is a kind of ancient gold process, which is simple and convenient and economical. Mercury mixing gold leaching process is suitable for recycle coarse grain monomer gold but is harmful to environment. So this process is gradually replaced by gravity separation, flotation and cyanidation gold leaching process. Cyanidation gold leaching process includes a few of basic processes: cyanide leaching, washing filtering of ore pulp leaching, gold extracting from cyanating solution or cyanating ore pulp, and finished product smelting.

Gold Ore processing Equipments
Jaw Crusher is used for coarse crushing, normalized cone crusher is used for secondary crushing, brachycephalic Cone Crusher and Roll Crusher are used for fine crushing.
Grinding equipment: the Ball Mill is mainly used in gold grinding stage.
Gravity separation: gravity separation is the method that ore dressing is according to the different mineral density. In contemporary mineral dressing processing, the gravity separation is occupying an important position. The main equipments are chute, shaking table, jigger and short cone swirler.
Flotation machine is the important device to do flotation.
The classifier, mixing tank and chute are also essential equipments.

Crushing Process

Ore processing plant commonly has two processes: crushing & screening, beneficiation process.

In this process, large ore materials become small by the help of mechanical force. The crushing process is important during the treatment of ores. It is divided into four stages: crushing, grinding & classification, superfine crushing and micronization. It is a high energy-consuming operation, and its basic principle is “more crushing, less grinding”.

Vibrating screen: Of all the dressing machines, the vibrating screen is designed to screen stone materials. The movement locus of vibrating screen is a circle. Inclined vibrating screen, which makes circle motion, is a new-style vibrating screen with multiple levels and high efficiency. By adopting barrel–type eccentric shaft vibrator and technology of partial block adjusting amplitude, screening line becomes longer.

grinding and classification system

Ball mill: after crushing, ball mill is the key plant equipment which is used for further crushing. It is one of the widely used fine grinding plants in industrial production.

  Classifier:
1.Combining the classifier with ball mill, the closed circulatory process is formed to classify ore sand.
2.Also, the classifier is used in gravity mill to classify ore sands and fine clay.
3.The classifier functions in ore pulp grading in metal ore dressing process.
4.The classifier works in the processes of desbmw and dehydration in ore washing operation.

Ball mill and classifier form a close circuit system,make the solotion meet requirement.

Carbon in leaching process also be called CIL plant. In this production line, use cyanide leading and carbon absorbing technology to get gold.
 
CIL plant consists of following steps:
 
1 The ore is first reduced in size (typically 80% passing 200mesh ) to ensure that all nonrefractory gold is readily accessible for cyanide leaching, There are several variations of comminution circuits used in the gold
industry, such as: Multi-stage crushing, then ball milling circuits, typical of ball mill and hyrocyclones.
 
2 Thickening(add lime flocculant)
After comminution the pump is normally dilute and thickening. High efficient thickener is performed to increase the pulp density to about 50% solids by mass. 
 
3 Leaching
Leaching reagents in the form of cyanide and and oxidant such as air or oxygen are added after thickening. Leaching take place in a series of agitated leaching reactors.
 
4 Carbon adsorption
After leaching, the pulp is passed over a feed screen to ensure removal of tramp materials about 0.6mm. This is done to minimize screen blocking in the adsorption section. After feed pre-screening, the pulp flows trough a cascade of well mixed adsorption tanks, typically 6-8 in number. The pulp residence time is about one hour in each tank. The tanks are normally mechanically agitated and each will contain a batch of carbon of concentration 10-25grams of carbon per litr of pulp. The carbon size is 0.6-0.8mm. The gold recovery is 90-99%.
 
5 Desorption and electro-winning
The loaded carbon is processed by desorption and electro-winning set, by this solution, it gets grain gold.
 
6 Gold melting