In one example of an embodiment of the invention, a method for producing
an aggregate is disclosed comprising mixing sewage sludge from a waste
water treatment facility with a non-coal combustion ash silicoaluminous
waste material, agglomerating the mixture to form an agglomerate, and
pyroprocessing the agglomerate to form an aggregate. The waste material
may comprise municipal solid waste incinerator bottom ash, incinerator
fly ash, incinerator filter dusts, cement kiln dusts, waste glass, blast
furnace slag, kiln dusts, and/or granite sawing residues, for example.
The method may further comprise milling the waste material prior to
mixing. Preferably, the milling is wet milling. Pyroprocessing of the
agglomerate may take place in a rotary kiln. The resulting aggregate may
be a lightweight or a normal weight, sintered or vitrified aggregate.
Aggregates and methods for making aggregates of high and low calcium
silicoaluminous materials are also disclosed.