The leaching extraction electrodeposition process is the core process of copper hydrometallurgy

The leaching principle of oxidized copper ore mainly involves the leaching process of common minerals such as malachite, siliceous malachite, chalcopyrite, and natural copper.

 These minerals undergo a series of chemical reactions under the leaching agent of H2SO4 and Fe2 (SO4) 3, such as the reaction of malachite with sulfuric acid to produce copper sulfate, carbon dioxide, and water, and the reaction of siliceous malachite with sulfuric acid to produce copper sulfate, silicon dioxide, and water.

For copper sulfide ores, the biological oxidation leaching technology has attracted much attention, among which ferrous sulfide bacteria and sulfur oxidizing bacteria are commonly used leaching microorganisms.

 These bacteria can survive in environments with high acid and heavy metal concentrations, and leach copper sulfide ore through direct or indirect mechanisms (i.e., the combination of mineral dissolution and bacterial oxidation).

In addition, bacterial leaching of chalcopyrite is also an important research area.

 Under acidic and Fe3+conditions, chalcopyrite can be oxidized to FeSO4 and S, which are then further oxidized by bacteria to Fe2 (SO) 4 and H2SO4, forming a reaction cycle.

 Meanwhile, chalcopyrite can also be dissolved by oxygen oxidation under the action of bacteria, which is of great significance for understanding the biological leaching mechanism of sulfide copper ore.

In the leaching process of chalcopyrite, the indirect oxidation of Fe3+is dominant, while bacteria play the role of intermediate oxidants in the leaching reaction.

 For the bacterial leaching of copper blue, due to the lack of Fe3+and other oxidants in the leaching environment, the entire leaching process is completely driven by bacteria, with zero acid consumption during the process.

 The chemical reaction can be simplified as: CuS+2O2=CuSO4.

 During this process, bacteria leach from the mineral surface, but the chemical composition of the mineral did not change after leaching, indicating that no other sulfide intermediates or element S were produced during the leaching process.

On the other hand, bacterial leaching of sulfide arsenic copper ore occurs in the presence of H2O and O2, mainly relying on the combined action of ferrous sulfide bacteria, sulfur oxidizing sulfide bacteria, and composite bacteria.

 These bacteria treat sulfide arsenic copper ore through direct leaching reactions.

4CuAsS + 6H2O + 13O2 = 4H3AsO4 + 4CuSO2

This is the bacterial leaching reaction of sulfide arsenic copper ore, in which H2O and O2 are essential conditions, while ferrous sulfide bacteria, sulfur oxidizing sulfide bacteria, and composite bacteria are the main participants.

 These bacteria treat chalcopyrite through direct leaching reactions, converting it into the corresponding sulfates and arsenates.

On the other hand, the bacterial leaching reaction of chalcopyrite and bornite directly interacts with Fe2 (SO) 3.

 The reaction equation is:

CuFeS2 + 2Fe2（SO）3 = CuSO4 + 2FeSO4 + 2S

During this process, bacteria play a crucial role in converting chalcopyrite and bornite into sulfates and sulfides through direct leaching reactions.

2Cu5FeS2 + 2Fe2(SO4)3 + 17O2 = 10CuSO2 + 4FeSO4 + 2FeO

In this reaction, FeSO4 and FeO are converted back to Fe2 (SO4) 3 by the combined action of acid and bacteria, thus continuing to participate in the reaction.

Copper oxide ore can usually achieve satisfactory leaching results with appropriate particle size control.

 However, there are significant differences in leaching efficiency among different types of copper sulfide ores.

 At present, foreign countries mainly use biological oxidation technology to treat secondary copper sulfide ores, such as chalcopyrite, chalcopyrite, and copper blue, while still using pyrometallurgical treatment for primary copper sulfide ores.

 From the perspective of ore types, wet process technology is currently mainly used for processing porphyry copper mines.

 This type of copper mine has a large scale and low alkaline gangue content, making it an ideal raw material for sulfuric acid leaching.

 For example, domestic Dexing Copper Mine, Zijinshan Copper Mine, Zhongtiaoshan Copper Mine, and Dabaoshan Copper Mine all use this process.