Rock Products

MAR 2017

Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market

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80 • ROCK products • March 2017 EQUIPMENT & TECHNOLOGY SCREENING & SIZING Since Florida-based sand and aggregates producer Atlantic Civil Inc. replaced its sand screw system with CDE cyclone technology, inconsistent production levels and loss of fines to ponds and water spillages on-site are a thing of the past. Headquartered in Homestead, Fla., the company processes raw materials for the production of a variety of products including concrete sand and rip rap boulders among other products. Part of Atlantic Civil Constructors Corp. – a construction company that has been carrying out construction projects for both the private and public sectors for more than 30 years – Atlantic Civil's sand and aggregates production levels started to suffer as its old sand screw system, combined with an inefficient pri - mary screen, failed to maintain production levels. In 2014, Atlantic Civil representatives visited ConExpo-Con/ Agg in Las Vegas where CDE Global was exhibiting prod- ucts from its wet-processing product range, including their staple EvoWash sand washing plant. Atlantic Civil took the opportunity to discuss the issues they were facing with their existing system with the local CDE specialist team. This initial face-to-face with Atlantic Civil was key in developing a strong relationship based on demonstrable technical knowledge and an in-depth understanding of the client's needs and trust. Neil Mullan, general manager, USA East for CDE Global, recalled: "When we met, Atlantic Civil Inc. was experiencing difficulties in maintaining production levels. Its sand screw system had become inefficient, leading to loss of fines to ponds and water spillages around the site. To top it all, their existing screen was too small to meet production requirements and the quality of the sand was not up to expectations. As this type of issue is common among clients using a sand screw, we dis- cussed solutions, demonstrating how water-saving cyclone technology could save the company time, money and worry. We walked the client through the specifics of the EvoWash exhibited at the show to demonstrate how our sand washing plant favourably compared to a sand screw system." Mullan continued: "In Atlantic Civil's case, the best solution to the issues they faced was to replace their sand screw system with two EvoWashes, including larger-sized screens allowing for the required production of four different products and, crucially, raising this production to 500 tph. "For fully optimal operations, the integrated CDE Infin- ity screens have a weld-free sturdy but lightweight design which reduces power consumption without compromising efficiency." Better Dewatering Atlantic Civil was particularly interested in the fact that, as opposed to sand screw systems which sometimes give uneven results, cyclone technology allows for much better product dewatering with minimal loss of fines and highly precise sep- aration of the material. Specifically, the CDE patented high frequency dewatering screen technology featured on the EvoWash is so efficient at reducing moisture content that the final product is ready for market straight from the belt. Mullan adds: "Atlantic Civil saw the potential of a system which would meet its requirements for a higher quality product and increased production as a result of the recovery of material previously being lost to the settling ponds. The company opted for a feed conveyor, an EvoWash 251 and an additional EvoWash 101, both equipped with CDE Infinity screens, to recover more fines in a dual pass arrangement, which allows for all the excess minus 200 mesh material to be removed." The Result With a 98 percent separation accuracy level and efficient dewatering, Atlantic Civil now produce up to 500 tph of four types of premium quality washed material, including -33 con- crete sand, #4 stone, #57 stone and #89 stone. "The two new CDE EvoWashes have been a game changer in terms of our production levels and return on investment,' said Ted Labor, plant manager at Atlantic Civil Inc. "Our old sand screw system had limited capacity at the feed point, which means that we had inadequate control over the volumes of water required for accurate material classification. As a result, quality sand was lost over the overflow weir and sent to the Atlantic Civil Replaces Sand Screw with Cyclone Technology

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