The Secret to Continuous, Efficient Oil Removal in Steel Mills

In anticipation of next week’s annual Association for Iron and Steel Technology (AIST) trade show, we are sharing a case study about a steel mini-mill that solved a waste oil problem with the use of our Oil Skimmers.

NLMK Indiana (formerly Beta Steel) is a steel mini-mill that produces and sells hot-rolled steel in the north central United States and Canada. The plant produces about 700,000 tons a year and employs about 400 people.

NLMK Indiana’s raw materials are scrap metal and chemical additives. The scrap metal is melted and recast into slabs, which ultimately become coils of flat steel that customers purchase to make a variety of durable products. The heat-intensive process uses water to cool in-process materials to specified temperatures. 

During hot strip mill production, tramp oil mixes with the water, and this mixture collects in two basins and a scale pit. Before the water can be cooled and reused, the oil must be removed to keep the cooling towers and other plant equipment running smoothly, and to prevent contamination of the product.

PROBLEM: The plant had employed a company to periodically vacuum the oil out of the water as it sat in the pit and two collection basins — one with a 490,000-gallon capacity and the other one with a 285,000-gallon capacity. But this method did not adequately separate the oil and water, and it didn't provide an option to operate continuously, as the plant does.

SOLUTION:  NLMK Indiana now uses six Oil Skimmers, Inc. oil-recovery systems to remove the tramp oil from the water in the collection basins as well as from a scale pit at the hot-strip mill. In a unique anti-clogging design, the Oil Skimmers have a polyurethane tube that attracts and collects the waste oil/grease as it floats on top of wastewater. The tube passes through a scraper system to remove the oil, which flows into a containment drum.

BENEFITS: The system operates independently and can run 24 hours a day, seven days a week. This was a significant improvement over periodic vacuuming, Ehren Plew, Plant Mechanical Engineer, said. The skimmers run whenever needed and for as long as needed.

“They are relatively maintenance-free, and they are certainly trouble-free,” Plew said. “They run 24/7 with no manpower. It would be uneconomical to have a vacuum truck running 24 hours a day.” Additionally, the skimmers are more effective at separation, according to Plew. “The vacuum truck sucks out a lot of water, and these remove just the oil. So there is a lot less waste.”

Jim Petrucci, Vice President of Oil Skimmers, Inc., said the vacuum method of oil removal has its place in the industry, but it’s not the best choice for an ongoing need, such as steel mini-mills. 

"Our system runs continuously. Vacuuming is great when you have a spill, but it doesn’t address continuous build up.” 

NLMK Indiana uses the Model 5H Oil Skimmer and the Model 6V Oil Skimmer. Both are made with internal components of high-strength steel and bronze for durability. External parts are made from abrasive-resistant ceramic. The machine has a lifespan of more than 25 years.


If you have any questions or comments, please share! We love to hear from our readers!

  Above: Model 5H Oil Skimmer side-mounted on a tank. 

To see a video of the Model 5H in operation, visit our Youtube page.