Continuous measurement of the dissolution rate of ions from glasses

A method for measuring the early stage ion release of glasses was developed in order to gain information on leaching kinetics and chem. resistance of glasses in aq. environments.  A continuous flow-​through-​reactor was designed in which the aq. soln. is fed through a bed of glass particles and the dissolved ions continuously recorded with a sensitive online anal. system.  Exptl. parameters, such as solvent flow rate and temp., could easily be adjusted according to the needs.  The flow-​through-​reactor system was tested with powd. samples of float and lead glasses, E-​glass and bioactive glasses 45S5 and 1-​98, all of which showed very different chem. durability in aq. environments.  The reactor was connected to inductively coupled plasma optical emission spectrometry (ICP-​OES) and concns. of the dissolved ions were measured simultaneously online every 30-​40 s.  In this work the initial stages of ion release were measured during the first 15 min of the leaching expts. at 40° and 80°.  The results were compared with std. water durability test of the glasses.  The dissoln. of the glasses according to both methods showed similar behavior.