General process of oxidized gold ore process

In modern industry, gold is widely used, not only in currency manufacturing and jewelry, but also in electronic equipment, medical equipment and aerospace equipment. With the development of science and technology and market demand, higher requirements are placed on gold mining and extraction processes.

As an important gold resource, oxidized gold ore has unique geological characteristics and mineralization conditions, which makes its beneficiation process different from other types of ores such as sulfide gold ore.

Oxidized gold ore usually exists in surface or near-surface environments, and is formed by primary deposits through external effects such as weathering and leaching. Although the gold content of these ores is low, their dispersion and large oxidation area make them of great mining value. The following is the general process of oxidized gold ore process. 

1 Crushing of raw ore Crushing

Crushing is the first step to release gold particles in gold ore. For oxidized gold ore, a reasonable crushing process can not only improve the recovery rate of gold, but also reduce energy consumption and wear. In view of the physical hardness and structural characteristics of oxidized gold ore, a one-stage open-circuit crushing process is adopted. The raw ore is transported to the raw ore yard by vehicles and transferred to the crusher feeding hopper by loaders. Before entering the feeding hopper, the raw ore needs to pass through a 300×300mm grid screen, and the ore larger than the screen size is manually crushed with a sledgehammer. The ore is fed into the jaw crusher from the feeding hopper for coarse crushing, and the crushed product enters the powder ore bin. The final product particle size of the crushing operation is about 40mm.

2 Grinding and classification

Grinding is the process of further refining the crushed ore, the purpose of which is to fully dissociate the gold particles from the ore. Grinding to an appropriate fineness is the key to ensuring a high recovery rate. For oxidized gold ore, it is usually required that the particle size of -0.074mm in the ore after grinding accounts for about 75%.

Classification is an indispensable step in the grinding process, which ensures that the particle size of the mill discharge is uniform. The experiment selected a combination of a submerged spiral classifier and a hydrocyclone to carry out continuous classification during the grinding process. This combination can not only effectively control the grinding fineness, but also timely discharge the over-fine particles from the grinding cycle, thus improving the grinding efficiency.

3 Pre-leaching concentration and leaching adsorption

In the gold extraction process, the pre-leaching concentration step is an important link to improve the gold leaching efficiency. For oxidized gold ore, pre-leaching concentration can effectively increase the pulp concentration and reduce the volume of the subsequent leaching and adsorption stages, thereby reducing the consumption of reagents and operating costs. The use of high-efficiency thickeners can increase the pulp concentration to 40%, while ensuring that the clear liquid in the concentration process can be recycled to reduce the consumption of water resources.

Leaching adsorption is the process of transferring gold from the pulp to the activated carbon. By adding sodium cyanide solution, gold is dissolved in the solution to form a gold-cyanide complex, and then the gold is adsorbed by the activated carbon. During the adsorption process, the particle size, concentration and contact time of the activated carbon are finely controlled to ensure the highest gold adsorption efficiency.

4 Desorption and electrolysis

Desorption is the process of recovering gold from the activated carbon leached with gold, which is a key step in gold production. The desorption liquid uses sodium hydroxide solution, and its concentration and temperature are strictly controlled to ensure efficient desorption of gold. During the desorption process, the system temperature is generally maintained at 90℃ to 150℃, and the pressure is maintained at about 0.5MPa. These conditions optimize the desorption rate and reduce operational risks.

The gold grade of electrolytic precious liquid is generally 300-600mg/L, and the gold grade of lean liquid can be reduced to below 10mg/L. The gold content of electrolytic gold mud is generally 30%-40%. The recovery rate of electrolytic operation can reach more than 99.5%. Electrolysis is a refining step in the gold production process, in which gold is deposited from precious liquid on the cathode through electrolysis. The electrolysis process requires precise control of current and voltage to ensure effective deposition of gold.