Experimental design and process analysis for acidic leaching of metal-rich glass wastes

The removal of iron, titanium and aluminium from colourless and green waste glasses has been studied under various experimental conditions in order to optimize the process parameters and to decrease the metal content in the waste glass by acidic leaching. Statistical design of experiments and ANOVA (analysis of variance) were performed in order to determine the main effects and interactions between the investigated factors (sample ratio, acid concentration, temperature and leaching time). A full factorial experiment was performed by sulphuric acid leaching of glass for metal removal. After treating, the iron content was 530 ppm, corresponding to 1880 ppm initial concentration of Fe2O3 in the original colourless sample. This result is achieved using 1M H2SO4 and 30% sample ratio at 90oC leaching temperature for 2 hours. The iron content in the green waste glass sample was reduced from 3350 ppm initial concentration to 2470 ppm after treating.