It is common for gold and silver to be associated with copper mines, but most of them have low content. Under the premise of comprehensive consideration of recycling value, gold and silver in copper mines can be comprehensively recycled. This not only improves the economic benefits of the mine, but also reduces resource waste and environmental impact. This article introduces the recycling value and recycling methods of gold and silver associated with copper mines.
The occurrence states of gold and silver associated with copper mines are diverse, usually in the form of fine particles in sulfide ores or oxide ores. Its behavior characteristics in the beneficiation process are closely related to copper minerals, but the recovery rate of gold and silver is often affected by the properties of the ore, the beneficiation process and the reagent system.
From an economic point of view, although the content of gold and silver in copper mines is low, their market prices fluctuate greatly, and the economic benefits of recovering these precious metals are very significant. For example, the grade of gold associated with a copper mine is only 0.5 g/ton, but through an effective recovery process, the recovery rate of gold reaches more than 70%, which can still bring considerable economic benefits.
(1) Flotation method for gold and silver recovery
Flotation is one of the most widely used methods for recovering gold and silver associated with copper mines. Its basic principle is to use the differences in the physical and chemical properties of the mineral surface to separate gold and silver minerals from gangue minerals by adding reagents. The flotation process mainly includes grinding, slurry adjustment, and flotation. In the grinding stage, the ore is ground to a particle size suitable for flotation; in the slurry adjustment stage, the surface of the gold and silver minerals is activated by adjusting the pH of the slurry and adding reagents; finally, in the flotation stage, the gold and silver minerals are enriched in the foam through bubbles to achieve separation.
Reagent selection and optimization are the key to flotation. Commonly used flotation reagents include collectors, frothers, and regulators. The function of the collector is to enhance the hydrophobicity of gold and silver minerals, making them easier to attach to bubbles; the frother is used to stabilize bubbles and improve flotation efficiency. According to the different properties of the ore, the reagent system needs to be optimized and adjusted. For example, for ores with high sulfur content, sulfide mineral collectors are more effective; while for oxidized ores, oxidized mineral collectors are required.
(2) Cyanide method for gold and silver recovery
The cyanide method is mainly used to recover gold and silver associated with oxidized ores. Its process includes cyanide leaching, solid-liquid separation and gold and silver extraction. Cyanide leaching is to mix the ore with cyanide solution to dissolve gold and silver in the solution. Solid-liquid separation separates the leachate from the slag by filtration or precipitation. Finally, gold and silver are extracted from the leachate by methods such as zinc powder replacement or activated carbon adsorption.
Although the cyanide method has a high recovery rate, it has a greater impact on the environment. Once cyanide leaks, it will cause serious pollution to the environment. Therefore, advanced environmental protection measures are essential. Our company adopts advanced cyanide tailings treatment technology to reduce the cyanide concentration to a safe level through chemical neutralization and biodegradation to ensure environmental safety.
(3) Other recovery methods
In addition to flotation and cyanidation, there are other methods that can be used to recover gold and silver associated with copper ores. For example, gravity separation is suitable for recovering coarse-grained gold and silver, and the separation of gold and silver from gangue is achieved through the principle of gravity separation. For difficult-to-leach oxidized ores, the roasting-cyanidation method can also be used, which first changes the physical and chemical properties of the ore through roasting pretreatment, and then performs cyanidation leaching.
Xinhai Mining has rich experience and advanced technology in the field of gold and silver recovery associated with copper mines. Our independently developed mineral processing technology combines the advantages of multiple recovery methods and can provide customized solutions according to the properties of the ore. For example, for a complex ore, we have increased the gold recovery rate from 60% to 75% and the silver recovery rate from 50% to 65% by optimizing the flotation reagent system.
Our professional equipment also provides strong support for efficient recovery. The flotation machine produced by our company adopts advanced bubble generation technology and stirring system, which significantly improves the flotation efficiency. The new cyanide leaching device shortens the leaching time and increases the leaching rate of gold and silver by optimizing the leaching conditions.
Xinhai has undertaken a large-scale copper mine associated gold and silver recovery project. The ore of this project contains a variety of valuable metals such as copper, gold, and silver, and the ore properties are complex. Through detailed analysis of ore properties, we designed a customized recovery process for the project, combining flotation and cyanidation to achieve efficient recovery of copper, gold and silver. Ultimately, the recovery rate of copper reached 90%, the recovery rate of gold reached 80%, and the recovery rate of silver reached 70%. During the implementation of the project, we also reduced production costs and improved economic benefits by optimizing the reagent system and equipment configuration.
