**4. Conclusions**

312 Ion Exchange Technologies

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**Figure 3.** EDXS spectra recorded on the surface of samples subjected to ion exchanged for 24 h. The spectrum recorded on as-cut glass is shown for comparison. The potassium Kα peak is indicated by an The composition of the potassium nitrate salt bath in terms of impurities, mostly Na, seems to have an important role in the strengthening process of soda lime silicate glass by ion exchange. It has been found that chemical reinforcement is more effective when it is carried out in the bath containing the highest amount of sodium (≈ 0.5%). The results point out interesting practical and industrial aspects regarding chemical tempering processes with higher efficiency.
