The effect of high cullet levels on amber container glass was studied. A statistical approach was taken in assessing glass quality, glass workability and commercial viability. Cullet levels were increased from 40% to 70%. Glass quality was assessed in terms of stone, seed and blister levels, as well as composition and colour stability. Glass workability was assessed in terms of bottle faults due to checks, thin walls and cavity related defects. Commercial viability was assessed in terms of production efficiency and bottle breaking pressure. The results show that there was an
overall improvement in glass quality, glass workability and
commercial viability after the batch sulphate levels were increased at 60% cullet. It was found that the glass viscosity characteristics had an overriding effect on glass workability and commercial viability.