Corrosion study of glaze-cermics doped cement-kiln-dust soaked in concentrated HCl

New glaze-ceramics formulated from industrial waste have been prepared. The method consists of introducing cement-kiln-dust [CKD] in the industrial glaze-ceramics with various ratios [10-50%] together with the addition of 10gm boric acid. The chemical durability of the prepared composite cement-dust-glaze-ceramics [CDGC] is investigated using high concentrations of [2,5 and 8N] HCI acid solutions. CDGC are vitrified by melting for four hours at 1400[degree sign] C +/- 250[degree sign] C depending on the amount of CKD introduced. Specifically, the experimental results indicate that the introduction of CKD in industrial glaze decreases durability. At high HCI concentrations, the durabilities of the prepared glaze-ceramics are observed to decrease with increasing the percentage of [CKD] until certain limit and almost constancy. The corrosion results are explained according to the ion exchange mechanism and formation or dissociation of the modified depleted layer. Some hollow and jogged areas are observed by SEM which might be interpreted as evidence of local corrosion phenomena. In addition, the pH values of the leachant solutions are measured. The comparison of hardness for the optimum glaze-ceramic and glaze-ceramic derivatives prepared in this study indicates a degradation% in their chemical and physical properties depending on the amount% of CKD introduced. It is observed that the degradation not only depends on the amount of CKD introduced, but also on the strength of the leaching HCI acid solution. Also, the results show that, the prepared glazes have a surface hardness values ranged from 5.5 to 2.5 in the Mohs scale

Effect of different aqueous solutions on gamma irradiated commercial and simulated soda lime silica glasses

This study presents the results of chemical durability of either commercial or prepared soda lime silicate glasses immersed in different aqueous solutions of [HC1, HNO[3], NaOH or H[2]O] for different duration. The chemical durability of the glasses was investigated by the weight loss determined per unit surface. The monovalent network modifier ion Na[+] is leached out more easily than the divalent cation Ca[2+], which is probably due to the stronger bond of the divalent cation Ca[2+] to the nonbridging oxygen sites in the glass. In explaining the results obtained two possible mechanisms [ion exchange leaching and matrix dissolution] were considered to explain .the release of cations from the glass structure in different aqueous solutions. The leaching mechanism involves the replacement of Na with a hydrogen bearing ion from the solution leading to the formation of surface layer, i.e. alkali depleted layer. The relative higher weight loss as a function of time, which characterizes the corrosion in alkaline media can be referred to the local rise of the solution pH, which could facilitate the dissolution of the glass Si-network. Also the results reveal that the commercial SLS has a very good durability at room temperature in the acidic medium. This durability decreases with the increase of temperature but at 100°C the glass durability increases again. Corrosion of gamma irradiated SLS shows a marked increase in weight loss as a function of time, and leads to a higher weight loss. Our results and interpretations were supported through FTIR reflectance and SEM investigations