Zinc is one of the hazardous metals commonly found in municipal solid waste incineration(MSWI) ash

and this study reveals the stabilization mechanisms when sintering zinc-laden ash and ceramic precursors as a waste-to-resource strategy.Using ZnO to simulate the zinc-laden ash and sintering with kaolinite and mullite ceramic precursors

both zinc aluminate spinel(ZnAl

2

O

4

) and willemite(Zn

2

SiO

4

) phases were found in the products under the tested thermal conditions.The results also indicate that kaolinite and mullite precursors exhibit different incorporation behavior

and ZnAl

2

O

4

and Zn

2

SiO

4

were found to be competitive as the Zn-hosting phases in the system.A prolonged leaching test was used to evaluate the leachability of potential product phases in the system.The concentrations of zinc in ZnO and Zn

2

SiO

4

leachates were about two orders of magnitude higher than that in ZnAl

2

O

4

leachate

indicating the preference of forming ZnAl

2

O

4

for zinc stabilization.Furthermore

the aluminum-rich sludge generated from waterworks could be beneficia

lly used as a material resource to stabilize zinc in this study.The X-ray diffraction(XRD) pattern collected from the 1150℃ and 3-h sintered sample shows the suc-cess of incorporating zinc into the ZnAl

2

O

4

spinel structure with waterworks sludge precursor.The formation of ZnAl

2

O

4

indicates a strong potential for employing aluminum-and silicon-based materials to thermally immobilize zinc and achieve the beneficial use of metal-laden MSWI ash.