Crisafulli's Rotomite-6000. Dredging highly abrasive mill scale.
Customer: The customer purchased its first SRS Crisafulli Rotomite, a Model 180P, in August 1997, and purchased its second Rotomite, a 6000 model, in the summer of 2007.
Application and reason for dredging: The customer provides slag processing, metal recovery, material handling, scrap management, surface conditioning ("scarfing") and a wide range of specialty services to the North American steel industry. The customer uses its Rotomite-6000 to remove iron mill scale to maintain capacity in its cooling water lagoon that supplies wash water to the steel processing facility. The process helps the customer maintain the plant's cooling water capacity at satisfactory levels. They operate the dredge 1 to 2 hours per day, year around. Their dredged iron mill scale slurry is about 20% solids by volume. Mill scale is a very abrasive material that weighs 168 lbs per cubic foot."
Site description: One lagoon with a berm to separate the lagoon into two cells. The lagoon is unlined and measures approximately 220' x 250' with a depth of approximately 8 feet.
Quantity of material dredged: The dredging and dewatering process produces 11 tons of solids every minute.
Description of material dredged: Mill scale is a black, slimy, heavy sludge that contains heavy metal filings, oil, and mill scale. Mill scale is a milling waste generated while rolling metal in metal extrusion industries. Iron mill scale generally contains more than 70% of FE (Ferrous Oxide). The customer's plant superintendent paraphrased his dredge application as follows: "We have a used machine (Crisafulli Rotomite-180P) since April 1997. The amount of material in the lagoon was to the point that we could not even turn the dredge during initial operations. That machine has since removed approximately 65,000 metric tonnes of material."
Testimonial: the plant superintendent asserts: "The machines are very dependable, the design excellent, turning is great, and all workmanship is to be commended. If others would like to call I would be happy to talk with them."
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