In accordance with an embodiment, a method for producing an aggregate is disclosed comprising mixing incinerator bottom ash (“IBA”) from a municipal solid waste incinerator and pulverized fuel ash (“PFA”) from coal combustion. The method further comprises agglomerating the mixture, such as by pelletizing, and pyroprocessing the agglomerates, such as by sintering or vitrification, to form the aggregate. The addition of PFA to IBA has been found to facilitate production of lightweight and normal weight aggregates. Preferably, the IBA or the mixture of IBA and PFA is wet milled prior to agglomerating. A preferred proportion of IBA to PFA is 40%/60%. The agglomerates may be coated with an inorganic material to create a surface layer on the aggregate. Organic material may be included in the mixture to increase the porosity of the aggregate. A lightweight sintered aggregate comprising IBA and PFA and an aggregate comprising IBA and PFA are also disclosed.