Effective utilization of incinerated municipal solid waste incineration ash: zeolitic material synthesis and silica extraction.

In this study the effective utilization of two types of municipal solid waste incinerator (MSWI) ashes, namely air-cooled ash (ACS) and water-cooled ash (WCS) samples obtained from a municipal solid waste incineration plant, was examined by applying zeolitic material synthesis and silica extraction. The influence of the experimental conditions including the ratio of sample : NaOH solution, the reaction temperature and time, and the concentration of NaOH solution were investigated. The results for the 25 experimental trials can be summarized as: (1) the formation of tobermorite and/or pectolite-1A as a major component in most conditions; (2) the synthesis of hydroxycancrinite as a major phase at 200 °C; (3) a dramatic increase in the extracted SiO2 yield at 1 : 30 value of sample : NaOH ratio and 200 °C, even at short reaction times; and (4) relatively high SiO2 yields for WCS ashes rather than ACS ashes. An increase in the reaction time improved the quantity of synthesized zeolitic materials. The reaction...