ALP: How “green” is our iron and steel industry?
Environmental regulation, the demand for reduced energy and raw material consumption, the advent of continuous casting and proliferation of mini-mills, industry consolidation, and foreign competition have combined to reduce our iron and steel industry’s impact on the environment dramatically. In the past 15 years alone, the industry has reduced its air and water emissions by over 90%. Similar reductions in raw material and energy usage and solid waste generation have been achieved. Today, almost all solid residues are channeled into production or used as raw material by other industries. “Sustainable development” has been the steel industry’s watchword for many years.
Examples abound. Coke oven gas and coke quench water are routinely recycled. Coke-making by-products like naphthalene, ammonia, and light oil are either used by other industries or eliminated entirely by non-recovery coke batteries. Coke substitutes like pulverized coal and natural gas also help to reduce emissions.
Slag from blast furnaces is used for road construction, fertilizer, and glass-making. Blast furnace flue gas is cleaned and reused to heat coke plants and other processes. And, the resultant dust is often reused in the sintering process, as is slag from basic oxygen furnaces.
Perhaps, the best examples of recycling in the steel industry are the mini-mills. Instead of consuming coal and iron ore, mini-mills make steel by melting scrap metal in electric arc furnaces. In addition to preserving valuable natural resources, coke plant and blast furnace emissions are eliminated. And, heavy metals in the dust generated by EAFs can be recovered – leaving iron and iron oxide dust that can be used to make bricks and cement.
Our steel industry invests over $3 billion a year in new processes designed to improve the environment and reduce energy and raw material usage. Steel is also North America’s most recycled material, having a recycling rate of over 60% since 1970.
Finally, even the consolidation of our iron and steel industry has presented environmental opportunities. The industry has assumed a leadership role in redeveloping brownfield sites by replacing old shutdown steel mills with light commercial and retail facilities.