IIT technology can process contaminated cullet, or treated glass scrap, rejected by the primary cullet treatment plants, offering a greater amount of high quality recycled glass to the glass industry. Using post-consumer recycled glass in glass container manufacturing means less reliance on primary raw materials and reduced CO2 emissions.
When getting recycled glass to a point where it is ‘furnace-ready’ for the glass container industry, waste glass needs to be free from all contaminants such as ceramics, stones, porcelain (CSP’s) and organic matter. These contaminants can clog up the furnace, create glass fining problems, increase energy consumption and lead to defects in the final product.
Glass cullet currently has a low market value because there is lack of properly organised collection systems to generate what would be a valuable glass-making secondary raw material.
In preparing recoverable grade glass, some 23-35% of the glass recovered through separated waste collection is currently disposed of in landfills, this figure is expected to rise as the glass container industry’s requirements become more stringent.
IIT have developed system solutions to improve the processing of cullet for the glass container industry. This presents an opportunity to gain a greater amount of high-quality recycled glass, saving significant amounts of raw materials, preserving natural resources and reducing energy use.
One IIT customer operates a glass treatment plant where the process inadvertently rejects an extra 10-12% of the feedstock. That percentage contains a mix of glass and non-glass contaminants that have not been picked up by any optical sorting machines, specifically, CSP’s. Ordinarily, this 10-12% would be rejected from the process stream and disposed of in landfill.
The IIT m-series mill grinds this cullet small enough to eliminate problems caused by CSP’s with an added bonus; cullet behaves better in the melting process used by the glass container industry. Cullet melts at a lower temperature than primary raw materials and smaller pieces of cullet melt quicker still, requiring less time and energy in the glass furnace.
Another customer has an excessive waste issue due to heavily contaminated mixed cullet feed. Organic contaminants can cause a variety of issues in the final product so large percentages of the feedstock are rejected from the process, containing both organic contaminants and perfectly suitable glass cullet. The IIT mill and vibratory sieve can provide a solution to recycle low grade glass feed stocks and provide a cleaner end product between 0-3mm.
Ultimately, IIT can help glass container manufacturers recover greater amounts of quality glass from recycled glass stock with less energy use, enabling companies to contribute to a resource-efficient Europe.