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How is sulfuric acid made as a by-product of lead smelting?

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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 lead smelting, sulfuric acid is produced by capturing and processing the sulfurous gases generated during the oxidation of sulfide ores. The method of production depends on the smelting process employed:

Indirect Smelting: During the roasting phase, lead concentrate is mixed with fluxing materials and heated on a moving grate. The sulfur in the ore is combusted to form sulfur dioxide gas. This gas is recovered and directed to a sulfuric acid plant for conversion.21
Direct Smelting: In processes such as the KIVCET process, sulfurous gases are generated during autogenous flash smelting. These gases are tapped from the waste-gas shaft and utilized to heat steam and produce sulfuric acid as a by-product.3

By capturing these gases, smelters mitigate environmental impact while creating a valuable industrial chemical.32