CASTING INNOVATIONS
Recovering Aluminum Through Dross Processing Despite the industry’s focus on recovery and reuse,
metalcasting facilities cannot avoid waste entirely. While skimmings and drosses are unavoidable, the amount of melt loss doesn’t have to be the 8% or more that can be found at some operations. Dross treatment processes from aluminum melts vary.
Some facilities install comprehensive fluxing and cleans- ing practices, while others merely skim untreated material. Accordingly, the aluminum content of dross shipped for reprocessing can range from 30%–75%. City Aluminum Foundry Co., Waterford, Mich., used to
generate a 400-lb. drum of dross daily when pouring Almag 535. After installing a 60-lb. Dross Boss portable unit from Q.C. Designs Inc., St. Joseph, Mich., dross production dropped to a single drum every three days. “Te difference is in recovered aluminum,” said Chuck
Julian, City Aluminum Foundry vice president. “It seems as though we are saving 800 lbs. of metal every three days. It has been possible to reduce our loss by having the furnace tenders massage the dross very diligently. We consistently get good recovery with the Dross Boss unit.” Metallic separation is accomplished in a hinge-mounted
reaction vessel, where metallics are collected via an exother- mic flux added to the mixture, mechanical agitation and gravity. After separation, the recovered metallics are drained through a gate valve into an ingot pan or transferred back to the melter directly. Depending on the aluminum alloy being poured across
City Aluminum’s seven furnaces, Julian estimates his facility saves at least $500 per week, in addition to energy savings from recharging hot material. “Te manual stirring operation was accomplished in less
than three minutes, with recovered metal being returned at elevated temperature to the holding furnace,” Julian said. “No significant change in metal chemistry had occurred during processing.” As a result of decreasing waste via the dross filtering
The ingot pan of the Dross Boss portable cart shows the typical volume of on-spec alloy recovered from a process cycle.
process, all Dross Boss customers have reported ROI in less than a year, according to Q.C. Designs. “The results are variable,” Julian said, noting the differences among alloys, “but we have been very happy
with the savings.” For more information, visit
www.qcdesignsinc.com.
An operator fills the portable 60-lb. reaction vessel with Almag 535 dross. September 2013 MODERN CASTING | 51
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