How can metal smelters provide a source of sulfur?

Metal smelters serve as a significant source of sulfur by processing metal sulfide ores, such as those containing copper, zinc, lead, nickel, or cadmium. During the extraction process, these ores undergo a procedure known as roasting, which involves heating the concentrates in an oxidizing environment.123

This roasting process releases sulfur in the form of sulfur dioxide ($S{O}_2$) gas. Rather than allowing this gas to escape into the atmosphere—which would contribute to air pollution—smelters capture it to produce sulfuric acid. The sulfur dioxide is converted to sulfur trioxide ($S{O}_3$) and subsequently processed into sulfuric acid, which is then utilized in various metallurgical and industrial applications.1425

In many cases, the sulfur recovered from these smelter gases is a vital component of the global sulfur supply, helping to meet industrial demand while simultaneously mitigating the environmental impact of smelting operations.14