HOW FOREIGN CULLET USAGE AFFECTS CONTAINER PRODUCTION.

The better qualities of postconsumer cullet can be advantageously incorporated into the glass container-manufacturing process. Supplies of suitable foreign cullet are not abundant and are seen to increase at rates not exceeding 10 per cent per year. Although not achieving all its proponents' claims, raw material cost savings, melt energy efficiency improvements, and reduced operating temperatures do result from cullet usage above 20 per cent. Reduced glass furnace pollution emissions are expected to result from increased cullet usage. Increased furnace lifetimes and higher outputs have yet to be confirmed in practice. Suitable glass quality and preservation of furnace refractories do result from the well-supervised mechanical beneficiation of foreign cullet. Separate foreign cullet storage and proportioning systems and the use of electric boosting are seen to maximize the benefits of high cullet ratios.