Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft
Doi
Abstract
On commercially available lead crystal glass tumblers (24 % PbO), the interaction between their bulk and grain forms and aqueous Solutions of various concentrations of acetic acid at different temperatures (22 to 95 °C), and for different times (30 min to 300 d) was studied. The extent of interaction was evaluated by determining the concentrations of K⁺, Na⁺, Pb²⁺ and Si⁴⁺ ions extracted by acetic acid, the change in the pH value of aqueous acetic acid Solutions and the weight loss of glass grains. The results showed that: a) Pb²⁺ was released from the glass studied under the Standard testing conditions in concentradons that were smaller than those specified in the various Standard specifications. b) The extraction of the different cations was significantly affected by the form of the test sample; glass grains were more reactive than the bulk form. c) Extraction of modifier cations, K⁺, Na⁺ and Pb²⁺, during short times of attack, up to 6 h at temperatures u p to 95 °C or during long-time attack up to 20 d at 22 °C, could be represented by a straight-line relationship when plotted against t^(1/2).Deviation was observed for times longer than 20 d but the straight-line relationship could be restored by plotting the extraction data against t. Such behaviour indicates that the leached layer became sufficiently thick after 20 d, so that the leaching and etching reactions proceeded at equal rates. d) The dissolution of glass increased with increasing temperature of attack up to 95 °C, but the mechanism of attack remained essentially of the leaching type. e) The extraction of K⁺, Na⁺, Pb²⁺ and Si⁴⁺ ions was affected by changing the concentration of acetic acid, which was correlated with the corresponding change in its pH value. f) The quantities of Pb^^ ions released by 4 % acetic acid Solution were several Orders of magnitude greater than that released by 40% ethyl alcohol Solution indicating that the Standard 4 % acetic acid test Solution is quite suitable for Pb²⁺ release safety
