Lead-Zinc Ore Smelting Methods

Lead and zinc are among the earliest metals extracted from lead-zinc ores by humankind. Lead and zinc are widely used in the electrical, mechanical, military, metallurgical, chemical, light, and pharmaceutical industries. In addition, lead metal also has significant applications in the nuclear and petroleum industries. Zinc ores include sphalerite (ZnS), smithsonite (ZnCO3), zinc ore (ZnO), zinc silicate (Zn2SiO4), zinc manganese silicate (ZnMn)2SiO4, and hemimorphite (Zn4Si2O7(OH)2·H2O), etc. In my country, zinc ores are generally found in association with lead, hence the term lead-zinc ore, with deposits distributed throughout the country.

Lead-Zinc Ore Smelting Methods: Lead sulfide concentrate is the main mineral raw material for lead smelting. There are two smelting methods: pyrometallurgical and hydrometallurgical. Currently, pyrometallurgical is the primary method, while hydrometallurgical is in the experimental research stage. Pyrometallurgical lead smelting employs methods such as sintering and roasting, blast furnace smelting, reaction smelting, and precipitation smelting. Lead refining primarily employs pyrometallurgical refining, followed by electrolytic refining.

Zinc sulfide concentrate is the main mineral raw material for zinc smelting, and it is also refined using pyrometallurgical and hydrometallurgical methods. Pyrometallurgical refining utilizes vertical distillation, horizontal distillation, or electric furnaces. Hydrometallurgical zinc smelting has developed rapidly in the last 20 years and has become the main method for zinc smelting. The crude zinc obtained from pyrometallurgical zinc smelting is refined by distillation or used directly. Electrolytic zinc obtained from hydrometallurgical zinc smelting is of higher quality and requires no refining.

For difficult-to-separate mixed lead-zinc sulfide concentrates, a closed blast furnace smelting method that simultaneously produces lead and zinc is generally used. For extremely difficult-to-separate mixed lead-zinc oxide ores, my country has a unique processing method: the raw mixed lead-zinc oxide ore or its enriched products are sintered or pelletized and then melted in a blast furnace to obtain crude lead and lead-zinc-containing molten slag. The slag is further fumed in a fuming furnace to obtain zinc oxide products, which are then processed using hydrometallurgical zinc smelting to obtain electrolytic zinc. In addition, zinc oxide products can also be obtained by direct fumigation in a rotary kiln.