Abstract:
The possibility of recycling the incinerated municipal solid waste (IMSW)bottom ash by its
incorporation in structural bricks was investigated. This study starts with the collection and
incineration of the municipal solid waste. Then physical and chemical characterizations of the
IMSW ash were done. Finally these ashes were used as a major constituent to make the brick. In
this purpose, 0 to 50% (by weight) IMSW ash was mixed with the normal clay.
This study constitutes of observation of particle size and particle size distribution, determination
of chemical composition by chemical analysis and x-ray fluorescence spectroscopy (XRF),
determining the compounds present by x-ray diffractometry (XRD), etc. of the incinerated ash. It
was found that the analysis of particle size distribution of ash resembles to that of clays. The
chemical analysis reveals that the ash has larger amount of CaCO3 than the clays. The results of
XRD supported the presence of quartz (SiO2), calcite (CaCO3), hematite (Fe2O3) and potassium
calcium sulphate [K2Ca2(SO4)3] in the ash sample. Here a basic type of natural clay was also
characterized as a reference material.
The green molded bricks which were made from the mixture of clay and ash, were air-dried at
room temperature for 24 h, and then oven dried at 100oC for another 24 h to remove the water
content. The raw bricks are then fired in the Blue-M metallurgical muffle furnace to a designated
temperature (800, 900 and 1100oC). Then the bricks were characterized both physically and
mechanically. The firing behavior (mechanical strength, water absorption, and shrinkage) was
determined. The microstructure, phase composition and leaching were evaluated for bricks
manufactured at different firing temperature. These results demonstrate that IMSW ash can be
recycled in clay bricks. The concentrations of hazardous components in the leachates are below the standard threshold for inert waste category landfill; however, their environmental risk during
their use-life step can be considered negligible.
