Extraction method of silver from lead-zinc ore

Silver is an important associated element in lead-zinc ores. 95% of the silver enters the crude lead during the smelting process, and 99% of the lead enters the lead anode mud during crude lead refining. Lead anode slime is usually mixed and processed after removing copper and selenium from copper anode slime. The process of treating lead anode mud alone can be divided in principle into three categories: fire-electrolysis process, wet process and wet-fire combined process.

(1) Fire method-electrolysis process: The main steps include: copper anode mud is first sulfated and roasted to separate selenium, and dilute sulfuric acid leaches copper and part of silver; after the acid leaching solution is mixed with lead anode mud, it is smelted to obtain noble lead; noble lead is continuously Blow and add flux to make slagging to separate base metals such as Sb, Bi, Pb, As, etc. to produce gold and silver alloys; perform silver electrolysis and gold electrolysis to produce silver and gold; reduce and precipitate gold from gold electrolyte to separate, replace and separate Platinum, palladium.

(2) Wet process: A typical wet process is a comprehensive process of chlorination and extraction of gold and silver. The main processes are: chlorine leaching of lead anode mud with hydrochloric acid and chlorine, leaching the chlorinated residue with ammonia to separate silver, separating silver and lead, and reducing the solution to obtain silver; chloride leachate extraction to recover base metals, and separation and recovery of gold; water washing of lead anode mud, Sulfuric acid leaching removes copper, and acid leaching residue is separated and extracted by alkali leaching to extract gold and silver.

(3) Wet fire method combined process: first heat the lead anode mud to remove arsenic, and then raise the temperature to remove antimony; remove arsenic and antimony anode mud by reduction and smelting to obtain a noble lead melt; the noble lead water is quenched into powder and then leached, and the leached slag is then used Fire method recovers gold and silver.