There are two main methods for copper-lead separation: one is copper flotation and lead flotation, and the other is lead flotation and copper flotation. Commonly used methods include:

(1) Dichromate method. This is a relatively traditional method that uses dichromate to suppress galena, thus achieving lead suppression and copper flotation. This method has poor suppression of galena activated by copper ions, and is not suitable when the ore contains easily oxidized secondary copper sulfide minerals. This method is more effective at suppressing peroxidized galena, but due to its environmental pollution, fewer and fewer beneficiation plants are using this method.

(2) Cyanide method. Cyanide has a strong suppressive effect on chalcopyrite, but it has almost no suppressive effect on galena. Therefore, this method can be used to suppress copper and float lead, achieving good results. When there are many secondary copper minerals in the ore, because cyanide has a weak suppressive effect on secondary copper minerals and consumes a lot of cyanide, the cyanide plus zinc sulfate method is often used to enhance the suppression of copper minerals. Because cyanide is highly toxic and can dissolve precious metals, its use should be minimized, and cyanide-free processes should be promoted.

(3) Sulfur dioxide method. This method uses sulfur dioxide or sulfites in combination with other inhibitors to suppress the flotation of galena and chalcopyrite. Common combinations include: sulfur dioxide (or sulfites) + starch; sulfites + sodium sulfide; sodium thiosulfate + ferric chloride. When using this method, because sulfites also inhibit sphalerite and pyrite, zinc and iron sulfides mixed in the mixed concentrate will enter the lead concentrate, resulting in poor lead concentrate quality but higher copper concentrate quality. If galena has been activated by copper ions, the separation effect is poor, and this method is not suitable.

(4) Carboxymethyl cellulose (CMC) + water glass (or sodium pyrophosphate) method. A certain mine used a mixture of carboxymethyl cellulose and water glass at a mass ratio of 1:100 (or a mixture of carboxymethyl cellulose and sodium pyrophosphate at a mass ratio of 1:10) to separate copper-lead mixed concentrate, achieving good results in lead suppression and copper flotation. The specific reagent ratio can be determined through experiments based on specific circumstances.

(5) Heating method. This method involves heating the copper-lead mixed concentrate to about 60°C with steam. In an acidic or neutral slurry, the collector on the surface of galena is desorbed, the surface oxidizes and becomes hydrophilic, while chalcopyrite still floats. This method eliminates the need for additional reagents, resulting in high-grade copper concentrate with low lead and zinc content. Furthermore, since no other reagents are required, pollution can be reduced.