Experimental study on the effect of cullet and batch water content on the melting behavior of flint and amber container glass batches

Abstract

The melting behavior of two commereial flint and amber glass batches with varied cullet content (0, 40, 65 % and 0, 40, 76 %, respectively) and batch water additions (0 to 5 %) was investigated. The cullet was a blend of up to five industrial types and grades, including ground cullet. Local temperature, electrical conductivity, and thermal diffusivity were determined in 200 g scale tests as a function of temperature, while the vertical distribution of the former two properties was determined by 10 kg tests in 5 cm high batch piles charged on top of a pre-heated glass melt (7 kg). The set of methods applied was established as a service tool for the quantitative comparison of the batch-to-melt conversion of different batches in general. For the flint and amber glass batches investigated, cullet additions primarily improved the thermal behavior, with moderate versus high additions required for flint and amber, respectively. The silica dissolution in cullet-free batches was enhanced by batch water additions, but retarded again with increasing cullet eontent. The presence of phonolite besides batch water and cullet yielded especially negative results.