Date: March 30th, 2011
FOR IMMEDIATE RELEASE

[Cambridge, Ontario] -- One of the largest mini-mill steel producers and recyclers in North America is putting a “wet blanket” on slag dust from ladle and tundish dumping, improving safety and cleanliness, while preventing dust migration. Gerdau Ameristeel Cambridge uses a specially-designed atomized mist system developed specifically for dust suppression, reducing potential hazards and improving visibility around the dumping pit and in the nearby service area. The versatile equipment from Dust Control Technology (Peoria, IL) can be operated by remote control from the overhead crane or from a front loader, or by the ground-level control panel.

The Cambridge facility has the capacity to produce 300,000 standard tons annually of low- to medium carbon steel bars, primarily from feedstocks of recycled materials. “At the end of a casting sequence, several tons of slag can be left over that must be purged,” explained Senior Engineer John Andric. “When ladles and tundishes are dumped, the falling slag has the potential to create large quantities of dust.”

Andric described the conditions that factored into the company’s dust management decision. “Although it’s indoors, the melt shop has a draft from one end to the other,” he continued. “We did preliminary engineering for a bag house dust collector and overhead canopy, but the project estimate was well over a million dollars, and there were doubts as to how successful it would be.

“The concern was how effectively the canopy over the cranes would prevent migration,” Andric said. “We needed something that could control the dust quickly as it was generated, at ground level.”

After seeing a DCT unit in action in another steelmaking facility, Gerdau Cambridge opted to specify a DB-30 for the slag dump area, the smallest member of the DustBoss product family. The DB-30 has long been known for performance that belies its smaller size, capturing dust particles more effectively than many larger machines.

Mounted on a movable carriage, the unit has a 7.5 HP (5.6 Kw) motor that generates 9,200 CFM (260 CMM) of air flow. The ducted fan design has an adjustable throw angle from 0-50° elevation and the standard unit oscillates up to 70°. When equipped with the new 359° oscillation option, the DB-30 can cover more than 30,000 square feet of area (2,787 square meters) -- nearly ¾ of an acre -- using just a standard 5/8² garden hose.

The Science of Slag Dust
According to Dust Control Technology CEO Edwin Peterson, there are typically three different opportunities for fugitive slag particle emissions to emerge during steel processing. “The first is from the initial fall of material, and is usually of short duration,” he said. “The second occurs during subsequent tempering and cooling operations, when vapor from the cooling water rises and carries particulates into the air. Dust can also be released any time a particle’s terminal settling velocity (from gravity) is lower than the thermal updraft velocity (from heat), which causes it to rise and potentially migrate.”

Unfortunately, slag dust is made up of a number of different-sized particles, some of which are extremely small and lightweight, therefore mobile. DustBoss equipment has been extensively tested at a number of slag processing sites, with various modifications and configurations evaluated in a range of combinations to gauge their effectiveness. Some units have been mounted on trailers and flatbed trucks to deliver virtually unlimited mobility, and others have been permanently mounted in elevated locations.

One of the keys to the equipment’s success has been the ability to automate operation, allowing slag processors to control on/off cycles, direction, oscillation arc and other features from a remote location or via hand-held wireless control. Fully-integrated systems can be operated
entirely by remote control whenever a slag dump is underway, allowing a single staff member to selectively adjust as many as a hundred of the high-output misting units without having to physically visit any of them.

At Gerdau Cambridge, the DB-30 is carriage-mounted and direct wired to 575 volt, 3-phase service. The company uses the city water supply, delivered through a heat traced and insulated line, so pressure remains at a fairly constant 40-60 PSI (2.76-4.14 BAR).

Andric says he’s pleased with the results from the DustBoss. “It does just what it was designed to do, delivering the mist over a wide coverage area” he added. “The dust particles and water droplets are brought into collision with each other, which prevents the dust from drifting through the shop.”

Gerdau Ameristeel is the second largest mini-mill steel producer in North America, with annual manufacturing capacity of approximately 10 million metric tons of mill finished steel products. Through its vertically integrated network of mini-mills, scrap recycling facilities and downstream operations, Gerdau Ameristeel serves customers throughout the United States and Canada. The company's products are generally sold to steel service centers, steel fabricators, or directly to original equipment manufacturers for use in a variety of industries, including non-residential, infrastructure, commercial, industrial and residential construction, metal building, manufacturing, automotive, mining, cellular and electrical transmission and equipment manufacturing. Gerdau Ameristeel is a wholly-owned subsidiary of Gerdau S.A., the leading producer of long steel in the Americas and one of the world’s largest suppliers of specialty long steel. www.gerdauameristeel.com

Dust Control Technology is a global leader in dust and odor control solutions for steel and slag, material recycling, scrap processing, mining and rock industries. The company’s DustBossÒ product line helps reduce labor costs vs. manual sprays, freeing up manpower for more important tasks. The automated units also use less water than hoses and sprinklers, with some customers realizing payback in less than six months and netting an annual cost savings of more than $50,000. DCT equipment carries the industry’s longest warranty, and can be purchased outright or leased from the world’s largest dust suppression rental fleet. www.dustboss.com

FOR MORE INFORMATION

Dust Control Technology
1607 W. Chanute Rd.
Peoria, IL 61615
Tel: (309) 693-8600
Toll-free: (800) 707-2204
Fax: (309) 693-8605
Email: info@dustboss.com
Web site: www.dustboss.com

For editorial assistance:
Rick Felde / (503) 534-0800
rick@dustboss.com