Abstract: Construction material from granular material reclaimed from the ash of a municipal waste combustor wherein the ash is subjected to sorting and separating recovered metals, the granular material including particles having a maximum particle diameter of 5 to 40 mm, a U-coefficient of 10 or more, and ignition loss of 10% or less in weight and being subjected to at least one heavy metal immobilization agent, preferably phosphoric acid; and a second heavy metal immobilization agent consisting of ferrous sulfate. The ash is further subjected to drying before subjecting the ash to the at least one heavy metal immobilization agent. The ash is further subjected to mulling the material after subjecting the ash to the at least one heavy metal immobilization agent.

Abstract: An improved process for processing ash resulting from the mass burning of municipal waste includes a shear-force shredder for the size reduction of bulky items, impact cleaning of ferrous metal items, and a rotary washer for cleaning non-ferrous metals. Further improvements include sending the ash through an air separation unit to remove paper, wood, plastic and other unburned debris before providing ash to an eddy current separator for non-ferrous metal removal. The resultant ash which is essentially free of ferrous metals and non-ferrous metals, unburned material and unshreddables is then treated to immobilize certain heavy metals thus creating treated ash aggregate (TAA). Ash is recycled through a closed loop in the process to increase removal efficiency of metals and the homogeneous nature of the recovered (TAA).