Rock Products

OCT 2018

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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Page 12 of 87 ROCK products • October 2018 • 11 IN THE KNOW once again locally and independently owned Durex ® Screening Accessories • Steel Stringers, Steel Studs and Steel U-Channels for modular panels • Tension Rails • Center Hold-Down Components • Spray Piping, Nozzles, V-jet Sprays • Channel (Bucker Bar) Rubber • Skirt Board Rubber • Hardware (Donuts & J-Bolts, Tension Wedge Assemblies, etc.) 715-472-2111 ∙ ∙ Invest in our quality Profit from our solutions TM Boral to Make Lightweight Aggregate from High Carbon Residuals FAST FACT This technology offers an opportunity to uti- lize both high- and lower-quality fly ash resources in the produc- tion of a high-value con- struction material. Boral, the leading marketer of ASTM C618-grade fly ash, secured U.S. rights for processing ceramic lightweight aggregate from high carbon residuals generated at coal-fired power stations or impounded at their sites or landfills. "This technology offers an opportunity to utilize both high- and lower-quality fly ash resources in the production of a high-value construction material," said Rafic Minkara, Ph.D., P.E, vice president of technology, Boral CM. "It is ideal for utilizing ash harvested from disposal impoundments that are being closed in response to environmental regulations." The technology utilizes a proprietary dryer and a high-temperature/high-effi- ciency rotary kiln to convert raw feed to sintered spherical pellets. The sintering operation is autogenous, as it does not require external fuel aside from the coal remaining in feed material. The excess heat production capacity can be used for hot water or converted into electricity, for an additional revenue stream. Automated production based on the technology can be overseen by as few as four people. It allows for set up as a a) separate, stand-alone operation to pro- cess pond- or landfill-derived material, or b) integrated installation to be incor- porated into a power plant for aggregate production and heat recovery. The process yields a concrete-grade aggregate of ceramic composition, chemically neutral and bearing physical characteristics equating to potentially wider application than natural aggre- gates. The product has a bulk density ranging from 35 to 45 lb./cu. ft.; high strength-to-weight ratio; resistance to fungi, mildew, fire and effects of freeze- thaw cycles; plus, heat and sound insulation properties. Since 2015, a full-scale plant in Poland has processed coal ash from a utility landfill as feed material, yielding 50,000 mtpy of lightweight aggregates. The material has been sold domestically and exported for high-performance concrete.

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