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How is antimony removed from recycled lead?

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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.

In the context of lead processing, antimony is removed from recycled lead primarily through oxidation. During the refining process, oxygen is injected into the molten lead, which oxidizes the antimony and other impurities, allowing them to be skimmed off the surface.1

In broader lead bullion refining, this process is often referred to as "softening." This is typically conducted in a reverberatory furnace where the molten lead is stirred and subjected to a blast of air, which oxidizes antimony and arsenic—elements that harden lead—so they can be removed. Alternatively, the Harris process may be used, which involves stirring molten caustic salts into the lead to react with metallic impurities, collecting them as oxides or oxysalts.2

Once removed, these impurities can be recovered for other uses. In the case of battery recycling, the process is essential for producing either pure lead or specific lead-antimony alloys for the manufacture of new batteries.23