Sustainability-Environmental-Waste Management, Recycling & Reuse - www.ussteel.com
Steel is the most recycled material in the world, but that’s not the only thing we recycle and reuse from our operations.
U. S. Steel’s commitment to environmental compliance includes responsible management of wastes generated at our facilities. At U. S. Steel, recycling is not just good for the environment, it’s good for business.
At the heart of our commitment to recycling is the fact that the very material we make every day is the single most recycled material on the planet with an overall recyclability rate of 86%. As you can see, nothing else comes close.
Recyclability rates in the
(data by Steel Recyclability Institute)
U. S. Steel’s waste management, recycling and reuse efforts focus on the following areas:
Blast furnace (iron) slag and basic oxygen furnace (steel) slag are highly sustainable products that are used in place of natural aggregates such as limestone and gravel in numerous construction and product applications. Use of iron and steel slag in place of mined and quarried rock and mineral aggregates saves these natural resources and reduces impact on the environment.
Blast furnace slag is used in cement manufacturing, asphalt mixes, glass manufacturing, precast concrete, wallboard, mineral wool and sub-base for road and interstate highway construction.
Steel slag, which like blast furnace slag can be used in cement manufacturing and asphalt mixes, is also recycled in applications such as landfill daily cover and internal haul roads, phosphorus removal in wastewater treatment, ground water remediation reactive barrier walls, and agricultural applications, including as a liming agent and micronutrient in fertilizer.
We reuse the by-product gases generated in our cokemaking and steelmaking activities to power our facilities. By using coke oven gas and blast furnace gas, we avoided consuming enough natural gas and other fuels from 2017 to 2019 to heat more than 3.6 million households each year.
U. S. Steel’s mining facilities in Minnesota—Minntac and Keetac—mine and process taconite, an iron-bearing rock, to produce iron ore pellets.
Waste rock and surface material must be removed to uncover the taconite that will be processed. Waste rock and surface overburden are stockpiled around the active mining area, in compliance with state guidelines for stockpiles and reclamation.
Approximately 70% of the processed taconite is non-iron bearing material that is generated as tailings. Minntac and Keetac both operate tailings basins for the storage of tailings that are approximately 8,000 and 6,000 acres, respectively. Each of the tailings basins feature active interior tailings disposal basins with separate exterior perimeter dams. Routine inspections are performed at both facilities, including observing for dam seepage. Inactive areas of the tailings basins are reclaimed.
U. S. Steel recycles several other materials from the by-products of our cokemaking, ironmaking, steelmaking and steel finishing operations.
Process materials from the cokemaking by-products plant are collected and returned directly to the coke ovens.
Carbon, iron, and steel bearing residuals such as coal and coke fines, taconite pellet fines, blast furnace and steel furnace air pollution control dusts, and sludges are used to produce sinter and briquettes that are then used as feedstocks for ironmaking and steelmaking, respectively.
Mill scale not used internally to make sinter or briquettes is sold to cement manufacturers that use the mill scale for its iron content, a critical ingredient in cement.
Hydrochloric acid, which is used in steel pickling operations to remove heavy iron oxide rust from the surface of steel coils in order to prepare the coils for surface coating, results in an iron oxide-rich material called spent pickle liquor, which is recyclable. The spent pickle liquor is sent to a recycling plant to regenerate the hydrochloric acid. It is either returned to the plants for reuse in pickling or it is sold for beneficial use as a wastewater treatment chemical.
Steel can be recycled over and over without any loss of quality in the material itself. As a result, U. S. Steel recycles substantial quantities of scrap metal and other steelmaking co-products and by-products back into our process. This includes the disposal of weapons and metal currency confiscated by law enforcement agencies.
U. S. Steel’s facilities utilize large amounts of water for both cooling and process purposes. U. S. Steel is committed to reducing our water consumption and implements conservation practices to meet that goal.
Numerous processes use water recycle systems that return the water for reuse in the operations, which drastically reduces the amount of water brought into the plants. Another water conservation measure is to utilize treated process water as a source of cooling water for our blast furnace slag pits. U. S. Steel also employs leak detection measures and monitoring of processes, influent water and effluent water to assist in conservation measures.
Wastewater treatment is another important part of our recycling and reuse efforts, and employees at our Granite City Works were honored in 2019 for their work in this area. The Illinois Association of Water Pollution Control Operators (IAWPCO) named the plant the winner of the “Industrial” category for its “Best Operated Wastewater Treatment Works Awards.” This is the third time Granite City Works has received this award.