Cement Americas

WIN 2018

Cement Americas provides comprehensive coverage of the North and South American cement markets from raw material extraction to delivery and tranportation to end user.

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16 CEMENT AMERICAS • Winter 2018 • www.cementamericas.com FEATURE A Detroit cement producer has put a stop to excessive carryback and equipment fouling by installing a revolu- tionary primary cleaner designed for punishing applications. With a significant reduction in carryback, spillage and labor for cleanup, the plant was able to improve workplace safety, lower the cost of operation and see a quick return on investment. The St Marys Cement plant – located along the Rogue River in Detroit – produces 200 to 250 tph (181 to 226 mtph) of portland cement. Front loaders transfer dusty 1.5 to 2 in. (38 to 50 mm) minus limestone and gypsum aggregate onto the 30-in.-wide #14 belt. Inclined approximately 20 degrees at the point of loading, the belt conveys cargo for 20 ft. up to ground level, moves horizontally for 200 ft. (61 m), then begins another long 30-degree incline into the top of a 50-ft.-tall tower. The con- veyor discharge zone, with only enough room to fit one pri- mary cleaning blade, offloads into a chute. Roughly 30,000 tons (27,215 metric tons) of raw material and clinker arrives weekly by truck and ship. The aggregate is offloaded to an outdoor storage area, where the materi- al tends to get saturated when the Michigan weather turns wet and cold. This causes large amounts of mud and sludge. Operators found that polyurethane cleaner blades were unable to completely clean the belt. "The fines and mud take on the tacky consistency of toothpaste, causing it to cling to the belt along with smaller pieces of aggregate and shale," said David Accomando, plant maintenance super- visor for St Marys Detroit. "This led to a lot of carryback spilled along the return path, where it fouled idlers and built up so high under the loading zone that it would encap- sulate the tail pulley." Maintenance technicians periodically had to stop other essential duties and shut down the system to replace fro- zen return idlers and prevent further damage. After dig- ging out the tail pulley, workers needed to clean the face, which often had abrasive buildup that could reduce the belt life. The cleaner required regular tensioning and periodically needed to be removed, re-cut and shaped. In addition, two to three workers spent up to eight hours twice per month to clean the loading zone and the belt path using shovels and a vacuum truck. A Clean Start Innovative Belt Cleaning Technology Eliminates Carryback at Cement Plant. By Mark S. Kuhar The St Marys Detroit plant is prominent on the skyline as commuters drive across the Rogue River.

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