Dissolution behaviour of sodium silicate glasses for the production of water glasses

在工业上，水玻璃主要是通过溶解硅酸盐玻璃来生产的，这在这里被视为玻璃腐蚀的极端。为了表征和模拟传统玻璃的腐蚀，采用了新开发的工艺方法。在此，要求将运行时间延长12个月。到目前为止所获得的结果证实了硅酸盐玻璃的已知腐蚀机制，如离子交换、网络溶解、形成蚀变表面层。然而，有研究表明，在腐蚀过程中已经出现了裂纹。此外，在旋转转鼓中工业生产液态水玻璃的过程中，机械磨损可以支持溶解过程。如果可能，将对这一新发现的机制进行调查、量化，并将其纳入这一过程的模拟。此外，一些已经获得的关于腐蚀样品的结果还需要进一步调查。特别是，应进一步检查玻璃或蚀变表面中掺入水的特征。在这里，我们有一个化学研究所同事的实验室里的共焦激光-拉曼-光谱显微镜，它允许以几微米的深度分辨率来表征表面。这些拉曼光谱将提供有关所结合水的形态的更多细节。在碱性盐水中用聚合碱腐蚀水玻璃，可进一步提高腐蚀效果。这些碱性卤水可能是KOH和NH4OH，而LiOH对腐蚀有抑制作用。通过这种方法，即使玻璃在碱性盐水中被腐蚀，也应该可以对离开玻璃的钠进行分析。

In industry water glasses are mainly produced by dissolving sodium silicate glasses which is treated here as an extreme of glass glass corrosion. To characterise and modell the process methods are applied whiche were developed for the corrosion of conventional glasses.Here the prolongation of a running for additional 12 months is trequested. The results obtained so far confirm known corrosion mechanisms of silicate glasses like ion exchange, network disolution, formation of an altered surface layer. Nevertheless, it was was shown crack formation occurs already during the corrosion process. Additionally, mechanical abrasion may support the dissolution process during industrial production of liquid water glasses in a rotating drum. This newly found mechanism will be investigated, if possible quantified, and integrated into the modelling of the process. Also, some of the already obtained results on corroded samples need addition investigations. Especially the characterisation of water incorporation into glass or altered surface should be examined further. Here we have acces to confocal Laser-Raman-Spektroskopie in the laboratory of a colleague in the institute of chemistry which allows the characterisation of the surface with a depth resolution of a few micrometers. These Raman spectra shall deliever more details on the speciation of the incorporated water. A further improvement of the corrsion results will be obtained by corroding the sodium silicate glasses in alkaline brines with ather alkalis. These alkaline brines are probably KOH and NH4OH, whereas LiOH will inhibit corrosion. By this means the analysis of sodium leaving the glasses should be possible, eeven if the glasses are corroded inalkaline brines.