Why is sulfur dioxide gas from zinc roasting sent to a sulfuric acid plant?

In the context of zinc metallurgy, sulfur dioxide ($S{O}_2$) gas is generated during the roasting of sulfide ores, a necessary step to remove sulfur before metal extraction. This gas is sent to a sulfuric acid plant for two primary reasons:12

• Environmental Protection: Sulfur dioxide is a poisonous gas and a major air pollutant that contributes to acid rain. Capturing it prevents its release into the atmosphere, where it would otherwise cause significant harm to plant life, animal life, and infrastructure.32
• Resource Recovery: Sulfur dioxide serves as a valuable precursor for the industrial production of sulfuric acid. By converting the captured $S{O}_2$ into sulfur trioxide ($S{O}_3$) and subsequently into sulfuric acid, metallurgical facilities can produce a useful chemical commodity on-site, which is often required for other stages of the extraction and refining process.34

This practice aligns with the ethical imperative to minimize industrial waste and mitigate the environmental impact of heavy metal processing.35