Experimental design for optimisation of density and water absorption capacity of glass–ceramic foams prepared from silica rich wastes

The preparation of glass–ceramic foams from slag and other components including glass cullet and foaming agent (SiC) is a challenge in the development of marketable and valuable materials. Box–Behnken experimental design was used to investigate the impact of operating conditions (i.e. temperature, reaction time and foaming agent percentage) on density and water absorption capacity of glass–ceramic foams. The optimal process parameter settings to achieve a maximum water absorption capacity (71·34%) and minimum density (0·61 g cm⁻³) were determined. The failure mode of glass–ceramic foams occurs via layer crushing mechanism. The correlation between the process controlling parameters and the responses (density and water absorption) of the produced foams were represented by two polynomial quadratic models. The determination of main process conditions through Box–Behnken experimental design offers a technological and economic competiveness in the mass production of glass–ceramic foams with specified physical properties for a wide range of applications.