Solidification of hazardous heavy metal ions with soda-lime glass - Characterization of iron and zinc in the waste glass

X-ray spectrometry and X-ray diffraction (XRD) studies indicate that yellow sludge containing hydroxides of several hazardous heavy metal ions, i.e., Cr, Fe, Cu, Zn and Pb, has an amorphous structure. The XRD and Fe-57 Mossba uer studies of the yellow sludge indicate the formation of a small amount o f gamma-FeOOH particles. Heavy metal waste glass of a light green color cou ld be prepared by melting the yellow sludge together with synthetic soda-li me silicate glass of a light brown color. Additional waste glass could be p repared from a glass bottle for commercial drinks. Leaching test for Zn and Fe with the acid rain simulant (pH 3.5), which was prepared from a nearly equal amount of HNO3 (pH 3.5) and H2SO4 solution (pH 3.5), proved that the waste glass has higher chemical durability than the sludge adsorbed on "dia tomaceous earth." These results indicate that soda-lime silicate glass is a very effective medium for stable solidification of heavy metal ions, and t hat the "glass wastes" can be reused for this purpose.