Home >> Science & Nature >> Nature

Does Copper Smelting Cause Pollution?

Like most industrial processes, copper smelting can release significant amounts of pollution. The smelting process separates the precious metal from its ore and refines it into a more usable state. From toxic emissions to solid wastes, many byproducts of copper smelting are considered hazardous, and most governments have passed laws regulating the pollution caused by the copper industry.

Sulfur Dioxide
- The quantity of sulfur dioxide discharged from the copper smelting process depends on the makeup of the ore being refined. Complex ores may include lead, zinc, nickel and other metals. Total emissions from the process also depend on what methods are in place for capturing and converting the sulfur dioxide, typically ranging from less than 4 kilograms per metric ton (8 pounds per ton) of copper to 2,000 kilograms per metric ton (over 4,000 pounds per ton).
Particulate Matter Pollution
- Particulate emissions can range from 0.1 kilograms per metric ton (0.2 pounds per ton) of copper to as high as 20 kilograms per metric ton (40 pounds per ton). The chief components of the particulate matter emitted by copper smelting are copper and iron oxides. Additional copper and iron compounds as well as ̶0;sulfides, sulfates, oxides, chlorides and/or fluorides of arsenic, antimony, cadmium, lead, mercury and zinc̶1; may also be in particulate matter emissions, according to the World Bank.
Waste Water
- Waste water from copper smelting has dissolved and suspended solids that may include copper, lead, cadmium, zinc, arsenic and mercury -- as well as lime or aluminum oxides. Fluoride may also be in waste water, and the effluent may be slightly acidic. Negative water quality impacts are caused mainly by disposal practices that are not successful in containing wastes, run-on and runoff controls that are insufficient in preventing surface water from flowing through barriers or groundwater from infiltrating surface impediments.
Solid Waste
- The smelting process typically produces less than 3 tons of solid waste per ton of copper produced. These solid wastes include sludges generated by sulfide precipitation (followed by sedimentation), sludges from acid plants and dusts from converters and furnaces. Volubility tests have shown that these wastes can leach toxic metals into the environment. The U.S. Environmental Protection Agency considers these wastes hazardous under the Resource Conservation and Recovery Act and the potential control costs feasible.

Nature