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How is lead ore prepared before it is smelted?

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Metallurgy — lead processing A zinc-lead blast furnace and lead-splash condenser. This technology is utilized mainly for producing zinc while managing both lead and zinc from raw materials, a technique that was highly influential in 20th-century smelting.

Before lead ore can be smelted, it undergoes two primary stages of preparation: concentration and roasting.

Concentration

After extraction, the ore is finely crushed at concentrating mills to separate it from waste rock, known as gangue. For sulfide ores, flotation separation is typically used. The crushed ore is mixed with water and chemicals, such as pine oil, and agitated with air. Metallic particles attach to the resulting froth and float to the surface, while the gangue sinks. This concentrate is then dried for transport to the smelter.1

Roasting

To prepare the concentrate for a blast furnace, it must be roasted. The concentrate is mixed with fluxing materials like limestone or iron ore and heated on a moving grate. This process removes most of the sulfur—which is often captured to produce sulfuric acid—and fuses the material into a brittle, lumpy product called sinter. This sinter is then broken into pieces, making it suitable for loading into the furnace.2