Commonly used copper and lead separation methods are as follows:
(1) Dichromate method: dichromate is used to suppress galena and flotate copper minerals.
(2) Cyanide method: using cyanide to inhibit copper minerals and flotate lead minerals.
(3) Ferricyanide method: When the content of secondary copper minerals in the ore is high, the effects of the above two methods are not good enough. At this time, if the content of lead in the ore is high, ferricyanide (yellow blood salt) can be used and hemoglobin) to inhibit the flotation of secondary copper minerals and lead minerals; if the content of lead is much higher than copper, the following two options should be tested.

(4) Sulfurous acid method (sulfur dioxide method): The mixed concentrate is treated with sulfur dioxide gas or sulfurous acid, so that the lead minerals are inhibited and the copper minerals are activated. In order to strengthen the inhibition, potassium dichromate or zinc dithionite can be added, or the slurry can be heated (heated flotation method). Finally, lime must be used to adjust the pH of the slurry to 5-7, and then copper Flotation of Minerals.
(5) Sodium sulfite and iron sulfate method: use sodium sulfite and iron sulfate as mixed inhibitors, acidify the slurry with sulfuric acid, stir under the condition of pH=6-7, inhibit galena and flotate copper minerals.
One of the main reasons why it is difficult to separate copper-lead mixed concentrate is that the mixed concentrate contains excess chemicals (collectors and foaming agents). Removing excess chemicals from the slurry and removing the collector film from the mineral surface before separation of the mixed concentrate can greatly improve the separation effect of the mixed concentrate.