Corrosion of Silicate Glasses and Glass-Ceramics Containing EAF Dust in Acidic Solution

摘要

The corrosion behavior of glass and glass-ceramics fabricated with silicate glass frit mixed with 50～70 wt% EAF dust in the acidic solution was analyzed by both heavy metal leaching test and microstructural observation. The crystallization temperature, T_c of glassy specimens was around 850 °C measured by DTA and the heat treatment temperature to crystallize a glassy specimen was selected as 950 °C/1 hr. The spinel crystal peaks were found in XRD analysis for the glass containing dust > 60 wt%. For the glass-ceramics, however, the spinel peaks in a specimen containing dust > 50 wt% was found with weak willemite peaks. The glass and glass-ceramic specimens showed the first stage of corroding reaction according to Clark models in acidic solution. The glass-ceramic specimens showed much lower a heavy metal leaching concentration than that of glass specimens in the corrosion test in acidic solution of pH=2.95. Especially, the glass-ceramics containing dust 60 wt% showed a heavy metal leaching concentration of 66 % Pb, 60 % Zn and 98 % Fe lower than that of glass specimens due to crystal phases formed, thermodynamically more stable than a glass network structure. From the leaching test that more Zn ion leached out than Fe ion, the spinel crystal phase [ZnFe_2O_4] showed better corrosion resistant in the acidic solution than the willemite [Zn_2SiO_4].