Anode slime is a byproduct from copper or lead electro-refining process. The copper/lead anode slime usually contain As, Sb, Bi and precious metals like gold and silver.

Smelter of anode slime is most likely divided into two groups by the two different recovery processes based on its property and treatment capacity, i.e. pyrometallurgy and hydrometallurgy. The anode slime sometimes needs to be pre-treated by beneficiation to enrich valuable metals.

Conventional pyrometallurgy process of copper anode slime consists the following steps:

Roasting with sulfuric acid and de-selenium – Acid leaching and decoppering – Noble lead furnace reduction smelting – Oxidation refining to separate silver – Silver electro-refining – Gold electro-refining – Extraction of platinum and palladium – Refining of crude selenium – Extraction of tellurium.

As for hydrometallurgy of copper anode slime, the process is relatively flexible and smelters adjusts the process as per the characteristics of the raw material.  

Whereas the lead anode slime is firstly treated with chloride leaching and then the leaching residue can be mixed with de-selenium and de-coppered copper anode slime for further recovery. The chloride leaching solution of lead anode slime is used to recover Cu/ Bi/Sb separately. 

As a conclusion, it is widely acknowledged that the anode slime is complex in content but of high value, and the tendency to utilize the anode slime is to shorten recovery process and production period, reduce circulating loss and increase recovery rate.

Metalcess focuses on customer needs and provides the optimal solution. Modern technologies such as pressure leaching of anode slime, TBRC smelting of small capacity project, separating lead from gold by vacuum distillation, etc. are available at your service from Metalcess.