Glass plants have found increasing the percentage of scrap container glass, or cullet, in their manufacturing processes saves on maintenance and energy. However, glass plants have certain quality standards recyclers should know to receive the best prices for cullet.
Contaminants can seriously damage the furnace or result in poor quality of the plant's product.
Examples illustrate what could happen. Lead and aluminum melt at this temperature while iron and lead settle to the bottom of the furnace tank and corrode its brick lining. Stones and seeds can be deposited in the walls of the glass containers being made, causing aesthetic problems and weakening the bottle's wall. Steel lids also do not melt at furnace-operating temperatures. As a result, they sometimes block feed lines going from the furnace and cause production to shut down.